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ocket Strobe - American Radio History

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1. 10 MHz Frequency Counter Build a useful addition to your workbench SCA Adapter Tune in hidden FM broadcasts The Audio Coupler Add an audio input to your cassette deck Find that model rocket even at night or in tall weeds lal Pocket Paaer A E goer ST g Keep in touch at home work or play wit r receiver pair build it purself transmiti Bui af ie Speedi Watt to imme r a motor ore 0 71896 48784 B8 01 2 50 U S a er 2 95 CANADA Fa ee This Issue our 800 344 4539 AK Puerto Rico 218 681 6674 Teien 62827914 FAX 218 681 1180 9103808982 DIGI KEY CORP Ie METAL OXIDE FILM RESISTORS Svadakts in V9 Wart as oo w Borer omg ft ine Sane IM Wor Mere Fim Reestor Assortments as Rete RLIK PE a a Pale J 7 4 70S 8 T e PTA onan Man Led 30 w WIREWOUND REC RESISTOAS 10 A vatan a A a A n rE an w a ES 400 HOO EX xm OD w Bda 00 BO KDO 7x00 w EZ wp P2708 A D w FO 00 a0 gt 208 ap a a aD oo b Wott bets Reweto Assortments yx w a z i bad bh w o so ku wh mo w a o a0 9 y7 1924 PANASONIC V SERIES Mamae ererat Om oneta H Watt Reeeta A ranrtman to S METAL OXIDE PLM RESISTORS Anian a 1 Wen HEEG See NASA MO 1 Wet Metal Reomp Aserimenw i iz ri we e mo wo t 00 B A 50 om lt 0 t pah A 50D b
2. Fig 18 The possible outputs for circuit A can be displayed in a truth table like B puts the total number of different input states is 2N The circuit shown has three inputs so with three inputs there are 8 23 Those eight possible combinations are the binary numbers 000 decimal 0 through 111 decimal 7 Therefore we will make a truth table with eight possi ble input states as shown in Fig 18B The remainder of the truth table will contain the outputs at each element in the circuit For example note that we have the output of AND gate 1 the out put from inverter 2 and the output from or gate 3 Knowing how each of the logic gates work you can then deter mine the output of each gate given the various combinations of inputs and record those values in the table For example the input to gate 1 is D and E Since it is an AND gate the only time it will produce a binary 1 output is when both D and E are binary 1 s Sim ply locate those states in the inputs and record binary 1 s beside them All of the other entries in the DE column will be binary 0 The F column is created by simply inverting the F column You now know both inputs to or gate 3 The DE and F columns can then be ored together to produce the final output G Again remembering that an or gate produces a binary 1 output if either or both of its inputs are binary 1 you can complete the G column Be sure you go through the circuit and the truth
3. DIAMOND SCRIBING TOOL Minitool s PV 078 Pin Vise Handie has tiny 0 5mm 020 inch and 0 25mm 010 inch tip sizes It can be used for repair ing thin film circuits micro circuits and fine line PC boards and integrated circuits Other applications include scribing under a mi croscope and precision scribing The high precision pin vise handle in cludes a collet adapter for use with those diamonda scribe tips It also comes with a Standard collet for use with knives and spe cial tools from 1 5mm to 2 3mm in size The non roll handle offers a precision draw bar ridged finger grip and low friction bronze bushing The PV 078 Pin Vise Handle costs 14 95 The 5mm tip PV 078 U costs 9 95 and the 25mm tip PV 078 U2 costs 14 45 For more information con tact Minitool Inc 1334 F Dell Avenue Campbell CA 95008 CIRCLE 77 ON FREE INFORMATION CARD TWO PORT RS 422 INTERFACE MetraByte s DUAL 422 two channel RS 422 interface board provides high speed communications capability for IBM PC XT AT and compatible computers It allows data transfers at speeds of up to 57 6 Kilobaud over distances as large as 4000 feet The baud rate can be selected over a wide range of values between 120 baud and 57 6 Kilo baud Through simple BASIC programming the 9600 baud limitation of most DOS and BASIC communication routines can be over come Appli
4. HANDS ON ELECTRONICS POPULAR ELECTRONICS Letters GIVING CREDIT As many readers know the authors of the majority of the articles that appear in Popu lar Electronics Hands on Electronics are not employees of the magazine Instead they are freelance authors who do the work on a contractual basis As part of that contract the author warrantees that the work is origi nal and that nothing contained in the article violates copyright laws or any rights of third parties The point of all of that is that in August 1988 we published an article 50 Years of Car Antennas bylined by Edward Janicki Mr Janicki signed our standard contract therefore promising that the work was origi nal and accepted payment for the article We have since received word from SAE The Society of Automotive Engineers Inc that the article was taken nearly verbatim from an SAE paper written by Carlos Altgelt Ken Duffy and Clem Rowan of the Ford Motor Company The paper was presented at the SAE International Congress and Ex position and was part of an SAE publica tion titled Audio Systems for the Automo bile The book and paper were published and copyrighted on February 29 1988 We regret that the rightful authors of that excellent article were denied the credit they deserved and deeply apologize to them and to the SAE for this unfortunate incident Editor SORRY WRONG NUMBER We have learned that the toll free number giv
5. 195 Gara en REPLACEMENT TIPS CARD FINGERS AND SILK SCREENED LEGENDS 1 95 PN2222 4N27 f AVAILABLE 2 95 E ewe 1 95 2N2222 f 4N28 i 168 2C mH 1 95 2N2907 f 4N33 i 3 1 95 2N3055 i 4N37 l sA g gt l 1 95 2N3904 l MCT 2 1 95 2N3906 MCT 6 1 95 2N4401 TIL 111 1 95 1 95 FOR PS 2 1 95 JDAR PR32 32BIT PROTOTYPE CARD 69 95 14 31818 1 95 CAPACITORS FULL f YEAR JDR PR16 16BIT WITH VO DECODING LAYOUT 49 95 16 0 1 95 E TANTALUM ELECTROLYTIC a am Ma JDR PR16PK PARTS KIT FOR JOR PR16 ABOVE 15 95 18 492 1 95 ide ti ee WARRANTY ON JDR PRI6V 16BIT aa P d 39 95 68 15v ipf 50v 5 22n 195 B10 isv TO Sy 133 Ma 8 1 E a a RD SoRen pantskitronJonpnio COVE 1295 OSCILLATORS 22 15V 50V FOR XT 1 0MHz 5 95 na wy oe IBM PRI1 WITH 5V AND GROUND PLANE 27 95 1 8432 y Fp IBM PR2 AS AGOVE WITH VO DECODING LAYOUT 29 95 5 95 35V A POWER SUPPLIES GENDER CHANGERS ee APPLE TYPE SUPPLY 75 WATT SUPPLY r 22 i a GENDER FF FEMALE FEMALE 7 95 1 m GENDER MM MALE MALE 7 95 sn A SEA A A MALE FEMALE 7 95 r i g NULL MODEM 8 95 4 95 49 95 PS 1558 34 95 GENDER JB JUMPERBOX 8 95 pi FLOPPY DRIVE SUPPLY MICRO SUPPLY GENDER MT MINITESTER 14 95 1 95 i d i s went i j 4 95 e u 4 95 r 4 a 4 95 oe PS 1554 29 95 4 95 i 16V 1 25 PS ASTEC 24 95 BIT RATE BYPASS CAPACITORS DISK CONTROLLERS SNAPABLE RS 232 GENERATORS CERAMIC DISC 100 5 00 l HEADERS MONOLITHIC 100 10 00 1771 4 95
6. R15 C10 6 8K 01 R16 1302 OPTIONAL MP e C7 039 R5 4 7K C8 10 R7 100K R4 2K R6 470K R8 100K S1 i TO vel ti Fig 2 The RF receiver is built around an LM358 dual op amp U1 an LM567 PLL tone decoder U2 and a 555 oscillator U3 Fig 3 Shown here is a full sized tem plate of the transmitter s printed cir cuit board from an AC to DC wall transformer If so the receiver will fit into an enclosure about 2 by 3 inches Alternatively make the receiver portable by select lt gt va nenes Fig 4 Here is a full sized template of the receiver s printed circuit board TP1 GND Ca FERRITE FERRITE BEAD J BEAD rio C9 5 p 2L M358 B21 ing an enclosure that is large enough to hold a battery almost any re chargeable battery in the to 12 volt range works fine Before assembling use the receiver s printed circuit board as a template to mark mounting holes in the enclosure Drill the holes using a 32 inch bit for the mounting hard ware In addition drill a hole for the antenna a inch hole for the wire from the wall transformer if applica ble and mounting holes for fhe piezo buzzer on off switch S1 and LED1 For the transmitter select an en closure with enough room for the printed circuit board a whip antenna and a 9 volt battery Before assem 6861 AYVNNVES E b HANDS ON ELECT
7. novice transceivers For those people a 600 watt linear is a 6 1 change which is a gain of nearly 8 dB almost three S units For that person the 600 watt lightweight linear is a good bet and keeps TVI at minimal levels The 1000 watt linear yields a 10 1 increase repre senting 10 dB more than three S units such a change is surely worthwhile Power is not everything in amateur radio communications Increasing power enables you to communicate in marginal situations But it also brings other problems If you have only enough money fo sink into either a good antenna or a linear power am plifier and no way to own both then sink the money into the antenna sys tem Such an investment pays rich divi dends If you get an optimized three element beam antenna the forward gain will be around 8 dB which is the same as buying a linear amplifier that increases power by about sixfold But power increase is not the main reason why an amateur needs a good beam antenna for marginal commu nications The main reason involves re ception The directivity of a beam allows you to notch out interfering sig nals from certain directions On the east coast we are overwhelmed with W6 stations when chasing European and African DX Placing the notch on the back of the beam facing the west reduces the problem considerably Even if the main lobe of the beam is not directly on the DX station they ll still hear you loud and clear Tak
8. 0 033 wF 250 WVDC Digi Key E2333 or equivalent C6 047 F 400 WVDC Digi Key E4473 or equivalent C7 33 F or value to suit see text 350 WVDC miniature electroytic ADDITIONAL PARTS AND MATERIALS FL Xenon flash lamp NEI NE 2 120 volt neon lamp Ti See text T2 4kV trigger transformer Printed circuit or perfboard materials 9 volt nickel cadmium battery snap in battery holder part number 16064 from Sintec Electronics 28 8th St Box 410 Frenchtown NJ 08825 or equivalent wire solder hardware etc Note The following parts are available from Allegro Electronic Systems 3 Mine Mountain Road Cornwall Bridge CT 06754 A kit containing T1 T2 and FLI with data sheets is available for 5 75 postpaid Connecticut residents please add appropriate sales tax Free technical assistance is available by writing Allegro Electronic Systems at above address or calling 203 672 0123 weekdays from 9 AM to PM in the afternoon Model Rockets are available from local hobby shops or by mail order in kit form from Estes Industries PO Box 227 1295 H Street Penrose CO 81240 Catalog 1 TABLE 1 ROCKET ENGINE COMBINATIONS Engine Model Name Type Phoentx D12 3 Mercury Redstone C5 3 Jupiter C C5 3 Black Brant Il D12 5 Pathfinder D12 5 Mega Sizz D12 5 Ranger D12 5 Der V 3 D12 3 Der V 3 D12 5 Eggspress C5 3 D A R T C5 3 Transtar Carrier C5 3 Note All we
9. 9 885 and 12 035 kHz Feedback Your letters are always welcome Send details of your SWL ing your comments or questions to DX Lis tening Popular Electronics 500 B Bi County Blvd Farmindgale NY 11735 Donald Callahan Gray ME writes to say that he s very new to DX ing and uses an older Lafayette shortwave re ceiver i hear quite a bit he says but lam particularly interested in a signal I m hearing from the Yukon Donald says he d like to eliminate interference from Latin America and wonders if a dipole antenna will do the trick First Don think you must be listen ing to a ham on one of the amateur radio bands There are no shortwave broadcasting stations thatt is stations that broadcast programs in the Yukon Territory aithough there are hams operating from the Canadian far north One of the commercial amateur ra dio beam antennas on a rotor Could Continued on page 95 i The fast easy and low cost way to meet the challenges of today s electronic innovations A unique learning series that s as innovative as the circuitry it explains as fascinating as the experiments you build and explore From digital logic to the latest 32 bit microprocessor the McGraw Hill Contemporary Electronics Series puts you into the electronic picture one easy step at a time Fifteen MASTER THE NEW ELECTRONICS WITH McGRAW HILL S ee unique Concept Modules sent to you Sa one e
10. Q1 2N6714 E TSA an w 0 D wee we a a e a a a a al I Se ala al lM g5 Muir Electronics Vin 9V TO 30V C1 1000yuF Ql 2N2222 RI 1002 Clip your cards save them and start building your FactCards library today Ro SETS OUTPUT IMPEDANCE OF CHARGER Zoyt USE OF R ALLOWS LOW CHARGING RATES WITH FULLY CHARGED BATTERY INPUT TRANSIENTS z ee b SP SF SO Se FM 2ST SOF SF FF S88 SG SF VFS eS eS STE TS eS TT 2 e oa a Popular i Microprocessor Com Electronics FactCard MM58274 patible Real Time Clock bi GENERAL DESCRIPTION The MM58274 is fabricated using low threshold metal gate CMOS technology and is designed to operate in bus ori ented microprocessor systems where a real time Clock and calendar function are required The on chip 32 768 kHz crystal controlled Oscillator wili maintain timekeeping down to 2 2V to allow low power standby battery Operation ABSOLUTE MAXIMUM RATINGS DC input or Output Voltage 0 3V to Voo 0 3V DC Input or Output Diode Current 5 0mA atthe a Tampu TsTa 65 C to tIS FEATURES uppiy Voltage naid Dissipation P 500 mW w Same pin out as MM58174A Lead Temperature Soldering 10 seconds 260 C E Timekeeping from tenths of seconds to tens of years in independently accessible registers OPERATING CONDITIONS w Leap year register w Hours counter programmable for 12 or 24 hour operation Min Units u Buffered Crystal frequency output in test mode
11. ments without removing the front pan el of the enclosure Testing To rapid test the circuit with a frequency that is less than 100 Hz use a temporary jumper to take U1 pin 7 23 or 27 to 5V as indicated by the dashed line shown in Fig 1 Integrated circuit U1 then applies the count fo all digits higher than D2 Data for U2 indicates that Ci may be a trimmer however a 22 pF fixed disc capacitor is satisfactory for most ap plications and provides accuracy to 005 If a closer tolerance is required use a 6 50 pF trimmer Capacitor such as a Radio Shack 272 1340 Set the range switch to 1 second apply the multiplexing frequency from U2 pin 12 to the input of U3 and adjust the trim mer for a readout of 1280 Hz Frequency Counting When S1 is in the 1 second position the count range is1Hz to1 MHz and can be read directly from the display When S1 is in the 0 1 second position the count range is 10 Hz to 10 MHz The number then appear ing on the display is Yo the frequency being measured 1 KHz appears as 100 When a new frequency is being Continued on page 103 6861 AYVANWS fe Use this handy BASIC program to transform abstract equations into tangible graphs BY JAMES E TARCHINSKI ver the years A picture is worth a thousand words has become just another trite cliche But in the world of electronics it certainly is the truth As an example of how
12. 20 31 00 21 32 55 22 34 10 23 35 65 24 37 20 25 38 75 26 40 30 27 41 85 28 43 40 29 44 95 30 46 50 31 48 05 32 49 60 33 51 15 34 52 70 35 54 25 We accept MasterCard and Visa for payment of orders If you wish to use your Credit card to pay for your ad fill in the following additional information Sorry no telephone orders can be accepted Card Number Expiration Date PRINT NAME SIGNATURE IF YOU USE A BOX NUMBER YOU MUST INCLUDE YOUR PERMANENT ADDRESS AND PHONE NUMBER FOR OUR FILES ADS SUBMITTED WITHOUT THIS INFORMATION WILL NOT BE ACCEPTED CLASSIFIED COMMERCIAL RATE for firms or individuals offering commercial products or services 1 55 per word prepaid no charge for ZIP code MINIMUM 15 WORDS 5 discount for same ad in 6 issues within one year 10 discount for 12 issues within one year if prepaid NON COMMERCIAL RATE for individuals who want to buy or sell a personal item 1 25 per word prepaid no minimum ONLY FIRST WORD AND NAME set in bold caps at no extra charge Additional bold face not available as all caps 30 per word additional Entire ad in boldtace 1 85 per word TINT SCREEN BEHIND ENTIRE AD 1 90 per word TINT SCREEN BEHIND ENTIRE AD PLUS ALL BOLD FACE AD 2 25 per word EXPANDED TYPE AD 2 05 per word prepaid Entire ad in boldface 2 45 per word TINT SCREEN BEHIND ENTIRE EXPANDED TYPE AD 2 55 per word TINT SCREEN BEHIND ENTIRE EXPANDED TYPE
13. 8 95 complete receiver kit RC2 including all semiconductors resistors capacitors ferrite beads LI T1 antenna wire and RELATIVE OUTPUT dB 5kH2 DIV C6 18 pF ceramic disc C7 0 039 uF metallized film C8 C16 Ci7 10 pF electrolytic C3 C9 C18 0 0l uF ceramic disc C10 Cl4 O I pF metallized film Ci1 4 7 pF electrolytic Ci2 0 47 pF electrolytic C 3 100 pF electrolytic C1S5 1 0 pF electrolytic ADDITIONAL PARTS AND COMPONENTS Li 50 yH RF choke TI RF transformer Si Single pole single throw toggle switch Printed circuit board see below or perfboard VHF ferrite beads antenna two feet of 22 hookup wire 8 pin DIP sockets plastic enclosure piezo buzzer hookup wire solder hardware etc DIP sockets is available for 27 95 Enclosure and battery not included Add 4 50 for shipping and handling a one time charge covering all items ordered NC residents must add sales tax For technical information write to Time Space Scientific at the above address and include a self addressed stamped envelope fe 5kH2 DIV 49 890MHz Fig 8 This diagram illustrates the RF of the transmitter as seen on a spectrum analyzer As Required by FCC regulations Part 15 the bandwidth is less than 10 kHz munications Commission However it is recommended that you read part 15 sections 15 1383 15 118 and 151 19 of the Federal rules and regulations which are availabl
14. ADDITIONAL DISPLAY MODULES da c ce 96 bea used to illustrate the multiplexing con cept there are two common cathode terminals pins 3 and 14 since the two pins are internally connected only one of those terminals need be con nected to the circuit in order for the display to function properly although connecting both would not cause any problems While the pinouts may vary from one display type to another the concept remains the same If you opt to go with a salvaged dis play unit it will be necessary to deter mine the pinout and configuration common cathode or common anode To test a salvaged display when the pinout is not known temporarily con nect a 1000 onm resistor from a 5 to 9 volt source to pin 1 then touch the TO DIGIT DRIVERS Fig 2 A multiplexed display can be fabricated from discrete seven segment display modules by connecting all like pins in parallel For example pin I of the first seven segment unit connects to pin I of all the other modules SEGMENTS CATHODES source ground to each of the other pins in sequence If any segment lights the pin at the resistor is the anode for all like segments in all digits and the pin at ground is the common cathode for the digit with the lighted segment Repeat that procedure to identify all segments and cathodes by moving the resistor to the other pins Make a record similar to that shown in Fig 1 b for use as a reference during circuit assembly
15. At this point you may want to check your completed circuit with an ohmmeter to be sure all connec tions are good Now secure the resistor and wire so that they will not come into contact with the rotating spindles of the tape player You could just glue them securely or wrap them around some of the tape guide pins located in the comers of most cartridges Route the wire through the exit hole and carefully re assemble the cassette cartridge If the piece of equipment you wish to amplify has an auxiliary output jack such as for headphones or earphones connect the appropri ate plug to the end of the wire If the equipment in question does not have such an output you will have to con nect the wire to the intemal speaker terminals of the unit Before putting the cartridge into a tape player to test it carefully examine the newly created coil in particular check to be sure that the ends of the coil or anything else will not get snag ged on any of the mechanisms inside the tape player To use the device simply pop it into a tape player and plug or connect the Audio Coupler to the unit needing am plification The tape player must be in the play mode just as if you were ready to listen to a tape Adjust the volume control of the tape player and the volume control of the signal source to your liking If you have a 40 watt booster on your tape player you can really bring that little handheld unit to life have made three of
16. C 6861 AYYNNYT J on HANDS ON ELECTRONICS POPULAR ELECTRONICS d oO signal An example is a binary signal called clear which might be repre sented by the mnemonic CLR Many times binary signals are grouped to gether and related as in a binary number For example the bits in an 8 bit word might be given the names AQ through A7 In any case you will see many different variations Inversion Inversion is expressed mathematically by placing a bar over the variable In Fig 6 the input of the inverter is A while the output is B Note that B is expressed in terms of A That Aa gt 5B A Fig 6 The complement of a variable can be represented by placing a bar over that variable as shown here expression is read B is equal to Not A The not bar indicates that signal A has been inverted Remember that A can be either a binary 0 or a binary 1 NOT A of course is the opposite or comple ment Since it is difficult to type a bar overa letter as shown in Fig 6 other simpler methods have been devised for repre senting inversion Sometimes the inver ted variable is indicated by an asterisk or a prime similar to an accent Using the variables in Fig 6 B A or B A AND Function The logical AND operation is indicated by placing a dot between the two variables to be ANDed That is illustrated in Fig 7 The two inputs to the AND gate are A and B Fig 7 ANDing of variables is indicated by using
17. CA 90810 Price 209 OK everyone s agreed the age of vi nyl is drawing to a close and the anointed successor the compact disc aided and abetted by audio tape is turning the LP record Out to audio reproduction pasture But there still remain many millions of vinyl records with new ones pressed every day that stilt have a few more millions of miles to go around the turntable spindle before being trashed With the music industry whole heart edly supporting the CD revolution con Sumers owe companies like Kenwood U S A Corp a vote of thanks for actually marketing new turntables Don t they know the vinyl record is doomed Last year Kenwood introduced two linear tracking units the deluxe KD 77FC and the tumtable GIZMO had an opportunity to use the AD 67F Minus the KD 77FC s seven program random ac cess memory function the KD 67F seems a good example of what a basic turntable is like tn this electronic age of feature laden components Not that this slick unit is just any platter and tone arm generic turntable Like its higher priced sibling the 67F mimics the music selection methods associated with both tape and CD players But undoubt edly to some consumers relief it does so in a simpler manner The table s smoked finish clear cover is designed to stay closed at just about all times except when the record is being flipped or replaced 2 Page 6 GIZMO YS m CIRCLE 65 ON FREE INFORMATION CARD
18. COMES EASY By Jack Schmidt M Lord I can t pick up not a thing on my stereo headphones in here Melvin is it true you bought an exercise hike for your robot the delayed sweep by simply positioning the scope s cursors on the expanded wave form the numeric value appears on screen Operator prompts and on screen error messages guide users through the proper setup and measurement procedures There are prompts for proper AC or DC settings and for proper control settings Continued on page 22 When I said that we are dealing with limited memory was not talking about the computer was talking about you Oh Mr Communicator don t think you re putting out enough power Byron the computer company sent the retrofit instructions on a floppy disk NOW Training includes XT compatible computer It s no secret Industry is being transformed by technology with everything from precision electronic instruments to giant locomotives now being produced with the help of advanced robotic systems And with automation have come jobs thousands of jobs building programming and servicing the robotic systems in use today Now unlike any other school NRI offers you training that prepares you to take advantage of these new opportunities training that gives you the practical know how and the hands on skills to advance on plus NRIs remarkable Robotic Discovery Kits
19. DEPARTMENTS Editorial adieu Herb Friedman ail Letters the readers speak out Antique Radio page 82 Electronics Library prepare today for tomorrow s tasks New Products what s new in the electronics market FactCards the fingertip electronics library GIZMO Special Section for the grown up kid Free Information Card get the complete lowdown Advertising Index find the products and services you need Scanner Scene page 93 6861 AYVNNVS ans HANDS ON ELECTRONICS POPULAR ELECTRONICS N COMBINED WITH Adieu Herb Friedman Herb Friedman has passed away Herb was the colum nist for our computer column first met Herb 30 years ago when we both were new to magazine publishing was on the job only a week or two when this huge man filled the frame of my office door At first he startled me but spotted the smile on his face and a project that he held in his hands smiled and that began a friendship that was never shaken never en cumbered l Il never know how many magazines Herb wrote for but can name a few Popular Elec tronics Radio Electronics Elec tronics Illustrated Radio TV News Electronics World Elementary Electronics Popular Mechanics Popular Science Mechanics Illus trated Science and Electronics Photography Hi Fi Stereo Review i Hi Fi Stereo Buyers Guide and v many computer magazines d doubt that anyone has had more HERB FRIEDMAN freelance articles purcha
20. Don t change the unity gain of op amp Ui b because its only function in the circuit is to invert the output of Ul a Tne output of Ui c can be fed to a dual diode rectifier circuit as was done in Fig 3 to provide a DC output to drive a variety of circuits Encoder Decoder he transducer Circuit shown in Fig 5 consisting of a 567 phase locked loop PLL a piezo transducer LED and a few support components can be operated as ei ther a tone encoder or decoder by changing the position of 1 The oper ating frequency of that dual purpose circuit is determined by C3 and R2 Capacitors Ci and C2 are not critical and can be of almost any value be tween 1 and 5 microfarads When the circuit is receiving an on frequency signal LEDI lights Although a two wire piezo trans PARTS LIST FOR THE LU S67 phase locked loop PLL integrated circuit LED light emitting diode amy color RI 1000 ohm wati 3 resistor R2 25 000 ohm potentiometer Cl C2 41 7 nF 16 WV DC electrolytic capacitor C3 1 02 pP ceramic disc capacitor B41 Piezo transducer Radio Shack 273 073 of similar Printed circuit or perfboard materials enclosure IC sockets battery and battery holder wire solder hardware ele s Fie This transducer ciretii cConsiM ing of a 567 phase locked loop PLL a piezo transducer LED and assorted compo nents can be operated as a tone encoder or decoder depending the positi
21. If no segments light but do light when the source leads are re versed the unit is a common anode type and is not suitable for use in the counter Do not discard the display make a record and save the display for some other project Power Supply When all digits are lit the circuit draws about 160 milliamps A 5 volt bench supply that is rated at more than 1 ampere may be used however a heavy duty 6 volt battery with a 1 ampere diode connected in series with one of the leads will work and makes the unit portable space is available on the circuit board at the top to mount a 5 volt regulator and capacitors if desired If a regulator is used a 6 to 9 volt AC adaptor may be used to supply the basic DC voltage To preclude damaging the integrated circuits U and U2 must be powered up before or simultaneously with the application of input signals to U3 The entire circuit is designed to be powered by one com mon supply Assembly See Fig 3 The author s prototype of the 10 MHz Frequency Counter was built on a universal printed circuit board Radio Shack catalog number 276 170 Note that the horizontal holes in Fig 3 are la 3dp Of ET TO SEGMENT DRIVERS 5d c 9 ob 5V e o beled A through J and that the vertical holes are number 1 through 47 Col umns of holes designated X and Y are the 5V and ground buses respec tively Carefully locate the positions of the IC s and mark the pin 1 holes w
22. MINIMUM ORDER 10 00 FOR SHIPPING AND HANDLING INCLUDE 2 50 FOR UPS GROUND AND 3 50 UPS AIR ORDERS OVER 1 LB AND FOREIGN ORDERS MAY REQUIRE JOR MICRODEVICES 110 KNOWLES ORIVE LOS GATOS CA 95030 ADDITIONAL SHIPPING CHARGES PLEASE CONTACT THE SALES DEPARTMENT FOR THE CAL 408 866 AMOUNT CA RESIDENTS MUST INCLUDE APPLICABLE SALES TAX PRICES ARE SUBJECT LOCAL 408 6200 FAX 408 378 8927 TELEX 171 110 TG CHANGE WITHOUT NOTICE WE ARE NOT RESPONSIBLE FOR TYPOGRAPHICAL ERRORS WE RESERVE THE RIGHT TO LIMIT QUANTITIES AND TO SUBSTITUTE RETAG STORE 1256 SOUTH BASCOM AVE SAN JOSE CA 408 947 8881 manuFACTURER ALL MERCHANDISE SUBJECT TO PRIOR SALE A FULL COPY OF OUR HOURS M F g 7 SAT 9 5 SUN 12 4 TEAMS IS AVAILABLE UPON REQUEST ITEMS PICTURED MAY ONLY BE REPRESENTATIVE MS ORDER TOLL FREE 800 538 5000 Pem COPYFIGHT 1988 JOR MICRODEVICES CONTINENTAL U S AND CANADA dl CIRCLE 13 ON FREE INFORMATION CARD 6861 AYVNNVES HANDS ON ELECTRONICS POPULAR ELECTRONICS e Foli Library To obtain additional information on the books and publications covered in this section from the publisher please circle the tren s code num ber on the Free Information Card AUTOLISP IN PLAIN ENGLISH A Practical Guide for Non Programmers by George O Head This book introduces readers to the funda mentals of AutoLISP AutoCAD s powerful internal programming language A basic knowledge of AutoCAD is
23. PO Box 997 Mercer Island WA for a free Catalogue Here s another tip from John He s found that Omnnitron Electronics 770 Amsterdam Ave New York NY 10025 is a good source of hard to find tubes and other parts Keenan Whitley joins the growing group of people see last month s col umn who have written to say that the Zenith dial glass and dial belt that was looking for could be obtained at Antique Electronic Supply 688 W First St Tempe AZ 85281 And he took the trouble to photocopy the entire A E S catalogue for me Keenan went on to say that those with cabinet restoration problems might like to read The Complete Man ual of Wood Finishing by Frederick Di eghton He says that its an excellent book and even contains a chapter on faking woodgrain finishes in case you ve lost a photographic one as suspected that had before stripping my Zenith cabinet Its published by Stein and Day Scarborough House Briarcliff Manor NY 10510 It s even more impressive to compare the rear view of the replica op to the actual set s bottom Except for the tube Dan made every one of his parts from scratch Finally Keenan suggested that re store a really impossible set in the col umn perhaps one with extensive lightning damage Having just de voted several months worth of columns to a restoration I d like to deal with some other kinds of subjects for a while But Keenan s suggestion did give me a terrifi
24. Russian mathematician and physicist and published in the Soviet Union presents mathematics as an integral part of the natu ral sciences It concentrates on concrete mathematical solutions to scientific prob lems without getting mired in the formal foundations and logical subtleties that con found many beginners in higher math In doing so the authors intend to transform mathematics from a dry difficult subject to one of clear and natural Concepts While aimed at newcomers to higher mathematics advanced high school voca tional and college students the book is not simplistic Along with traditional topics including analytic geometry and differential and integral calculus it introduces the no tions of power and trigonometric Series and examines simple differential equations It contains hundreds of examples and calcu lations some are examined from more than one angle and many are accompanied by CABLE TV BONANZA ITEM CALL FOR AVAILABILITY Output Quantity ORAHE California Penal Code 593 D forbids us SUBTOTAL from shipping any cable descrambling unit Shipping Add to anyone residing in the state of California 3 00 per unit amp Credi Prices subject to change without notice ae robe PLEASE PRINT TOTAL Name Address City State Zip Phone Number Cashier s Check Money Order COD Mastercard Acct Exp Date Signature FOR OUR RECORDS DECLARATION OF AUTHORIZED USE the undersigned do hereby dec
25. S Nine controls and two indicator lights are grouped across the front panel of the unit The streamlined but standard turn table adjustments are power a repeat func uon and selection between long play and single 30 and 17 inch records The size selection in turn cues a speed selection unless the user independently selects rpm A manual search function two con trols that move the tone arm forward and back and a two way cuing control add some full automatic flexibility to the LP listening experience Underneath the hinged cover a light weight linear tracking tone arm made of plastic moves with a minimum of friction and contact across the record Powered by Kenwood s advanced motor the 67F s quiet Operation is immediately apparent to ears accustomed to the rumble and surface noise that standard turntables often seem to pick up After a tew weeks of using the 67F we wouldn t go as far as the Kenwood product news release which describes the KD 67F as eliminating all tracking errors That leaves the record s condition out of the listening equation and unfortunately the turntable doesn t treat banged up or often played LPs with any more tenderness than the standard traveling tone arm Some of our more beloved albums revealed skips previously undiscovered and unheard When the tracking error belongs to the record no amount of precision engineer ing will help Although we re sometimes i
26. and translations can prove to be a real time waster For example you could probably make lunch in the time it would take some programs to page format a 2000 word ASCII document Word For Word gets around the problem by having both ASCII and Smart ASCIl translations Generally conventional ASCII contains no page formatting of any kind the file contains only text characters Smart ASCll con tains ASCII text characters and the page formatting commands How ever keep in mind that a non word processed document such as a spreadsheet should be converted in conventional ASCII 2 A Disability Can Be An Asset BUILD IT BOOKS FOR EXPERIMENTERS Modern OpaAme d 8P106 MODERN OP Projects AMP PROJECTS 5 75 Wide range of build it projects that use op 223 PROJECTS gt USING THE CA3130 amps Easy to build board layouts provided for most A 5 00 50 different ways to put this op arnp to work in variety of projects of all cluding audio RF test kinds are included equipment household and miscellaneous projects 4 BP44 IC 555 PROJ ECTS 55 95 Included are basic and general timer circuits automobile and model railroad circuits alarms and noise makers as well as a section on 556 558 and 559 timers 224 50 CMOS ICD PROJECTS 5 25 These IC s are suitable for an extraordinary range of applications This book shows you just how much you can
27. and many more Also included is a new chapter skow ing how you can use transistors to re place hard to find vacuum tubes You ll even see the circuit that was lashed together on a table top one night using junk box parts a hair curler and alliga tor clips Attached to an an tenna strung across the base ment ceiling and a 9 volt bat tery Signals started popping in like crazy In a couple of tes minutes an urgent message from a ship s captain off Se amp n attle over 1500 miles away i was heard asking for a naviga J tor to help him through shallow water These small regenerative receivers are extremely simple but do they ever perform This is a must book for the experimenter the survivalist who is concerned about basic communication shortwave listeners ham radio opera tors who collect old receivers and just about anyone interested in old time radio Great book Fun to read One of the best old time radio books to turn up in years Heavily illustrated Order a copy today 8 1 2 x 11 paperback 260 pages only 15 70 postpaid c Lindsay Publications Box 12 WF3 Bradley IL 60915 i Send a copy of Short Wave Radio J i Manual Enclosed is 15 70 Chk MC Visa Send a free cata log of other books Name SS SSS eS l Address Lra m a 6861 AHYNNYTF b wm HANDS ON ELECTRONICS POPULAR ELECTRONICS mo New Products To obtain additional information on new pro
28. build yourself an electronic car dashboard Free details 1 00 P amp H MODERN LABS 2900d Ruisseau St Elizabeth QC JOK 2JO Canada Phone Devices Surveillance Items More Catalog 1 00 XANDI ELECTRONICS Box 25647 32X Tempe AZ 85285 5647 COMPUTER kits 49 95 complete Build your own Sinclair ZX81 with built in BASIC School discounts availabte Add 3 00 for shipping VISA MC ZEBRA SYSTEMS INC 78 06 Jamaica Ave Woodhaven NY 11421 718 296 2385 BUILD serious electronic devices to protect and improve your home Send SASE for free plans cata log to UNIQUE CIRCUITS 6101 Maxwell Odessa TX 79763 LONG range listening Tube mini tube Bug swat ter RF sniffer BC Magnum Booster Scanmate Voice scramblers descramblers Sequential LEDs FM TX Kits Plans and File Notes Catalog 1 00 KRYSTAL KITS P O Box 445 Bentonville AK 72712 AUTOMATIC Solder Iron Shut Off Circuit Detaits SASE Complete plans schematic and P C Board 8 00 R KRIEGER PO Box 3385 Davenport IA 52808 FMINI Transmitter and TelephTransm plans With PCB both 9 95 PH 1 50 Risco Inc 1335 W 68 St 410 Hialeah FL 33014 SPEAKERS Subwoofers Woofers Midranges Tweeters for Auto Home MI Commercial applica tions 88 page color catalog 2 00 Amplifiers mi crophones DJ equipment MCGEE RADIO 1901 McGee Kansas City MI 64108 THE ULTIMATE KIT The CDK 52 Controller de Sign kit allows you t
29. easy way By Design Software 2262 Pear St By Computer Ca on City CO 81212 For IBM PC 100 compatibles Checks Payable to By Design and Tandy 1000 NO CASH PLEASE 256K memory 5 Hoppy drive Allow 46 whs delwer j FM Transmitter fits in matchbox with N cell battery or phoneline powered Tunable 60 95 MHZ Super sound sensitive powerful Board parts instructions 19 95 PTS Box 1951 Fort Worth TX 76101 ALARM SUPPLIES Wholesale Prices Save 60 1000 items Catalog 2 00 ALARM DISCOUNT ERS P O Box 215 Kingsville MD 21087 CB RADIO OWNERS We specialize in a wide variety of technical information parts and services for CB radios 10 Meter and FM conversion kits repair books plans high performance accessories Over 12 years of satisfied customers Catalog 2 CBC INTERNATIONAL P O BOX 31500H PHOENIX AZ 85046 MICROPROCESSOR based prototype board Zilog Z8 RAM EPROM serlalparallel I O prototype area Free catalog with application notes SOFT WARE SCIENCE 3535 Roundbottom Road Cin cinnati OH 45244 SATELLITE RECEIVER SALE Regency SR1000 130 SR3500 stereo 150 00 downconverters in cluded GORDY S REPAIR SHOP 207 666 3356 PICTURE flyer lists quality electronic parts at low prices Since 1970 Send for 3 sample issues Star Tronics Box 683 McMinnville OR 97128 CABLE TV DESCRAMBLERS Jerrold Scientific Atlanta Zenith Most major brands Dealer inquiries welcome Visa
30. give vou some idea of its actual size Be cause of tight spacing the resistors have been vertically mounted PERSONAL POCKET C C7 and s collector base ca pacitance to a resonant frequency of 49 890 MHz RF transformer T1 matches the low impedance of the whip anten na to the 780 ohm load resistance re quired by the oscillator The antenna loading coil L2 tunes out the capaci tive reactance exhibited by the elec trically short whip antenna changing the antenna into a resistive load Ca pacitors C1 C4 and C8 filter the V power supply bus With switch S1 closed the square wave signal from U1 periodically grounds the pin 3 end of resistor R With R grounded 1 is supplied a DC current that in turn allows QI to gener ate an RF carrier In that way U1 switch es Qi on and off at a frequency of 490 Hz to generate an amplitude modu lated RF envelope The RF Receiver Figure 2 shows the schematic diagram of the RF receiver Transistor Q1 and its components com prise a super regenerative receiver Resistors M R4 bias for a quiescent emitter current of about 1 mA il A Metia i m AE PAGER This local area paging system can help keep you in touch with family friends and co workers By Dan Becker The primary and secondary Currents of T1 are 180 degrees out of phase providing positive feedback Capaci tor C6 tunes T1 to resonance at 49 890 MHz Capacitor C6 and t
31. ified in the Parts List Gate Ut b squares up the output of Ut a and feeds a squarewave to C2 C3 R2 R3 D1 and R4 Trimmer potenti ometer R4 controls the duty cycle of the resulting pulse When R4 is set to its maximum resistance the maximum pulse width and power is available from the circuit The remaining gates U1 c Ut d U e and U f serve to amplify and invert the output of the PWM pulse width modulated part of the circuit The am plified pulse is fed to the IRF Z20 hex FET whose super low on state resis tance of Only 0 07 ohm switches the primary of T1 with great force Pull down resistor RS keeps the IRF Z20 to tally off during the logic O0 state of gates Ul c to Ut f The output is rectified by D2 and is used to power the Strobe s flash lamp circuit A word is needed about miniature transformers Most units have an ac cessory winding used in self oscillating circuits powered by bipolar transistors That winding is not needed since we have our Own on board PWM os Cillator circuit A simple test with an ohmmefter will reveal that low resis tance feedback winding Do not con fuse if with the low resistance heavy gauge primary winding Typical trans former configurations are shown for you in Fig 3 Another consideration is that lots of transformers are connected for Euro pean and Oriental active negative circuits Akin to driving on the wrong side of the road to us That confusion is easily overco
32. showing the outputs for all inverters and gates Writing from a Truth Table In many cases you will start with a truth table and develop the Boolean expression from it That is what usually happens when you are designing a digital cir cuit Typically you will define a desired p INPUTS amo D _2 G D 60 6 amp o 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 a OGoecdea22 E0 0 2 0 GG O O Om a Oal mh ot ot ot d ot ot ot ot ot OO OC G GATE A B GATE GATE2 C D D GATE 3 GATE3 E ene i h Oa at aot Oat ae ot Oe o ot G Fig 19 You must use all possible input combinations for the circuit A for the table B output condition that is generated when specific input states occur To develop your design you build a truth table filling in the columns with the de sired output states for the given inputs Then the truth table can be used to help write the Boolean equation and the logic circuit itself can be deduced from the equation Once the logic cir cuit is drawn it can be implemented with ICs or other components Asimple example of that is a design where we have two inputs and want a specific output to occur For example perhaps you want the output F to be binary 1 when input D is equal to 1 and input E is equal to 0 For all other input states we want the output to be binary 0 That set of conditions can be drawn in a truth table as shown in F
33. sults in some audio distortion With some speakers the distortion is so small that it is of no concem Optics The projection lens need not have all the optical quality of a typical slide projector lens Since the ka leidoscope particles are in motion and at times are flying above the sur face the image is constantly chang ing in and out of focus You might try using a simple double convex lens as a star Depending on the size of your ka leidoscope you will need to use a lens with a focal length of 4 to 6 inches You can try lenses from small hand magni fiers or the so called close up lenses used with cameras They usually have the focal length marked on them A quick way to check your lens is to focus the image of a distant object on a white card If the distance from the lens to the card is about 4 to 6 inches it s worth a try Some ingenuity may be required to mount the lens If it is a loose lens mount it in a cylinder made from sev eral layers of card stock A ring of cardboard glued on each side of the lens will hold it securely in place It is suggested that you build a model be fore building the final carrier Your final unit can be as professionally finished as your time and talent allow If you are using a projection lens from a small slide projector it can be held in place using the method illus trated in Fig 3 The cardboard tube is wound tightly around the lens glued This simple mount can be use
34. t bbi a diijme ajii pia jorian mmm lle deal damarin TE E T TATE Fig 5 This is the XvWrite translation of the WordStar file shown in Fig 1 All formatting is correct but there are single and double spaces between the words shown in Fig 6 The only manual clean up thats necessary is to remove the extra space between the second and third paragraph the space in front of the left pointing arrow that signifies a line space sb fik espe Doh P arera APA IE fa ee is misini W far namia Lo j jere dl ri i iiij jam E p ee a ee fe ibia ja mila aill siecle gual panenn Men L a sgr aaa FiA hela SU ee ef ds eee ceri a a ee lis fered ike prigaia ia apd io Pee oie ee n kni Laem ja l Ba ja URE iii gag lpia Biala bs i di pie ef A ee Y Bei i db jai ria a am gE Fig 6 An automatic search and replace eliminates the extra spaces between the words In less time than it takes to read this caption the Electronic Rosetta Stone has given us a perfect translation of the WordStar file shown in Fig l Smart ASCII Now if youre up on software you know that many word processors save or can save their files in ASCII format which is transportable to other word processors The prob lem however is that either all page formatting is stripped off or the target computer hasnt the vaguest idea what the page formatting commands mean Either way the translation is nei ther complete nor accurate
35. tion Catalog which is updated and published quarterly it ll be a great help you ll see Just write Consumer Information Center Dept TD Pueblo Colorado 81009 US General Services AdminiStration w 866861 AYYNNYT HANDS ON ELECTRONICS POPULAR ELECTRONICS oa mH ADVERTISING INDEX HANDS ON ELECTRONICS magazine does not assume any responsibility for errors that may appear in the index below Free Information No Page A LS Satellite 105 AMC Sales 22 17 Ace Communications 97 All Electronics eee ee 14 Amazing Devices PELAAN 101 By Design Software 104 22 C amp S Sales a eer ae 25 CBC eaa 104 7 Cli 20 eee 11 20 Chemtronics PERNES 22 Command Productions 97 Cook s Institute 95 10 Digi Key CV2 Electronics Book Club 3 Electronic Tech Today 87 CV3 8 Halted Specialties 14 Hands on Bookstore 102 23 Heathkit CV4 INCE eee ee 99 12 13 JDR Microdevices 6 18 Jensen Tools 101 LT Sound 27 Lindsay Publications 1S 11 MCM Electronics 23 Mark V Electronics 95 Midwest Electronics 105 NRP oe a eee 21 Pacific Cable oeae ceo 13 16 Parts Express 5 19 The Datak Corporatio
36. 1750 1830 1850 2880 Graph both functions one pixel at a time Wait for an E to be pressed then exit the program LISTING 2 GRAPHER BAS MODIFICATION 7000 s22me22ne PLACE CONSTANT VALUES HERE 2222e222 2 n2r2 7010 7020 YMIN 0 7030 YMAX 10 minimum y value maximum y value 7040 place y axis title below 18 characters max 7050 YS VOLTAGE Volts 7060 7070 XMIN 0 7080 XMAX 5 minimum x value maximum x value 7090 place x axis lable below 60 characters max 7100 XS TIME in seconds 7110 7120 place two title lines below 60 characters max 7130 TiS EXPONENTIAL FUNCTIONS 7140 T2S For the second example 7150 7160 RETURN 7170 7180 8000 zuusenexane z PLACE FUNCTION 1 BELOW ssszasssasszsszzza z 8010 8020 Y 10 10 EXP X 8030 8040 RETURN 8050 8060 9000 a ecazezzexn z PLACE FUNCTION 2 BELOW zsxsamazzaszzsaszes 9010 9020 Y 10 EXP X 9030 9040 RETURN Jampacked with information at your fingertips DS b ay ea o f AEF pai H i Ms h A T F TO ET al F ay i ET CESS any p See ia cp ee es aaa ataa ALL YOU NEED to know about electronics from transistor packaging to substitution and replacement guides FACTCARDS numbers 34 through 66 are now available These beau tifully printed cards measure a full three by five inches and are printed in two colo
37. 2 12 95 286716 ASIC 9 95 LINEAR COMPONENTS 69 1 09 1 95 59 99 1 49 34 1 25 1 75 59 89 3 49 1 75 69 1 49 1 25 3 49 34 3 95 1 19 1 79 1 75 L380 89 LM383 L386 LM393 LMI394H LMI99H TL494 TL497 NE555 NE 556 NE558 NE564 L565 L566 LM567 NES70 NES90 NE592 LM723 LM733 LMT41 LM747 MC 1330 MC1350 LM1458 LM1488 LM1489 LM1496 ULN2003 XR2206 XR2211 LM2917 CA3046 CA3146 MC3373 MC3470 mC 3480 MC3487 LM3900 LM3909 LM3911 LM3914 LM3915 MC 4024 MC4044 RC4136 RC4558 LM1360 75107 75108 75110 75150 75154 75188 75189 75451 75452 75477 ADC0804 ADC0809 DaCcos00 DaCoaos DAC1022 MC 1408L8 8T28 8T97 OP8304 74HCO00 21 74HCO4 25 74HCO8 25 74HC14 35 74HC32 35 74HC74 35 74HC138 74HC139 45 74HC154 09 74HC157 55 74HC161 65 74HC164 65 74HC175 59 9334 9368 9602 ULN2003 MAX2Z32 mC3470 mC3487 AY5 3600 PRO 1275 2 85 69 i 7 95 1 95 2 95 11 95 INS8250 NS116450 10 95 INTERSIL tCL7107 10 95 ICL7660 1 99 ICL8038 3 85 ICM7207A 5 95 ICM7208 15 95 HIGH SPEED CMOS LOGIC 74HC244 74HC245 74HC273 74HC 367 74HC373 74HC390 45 74HC374 74HC4040 74HCTOO 74HCTO4 74HCTOS 74HCT32 74HCT74 85 85 69 69 69 79 69 74HCT138 74HCT139 74HCT157 74HCT161 74HCT 240 74HCT 244 74HCT245 74HCT273 74HCT373 74HCT374 74HCT393 7T4HCT4040 74HCT4060 1 49 STANOARO CMOS LOGIC 19 4028 19 4040 35 4042 29 4044 29 4046 49 404
38. 2797 29 95 CAN BE SNAPPED APART BREAKOUT BOX cert es CERAMIC DISC 100 6 50 1791 9 95 8272 4 39 TO MAKE ANY SIZE HEADER FOR TROUBLESHOOTING oo TS i eee TELAN 1793 9 95 UPD765 4 39 ALL WITH 1 CENTERS SERIAL COMMUNICATIONS 4702 9 95 1795 12 95 MB8876 12 95 pete T CLOCK CIRCUITS pam ee pe STRAIGHT LEAD OPEN CLOSE INDIVIDUAL CIRCUITS ieee C95 MC146818 5 95 MM58174 9 95 RIGHT ANGLE LEAD j 20 JUMPERS CROSS CONNECT ANY MM58167 9 95 MSM5832 2 95 2793 19 95 2143 6 95 2 STRAIGHT LEADS TWO CIRCUITS 2 RIGHT ANGLE LEADS 2 10 LEDS SHOW CIRCUIT ACTIVITY GENDER BO 34 95 IDC CONNECTORS RIBBON CABLE DESCRIPTION ORDER BY CONTACTS 40 SC DER HEADER IOHxxS 2 58 RIGHT ANGLE SOLDER HEADER IDMaxSR 85 135 2 72 WIRE WRAP HEADER IDHaxW 1 86 2 98 50 5 28 RIGHT ANGLE WIREWRAP HEADER IDHxxWA 3 28 4 22 4 45 4 80 RIBBO HEADER SOCKET IDSxx i B9 1 49 gt RI3BON HEADER 1OMxx 50 6 25 7 00 7 50 8 EPROM ERASERS JOYSTICK RIBBON EDGE CARD IDExx 85 1 75 2 05 2 FFT SPECTRONICS CORPORATION SET X Y AXIS FOR AUTO CENTER 10 PLASTIC RIBBON CABLE RCxx 1 60 3 20 4 10 5 40 6 40 7 WW m OR FREE MOVEMENT of lintensity Unit FIRE BUTTON FOR USE WITH GAME FOR ORDERING INSTRUCTIONS SEE D SUBMINIATURE CONNECTORS BELOW Model Timer Fp ww we Pig soctwanie PE 140 NO 9 8 000 B89 COMPATIBLE WITH IBM APPLE II IIE HC ATARI amp VIC 20 64 D SUBMINIATURE CONNECTORS Piui pes o eee ee cod CONTACTS CES
39. A moment or two after the fitle ap pears if you ve entered the program correctly a graph similar to the one shown in Fig 1 should materiatize on your screen The graph is a plot of two sinewaves having the same frequen cy but different magnitudes and phase angles When the plotting process is com piete the program begins running a loop that is constantly looking for a press of the E key Once E has been pressed the program halts execution and retums you to the BASIC language editor with the OK prompt dis played The Program Having looked at an example of the type of chart Grapher is capable of producing let s discuss how you can modify the program to graph the functions that you d like to see displayed Lets analyze lines 7000 7140 of the program looking at the sample graph shown in Fig 1 Notice first of all that the variables YMIN and YMAX of the pro gram which are defined by lines 7020 and 7030 are used to specify the mini mum and maximum values of the Y variable that will be displayed on the screen In lines 7070 and 7080 XMIN and XMAX are defined in the same manner for use with the graph s X axis Simply modify the values before you run the program to accommodate the range of the variable you wish to plot Although any values for XMIN and XMAX will generally work sometimes you may select vaiues of YMIN and YMAX such that the points Grapher needs to piot are outside of the range displaye
40. An y Equ C Line Noi p iani REQUIRE A COMPUTER CON TROLLER NOT AVAILABLE FROM HALTED THEY CANNOT BE MANUALLY CONTROLLED As Is 99 00 Fi WIDE BAND AMPLIFIER NEC UPC1651G 1200 Mhz 3 db Gain 19db f 500 hz 5 voll X operation Small package 4mm dia x 2 5 mm thick CAT UPC 1651 2 tor 1 00 10 for 4 50 100 for 35 00 10 AMP SOLID STATE RELAY 1 long flashtube prepped with 3 1 2 red and black leads Ideal tor electronic flash or strobe projects CAT FLT 3 2 for 1 00 N CHANNEL We stock THOUSANDS ot parts IC s TRANSISTORS MORE CALL gt ELECTROL 2161 MOSFET CONTROL 5 5 10 Vdc will operate 3 32Vdc Gr SE tar Gane PAGING ER ga LOAD 10 Amp 240 Vac T PS J REC Ds Hz A P aiii 1 00 each ion Superhet 450 M 2 1 4 X 1 3 4 X 7 8 Dual Convers ever Module Plug in 10 for 9 00 Crystal Contotied Rece LED Display CAT SSRLY 10B 9 50 each 10 for 85 00 25 for 175 00 50 for 300 00 100 for 500 00 MAIL ORDERS TO LARGE QUANTITY ORDER TOLL FREE 800 826 5432 AVAILABLE Aipha Numenc nar Set ASCil Encoded ANSI c a RACER Nearer 9 99 o Peizoe 17 95 Vibrating silent Alen wo used Untested tor as is Call the HANDS ON ELECTRONICS POPULAR ELECTRONICS D ALL EL
41. Dynamic Stereophone EP400 is said to use a high flux Samarium Cobalt magnet and oxygen free silver copper wire for the voice coil winding The same oxygen free copper is used in the ten foot audio cord for maximum conductivity and minimal signal loss yielding extended dynamics and distortion free sound Audio engineering aside the EP400 s adjustable double headband system combines strength and rigidity even as it evenly distributes the weight of the unit Mesh covered foam earpads are mounted with a dual swivel system so that they can be adjusted to individual head shapes while providing the best possible performance and the greatest degree of comfort Price 100 CIRCLE 60 ON FREE INFORMATION CARD Build a 10 MHz Frequency Aw interested in electronics sooner or later usually sooner needs some sort of test equipment Al most every electronics hobbyist has a digital or analog multimeter but there are times when simple voltage cur rent and resistance measurements just won t do Sometimes such as when working with digital circuits a frequen cy measurement is needed That s the fime when you need an oscilloscope or frequency Counter Unfortunately a low end oscillo scope or a frequency Counter will cost 200 to 300 or more that s more than many beginning hobbyists want to spend Unless of course itis a Popular Electronics 10 MHz Frequency Coun fer Built around three integrated cir cuits that
42. EE iS iie m U S nology Today ondis consed to Gemsback Puimasier Manse send addas changes to Hands On Elec lar Electronics tronics i PO Box 338 Mouni IL 61054 9932 Siksa Pase As a service to readers Hands on Electronics including Popular Electronics publishes milabie plans or informaton relating to newsworthy products techniques and scienthc and technological developments Because of possible variances in the quakty and condition of matenais and workmanship used by readers A pror acts basal upon or Itom pies oc kiamat pubmed k magazme left is the dielectric material Wind the entire length with No 26 wire close wound and solder it to a male pin connector attached on one end Cover the length with heat shrink tubing You now have a flexible an tenna that is much more sensitive than the telescoping kind Attach the female pin connector to the case and it becomes removable M B Van Nuys CA Molded chokes do share their color code scheme with resistors although there are some differences in the way the two are read For exact information on how to read molded chokes see the ARRL Handbook s chapter on Construction Practices and Data Tables if you don t own a copy of the Handbook one is available at most local libraries Also a FactCard on inductors including RF chokes is planned for later in the year HAVES AND NEEDS recently purchased a used Bearcat 300 scan ner The instruction manual
43. IC s if you need a copy of an article that is in an issue we indicate is unavailable you can order it directly from us We charge 50 per page Indicate the issue month amp year pages and article desired Include payment in full plus shipping and handling charge Make checks payable to Gernsback Publications Inc ARTICLE PAGES MONTH YEAR TOTAL PAGES 50 each TOTAL PRICE MAIL TO Popular Electronics Reprint Bookstore P O Box 4079 Farmingdale NY 11735 Ail payments must be in U S funds 1 SHIPPING CHARGES IN USA amp CANADA 0 01 to 5 00 0 1 25 30 01 to 40 00 5 00 SORRY We only ship to 5 01 to 10 00 2 00 40 01 to 50 00 6 00 USA amp Canada i 10 01 to 20 00 3 00 50 01 and above 7 50 20 01 to 30 00 4 00 i Total price of merchandise lt 2 ks csc ich eeccwiw ade ccuedaessecedeeacencesaueeaci _ i Sales Tax New York State Residents Only 0 0 0 eee cece cree ee eee Shipping Charge see chart 0 0 0 0 c ccc cece cence rere eeeeeneveneures i Name Total Enclosed Address City State _____Zip P 189 ee ccc cen ou cc ch Sc se ccs es ad come We ll get started right now and present a few more of them next month and go on into the following month if necessary Wonderful Re Creation think fhe best way to get everyone back into a Crosley 50 mood is to show you the pictures Dan Damrow Burbank IL
44. In each case the reading should be close to 12 volts The voltage at pins 3 and 6 of each op amp and pin 3 of the PLL should be close to 6 volts DC The photo shows the SCA Adapter installed in an older AMIFM stereo receiver the Harman Kardon HKS701 Two brackets were used to suspend the Adapter above the tuner board Fig 3 Full size PC artwork for the SCA Adapter lts use is recommended POWER GND 15 30 VOLTS Fig 4 Take care when assembling the board UI is oriented differently from U3 and U4 If everything is okay you are ready to install the Adapter in your FM tuner or stereo receiver Finding the Signal Here comes the tricky part Ideally you need access to the circuit diagram of your tuner or re ceiver Next you need to identify a positive DC supply rail of between 15 and 30 volts Then you need to find the output of the FM demodulator of your receiver or tuner In a stereo tuner that comes before the multiplex decoder and treble de emphasis networks In a mono tuner you must identify the demodulator out put before de emphasis After de em phasis the 67 kHz signal will be non existent Most medium priced tuners use two IC s to do most FM signal processing They are the IF amp and detector IC followed by a multiplex MPX de coder IC The most convenient point to pick off the 67 kHz signal is at the input to the MPX decoder Setting Up Having found the signal and made the
45. Indoor FM Antenna which GIZMO tested Both the dish and the LS 4 use what s described as a Gallium Arsenide Field Effect Tran sistor for higher gain and lower noise levels to FM signals than traditional metal lic silicon transistors The LS 4 is 17 inch tall obelisk think of the Washington Monument with a small green power indicator light and a gain adjustment knob mounted on one side The unit which plugs into a wall outlet with an AC adapter is supplied with three types of receiver connectors F plug screw and pushbutton style Set ers a five year wasranty one of the longest in the telecommunications industry We have tested thousands of individual Swisstel instruments and each one offers superb audio quality Swisstel uses the finest audio components available It has received glowing reviews from Associated Press United Press International Busi ness Week the New York Daily News and Newsweek among others Swisstel is one of the most successful new phones introduced in the United States in the past quarter century It is selling briskly in department stores and specialty shops where many of our pur chasers are women ages 18 through 46 Available in ten attractive colors and with 5 colortul accessories Swisstel Tele phones are technologically advanced de signer telephones of the very highest quality To prove our point we invite ary CIRCLE 67 ON FREE INFORMATION CARD up takes j
46. LED1 through current limit ing resistor R20 causing it to light Capacitor C15 couples a high to low trigger pulse from U2 to U3 a 7555 oscillator timer After triggering pin 3 of U3 goes high tuming transistor Q2 on When Q2 conducts the negative lead of the piezo buzzer B21 is grounded causing BZ1 to sound Re sistor R22 and capacitor C16 fix the time interval during which BZ1 sounds to about one second Pushbutton Si allows you to transmit a signal by connecting power to the circuit A low power voltage regulator U4 provides a constant 5 volts source which is used to operate the circuit Capacitors C3 C8 C13 C17 and C18 and RF choke L3 bypass RF and the 490 Hz signals to ground filtering the V bus Construction Because both units in clude RF circuitry printed circuit boards are recommended Fuli sized templates of the printed circuit boards for Personal Pocket Pager s transmitter and receiver respectively are shown in Figs 3 and 4 You can etch your Own or you can purchase etched and drilled boards from the source given in the Parts List You may want to power the receiver U3 T1 U2 U1 Here is what the receiver s printed circuit board looks like with all the compo nents installed The receiver is somewhat larger than it s counterpart the trans mitter If used as a stationary unit it can be powered from a wall mounted power supply or a home brew power supply circuit C1 SpF Q1 MPSH11
47. LEDI Light emitting diode any color RESISTORS All resistors are Ya watt 5 units unless otherwise noted RI R11 R2I 10 000 ohm R2 2200 ohm R3 47 ohm Note The following components for the project are available from Time Space Scientific 101 Highland Dr Chapel Hill NC 27514 TRANSMITTER TS3 printed circuit board 9 95 TR6 inductor kit includes TI and LI L5 only 10 95 complete transmitter kit TR6 2 including all semiconductors 1 4 INCH PC BOARD TEST POINT RESISTOR 7 TEST POINT RESISTOR gt PC BOARD Fig 7 Shown here are construction details of the test point terminals FCC Rules The Personal Pocket Pag er is designed to comply with part 15 of the FCC rules and regulations It can be builf without having to obtain spe cial permission from the Federal Com R4 2000 ohm R5 4700 ohm R6 470 000 ohm R7 R8 R22 100 000 ohm RY 6200 ohm R1IO 56 000 ohm R12 47 000 ohm R13 33 000 ohm R14 20 megohms R15 6800 ohm RI6 1300 ohm R17 1 5 000 ohm Ri8 10 000 ohm 20 turn trimmer potentiometer R 9 20 000 ohm R20 1000 ohm CAPACITORS Cl S pF ceramic disc C2 C5 0 002 qF ceramic disc C4 24 pF ceramic disc ORDERING INFORMATION resistors Capacitors one DIP socket 26 95 Antenna switch and enclosure not included RECIEVER COMPONENTS TS3310 transtormer T1 7 95 TS2 printed circuit board
48. M C Accepted E amp O Video 9691 E 265th Street Elko MN 55020 1 800 638 6898 SALTON City California Large residential lots En joyable living jee Fishing Hiking Use or in vesvhold for future 40 down 40 monthly OE Box 35291 Los Angeles 90035 BANDSTOP FILTERS Remove Tang sig 6 1 WANTED VETREX Star Castle Game Cartridge DANIEL WALKER 1629 5 West 208th Street Torrance CA nals on Cable T V Channels 2 3 4 14 15 18 19 20 21 and 22 20 each Money back uarantee dB ELECTRONICS P O Box 8644 embroke Pines FL 33084 90501 CLASSIFIED AD ORDER FORM To run your own classified ad put one word on each of the lines below and send this form along with your check to Popular Electronics Classified Ads 500 B Bi County Boulevard Farmingdale N Y 11735 PLEASE INDICATE in which category of classified advertising you wish your ad to appear For special headings there is a surcharge of 11 00 Plans Kits Business Opportunities For Sale Education Instruction Wanted Satellite Television Special Category 11 00 PLEASE PRINT EACH WORD SEPARATELY IN BLOCK LETTERS No refunds or credits for typesetting errors can be made unless you clearly print or type your copy Rates indicated are for standard style classified ads only See below for additional charges for special ads Minimum 15 words 1 2 3 4 5 T en 7 g 9 o at AB 15 23 25 16 24 80 17 26 35 18 27 90 19 29 45
49. NAND Of NOT AND function is simply the inverted product of the input variables An example is shown in Fig 10 The output expression is written just as it would be for an AND gate but with a nor indication given to the entire expression That can be done by putting a bar over the entire expression as shown in Fig 10 Alter nately the ANoed input terms can be put into parentheses and an asterisk or z r gt p i aD ABC Fig 10 In a NAND expression the result of all ANDing ts simply inverted OQ wip apostrophe used to indicate the not of the function Note that the B term has a NOT bar over it The nor Function To produce the NOR function we simply invert a basic oR Output Figure 11 shows a four input NoR gate The output expression is formed by simply writing the input vari ables separated by plus signs Then a bar is placed over the entire expres sion to invert it Again note that one term DZ is inverted at the input 1EX AJ 8K C5 02 Fig 11 Multiple input NANDs do not need to have their variables separated by parentheses for clarity Now using those basic Boolean ex pressions for each of the logic gates more complex circuits can be easily represented Deriving Boolean Expressions Knowing the basic rules outlined in the previous section you can now derive a complete Boolean expression for any larger more complex logic circuit The process is simply to work your way through t
50. ON ALL KITS AND PRODUCTS fee ally POSTAGE PAID SEND CHECK MO VISA MC IN INFORMATION UNLIMITED FREE New Catalog of Hard To Find Precision Tools Jensen s new Catalog is jam packed with more than 2 000 quality items Your Single source for hard to find precision tools used by electronic technicians scientists engineers schools instrument mechanics laboratories and government agen cies This popular catalog also con tains Jensen s world famous line of more than 40 tool kits Call or write for your free copy today JENSEN TOOLS INC CIRCLE 18 ON FREE INFORMATION CARD 7815 5 46th Street Phoenix AZ 85044 E 602 968 6231 6861 AHYNNYT b HANDS ON ELECTRONICS POPULAR ELECTRONICS ANTIQUE RADIO Continued from page 83 entire June and July 1988 columns had been devoted to it and still hadn t gotten to the Crosley material Al though they were interesting columns indeed felt that should introduce more new material before discussing the remainder of the letters from the readers The Zenith restoration just being concluded was begun in August A SP1 Special Projects 1 Winter 1980 SP4 Special Projects 4 Summer 1982 SP5 Special Projects 5 Winter 1983 SP6 Special Projects 6 Spring 1983 SP7 Special Projects 7 Summer 1983 SP8 Special Projects 8 Fall 1983 SP9 Special Projects 9 Winter 1984 SP10 Special Projects 10 Spring 1984 111 Hand
51. Ohms Measures E 1 Resistance IT Current Capacitors with Freq Counter a ta Transistors and and deluxe case eed Diodes with case SOMMz Logic Probe Current Adapter os im y T 265 5 l 23 ve pns 15 22 casa pins 25 Cy Ss aaa 8 MO 1251 6 CAT Built in its all a with componeni tester BNC connector TL 3 BNC to Minigrabber 3 49 True RMS 4 Multimeter with 9 Funcions Me and Data hold v basic acc 3 digt LED Zero control with case 010004 AC M 3500 4500 Works with 3v digni 125 sv agit 175 mosi DMM 1 accy 05 acc went Wide Band Signal Generators 6 9000 119 re AF Freq 100K450MHz g T 45 AM Modulation of 1KHz Siig ee Variable AF output Convenient one hand pparation Measures DCY ACV Audible Continuity Shack cn hold GF 8016 Function Generator with Freq Counter 239 Sine Square Triangle Pulse Ramp 2 to 2MHz Freq Counter 1 10MHz 3 Digit Probe Type OMM i ce G 9500 with Digital Dis and 150MHz built in Fea Ch 240 GF 8015 wtthout Freq Meter 179 XP 765 Four Function Frequency Counters Sao F 1000 1 2GH with batteries and case 0 20V at 14 O 20V at 1A SV at 5A Fully Regulated Short circuit protected with 2 Limit Cont 3 Separate supplies XP 660 with Analog Meters 175 NEW ava F Period Totatize 179 V at SA requency Qo short circuit protected oe Seif Check with we Stabilized Crystal
52. SCR is cutoff at the gate But when the light level striking the LDR drops the SCR conducts and the circuit is com pleted We recommend that since the SCR is going to be controlling a lamp it would be a good idea to use a relay to operate the lamp rather than at tempt to operate it directly from the SCR Potentiometer M sets the sen sitivity of the Circuit Anyway hope this submission rates a copy of the Fips book Thanks Mark Salchow Brooklyn NY Great idea Mark Hope you like the book too Every Home a Disco Sure music is nice but by the addition of the simple Circuit shown in Fig 7 you can add a great deal of interest In these days of TV people want something to look at as well as listen to The light modulator can be single channel two channel for treble and bass or three channel if you prefer It will take your audio out put and modulate it so that the lights seem to dance in time with the music You can use any combination of col ored lights as well to make things even more interesting Line voltage lamps of about 40 to 100 watts do nicely And there s no rea son why you cant use lower voltage lamps if you prefer The required au dio driving power isnt large and you can get it from a tape or record player or an FM radio You simply attach the speaker output through a 1 1 audio transformer SINGERS REMOVE VOCALS You get the current for the lamp from a
53. Simpic Cuwrcuite lar the Aranes Bend Computer Roriets Control of vtC 98 00C Mere Rovete amp deers Beawen rm BP 144 FURTHEA C BP179 ELEC PRACTICAL ELECTRONICS CALCULATIONS AND FORMULAE 9 00 Companion voiume to BPS3 Book carners on with new dala not found m earher edition 450 pages BP125 25 SIMPLE AMATEUR BAND AN TENNAS 5 50 All kinds of antennas for ali tunds of amaleur ado reception BP117 PRACTICAL ELECTRONIC BUILD ING BLOCKS Book 1 5 75 Build the blocks and Ihen combine them lo form almost any custom project of your SYSTEMS AND CIR CUITS 5 95 Guide to the elements of mucro Neigh systems all Teaches all the tunda mentals _ _ _ iato the OL Arc Rive f i BP97 IC PROJ 5 50 Weitten es pecially for the hess expenenced experi menier Complete parts layouts and winng di agrams BP161 INTO THE QL ARCHIVE 4 95 Presents the powertul dalabase bor the Sinclar QL Step by step ap proach inciudes examples ECTS FOR BEGINNERS tactical _ TRONIC CIACUITS FOR THE COMPUTER CON TROL OF ROBOTS 7 50 Dala and orcults for intectacing the com puter to the robot s molos and sensors C BP134 EASY ADO ON PROJECTS FOR COMMODORE 64 VIC 20 BBC MICRO amp ACORN ELECTRON 6 95 Picture digitizer bgh pen modei contro let and more a m BP118 PRACTICAL ELECTRON
54. UJ Basic Electronics Name Address City State Zip Accredited by the National Home Study Cowra 18 019 6861 AYVNNVES KO CHEMICAL SOLUTIONS FREE CHEMTRONICS CATALOG Comprehensive new source for over 200 products used in electronic man ufacturing and field service Precision cleaning agents flux removers bulk solvents circuit refrigerants precision dusters non residual wipers foam swabs premoistened pads swabs antistatic compounds conformal coat ings lubricants adhesives desolder ing braids rosin core solder and solder masking agents Complete with tech nical specifications and application Hauppauge N Y 11788 guide 516 582 3322 Chemtronics inc 681 Old Willets Path bet Oe 15 A i ERA nagad Qe kee Oh pull veh PROC HANDS ON ELECTRONICS POPULAR ELECTRONICS N N CIRCLE 6 ON FREE INFORMATION CARD ee ee oe New Products Continued from page 18 such as triggering and Sensitivity levels The scope features smooth menu driven op eration automatic one button front panel setups and the ability to store and recall as many as 20 setups SmartCursors track changes in the voltage trigger and ground level of the displayed waveform shorten ing the setup time for single shot triggering and peak voltage DC and other measure ments The 2247A portable oscilloscope with a 3 year warranty on labor and parts in cluding CRT has a suggest
55. a LOW PASS FILTER GAIN 10 0 22 ji AUDID DUTPUT kHz center frequency Resistor R18 sets the gain of the bandpass filter stage Integrated circuit U2 is a National LM565 phase locked loop that ae modulates the 67 kHz frequency mod ulated FM signal from U1 The LMS65 PLL consists of a voltage controlled os cillator VCO set to 67 kHz and a comparator that compares the in coming frequency modulated 6 7 kHz signal at pin 2 with the VCO signal fed into pin 5 The output of the Comparator repre sents the phase difference between the incoming signal and the VCO sig nal and is therefore the audio modu lated by the subcarrier Treble de emphasis of 150 ps is provided by a 033 pF Capacitor at pin 7 The free running VCO frequency is determined by the 001 F capacitor at pin 9 and the resistance between the positive rail and pin 8 100 ohms in series with R19 Variable resistor R19 adjusts the oscillator frequency also known as the center frequency so that the incoming signal is within the lock range of the PLL To minimize noise in the Gemodu lated output it is important to reduce the lock range of the PLL to a minimum That is achieved by shorting pins 6 and 7 together To a lesser extent the lock range and therefore the noise out put becomes smaller for lower input 6861 AHYNNYf Ww on HANDS ON ELECTRONICS POPULAR ELECTRONICS i a signals so we keep the input signal as low as possibl
56. a massive scale will finally arrive We wonder will happen to the Post Office in thatevent What shape that era might take remains to be seen but judging from the Toshiba 3300 the technology is already at hand d Swisstel Retell The following is a response to GIZMO s report on the Swisstel Telephone October 1988 from Pe ter Buckles president of Swisstel Inc 300 1 c Route 17 Lodi NJ 07644 The test report on the Swisstel Tele phone which appeared in GIZMO bears only a passing resemblance to the actual Swisstel telephone which since its market Introduction in May 1987 has been well received by many satisfied consumers Instead of enumerating the often er roneous statements in the article we want to outline the overall technological qualities of the instrument Though it is a corded telephone it has virtually no inte rior wires instead it has Surface Mounted Design SMD circuitry pro duced by state of the art robotic produc tion technology While countless tele phones contain a jungle of interior wires Swisstel s interior is as clean sleek and well designed as the telephone itself In deed its SMD circuitry permits Swisstel to market a telephone that is a mere halft inch thick and weighs only 3 5 ounces Though we are proud of Swisstel s sin gular design features we are even prouder of its quality a direct result of its robotic production technology That technology has eliminate
57. and 151 73 MHz Questions to be dealt with relate to the amount of interference that might be expected to BRS and other service licensees should those new channels be created The Taxicab Radio Ser vice in particular may be on the re ceiving end of signals that will be flying around from transmitters established on such newly created frequencies The FCC may also open up a nation wide Automated Maritime Telecom munication System AMTS service in the 216 to 220 MHz band AMTS has been in use by Mississippi River System tugs and barges since 1981 providing automated voice and data communi cations similar to a cellular phone sys tem The FCC had originally been concemed that AMTS might cause in terference to Channel 13 TV reception however there haven t been any com plaints along those lines If approved on a nationwide basis licensing of individual coastal trans mitters in the service areas of Channel 13 TV stations would probably be sub ject to anti interference precautions and restrictions Just for the record in case you want to get set for scanning those stations there are 80 channels Scanner Scene By Marc Saxon Coast station channels start at 216 0125 MHz and progress upwards in frequency in steps of 25 kHz to 217 9875 MHz The paired ship chan nels run from 218 0125 through 219 9875 MHz Individual coastal sta tions each operate on 20 consecutive channels from the overall allocation with the cha
58. and future plans are now unclear 1 CIRCLE 9 ON FREE INFORMATION CARD EARN YOUR THROUGH HOME STUDY Our New and Highly Effective Advanced Place ment Program for axperienced Electronic Tech nicians grants credit for previous Schooling and Professional Experience and can greatly re duce the time required to complete Program and reach graduation No residence schooling re quired for qualified Electronic Technicians Through this Special Program you can pull all of the loose ends of your electronics background together and earn your B S E E Degree Up grade your status and pay to the Engineering Level Advance Rapidly Many finish in 12 months or less Students and graduates in al 50 States and throughout the World Established Over 40 Years Write for free Descriptive Lit erature COOK S INSTITUTE OF ELECTRONICS ENGINEERING coo E 4261 CYPRESS DRIVE E JACKSON MISSISSIPPI 39212 IF YOU HAVEN T SEEN THE FREE MARK V ELECTRONICS CATALOG HURRY UP YOU LL FIND EVERYTHING SUITABLE AND ESSENTIAL FOR FACTORIES SCHOOLS PROFESSIONALS AND ENTHUSIASTIC AMATEURS OVERA 60 S OF ASSEMBLES AND KITS WITH DIFFERENT LEVEL OF DIFFICULTY FOR KIT ASSEMBLY BEGINNERS 6WX2 STEREO MINI AMP LIGHT CONT ROLLER BATTERY FLUORESCENT LIGHT DRIVER AND MORE INTERMEDIATE D P M_O 50V 3A POWER SUPPLY 1204 MOSFET POWER AMP AND MORE PROFESSIONALS 1 2GHZ FREQ COUNTER 300W HO AMP 4680W 4 CHANNEL PRO COLOR LIGHT CONTROLLER AND MORE ANYWAY TH
59. away and send my complete membership kit O Check enclosed for 36 Gnade out to AHSA Billmv O VISA O MasterCard ard PS Exp Date wuuthorized Signatur y AON EEE 30 dav Money Back Guarantee Return completed coupon to Lz American Home Satellite Association Ine Suite 800 500 108th Ave NE Bellevue WA 98004 5560 American Home Or call Toll Free Satellite Association 1 800 321 AHSA 2472 QRB BY ANTHONY CHARLTON shot an arrow in the air it fell to earth know not where When Long fellow penned those words in the 1800 s he must have been thinking about my model rocketry career The bane of a model rocket hobbyist is losing a carefully Constructed and painstakingly finished model in shrub bery or trees But those days are over Our Rocket Strobe sends out a highly visible S O S for up to 2 hours providing ample time to locate and recover the model It also makes dramatic night launches a reality with the blue white flash of the Strobe visible throughout the flight sequence Seeing the Light Invented in 1932 by Dr Harold E Edgerton a Xenon flash lamp is the light producing device for our Strobe Flash lamps produce a short duration high intensity pulse of light by converting energy stored in a capacitor to visible light Each flash of the Strobe lasts about 500 microse conds For that brief instant the flash is as bright as a 4000 watt lamp It s the high intensity of th
60. choices Diploma awarded CIEE 13 Box 20345 Jackson MS 39209 CAN YOU SOLDER PROPERLY Find out Free information Soldering P O Box 6244 Abil enne TX 79608 MAGIC Four illustrated lessons plus inside in formation shows you how We provide almost 50 tricks including equipment for four professional effects You get a binder to keep the materials in and a One year membership in the International Performing Magicians with a plastic mem bership card that has your name gold embos sed You get a one year Subscription to our quarterly newsletter IT s MAGIC Order now 29 95 for each course plus 3 50 postage and handling New York residents add applicable State and local sales tax THE MAGIC COURSE 500 B BiCounty Boulevard Farmingdale NY 11735 CABLE TV BOXES Descramblers Converters FREE CATALOG TRANS WORLD CABLE CO 12062 Southwest 117th Ct Suite 126 Miami Florida 33186 800 442 9333 GET OUT OF THE DARK Open your eyes and see just how many subjects are covered in the new edition of the Consumer Information Catalog It s free just for the asking and so are nearly half of the 200 federal publications described inside Book lets on subjects like financial and career planning eating right exercis ing and staying healthy housing and child care federal benefit programs Just about everything you would need to know Write today We ll send you the latest edition of the Consumer Informa
61. controls For improved perform ance it offers Ultra Bias tape head In staloc automatic program control tuner and Dolby B noise reduction Circuitry The Catalog DON T LET THIS HAPPEN TO YOU I Was A Wreck Until I Started Ordering My Parts From The MCM Electronics unit which produces 10 watts per channel into four ohms also has a loudness con trol pre amp Outputs auto reverse and a power antenna lead The SJS 7000 fea tures Flex Fader that allows the fader to be used even with outboard amplifiers Model SJS 8000 a 3 hole universal mount unit ailows the radio to be heard while a tape is rewinding or advancing It has tape search Ultra Bias tape head Flex Fader and a CD input The unit pro duces 30 watts per channel of output into four ohms It also features scan tuning Dolby B noise reduction circuitry auto reverse 24 station presets and Separate bass and treble controls The top of the line Model SJS 9000 is designed for theft prevention The user can easily pull it out of the dashboard when leaving the car In addition it offers all the features of the SUS 8000 including 30 watts per channel of output into four ohms Models SJS 7000 SJS 8000 and SJS 9000 carry Suggested retail prices of 239 95 269 95 and 320 95 respec tively For more information contact Inter national Jensen 4136 North United Park way Schiller Park IL 60176 Tel 800 323
62. do with them lt q BP59 2ND BOOK OF CMOS IC PROJECTS 5 50 Still more ways to use these versatile devices None of these projects over lap those in book 224 The pair make a wonderful circuit reference set 8P84 DIGITAL IC gt PROJECTS 5 50 Both simple and more ad vanced projects to help the reader develop a knowl edge of the workings of digi tal circuits A number of board layouts are included MAIL TO Electronic Technology Today Inc PO Box 240 Massapequa Park NY 11762 0240 SHIPPING CHARGES IN USA AND CANADA 0 01 to 5 00 1 25 30 01 to 40 00 5 00 5 01 to 10 00 2 00 40 01 to 50 00 6 00 10 01 to 20 00 3 00 50 01 and above 7 50 20 01 to 30 00 4 00 SORRY No orders accepted outside of USA and Canada i oeo Total price of merchandise l Shipping see chart Subtotal l Sales Tax NYS only Total Enclosed Address City _ _ State __ Zip oo a a an on a a a a G Name m J 686L AHYNNYT o HANDS ON ELECTRONICS POPULAR ELECTRONICS fa APES SE GLASNOST AND DX ING X ers here often tune in Radio Moscow or other Soviet short wave broadcasters like Radio Kiev or Radio Yerevan But what about the re verse Can SWL s in the Soviet Union listen to broadcasts from the west Yes indeed according to a Soviet listener writin
63. for easy mero Pag ay Voltage 4 5 V oscillator settin Standby Mode Supply a Dew ohanged te allows simple testing for the time Voltage 2 V rollover DC input or Output Voltage 0 V w independent interrupting timer with open drain Output Operating Temperature w Fully TTL compatible Range 40 C am m a ries Sum Active Oscillator Frequency Output Voltage re 0 150 pA Sink V 1 Source V SS ea a input Guren a 0 AVV 6V Aor ove day mA ra pmm vS k a a aai ev O ee N a Logic 1 pas A a A mati es sy wine od During akan E Er TE the next FEE 4 12 months Radio Electronics VOLTAGE REGULATOR will carry up to the minute articles on hobby computers solid state technology e TV games Video color TV stereo test equipment radio e radar detectors industrial electronics servicing TV radio stereo experimenter circuits exceptional construction projects 4 5v TO 25V ELECTRICAL CHARACTERISTICS High Level Input Voltage Lat Le Input Current Vin Vss qi pA excep vente ae ee gasae ess e em T See Pe 2 Se Bee eee Dee Low Level Current Vi Vss pA amass ns H eaten loge ep as See we eS eS Se IS Oe TOSS See ee Be ee eee ew we hile working outdoors or in your garage often it would be help ful for those indoors to have a conve nient way to alert you if you are needed Or p
64. function called auto journal That last feature enables the 3300 to print out a record of the last 20 facsimile transmis sions During fax transmission the LCD con tinues to offer step by step guidance When a number is dialed the display shows it Once fax to fax connection is established the LCD shows on line and indicates what class of facsimile ma chine is on the other end G 3 or G 2 the 3300 is compatible with both Finally during transmission the display will indi cate success pg okay or a similar message or point out problems paper jam or send again indicating fouled up transmission A second source of information is the recording paper itself As the manual ex plains trouble codes are printed on the recording paper when operational prob lems have prevented normal communica tions If the display shows NG tor no good a two digit number will ap pear on the paper signaling such maladies as a paper jam or overheating Being new to the wonderful world of fax it took us a few false starts to get the hang of it but soon we were sending docu ments across town and across the country One problem we had was that the more slowly the transmitted document went through the fax the larger its transmitted version was That was caused by having the paper jam bar in the wrong position The Toshiba instruction manual isn t al together clear about the positioning of t
65. have 2 3 4 5 8 or 13 inputs or Gate An or gate is also a logic Circuit with two or more inputs and a single output Its output is a binary 1 if at least one of its inputs is binary 1 Other wise the output is binary 0 The logic symbols and truth table for an or gate are given in Fig 3 Note that the equal to or greater than 1 desig nation means the or function The truth table shows the output Z with the inputs W X and Y With three inputs there are ON 23 8 possible input combinations As with AND gates IC or gates typically come with 2 3 4 5 8 or 13 inputs A NAND Gate A NAND gate is the com bination of an AND gate and an inver ter It is often referred to as A NOT AND Circuit and thus its name N AND The output is binary 0 Only when all inputs are binary 1 For other input conditions the output is binary 1 ANAND Can be drawn as an anb with an inverter Nor Circuit as Fig 4A shows However the special symbol in Fig 4B is normally used The circle at the output indicates inversion An alter nate symbol is given in Fig 4C Here the triangle or half arrow on the output indicates inversion The truth table indi cates all possible inputs and the corre sponding Output states Looking back at the truth table for the AND gate you can see that a NAND Output is its com plement nano gates with 2 3 4 5 8 and 13 inputs are available in IC form NOR Gate The nor gate or NOT OR circuit
66. if on the outside of the rocket glued flat to avoid excess air drag If you run the wires inside the body make sure that they won t become tangled in the re covery system Also the ejection gases will quickly rot the insulation on wires if they are in an exposed area jacket and seal them in heatshrink tub ing or the kind of plastic tubing sold for aquarium air lines Wire size is not critical we had fine luck with 26 stranded hook up wire Make sure flash lamp polarity is ob served The end with the large round electrode is the cathode which is al ways connected to ground Some flash lamps have a trigger wire al ready attached to one end but on those that don t one wrap of bare wire around the lamp s center will do the trick Secure the wire with a tiny dab of epoxy or Crazy glue to the glass Make sure that the leads to the lamp are well insulated at the splices A con nector is handy to have in the circuit leading to the lamp That way the electronics can be quickly discon nected for testing or adjustment Even tually the lamp bums out and will have to be replaced but only after many flashes The author calculates the lamp listed in the Parts List will last COAST PHASE THRUST F PROPELLANT FOR LIFT OFF ANO ACCELERATION ROCKET IGNITION ANO LIFT OFF CUT AWAY OEPLOYMENT OF RECOVERY SYSTEM EJECTION CHARGE CLAY TOUCH OOWN ANO SAFE RECOVERY Fig 5 Here is t
67. initially you aren t alone according to R L Drake Co P O Box 112 Miamisburg OH 45342 In response to consumer demand that company has introduced a new Integrated Receiver Decoder ESRI024 an entry level satellite TV receiver In addition to a VideoCipher I decoder the system includes priority view a capability allowing the owner to pre program up to 30 channels and a lock out feature to restrict access to selected signals An infrared remote control offers simplified programming and the IRD allows recep tion of digital stereo from subscription channels The ESR1024 decoder ts de signed to make later upgrading or expansion of the system possible Price approximately 900 CIRCLE 57 ON FREE INFORMATION CARD Video Library File In the videocassette storage field the search for a better mousetrap con tinues Among the newest entries is a ten cassette capacity Video Library Case Organizer available in both VHS and Beta sizes From Certron Corp 1651 S State College Blvd Anaheim CA 92806 the unit stores cassettes in individual plastic compartments for extra protection from image degrading dust and dirt Each compartment has a separate cover that when opened provides a lever action response fOr easy fingertip access to each cassette Price 19 99 CIRCLE 48 ON FREE INFORMATION CARD Personal Facsimile The manufacturer is calling it the industry s lowest priced fully featured personal facsimi
68. mn AN ELECTRONIC ROSETTA STONE or many hundreds of years the language of ancient Egypt had been a riddle to scholars But in 1799 a French officer discovered a stone carved with a decree of Ptolemy V the king of Egypt from 203 to 181 B c The decree was carved in three lan guages ancient hieroglyphics De motic the popular language of Egypt at that time and Greek A schol ar was able to translate the Demotic from the Greek which then permitted translation from Demotic to hiero glyphics The door to ancient Egypt was literally thrown wide and scholars could now read the literature of an cient Egypt Now what has all that got to do with computers Simple At last count there were more than 1500 word processing programs for personal Computers Of them all about two dozen are biggies and of the biggies virtually none are interchangeable That means that if you started out in personal Computing back in the pioneer days you might be using WoraStar 20 of the word pro cessing programs sold are WordStar but your office might be using Multimate your college probably uses WordPerfect your child s high school might use PFS Write or IBM Writing As sistant and your lab partner might be using Volkswriter A Tall Tower Basically what we have is a word processing Tower of Babel because the most popular most fre quently used word processing pro grams cant read the text files of the other programs For exam
69. necessary connections from the Adapter to your tuner the set up procedure is relatively simple First make sure that R18 is set so that its wiper is tumed toward the LM565 That will provide maximum signal Now ad just R19 so that there is an audio signal Find the extreme settings of R19 where the audio signal drops out then set R19 between the two extremes Resistor R18 is used to minimize noise from the audio signal when the FM signal level is poor Adjust the trimmer until the sound becomes distorted and then back off the adjustment until the distortion is no longer audible If you have a strong FM signal adjustment ot R18 will have no effect on the noise level and so it should be left at its max imum resistance setting B LT a a aa E a G4 Sa FactCard MM58250 infrared Transmitter INFRARED TRANSMITTER 4 x 8 SINGLE CONTACT 5 KEYPAO CERAMIC 7 RESONATOR Here are your free FactCards Introducing Popular Elec tronics FactCaras Each issue Popular Electronics will present 3 new FactCards each deal ing with one of a variety of electronics topics Some will deal with electronics basics some will deal with discrete components some will deal with IC s and some will deal with circuits and applications All will contain the type of information electronics hob byists need but sometimes must search to find With FactCards you can find that information in a hurry XC 880 8 R02 XC 880 8
70. not to say that the complexities of MS DOS are neglected However by the time the reader reaches the advanced ses sions covering such topics as DOS VO redirection Customizing the system and using advanced system commands fe will have enough background knowledge of the basics DOS commands Edlin file manage ment batch processing and backup to grasp the concepts presented That step by step learning process is designed to build the user s confidence with each concept that is mastered Each session concisely explains a fundamental concept and gives examples illustrations and hands on exercises as well There is also a chapter Summary and a glossary of any new terms that have been pre sented Finally the book offers a compre hensive command reference section with definitions of functions accompanied by specific examples Using MS DOS is available for 22 95 from Osborne McGraw Hill 2600 Tenth Street Berkeley CA 94710 CIRCLE 96 ON FREE INFORMATION CARD THE COMPLETE COMMUNICATIONS HANDBOOK by John C Sans Jr Telecommunications is the fastest growing area of personal computing today It gives the user access to world wide information at his fingertips in his home It all but re moves the information float the time it takes for information to travel from source to end user stock market quotes for ex ample can be obtained immediately via tele communications This guide t
71. occur every 2 seconds and cause U2 pin 13 to go high for one second which prevents additional input signals from entering U1 That causes the count latched in Ut s intemal Counters to be transferred to the display integrated circuit U2 pin 13 then goes low for one second allowing a new count to be entered Into the seven decade counters of U That cycle is repeated continuously updating the display every two seconds When U2 pin 11 is taken to the positive supply rail 5V the store and reset pulses occur at 0 2 second intervals resulting in a 0 1 second cou nt period Ten input pulses must be counted in order fora to appear on the first digit D1 so the frequency being measured is Obviously ten times larger than the frequency that is shown on the display In that mode the decimal points are driven by M and visually indicate that the 0 1 second count period is being used Display The display must have at least seven 7 segment common cath cde multiplexed LED digits Any com mon cathode seven segment display may be used so no particular display is specified If the disolay Chosen has more than seven digits the extras are not used For example the display used in the author s prototype which was salvaged from an old calulator has nine digits only seven of which are used in this project Dont be pui off by the term mult plexed Multiplexed simply means that ail like segments of all dig
72. of Soviet Socialist Republics UTC GMT Universal Time Code Greenwich Mean Time VOG Voice of Greece Greece VOG offers some of the best ethnic music on shortwave to my way of thinking Tune it in at 0200 UTC You can t miss it with its haunting and me lodic interval signal Programming in Greek follows Iisrael 12 077 kHz Here is where you can find KOL Israel broadcasting from Jerusalem with world music and pops beginning at 2130 UTC Mexico 17 765 kHz The govern ment operated shortwave station Radio Mexico International RMI has been reported on this frequency with Spanish language programming in cluding Mexican music and identifi cations at around 0415 UTC New Guinea 4 890 kHz The Na tional Broadcasting Commission of Papua New Guinea s shortwave out let at Port Moresby has been logged on this frequency at 1000 UTC first with an English newscast then the news read in the native language Peru 4 9966 kHz Tuning this 60 meter band frequency during the ear ly morning hours around 1000 UTC may tum up Radio San Miguel RSM transmitting from the ancient Incan City of Cusco in Peru Radio San Miguel has been heard in the U S with Spanish programming and rustic sounding An dean music called huaynos Poland 7 270 kHz Radio Polonia Poland s shortwave service last May canceled its English programs di rected to North America at 0200 and 0300 UTC That remains the situation as of this writing
73. other applica tion where a fixed frequency tone sig nal is required An unusual function of that tone en coding generator is that both an audi ble tone and a signal are generated at the same time The circuits opera tion is simple A single op amp one fourth of an LM324 quad op amp is configured as a standard inverting amplifier At power up a positive voltage is applied to the non inverting input of Ul via R3 forcing its output high That high travels along three paths The first path is the tone output Along the sec ond path by way of R5 that high is used as the drive signal for BZ1 In the third path the high output of U1 is fed back via R4 to the inverting input of U That forces the output of U1 to go low And that low when fed back to the inverting input of U1 causes the op amp output to again go high and the cycle repeats itself As configured U1 provides a voltage gain of 4 7 gain R4 M Circuit Circus By Charles D Rakes Fig 1 This self oscillating circuit uses a three terminal piezo transducer as the frequency determining component There are a number of orphan piezo transducers available on the sur plus market Several three terminal piezo transducer elements were tried in the circuit and all performed well The transducer specified in the Parts List comes with three short colored co ded red blue and black lead wires as indicated in Fig 1 With the aid of the piezo tran
74. sent me illustrating his incredible re creation of that little set And I m also including matching photos of my own real Crosley 50 so that you can see just how faithful to the original this model is Every major component in the repro duction with the exception of the vacuum tube was built from scratch That includes the book type tuning condenser with its hardwood leaves the mica and bakelite bypass con densers the grid leak the tube socket made of PVC pipe sprayed black the spiderweb coils and even the filament contro rheostat Dan likes building replicas because he feels that they have a clean neat look that no 60 year old set could ever attain And when you realize that he retired after twenty one years as an electronic technician for Argonne Na tional Laboratories the well known atomic research facility you ll under stand that he has plenty of skills to sup port his hobby I ve run pictures of Dan s sets in the column before In fact he was one of the first readers to respond to the col umn when first began writing it a few years ago And hope I ll have the opportunity to show you more of his meticulous recreations in the future So Long If you are one of the several people who wrote in response to the two Crosley articles stay tuned for next month s column I ll probably be quot ing you then In fhe meantime keep those cards and letters coming Your comments and ideas are alw
75. stores the energy to light the flash lamp has to polarize if it has been sifting idle for long while Leakage within the capacitor is max imum when voltage is first applied and it has to charge and discharge several times before leakage subsides and absorbs less power If that prob lem exists run the Strobe from another 9 volt battery before launch and wait until the flash rate goes up Then you may install your flight battery and let er rip If you can get accurate specifica tions select C7 for low leakage Most miniature recent style capacitors work fine In our prototype Strobe we left out an on off switch opting instead to simply install the 9 volt battery when launching You may install a switch or leave it out as desired Finally remember to observe sensi ble practices when flying your rocket If it gets caught in a power line or high in a tree leave it No project is worth risk ing one s life Fly in clear areas es pecially for night launches and observe wind direction launch angle expected trajectory and landing site to optimize your chances of successful recovery Happy Flying z HERE S THE ANSWER to that eternal question among electronics hobbyists What will i do In WELS THINK TANK you ll find over 53 pages jam packed with over 130 one evening projects that will keep you ab sorbed These are tantalizing devices that you can quickly put together and then use immediately
76. students from all over the United States and in over 70 foreign countries And we ve been doing it for over 50 years helping thousands of men and women get started in electronics Careers We offer flexible training to meet your needs You can start at the beginner level or if you already know something about electronics you may want to start at a higher level But wherever you start you can go as far as you like You can even earn your Associate in Applied Science Degree in Electronics Let us get you started today Just call toll free 1 800 321 2155 in Ohio 1 800 362 2105 or mail in CIRCLE 7 ON FREE INFORMATION CARD Cleveland Institute of Electronics Inc 1776 East 17th Street Cleveland Ohio 44114 Please send your independent study catalog For your convenience CIE will try to have a representative contact you there is no obligation 6861 AYVNANYS Print Name Address Apt City State Zip Age Area Code Phone No Check box for G I Bill bulletin on Educational Benefits Veteran Active Duty MAIL TODAY Just call toll free 1 800 321 2155 in Ohio 1 800 362 2105 as a HANDS ON ELECTRONICS POPULAR ELECTRONICS RO Electronics Library Continued from page 8 This practical guide shows readers what to look for in Communications software and hardware It includes prices special fea tures and the names and addresses of manufacturers of each product It also gives all the necessary information for acces
77. that there has to be a better way Well now there is a better way Grapher Bas HANDS ON ELECTRONICS POPULAR ELECTRONICS Lea ho LISTING 1 GRAPHER BAS 1000 GRAPHER BAS PROGRAM FOR THE PC 1010 1020 CLEAR SCREEN 0 0 0 0 1030 WIDTH 80 CLS KEY OFF 1040 PI 3 14159265 1050 1060 PRINT 1070 PRINT 1080 PRINT 1090 PRINT 1100 PRINT 1110 PRINT 1120 PRINT 1130 COLOR 11 1140 PRINT 1150 PRINT 1160 PRINT 1170 PRINT 1180 PRINT 1190 PRINT 1200 PRINT 1210 PRINT graphs of the computer Before this program is run print values in Lines 7000 7160 COLOR 10 0 0 Ukkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkk A GRAPHER BAS c 1988 by James E Tarchinski x Vkkikkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk This program is a plotting utility that allows users to plot mathematical functions you may do so by using the SHIFT Prt C function If you wish to print out these however you must modify the You must also define the 1220 PRINT two functions that you wish to plot which may be entered as 1230 PRINT 1240 PRINT 1250 PRINT 1270 PRINT 1280 LOCATE 23 1 1290 COLOR 7 PRINT p starting at Lines 8000 and 9000 If you have not yet made these modifications press the 1260 PRINT E key to exit the program Press any key E to break 1300 INS INKEYS
78. that the delicate flash lamp needs breakage protection A rigid clear piece of plastic tubing placed FL1 ANODE R8 ONE TURN 1 MEG AROUND CENTER a T2 4kV TRIGGER TRANSFORMER 4 TRIGGER an 2 SEE TEXT PRI if fo SEC C6 Fe k 047 i a CATHODE SCR1 k TI10601 Fig 4 The triggering circuit uses a small voltage transformer that is grounded via a SCR which when triggered induces the high voltage pulse that ignites the flash lamp 6861 AHYNNYT G ani HANDS ON ELECTRONICS POPULAR ELECTRONICS w N PARTS LIST FOR ROCKET STROBE SEMICONDUCTORS QI IRF Z20 hex FET Digi Key IRF Z20 ND DI 1N4148 or equivalent general purpose diode D2 1N4007 1 A 1000 PIV general purpose rectifier diode UI CD4584 hex Schmitt trigger integrated circuit SCRI TII06D1 C106D1 ECG5S457 or equivalent 400 volt 4 amp sensitive gate silicon controlled rectifier RESISTORS All fixed resistors are s watt 5 units unless otherwise noted RI 6800 ohm R2 10 000 ohm R3 820 ohm R4 1000 ohm trimmer potentiometer R5 1000 ohm R6 4 7 megohm R7 3 3 megohm R amp 1 megohm CAPACITORS CiI 0 022 F 10 stable temperature coefficient Digi Key P1016 or equivalent C2 2200 pF 2 stable temperature coefficient Digi Key P3222 or equivalent C3 330 pF ceramic disc Digi Key P4106 or equivalent C4 330 to 680 pF 16 WVDC miniature electolytic C5
79. that the higher the location of the antenna the better the results In a horizontal posi tion however it becomes highly direc tional useful in receiving weak signals in some cases namely those in which the signal location of the desired station is known or more limiting still when the weaker signal isn t broadcast from a tower or structure shared with more powerful stations Horizontal use didn t have much effect when the LS 4 was used with our older receiver But connected to the Onkyo TX 850 the same positioning did bring in stations otherwise unavailable Assisted by the amp s computer controlled auto matic precision reception system weak signals were at least clean and unwavering if slightly less robust than easily received Stations It was useful to reposition the horizontal LS 4 occasionally while listen ing although in at least one case the station eventually disappeared under the assault of a bigger adjacent noise That was our experience What Parsec says makes it all possible is a noise figure less than 1 5 dB adjacent band rejection of better than 26 dB intermodulation of less than 0 08 percent at 100 mV and an amplification gain of 32 dB mini mum Our ears tell us that the Parsec LS 4 is no panacea when it comes to un satisfactory FM reception but that it does work better and looks a lot more attrac tive than a dipole antenna fastened to the wall Looking and
80. the parachute and shock absorb ing rubber cord leading to the rocket s body Strong assembly techniques are 300V FROM PWM POWER SUPPLY needed for the nose cone electronics package The nose cone must with stand considerable force at the apex of flight when the rocket engine acti vates its ejection charge There is nothing gentle about the hefty charge of black powder that pops off the nose cone and deploys the parachute Fig ure 5 shows the parts of a rocket en gine and their function Be sure to use enough silicone for good strength Weight must be minimized to allow your bird to lift off and attain maximum height Soft grades of balsa wood are the lightest and weight savings may be gained by careful assembly of the electronics on a small board using a minimum of solder All told our Strobe added 3 ounces to the rocket s weight You may also save weight by not painting the model with too many coats of finish if it s to fly a Strobe If the electronics are ahead of the model s center of gravity CG the rocket should fly fine with the added weight If for some reason you locate the electronics or battery behind the rocket s CG a counterbalancing weight must be added fo the nose to bring the CG back to its normal posi tion A rocket s CG is determined by its balance point with an unused engine installed See Fig 6 A flash lamp may be attached to the rocket s nose body or fins Be aware
81. to offer a new model from Scantech Computer Systems Inc 12981 Ramona Blvd Unit I amp H Irwindale CA 91706 3797 merits some attention The LCD 286 Portable Computer weighs just 22 pounds but includes an Intel 80286 microprocessor 20 miegabyte hard disk drive 5 a inch floppy disk drive 1 2 megabyte capacity an adjustable and tiltable 80 column by 25 row 9 inch LCD screen and one megabyte ot fast zero wait state RAM All that and 100 percent IBM PC AT compatibility too By not relying on special y manufactured accessories Scantech says the LCD 286 will never become obsolete Price 3 495 CIRCLE 44 ON FREE INFORMATION CARD Computerized Telephone Accounting System Businesses often fret about use and abuse of their telephones by employees A unique self contained Computerized Telephone Accounting System TA 100B aims to do something about reducing that worry From Camcorp 61 N Plains Industrial Rd Wallingford CN 06492 the product doesn t require the aid of a computer or PBX system When the unit is connected to a telephone or tax machine it records every call made by phone number date time of call and minutes per call The system can log up to 1 600 calls and furnish a summary of calls by phone or account number or give an itemized accounting of all calls The unit measures approximately 5 x 6 x 3 inches Power is supplied via an AC adapter In addition Camcorp offers a one
82. us know Send your loggings to the above address Now here are some of the catches recently reported by other DX ers Alaska 6 150 kHz KNL a mission ary broadcaster is the only way to hear a shortwave station from Alaska That station is reported with English programming religious talk and clas sical musical beginning at 0800 UTC Canada 6 000 kHz CFC X is the shortwave version of one of the oldest broadcasting stations in North Amer ica The SW outlet relays the medium wave signal which is why you may hear it announced as AM radio in Montreal It has been noted with a call in program at 0845 UTC Costa Rica 13 660 kHz A curious station with a very serious mission is Radio for Peace International RPI which transmits from Costa Rica in Central America It has been logged here at 2200 UTC with a talk in English on U S arms spending Greece 9 420 kHz The Voice of ABBREVIATIONS CKFX C is prefix for Canadian SW station call signs CKWX CKVP CFRB CFCX etc DX long distance over 1000 miles DX er listener to shortwave broadcasts DX ing listening to shortwave broadcasts EST Eastern Standard Time kHz kilohertz 1000 hertz or cycles per second RMI Radio Mexico International RPI Radio for Peace International RSI Radio Sweden International RSM Radio San Miguel SRI Swiss Radio International SW shortwave SWL s shortwave listener s US United States USSR Russia Union
83. valuable pic tures can be in electronics consider fora moment the schematic diagram A schematic is nothing more than a pictoral representation of an elec tronic circuit Without such diagrams we wouid be forced to describe even the simplest of networks by using pages and pages of text A watt 330 ohm resistor is connected be tween the output buffer of the 555 timer and the positive 5 volt terminal of the MAIN power supply The Graph Schematics aren t the only pictures that aid the electronic hobbyist there are also graphs Graphs are excellent for conveying the relationship between two or more variables such as how a voltage changes with respect to time in an AC network Essentially graphs transform very abstract mathematical equa tions into a visual pattern that our minds can easily process and com prehend While graphs are generally very easy to interpret and understand they are not always so easy to create Start ing with a blank sheet of paper you must first draw the two axis and divide each of them into an appropriate scale Next you plot anywhere from five to fifty or more points depending on exactly what if is that you are trying to graph Lastly you connect the points with a smooth curve and hope that the end result is worth the time it took to draw Sometimes it s worth the effort and you are pleased with the results Other times however you end up start ing the process over and thinking
84. when finished the fab ricated cover looked as if if was installed by the manufacturer The interconnecting leads from the autotransformer were too short to reach an external electrical box so they were extended using color co ded stranded wire The splices were soldered and electrically insulated with black plastic tape The rest was easy to do A 6 x 12 x in hardboard veneered on both sur faces was cut and the edges sanded smooth Any to 1 in board cut to a convenient size will do One idea is to purchase a cutting board in a house wares store should you dislike wood working The autotransformer is a one coil device wound on a cylindrical iron form with the AC line the base was floating around inside connected across the bottom of the coil and to a tap on a copper turn about 85 of the the case so affixed it with some ep distance from the first tap A Sliding contact selects one of the coils to pick off an AC OXY voltage The plastic piece hanging from the leads of the winding was discarded because it The plastic piece that housed the was damaged and the Single outlet was neither polarized nor of the three terminal type A broken off part was joined to the base with epoxy The piece which was found inside the unit contains an embedded nut used to secure the unit s shield A piece of a two pound coffee can was used to close up the hole left in the autotransformer s safety shield The can had an almo
85. will work fine for this application Use a plastic case and use a knob that completely covers the shaft and mounting hardware A good size plas tic case for Soeedi Watt should mea sure about 5 x 2 x 13 inches The author fitted a 3 terminal AC line sock et to a short length of three wire power INPUT POWER CORD PLASTIC CASE PLI CLAMP GROMMET OUTPUT POWER CORD CLAMP GROMMET Fig 4 Wiring the Speedi Watt is no problem at all once the printed circuit board is completed Connect the AC power cords to the plug and socket This is what Speedi Watt looks like when it s finished The neat all plastic construction ensures against possible shock hazard The circutt board looks like this when the potentiometer and the brass terminals are fitted The original design allowed for connecting the wire from the middle to the bottom terminal when an external power switch is used to control the circuit cord and a three pin AC plug to an other length of three wire power cord Both of those power cords had the in sulation stripped back at one end and then they were fed into opposite ends of the case and anchored with cord grip grommets speedi Watt is connected as shown in Figs 1 and 4 Note the optional two way insulation terminal block used to terminate the ground and the neutral galt SPEEDE WATT POWER CONTROLLER wires from the two power cords The terminal block should not be an chored to th
86. with the simple expression below W XY Z The various logic functions implied by the equation are pretty easy to spot The X and Y are written adjacent to one another indicating that the two signals are ANDed Simply draw an AND gate with X and Y as the input The output of that AND gate XY is then go ing to be ored with another input called Z The plus sign tells us we need an or gate to do that If only the varia ble Z is available an inverter is needed to produce Z The resulting cir cuit is shown in Fig 415 A slightly more complex example is given below X A B C D E F The parentheses tell you that you have three different groups of varia bles anped together to form the output X The variables in the groups are ored Fig 15 By drawing the logic symbols that correspond to the Boolean expressions you ll arrive at the correct circuit together You can start by creating the circuits for each group of variables The plus signs inside the parentheses indicate an or gate should be drawn To start you can draw an or gate with inputs A B and C Another expression is derived by Oring the input variables D and E Simply draw an or gate with the two variables as the inputs The variable F inside parenthesis will be anDed together with the other two ex pressions Finally to complete the cir cuit simply draw an AND gate with three inputs and connect them to the outputs of the two or gates and a source of sig
87. 0707 E CIRCLE 79 ON FREE INFORMATION CARD Since made the switch to MCM Electronics can choose from their huge assortment of over 11 000 products If have a question about a particular item can call and get the answer If need something fast can get it when need it And the best part of all is that everything I ve ordered has performed as promised with no exceptions couldn t ask for anything more And neither could you Make your switch to MCM TODAY Electronics Catalog 1 800 543 4330 In Ohio call 1 800 762 4315 In Alaska or Hawaii call 1 800 858 1849 SOURCE NO HO 22 CIRCLE 11 ON FREE INFORMATION CARD MCM ELECTRONICS 656 EF CONGRESS PARK DR CENTERVILLE OH 45459 4072 A PREMIER Company 6861 AYVNNYS NO wo HANDS ON ELECTRONICS POPULAR ELECTRONICS N Da SCR PROJECTS ack in the early days if you want ed to control a motor s speed you had a brute force rheostat with a control wheel the size of a small car s steering wheel on it It usually took an ape of a guy with two hands on the wheel to slow down or speed up the motor Then solid state came along and voltages were dropped to the point where you could actually touch a contact and not draw an arc And the steering wheel sized rheostat gave way to a small knob that you could operate with two fingers To a large extent that was due to a device called a silicon controlled rec tifi
88. 16 150 MK4332 4164 150 4164 120 4164 100 TMS4164 TMS4416 41128 150 TMS4464 15 TMS4464 12 41256 150 41256 120 41256 100 41256 80 HM5 1258 100 1 MB 120 1 MB 100 5 95 6 45 6 95 9 95 10 95 12 95 14 95 19 95 100ns CALL TO CONFIRM CURRENT PRICES S CALL FOR VOLUME QUOTES ORDER TOLL FREE amp CALL TO CONFIAM CURRENT PRICES a f KiGHTECH SPOTLIGHT SCSIHOST ADAPTOR 49 95 A LOW POWER SHORT SLOT CARD FOR PC COMPATIBLES THAT CAN CONTROL UP TO SEVEN SCSI DEVICES THIS POPULAR STANDARD OFFERS SPEED EXPANDABILITY AND THE ADVANTAGES OF USING A DEVICE INDEPENDENT BUS INCLUDES CABLES MCT SCSI 74L500O TTL LOGIC 74LS00 t6 74LS112 74LS241 74LS01 18 74L 5122 74LS242 74LS02 17 74L 123 74LS243 74LS03 18 74LSt24 74L5244 74LS04 16 74LS125 74LS245 74LS05 18 74LS126 74LS 251 74LS08 18 74LS132 74LS253 74LS09 18 74195133 74L S257 741910 16 74 8136 74LS258 74LS11 22 74LS138 74L 259 74LS12 22 74LS139 74L 5260 74L513 26 74LS145 74LS266 74LS14 39 74LS147 74LS273 74LS15 26 74LS148 74LS279 74LS20 17 74LS151 7415280 74L521 74LS153 74LS283 74LS22 74L 154 74L 290 74LS27 74LS155 74LS293 74LS28 74LS156 74LS299 74L 30 74LS157 74LS322 74L S32 74LS156 74LS323 74L 33 74LS160 74LS365 74LS 37 74LS161 74LS367 74L 38 74L 162 74LS368 74L 42 74L 163 74LS373 74LS47 74LS164 74LS374 74LS48 74L 165 74LS375 74LS51 74L5166 74LS377 74LS73 74LS169 74LS390 74LS74 74L8173 7415393 74L575 74L5174 74L 541 74LS76 74L 175 74L S624 M
89. 2 Wert Ament Agmortments w on a wo pl J0 a w oe m 1 th uD TRANSFORMERS E w Dual Secendary bagio Promary iY lt a 4 44 00 ard M VA Wort tranctecmers oar ax xm AL F i Eog 7 277D Ix mor mes PANASONIC 6 SERIES rar PANASONIC LS SERIES TILL Be 1 AMP SILICON RECTIFIERS 6 CARBON FILM RESISTORS Avainta m 14 Vee 1728 wan PANASONIC OPTOELECTROWICS tap to P t Wert Reasior Aceormrems tigt Part w tun IM Watt Arteta Ageortenenty The Key volume dacount and senaue chery ate myke to appty Most dems sold by Dey Rey nuy Le comiened for a vulume Geptuuti hena thet ata oot Ga ounlabbe gre denthed by the suth tee ier number After werting your order lolai all of the dc ounteble items end apply the epproprete dcount To thes subtotal add ihe non dacountette dems Then add the servete ICE CHARGES VOLUME DISCOUNT henge We pay all shepping end neurance fo addresses the US A Conada and Merco when chech or money order accompances order Deg Key oniy shar orders withen the continental U S Alaska ms or he OR NET Hawaa Canada and Memco Aad 00 75 9 100 00 4249 590 WHEN DROERING BY PHONE CALL 1 000 344 4539 AK coll 210 681 6674 BY MAIL SEND YOUR ORDER TO DIGIKEY P D Be O77 Thiet River Fais MM 56701 Add aaa 250 00 490 90 You may pay by chech money ode Master Charge VISA or COO DIGHMEY GUARANTEE Any perts uerit r y tht pemer GO Te deiat iye th e rele mrt oye hoak Up etl d retu
90. 5 80387 16 16 MHz 499 95 80387 20 20 MHZ 799 95 25 MHZ 999 95 intel YEAR WARRANTY WA OYNAMIC RAMS Ccpore SIZE SPEED PRICE 16384x1 200ns 89 16384x1 150ns 99 3276821 200ns 6 95 655361 150ns 2 89 655361 120ns 3 19 6553621 106ns 3 95 6553621 150ns 2 89 1638424 150ns 8 95 13107221 150ns 5 95 65536x4 150ns 10 95 65536x4 120ns 11 95 262144x1 150ns 12 45 262144x1 120ns 12 95 262144x1 100ns 13 45 262144x1 80ns 13 95 262144x1 100ns 13 95 1048576x1 120ns 34 95 1048576x1 100ns 37 95 STATIC RAMS PART Siz SPEE 2112 256x4 450ns 2114 1024x4 450ns 2114L 2 10244 200nS TC5516 204828 250ns TMM20 16 200 2048x8 200ns TMM20 16 150 2048x8 150ns TMM2016 100 2048 8 1t00ns HM6 116 4 2048x8 200ns HM6116 3 2048x8 150n5 HM61 16 2 2046x8 120ns HM6116LP 4 2048x868 200ns HM6116LP 3 2048x8 150ns HM6116LP 2 2048x868 120ns HM6264LP 15 8192x8 150ns HM6264LP 12 8192x8 120ns HM43256LP 15 32768x8 150ns HM33256LP 12 327688 1t20ns HM43256LP 10 32768x3 PART 2708 2716 2716 1 2732 2732A 27C64 2764 2764 250 2764 200 MC M68766 27128 27128 A 200 27C256 27256 27256 200 27512 27C512 27C101 20 Vpp PRICE 25V 4 95 25 349 25V 395 25V 395 21V 3 95 12 5 4 95 12 5V 3 49 12 5 3 69 12 5V 4 25 21V 15 95 12 5V 4 95 12 5 595 12 5 7 95 12 5V 5 95 12 5V 7 95 12 5V 11 95 12 5 12 95 12 5V 34 95 CALL TO CONFIAM CURRENT PRICES S 30 DAY MONEY BACK GUARANTEE TOLL FREE TECHNICAL SUPPORT PRICE PART 4116 200 41
91. 7 69 4049 59 4050 69 4051 25 4052 49 4053 25 4060 39 4066 65 69 59 69 69 69 29 4069 4070 4081 4093 14411 14433 14497 4503 4511 4518 4528 4538 4702 74LS83 74L585 74LS86 74LS90 74LS92 74LS93 74LS95 74LS10 74LS10 7400 7 9 74LS 191 74LS192 74 5193 74L 194 74L 195 74LS196 74LS197 74L 221 74LS240 74LS640 74LS9645 74L5670 74LS682 74LS 688 74LS783 25LS2521 26L 31 26LS32 3 26 2 40 22 95 2 86 1 95 1 95 7400 SERIES LOGIC 19 19 74121 29 74123 49 74125 45 74150 1 35 74151 55 74153 55 74154 1 49 74157 55 74159 1 65 74161 69 74164 85 74166 1 00 74175 89 74367 65 73F 73 74FO0 35 74F02 35 74F04 35 74F08 35 74F10 Be 74F32 35 74F64 74F74 74F86 74F138 74F 139 74F253 74F157 JOR MICROOEVICES AND THE JOR MICRODEVICES LOGD ARE REGISTERED TRADEMARKS OF JOR MICRDDEVICES IBM AT PS 2 ARE TRADEMARKS OF INTERNATIONAL BUSINESS MACHINES CIRCLE 12 ON FREE INFORMATION CARD 74F240 74800 74502 74504 74508 74810 74832 74574 74586 748112 748124 748138 748153 748157 745158 745163 743175 743195 74S 240 74S241 745244 748280 748287 745288 748299 745373 74S374 745471 745571 CRYSTALS DISCRETE SOLDER STATION WIREWRAP 32 768 KHz 95 1N751 2N4403 UL APPROVED PROTOTYPE CARDS 1 0 MHZ 2 95 IN5402 2N6045 2 95 IN4004 MPS A13 ADJUSTABLE HEAT SETTING FR 4 EPOXY GLASS LAMINATE WITH GOLD PLATED EDGE 1 95 IN4148 1 TIP31 TIP TEMPERATURE READOUT
92. 868 CIRCLE 69 ON FREE INFORMATION CARD MOVING COIL HEADPHONES Signet s EP400 is a moving coil design ste reo headphone that delivers Deak free re sponse and accurate reproduction at both ends of the spectrum A high flux Samar ium cobalt magnet and oxygen free silver copper wire are used for the voice coil wind ing Oxygen free copper is used in the 10 foot audio cord to provide maximum con ductivity and minimal signal loss and to yield extended dynamics and distortion free sound Its frequency range is from 20 Hz to 22 000 Hz The headband and earpads are com fortable even during extended periods of use The adjustable double headband sys tem combines strength and rigidity with even weight distribution Mesh covered foam ear pads mounted with a dual swivel system allow adjustments for individual head shape and provide good performance with the great est degree of comfort Strain relief pieces at the earpads and plug assure durability and trouble free operation The EP400 headphones cost 100 00 For further information contact Signet 4701 Hudson Drive Stow OH 44224 CIRCLE 70 ON FREE INFORMATION CARD WORDPREFECT LEARNING TOOL PC Template s PerfectPal version 5 0 is an updated version of their productivity tool and is designed to make WordPerfect easy to learn and use When used with WordPer fect versions 4 1 4 2 or 5 0 the system of more than 375 simple to call pre coded macros al
93. AD PLUS ALL BOLD FACE AD 2 95 per word DISPLAY ADS 1 x 2 175 00 2 x 2V4 lt 350 00 3 x 2y4 525 00 General Information Frequency rates and prepayment discounts are available ALL COPY SUBJECT TO PUBLISHERS APPROVAL ADVERTISEMENTS USING P O BOX ADDRESS WILL NOT BE ACCEPTED UNTIL ADVERTISER SUPPLIES PUBLISHER WITH PERMANENT ADDRESS AND PHONE NUMBER Copy to be in our hands on the 15th of the fourth month preceding the date of issue i e Sept issue copy must be received by May 15th When normal closing date falls on Saturday Sunday or Holiday issue closes on preceding work day Send for the classified brochure Circle Number 49 on the Free Information Card PLANS amp KITS BUILD this five digit panel meter and square wave generator including an Ohms capacitance and fre quency meter Detailed instructions 2 50 BAG NALL ELECTRONICS 179 May Fairfield CT 06430 CATALOG hobby broadcasting HAM CB Cable TV transmitters amplifiers bugging devices com puters more PANAXIS Box 130 F 1 Paradise CA 95967 PRINTED circuit boards drilled and etched Free delivery K amp F ELECTRONICS INC 33041 Groesbeck Fraser MI 48026 313 294 8720 VIDEOCIPHER Il Manuals Volume 1 hardware Volume 2 software Either 29 95 Both 49 95 NEW Volume 3 Projects software 39 95 All for 79 95 CODs 1 602 782 2316 Catalog 3 00 TELECODE Box 6426 H Yuma AZ 85366 6426 DIGITAL project
94. BLER PHONES Phone bug detectors Electronic countermeasures equipment Executive and personal protection products And much more Catalog 3 00 refundable with first order DIVER SIFIED WHOLESALE PRODUCTS P O Box 1275 HE Redondo Beach CA 90278 COMPUTERS COMMODORE Amiga chips factory fresh and guaranteed Lowest prices in the country including Impossible to obtain spare parts and diagnostics The Commodore Diagnostician 7 000 sold 6 95 plus 1 00 postage KASARA MICRO SYSTEMS INC 31 Murray Hill Drive Spring Valley NY 10977 1 800 248 2983 or 914 356 3131 Cable TV Converters Why Pay A High Monthly Fee Jerrold Products include New Jerrold Tri Mode SB 3 Hamlin Oak VN 12 M 35 B Zenith Magnavox Scientific At lanta and more Quantity discounts 60 day warranty For fast service C 0 D or ders accepted Send SASE 60 cents postage or call for info 312 658 5320 MIDWEST ELECTRONICS INC 5143 H W Diversey Chicago IL 60639 MC Visa orders accepted No Illinois orders ac cepted Mon Fri 8 A M 5 PM CST EDUCATION amp INSTRUCTION ENGINEERING software for IBM PC CompDes cir cuit design CompMath mathematics CompView waveform viewer 49 00 each 614 491 0832 BSOFT SOFTWARE 444 Colton Road Columbus OH 43207 LEARN new skills fast through our short specialized home study courses Condensed and highly effec tive Passport to success 50
95. CRIPTION ORDER BY i a 15 19 25 37 50 MALE DBxxP 59 69 69 SOLDER CUP ee FEMALE OBxxS 69 75 75 RIGHT ANGLE MALE OBxxPR 69 79 2 DATARASE PC SOLDER FEMALE DBxxSR 35 75 85 2 UMREW AAP MALE DBxxPWW 2 56 3 89 5 60 A NO BREWER A NO DRAWEI FEMALE DBxxSWW 4 27 6 84 9 95 METAL SHUTTER PREVENTS IDC RIBBON CABLE MALE IDBxxP 225 4 25 AE pen FEMALE IOBxxS 2 35 4 49 f LIG ROM ESCAPINC HOCDS METAL MHOODxx J 1 25 1 25 PLASTIC HOOOx 39 39 69 ORDERING INSTRUCTIONS INSERT THE NUMBER OF CONTACTS IN THE POSITION MARKED xx OF THE ORDER BY PART NUMBE LISTED EXAMPLE A 15 PIN RIGHT ANGLE MALE PC SOLDER WOULD BE DBI5PR MOUNTING HARDWARE 59 WC SOCKETS OIP CONNECTORS Wenortine LITHIUM BATTERIES DESCRIPTION ORDER BY CONTACTE BLOCKS 6 8V FOR 286 386 COMPUTERS l i 16 18 20 22 23 40 5 1 00 E MOTHERBOARC CONNECTOR SOLDERT IL SOCKETS xxs 11 12 95 18 15 201 22 30 ADHESIVE VELCRO STRIP FOR WIREWRA SOCKETS aaWW 59 69 69 99 1 09 1 39 1 49 1 691 99 EASY MOUNTING ZIF SOCKETS ZIF xx 95 4 95 5 95 95 6 959 95 LITHIUM 6 8V 11 95 TOOLED SOCKETS AUGATuxST 62 89 1 09 1 29 1 39 1 49 1692 49 TOOLED vw SOCKETS AUGATxxWW 1 30 1 80 2 101 2 40 250 2 90 3 70 5 40 COMPONENT CARRIERS ICCxx ag 99 99 99 99 1 09 1 49 DIP PLUGS IDC 1DPxx 95 49 59 129 1 49 1 49 1 59 LITHIUM 3V 3V COIN TYPE LITHIUM BATTERY 1 95 FOR ORDERING INS TRUCTIONS SEE D SUBMINIATURE CONNECTORS ABOVE 3V MHW BATTERY HOLDER 1 49 y TERMS
96. E SELECTION IS INCREOIBLE THE VALUES ARE EVEN BETTER AFTER ALL ASK FOR YOUR OWN COPY TODAY AND YOU LL HAVE MORE THAN A CATALOG MORE THAN A REFERENCE YES PLS SEND ME A COPY OF THE ALL NEW FREE MARK V CATALOG NAME ADDRESS CUTTY STATE MARK V ELECTRONICS INC 8019 E SLAUSON AVE MONTEBELLO CA 90640 FAX 213 888 1029 OFFICE HOURS PACIFIC TIME a E MON FAI 9 3010500 SAT 1000105 00 umma INFORMATION 213 888 8988 CIRCLE 14 ON FREE INFORMATION CARD 95 6864 AYVANVS HANDS ON ELECTRONICS POPULAR ELECTRONICS wo mH ROCKET STROBE Continued from page 33 does not need any heatsink Different types of mini transformers and compo nent tolerances may necessitate a small heatsink on amp if it gets foo hot to comfortably hold Sometimes due to winding differences you will need to increase C4 to 470 uF or 680 pF in order for the PWM circuit to work effi ciently A 16 volt capacitor is satisfac tory for use with a 9 volt battery Build the PWM part of the circuit first You should test it before installing the hex FET and T1 That is easily accom plished by using a small speaker with a 10 uF capacitor attached to one lead Connect the other lead to ground and the free end of the capacitor to pins 6 8 10 and 12 of U1 By adjusting R4 you will be able to hear the volume of the tone getting louder or quieter as R4 varies the pulse width Once the PWM circuit works attach the mini trans former u
97. ECTRONICS P O BOX 567 VAN NUYS CA 91408 TWX 5101010163 ALL ELECTRONIC OUTSIDE THE U S A SEND 1 50 POSTAGE FOR A CATALOG Haited Specialties Electronic Forum BBS 408 732 2814 INFO 818 904 0524 FAX 818 781 2653 merre MINIMUM ORDER 10 00 QUANTITIES LIMITED CALIF ADD SALES TAX USA 3 00 SHIPPING FOREIGN ORDERS ae INCLUDE SUFFICIENT ee SHIPPING NO C O D HSC of Santa Clara 3500 Ryder Street Santa Clara CA 95051 Call amp 800 4 HALTED Now 2 408 732 1573 CIRCLE 8 ON FREE INFORMATION CARD 10 MINIMUM ORDER QUANTITIES LIMITED CA RES ADD SALES TAX CIRCLE 5 ON FREE INFORMATION CARD USING THE MODELS 50 amp 60 by Herbert Schildt This guide to IBM s new machines in the Personal System 2 series contains all the information necessary to handle the Mod els 50 and 60 effectively The book s first section though intended primarily for beginners contains some in teresting facts about the history of those machines It goes on to discuss their ba sic components define several fundamen tal computer terms and to explain how to Start the computer and use the Reference Diskette Users of the Models 50 and 60 have a choice of operating systems and this book contains extensive sections on both the cur rent standard DOS and the powerful new OS 2 There is a brief discussion of their similaritie
98. Get training for industry s hottest new jobs as you build and program complete robotic contro systems Now you can get the skills in demand for the new jobs in industry today With NRI s new at home training in Robotics Technology you actually build a fully IBM XT compatible computer then use it to program and control working robotic systems engineered to recreate the exact operations performed by the robotic equipment found in today s industrial workplace each one Robotics comes to life as you see real world industrial control principles in action Your NRI Robotic Discovery Kits come complete with everything you need to create working moving robotic systems You get structural members motors gear drives sensors scanners potentiometers plus a special Robotics Interface that links the robots you build to your computer Together your computer and the robotic devices you construct become fully integrated the job or start a new career as a robotics and industrial control technician The powertul XT compatible computer you build becomes central control for the robotic systems you construct As an integral part of your NRI hands on training you build a fully IBM XT com patible computer from the keyboard up You assemble the power supply install the 514 floppy disk drive and attach the high resolution monitor Most important of all by performing meaningful tests and demon strations at each s
99. HANDS ON ELECTRONICS POPULAR ELECTRONICS wW amp E Z MATH ___INPuTs Continued from page 79 n C o E E 0 0 0 0 0 0 0 0 1 0 Exercise Problem Try this yourself to 0 0 1 0 0 be sure you understand the concepts 7 x presented 0 1 0 1 0 4 A logic circuit has four inputs A B C 0 0 0 0 1 1 1 1 ABCD and D Binary outputs occur when any l 0 0 0 0 three inputs are simultaneously binary 1 0 0 1 0 1 but not when all inputs are 1 Write the 0 0 0 lt 1 0 1 1 1 ABCO truth table develop the Boolean out 1 0 0 0 4 put equation F and draw the resulting 1 0 1 1 ABCD ee 1 0 1 ABC Circuit i i F ABCD ABCD ABCD ABCD A Answers to Exercise Problems A AB 6B C C DOD 4 H ABC DE FG 2 See Fig 23 3 See Fig 24 SS oe SS Ss ee 4 See Fig 25 ea io z aot Do pps S TS a a eee Las k et E EROR G EST H BAA CAY paia Sen Ead E e a in ae ka Seea S L B Fig 23 Your solution to problem 2 should Fig 25 When solving problem 4 vou should ve started with a truth table generated an look like this if not recheck vour logic equation A and drawn the final circuit B as shown VW X VX O Z Y VW X VX INPUTS OUTPUTS V W X Y INVERTER 1 INVERTER 2 GATE 3 GATE GATE 5_ ve V X VW VW X VX 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0O O 00m Oo amp OO ODO Of 0 Oe OO 30 amp oOoo0cooeccj oo ss es wwe m m O O O
100. IC BUILD ING BLOCKS Book 2 5 75 Amputiers lor all kinds lo add to Ihe cxcuts from Book 1 of tws senes BP169 HOW TO GET YOUR COMPUTER PROGRAMS AUNNING n 5 95 Have you ever wiitten your Own DO p only to hnd that ey do nat work This book shows you how to find errors ye if ee ee ee ay ee ea nn a N BP80 POPULAR ELECTRONIC CIA CUITS Book 1 5 95 More circutts for hoD byists Aucho racho lest musc househod and more BP98 POPULAR ELECTRONIC CIR CUITS Book 2 5 95 More useful cr curs None ot these proyecis duplicate those wn Book of this senes Anyone Can Buy Top Notch Audio Now You Can Build It With Heath s new build them yourself stereo components you create your own sound system Specially designed for Heath by industry leader Harman Kardon our new stereo line exceeds the standards of even the most discerning audiophile And because most of the components come in kit form you experience firsthand how electronic craftmanship results in premium hi fi performance Build the power amplifier preamplifier and stereo tuner Prewired and pretested circuit boards and minimal soldering mean each component takes only a few evenings to build And your success is guaranteed Our precise step by step manuals are industry recognized and our technical assistance team is just a phone call away CL 800B A subsidiary of Zenith Electronics Corporation To compl
101. ICROPROCESSORS 6500 8000 8200 6502 2 25 8031 3 95 6253 5 1 95 6502A 2 69 8035 1 49 8254 2 79 65028 4 25 8039 1 95 8255 1 49 65002 7 95 8052 AH 8255 5 1 59 6520 1 65 BASIC 8256 15 95 6522 2 95 8080 8259 1 95 6522A 5 95 8085 8259 5 2 29 6526 13 95 8085A 2 8272 4 39 6532 5 95 8086 8274 4 95 6545A 3 95 8088 8275 16 95 6551 2 95 8088 1 8279 2 49 6551A 6 95 8088 2 8279 5 2 95 CMOS 8155 8282 3 95 8156 8283 3 95 9155 2 8284 2 25 8741 8286 3 95 8742 8287 3 95 8748 8288 4 95 8749 8755 80286 80286 8 34 95 2 49 1 95 3 75 6 49 5 99 12 95 7 95 2 49 2 95 3 95 9 95 29 95 7 95 9 95 14 95 79 95 249 95 V 20 SERIES SPEED UP YOUR PC BY 10 TO 40 HIGH SPEED ADDRESS CALCULATION IN HARDWARE PIN COMPATIBLE WITH 8088 SUPERSET OF 8088 INSTRUCTION SET LOW POWER CMOS MHz 8 95 10 MHz 12 95 8 MHz 8 MHz 10 95 13 95 v20 v30 VOLTAGE REGULATORS 7812K 7905K 7912K 78L05 78L12 79L05 79L12 LM323K LMI338K Z 80 Z80 CPU 1 25 Z80A CPU 1 29 Z80B CPU 2 75 Z80a CTC 1 69 Z80B CTC 4 25 Z80A DART 5 95 Z80B DART 6 95 AY5 1013 AY331015 TR1602 2651 1416402 Im6403 8200 8205 3 29 8212 1 49 8216 1 49 8224 2 25 MISCELLANEOUS HANDS ON ELECTRONICS POPULAR ELECTRONICS o pi 8226 2 25 8237 3 95 8237 5 4 75 8238 4 49 8243 1 95 8250 6 95 8251 1 29 8251A 1 69 8253 1 59 Z80A DMA 5 95 ZB0A PIO 1 89 Z80B P10 4 25 Z80A SIO 0 5 95 Z2808 SIO0 12 95 Z8OA SIO 1 5 95 Z80A SIO 2 5 95 Z2808 SIO
102. IF INS lt gt THEN GOTO 1300 1310 INS INKEYS IF INS 1320 CLS 1330 1340 THEN GOTO 1310 IF INS E OR INS e THEN END 1350 kkAHKK INITIALIZE VARIABLES amp SCREEN eet ka RRR 1360 1370 SCREEN 2 CLS 1380 LINE 76 12 76 172 1390 LINE 636 172 1400 1410 FOR I 76 TO 636 STEP 56 1420 FOR I 12 TO 172 STEP 16 1430 1440 GOSUB 7000 1450 1460 IF LEN T1 gt 60 THEN T1S LEFTS T15S 60 LINE 1 170 1 174 gt LINE 74 1 78 1 get graph values enter graphics mode NEXT I NEXT I limit to 60 characters 1470 IF LEN T2S gt 60 THEN T2S LEFTS T2S 60 1480 IF LEN XS gt 60 THEN XS LEFTS XS 60 LOCATE 1 C i LOCATE 2 C gt LOCATE 24 C 1490 C 44 INT LEN T1 2 1500 C 44 INT LEN T2S 2 1510 C 44 INT LEN XS 2 1520 1530 L LEN YS 1540 FOR I 1 TOL 1550 LOCATE 1I 2 1 1560 NEXT I 1570 1580 DY YMAX YMIN 10 1590 FOR I 0 TO 10 1600 J YMIN I DY 1610 LOCATE 22 2 1 2 IF L gt 18 THEN L 18 Grapher is BASIC language pro gram for PC s that plots one or two mathematical functions on a high res olution screen There are no scales to calculate no points to plot by hand and no curves to draw All you need to do to get high quality graphs is to modify several constants in the pro gram enter the mathematical equa fions to be plotted and then run the program Grapher will do the rest Using Grapher To use Grapher load BASIC
103. LAR ELECTRONICS ELECTRONICS KET PLACE FOR SALE TRANSISTORS tubes MRF 421 24 00 MRF 454 14 50 MRF 455 MRF 477 11 75 MRF 492 16 00 SRF 2072 12 75 SRF 3800 17 50 25C2290 16 75 2SC2879 22 00 6LF6 6LQ6 6JS6 8950 etc call New RANGER AR3500 all mode 10 meter transceiver 319 Quantity dis counts Best prices on hard to find parts antennas mics power supplies amp equipment Catalog 1 00 refundable or free with order RFPC Box 700 San Marcos CA 92069 For information or same day shipment call 619 744 0728 Visa MC C 0 D CABLE TV CONVERTERS Remotes Accesso ries Tocom Zenith Oak Jerrold Scientific Atlanta FREE CATALOG ARIZONA VIDEO 3661 N Campbell 310 B Tucson AZ 85719 602 323 3330 TUBES 59 Year e Free catalog Tube tester 8 95 CORNELL 4219 University San Di ego CA 92105 CABLE TV equipment 5 A Jerrold Zenith Hamlin Oa fitters remotes and more Best prices ted Ours work where others failed and we quarantoo it THRANS WORLD CABLE CO 1 800 DESCRAMBLERS All brands Special combo Jer rold 400 and SB3 165 Complete cable de scrambler kit 45 00 Free catalog MJH INDUS TRY Box 531 Bronx NY 10461 0531 Program modules for Beginner to Advanced Complete program diskette and users manual SATISFACTION GUARANTEEO Send your name address and i Need to learn 29 95 2 00 shipping to MORSE CODE Morse Tutor This s the fun amp
104. O O00 One i OoooeTncnrooo0Tnoeo0 ec0oa OODODODO0ODO0OO0O0OO oon OO B Fig 24 Problem 3 should ve tested vour ability to generate the circuit in A and the table in B from the equation DX LISTENING Continued from page 88 give you what you want enhanced reception from the Yukon while at tenuating interference from the side or back But such a setup will be rather costly A simple dipole might help but dont expect too much from it in the way of rejecting unwanted signals Donald also has a question about converting Eastern Standard Time EST to the worldwide broadcasting standard Coordinated Universal Time UTC Coordinated Universal Time which is based on a 24 hour clock system is five hours ahead of EST or four hours ahead of Eastem Daylight Time during the summer months For example When its 1 AM EST it is 6 AM or 0600 UTC At 5 AM in Maine it is 1000 UTC 2 noon EST equals 1700 UTC and 2 PM EST is 1900 UTC If it is 8 PM EST on a Monday night for instance the UTC time is five hours later or 0100 UTC but remember that con version has taken it past midnight into the next day So both time and date can be affected Don when you con vert fo or from UTC The easiest way to get used to the time conversion is to keep a separate clock set to UTC or make a simple reference chart Down The Dial What are you hearing on the SW bands How about letting the rest of
105. ORE P O Box 4079 Farmingdale NY 11735 Ail Payment must be in U S P1 89 Zip Funds CIRCUIT CIRCUS Continued from page 85 Either a two or a three wire piezo transducer works well with the Circuit If a three wire transducer is used con nect the driven and common sections to the circuit see Fig 2 for pinout using if as a two wire device The filter s output is coupled to a volt age follower Uf c isolating the trans ducer from the output load If the capacitance value of the transducer used in the circuit isn t known sub stitute a capacitance decade box in place of C and set if to about 015 microfarads to start Apply power to the circuit and a signal generator to the input set the generator s frequency to about 1 kHz above the resonant frequency of the transducer and its Output level at about 500 millivolts Connect a os cilloscope or an AC voltmeter to the filters Output Adjust the oscilloscope s gain so that the filters Output signal covers about 70 of the vertical screen Adjust the capacitance decade box for a minimum Output signal Re move the decade box and connect a capacitor of the same value in its place Slowly sweep the audio gener ator to the transducer s resonance fre quency and observe the output level and the bandwidth of the filter The gain of Ul a can be raised or lowered as needed to work with just about any level of input signal the gain is calculated gain R8 M
106. ORMATION CARD 6861 AYVANVE N N All want is fair prices Is that too mu r ear r7 ge Taa lt nee oe rd a eee nT pos o ir _ ee oa ee ees There is a wav to get better prices on programming The American Home satellite Association An organization created exclusively to protect and enhance vour enjovment of your satellite TV system With AHSASsS group buying power voul save on prenuuin services superstations and basic programming services Enjoy Savings on accessories equipment and programming guides too A place to turn for help From locating satellite signals to locating a reputable dealer the toll free AHSA Helpline has the answer AHSA provides educational videotapes and Informative books too At very special member prices Plus 10 times a year AHSA s official newsletter Sky Report will bring you the latest word on products legislation programming and more Not to mention reviews of new products and services You re not alone anymore With vour voice behind us AHSA is promoting legislation to guarantee fair access at reasonable prices Addressing zoning and piracy issues Even sending expert witnesses to Congressional hearings Join other dish owners around the nation and become a force to be reckoned with BeFHREHHHHHHEEH HEE ee O ee ee C Rush my free information kit DOTEE EEE Address a es O Sign me up right
107. Oven XP 575 without meters 44 95 Oscilator digit LED display GREAT IDEA FUNCTION BLOX FOR EASY BREADBOARODING All blox interlock to make ke your desig design work a snap You can change the configuration 53 he oe Gey 9000 26 95 9610 18 95 9020 16 95 9630 2 22 95 FUNCTION GENERATOR ee DECADE BLOX CAPACITOR DECADE BLOX OIGITAL CLOCK BLOX LOGIC PROBE BLOX ave at A s re 4A 10 lier Sine ii eae aiplors 471M whe 20 capacitors 47 pt 10mid pulses from 1Hz 10 SOMHZ 4 logic level Ind Ya WE WILL HOT BE UNDERSOLD C A be SALES INC 15 Day Money baok Guaranies UPS Shipping US 5 1745 Rosewood Deerfield 1 60015 2 Year Warranty 10 Max tL Roa 7 Tas a imit FOR TTT S02 al aria WRITE FOR FREE CATALOG CIRCLE 22 ON FREE INFORMATION CARD Fully requiated mey 9550 7 50 550 te pts NR ow 686 AYVANYS HANDS ON ELECTRONICS POPULAR ELECTRONICS N Q THINK TANK Battery Charger its a cold one out there You get into your car and you cant wait to warm the old bus up and get the heater working You pump the gas peddle a couple of times tum on the ignition key and the most you get is a click The battery is as dead as a doomail Figure 4 is a trickle charger whose output falls as the battery voltage rises Nice huh As the charge on the bat tery approaches the maximum the charging rate is automatically re duced Connect it up and go back inside where its nice and warm and have another cup o
108. Projects 3105P billing me 3 95 plus shipping and handling charges If not satisfied may return the books within ten days without obligation and have my membership canceled agree to purchase at least 3 books at regular Club prices plus shipping and handling during the next 12 months and may resign any time thereafter Pp d f All Time Favorite Electronic Projects a 7 95 value Name Address City State Zip Phone Signature Valid for new members only Foreign applicants will receive special ordering instructions Canada must remit in U S currency This order subject to acceptance by the Electronics Book Club Signature of parent or guardian required for all new members under 18 RESP 189 a E JE SE E SE JE JE JE JE E E eee 8 8 eeeteeoeeee eevee eseseeoeaeeeeeenetoeeeseeoes S eeoseeceeoesCeeeeeeseseeeaeseeoeveesesceaoseaoee eases SIMPLIF2ED wWiTh 2826P 4 96 7B85 16 95 mm o 00 FIBEROPTICS C8 A REFOLUTION a Q F SHECTRONIC COM aitis Aa TIONS TRUMENT ATION oma ya RECTION E a mi m 2 i re Eon 3 o 2786 28 95 ZB60P 1 95 Counts as 2 How te Read Electronic Circett D agrams eae 2880 20 95 1793P 9 55 20 Epo SON PROHEC 2967 521 95 2910 24 45 7 THE MAST NDBOOK T CIRCUITS Tag Sy Ga Bapa tea seh a Oy A R z 2987 23 95 1370P 18 95 REMOTE CONTEOLLET 2992 24 95 2617 17 95 6861 AHYNNYT
109. RD FLOPPY DISK FILES Curtis line of floppy disk files are made of CTE acrylic copolymer a new plastic featuring high tevels of durability restltence The Curtis 5 4 inch and 3 2 inch disk files have adjustable dividers with color coded labels Carrying handles and anti skid feet to anchor them securely to any desk top They hold 50 and 40 disks respectively Snap lock models and units featuring an ail steel security lock with two keys are avail able in each size Every disk file has an outside shelf designed to hold two or three working diskettes The Curtis 3 2 and 5 4 inch disk files cost 12 95 each with security lock and and scratch and Crack resistance The files Offer maximum protection for delicate floppy disks 4 CABLE TV SPECIALS CONVERTERS 129 95 JRX 3 DIC 36 Channel Corded Remote RCA 58 3 58 channel set top with Jerrold Descrambler 99 95 SB 3 The Real Thing 109 95 SB 3 Taiwan Copy 05 89 95 DRZ 3D1C 68 Channel Wireless with Descrambler 199 95 Z TAC Cable Add On 169 95 MXC 2001 65 Channel Wireless ZENITH VIEW STAR with Parental Lockout 89 95 MXC 2001 A B Same as above with A B Switch 109 95 MXC 2501 65 Channel Wireless with Volume 119 95 Universal V7472 72 Channel Wireless Remote MTS S
110. REE INFORMATION CARD In a variety of situations the Action radio s reception both AM and FM was impressively clear and unwavering Lis tening in the office thanks to its headset the small radio s sound was as well modu lated and clear as the same FM station heard through GIZMOQ s rather ancient office stereo receiver Besides a built in automatic frequency control system to reduce station drift the 7 1990 uses an AM antenna built into the radio and an FM antenna that is combined with the headset cord This being the real world reception isn t of course perfect Walking down an urban street with signals bouncing off buildings and each other stations would cut in and out and static could build to unbearable levels But blaming the 7 1990 for that is akin to blaming the messenger tor bad news Within the given limitations the radio is a satisfactory personal size receiver In one respect this mighty mite tor the 90s represents little advance over its por table radio ancestors Portability 1s depen dent upon a vinyl like fabric case through which a strap passes allowing the radio to be wom on arm waist or even as a head band The carrving case openings tor the Continued on page 7 GIZMO Page 5 686l AHYNNYT n ON ELECTRONICS POPULAR ELECTRONICS a HANDS Linear Thinking KENWOOD FULL AUTOMATIC TURNTABLE KD 67F Manufac tured by Kenwood U S A Corp 2201 E Dominguez Long Beach
111. RONICS POPULAR ELECTRONICS d N bling the circuit board use it as a tem plate to mark the enclosure for mounting holes Drill the mounting holes with a 2 inch bit Finally drill appropriately sized mounting holes for pushbutton switch Si and a hole for the whip antenna Following Figs 5 and 6 assemble the transmitter and the receiver re spectively printed circuit boards Ob serve the proper polarity of the electrolytic capacitors the IC s and the diodes Mount the capacitors and resistors The capacitors are mount flush against the board to minimize lead lengths that s especially important in the RF and tone decoder circuits Note that all resistors vertically mounted Don t forget the test points Figure 7 shows the construction of the test point terminals Test point TPA on the transmit ter board see Fig 5 for its location PARTS LIST FOR THE RF TRANSMITTER SEMICONDUCTORS Li 15 AIS ii Hite ere ere LF WHeSHIL ree La t GK Tiia NPN RESISTORS i i i et aoe TEN i S E fs T E CAPACITORS LAN cupienors musi the WVIN LT i i 1 i 1k EUY Iii oe oe ee i 27 nk i E I l l INDUCTORS bball RE mdu a Leil eH amenn ESE l u H KI minune A i 1 i Paso e aee Ra ADDITIONAL PARTS AND COMPONENTS SNe pale Saree TA ee eer 1 METER WHIP ANTENNA Fig 5 Following this layout diagram as semble the transmitter being mindful that the resi
112. S TIME ALARM CHRO NOGRAPH SMWSS8 Distributed by NDQ Marketing Subsidiary of Hattori Seiko 989 Sixth Ave 7th FI New York NY 10018 Price 9 95 It was the news release that attracted our attention to the NDQ Sports Time Alarm Chronograph NDQ Marketing Intro duces Diver s Watch With Alarm amp Chro nograph it was headed It went on to describe the SMWS8 as a rugged diver s watch ideal for scuba diving snorkel ing Having a passing acquaintance with some of the truly extraordinary aquatic timepieces available we thought a diver s watch at less than 20 was a major market ing achievement But somewhere between the publicity and the product the SMWS8 diver s watch became water resistant to 150 feet All things considered however the NDQ Sports Alarm Chronograph is some thing of a marketing marvel although of the sort consumers have become jaded about Like the last century s dollar watches the contemporary micro chip watch has put accurate time keeping with in reach of millions at a very attordable price The laser quanz SMWS8 may not be a rugged diver s watch but hold ing it under a running faucet or keeping it in a container of water overnight didn t seem to affect its functioning during the week or so that we used it What almost capsized our test of the SMWSS however came at the start Over GE RADIO Continued from page 5 radio s tuning kno
113. There are projects for your Car your home your work bench other hobbys such as photography music and stereo Telephone projects light controis and a vast assortment of miscellaneous do it yourself items Flipping through the pages of this book the question becomes Which one will Start with THE THINK TANK originally appeared in Project Builders C 169 Please send multiplied by number of copies ordered Please print Name Street Address City State Hands On Electronics Magazine and imme diately won a good deal of reader accep tance The mail poured in as readers offered their own circuits or asked for assistance with electronics projects they worked on WHAT KIND OF PROJECTS will you find in the WELS THINK TANK BOOK The in dex which occupies the entire back page lists them Choose from nearly a dozen am plifiers an assortment of automotive projects from automatic parking lights to electronic air horns battery chargers to battery monitors You ll find fuzz boxes for your guitar to a trem olo unit A darkroom timer for you photo buffs And at a price of only 3 50 you can t go wrong THINK TANK Circuits for Experimenters and C 169 Please send one copy of THINK TANK at 3 50 Shipping 1 25 U S and Canada only copies of THINK TANK Total cost is sum of copy price and shipping cost Allow 6 8 weeks for the material to arrive Detach and mail today HANDS ON BOOKST
114. This is another example of the Grapher program s output Lines 7000 9040 of Grapher were modified as shown in Listing 2 on page 100 to allow the program to produce the graph shown in this illustration 4 8 5 listed below could be used to plot a 2 volt sinewave that has been clipped to 4 75 volts 8020 Y 24SIN X PI 80 8024 IF Y gt 1 75 THEN Y 1 75 8028 IF Y lt 1 75 THEN Y 1 75 8040 RETURN Another important point to re member is that subroutines must al ways end with a RETURN statement Failure to include that statement de pending on where it is supposed to be located is punishable by a simple er ror message the halting of program execution or the plotting of an incor rect graph Program Description From Listing 1 it can be seen that Grapher is com posed of three main sections of code and three support areas The code sections are 1 program initialization 2 screen and variable initialization 3 the main plotting section The three support areas which have already been discussed are 1 the constant values section 2 Function 1 definition area 3 Function 2 definition area A general description of each of the six segments of the program follows For those readers who are more inter ested in a line by line description of how Grapher works please refer to Ta ble 1 which contains such a descrip tion Program initialization takes place in lines 1000 1340 This section starts by cl
115. VE OPEN IGNORE THIS NINOING B D Fig 3 If vou use a miniature transformer salvaged from an old flash unit it will be necessary to figure out the proper windings andlor connections Shown here are two typical miniature transformer configurations R7 ensures that roughly 300 volts is stored in C7 before the neon lamp NE fires Neon lamps are designed to fire at different voltages The Common NE 2 lamp used in our circuit fires at about 120 volts DC When NEI fires it dumps the charge stored in C5 fo the gate of SCM That in turn produces a trigger pulse that is applied to flash lamp FM causing it to ignite which allows you to find your rocket in a flash Speaking of flashes let s look at dif ferent ways to attach a flash lamp to your rocket rocket stability what type of engines can loft your bird and a few suggestions for multiple strobes to increase visibility In our prototype the flash lamp is attached to the end of the rocket s nose cone with silicone glue The elec tronics are handily located in the nose and the battery is held by a snap in holder designed to withstand the shock and vibration of parachute de ployment without losing the battery The author used a combination 9 volt battery snap connector and holder assembly see Parts List for source A balsa wood plug is held securely in place by silicone which also seals the components inside the nose cone as well as providing an anchor point for
116. a dot between them while the output is designated C Look at this expression for the output C AB In regular algebra AB would mean multiply A and B together That s why the output of an anb gate is often called the product of the inputs As in regular algebra it is not necessary to show any symbol between the two variables although sometimes a dot is used Instead they are simply just writ ten adjacent to one another Figure 8 shows a four input AND gate with different inout variables Many times you will see the output expression written with some variables separated by parentheses Each input term ap pears within a set of parentheses to keep them visually separated to avoid confusion But since each expression is written directly adjacent to the next it GTX D7 EB CLK RST Fig 8 The variables in Boolean algebra need not be one letter in length but for clarity separating them with parentheses becomes necessary means that the variables are ANDed together In Fig 8 we say that the out put product is TX D7 EB CLK RST or Function The logical or is indicat ed by placing a plus sign between the variables That is illustrated with the three inout or gate shown in Fig 9 T1 G NZ T1 G RDY RDY Fig 9 oring of variables is indicated with plus signs Note the three inputs Often you will hear the output of an or gate referred to as the sum of the input variables NAND Function The
117. alarm circuit isnt there Such leakage might offer sufficient current to trigger the SCR but R2 sees to it that such leakage would have to be heavy for that to occur When the mat is stepped on R2 is just across the supply and has no effect Supplies of any other voltage can also be used Now that the system works and dad is convinced I m adding additional mats at the back door and the rear window suggest that the bell be mounted high over the front door out of reach where neighbors and the police can easily locate it also used waming stickers generously and foil taped all the glass Barry Sherman Seattle WA Il bet your dad is looking at you a little differently these days Also you didnt mention whether or not he got his discount from the insurance com pany but never mind You ve got a copy of the Fips book Rain Detector Something good has just got to come out of this That s why Im sending it to you want one of those Fips books It all began when put this circuit together for my wife told her to leave it out with the newly hung washing and if it started to rain a plate gets wet and the alarm sounds so you ll know to take the wash in The very next day came home to find her heating the etched plate with her blow dryer and didn t really care for the things she was calling me So added a switch S1 See Fig 3 The plate is a small 2 x 3 inch perfboard etched into strip
118. and parameters without giving much thought to what they mean As a result some plain old fashioned nonsense creeps into our daily language This month we will devote this column to looking at a couple of myths or semi myths frequently found in amateur ra dio as well as CB circles Signal Strength Reports Most of our receivers are equipped with S meters to indicate the strength of the received signal The S meter Fig 1 allegedly measures input signal strength in a rigorously defined manner The truth however is that receiver manufac turers cant even decide on what con stitutes the correct definition of an S unit Note how the S meter is cali brated The lower two thirds or so of the meter is calibrated in the nearly arbi trary S units The S scale is log arithmic The upper one third of the meter face is calibrated in decibels AB so it too is logarithmic Now lets consider what some of those S units are supposed to mean Table 1 shows the subjective meanings given to the signal strength portion in the standard amateur radio RST readability strength tone scale for CW or IS system in voice modes Note that S9 corresponds to a subjective determination of an extremely strong signal Hold that thought for a moment S9 extremely strong Recently heard a guy on 20 meters tell a DX station that he was 60 dB over 99 Wonderful report most amateur receivers only go up to 40 dB S9 If yo
119. apacitors the hum disappeared tuning across the band got loud whisties replaced the screen and AGC bypass caps and joy at half volume the radio came alive with stations With the tun ing at 620 kHz adjusted the IF can trim mers and the antenna trimmer on the tuning condenser at 1400 kHz At that point the radio was just about per fect There was a slight distortion that checked with a VOM found 12 5 volts on pin 5 the control grid of the 25L6 Chang ing the coupling capacitor a 022F unit that was also leaking cured that fault and the B voltage went up by 10 volts Now I m picking up stations from all over the place with a 9 foot antenna My advice to fellow restorers is to change all the paper and electrolytic capacitors they always dry out leak or short out Can anyone tell me just how old my radio is Were they making consumer goods too good in those days H L G Paim Bay FL SNIFFING AROUND would like to thank you for providing a great magazine geared toward the hobbyist par ticularly enjoyed building the RF Sniffer in the August issue However there are some errors in it LED 1 should be labeled as LED 2 and vice versa L2 is correctly stated in the parts list to be a 2 mH choke but the schematic shows it as a 2 H choke Speaking of RF chokes would like to see some information on how to read the molded kind Are they color coded and read the same as resistors They see
120. arget formats You then select the source file enter the name you want to use for the target file and you end up with the screen display shown in Fig 4 Basically Fig 4 is entertainment to keep you amused as the translation takes place A series of travelling dots tells you what percentage of the source was read in and a similar series of dots tell you what percentage of the translation was written to disk Figure Sis the translation of the hiero glyphics shown in Fig 1 Notice that Fig 5 is now in pure XyWrite format right down to the on screen displays for boldface and underline But there is a problem Because of the Original WordStar file s line formatting the inter word spacing vanes between one and two spaces But no problem A quick automatic search and replace of one space for two ciA gives us the almost perfect screen display TI bow a A ee ee ee ee ee a Paneer br iT il emia ail en rel 2 OT Pee ni li aiii m amm ee el en a a dii mpri ase premi ii be smaidi er ep e memme jaiilin jima pui et neki ol aid iria y m Ls P See ee peA bns ihis mim of mala bli ia ppi lil larika a Lan meri prm ereen a rililssi marh ii MAA TET Gederliniee s Fiel ted Imad Ex ei himee Apl eet ba hee ii hida Fim ail ELL Geek ime of siealale maprerisg ee ini grivipis copipred taste aa tt Wf lt nee ree of OE fee lll T citer ika mieia le aprile te riar vee fer emis sharm bash a ambaimmmia ln dimil
121. arious modules into different configurations to create rolling walking or talking robots robots that can serve drinks vacuum the floor protect the family against fire or theft or teach the children The book suggests alternate approaches and sources of electronic and mechanical components Most of the circuits use dis count priced surplus ICs that are easy on the builder s budget Along with illustrations schematics diagrams and parts lists for each module the book provides a listing of necessary tools and equipment a guide for matching up TTLs and ICs and drill bit and bolt chart and computer programs that are useful in robotics The Robot Builder s Bonanza 99 Inex pensive Robotics Projects costs 14 95 it is available from Tab Books inc Blue Ridge Summit PA 17294 0850 Tel 1 800 233 1128 CIRCLE 98 ON FREE INFORMATION CARD 62 HOME REMOTE CONTROL AND AUTOMATION PROJECTS by Delton T Horn Even readers with no previous electronics experience will find useful projects that they can build and put to use at home The de vices in this book were designed to make life safer more Convenient and more fun A wide array of door and window con troliers stereo and TV projects timers elec tronic switching units wireless controllers telephone related projects and a computer controller with programming information are presented Specific projects include an auto matic guest greeter sen
122. ase one S unit SIGNAL STRENGTH Fig 1 Most receivers are equipped with S meters to indicate the strength of the received signal So why is that important What dif ference does it make to know what it takes to blast an S meter one digit higher The answer is simple it tells us what to expect if we increase power How Much Station Power Most of us are enamored of high power linear amplifiers for boosting our signal In nearly 30 years of hamming I ve owned a one kilowatt linear amplifier only in the last five or so years Yet only occasionally suffered from power lev els that were too low Even today run barefoot more often than not which is in accordance with the FCC require ment to use the minimum power re quired to do the job High power brings problems that must be considered For example you can expect an increased probability of TVI television interference and BCI broadcast interference problems Antenna tuners must be the more cost ly heavy duty types Also little annoy ing anomalies such as RF bites on the microphone due to poor ground ing or RF in the shack are more se vere with a kilowatt So where s the benefit TABLE 1 DEFINITIONS OF S UNITS Si Faint signals barely perceptible S2 Very weak signals S3 Weak signals S4 Fair signals S5 Fairly good signals S6 Good signals S7 Moderately strong signals S8 Strong signals S9 Extremely Strong signals Linear ampl
123. assumed The book is designed as a learning tool to be read and used in front of a computer After reading it even beginners should be able to create simple AutoLISP programs to mod ify AutoCAD drawing commands access and revise drawing entities create simple geometric Constructions and curtail repeti tive drawing tasks Essential AutoLISP commands func tions and programs are taught and tips and tricks for basic programming testing and debugging are presented Readers learn to use AutoLISP effectively to solve everyday drawing problems AutoLISP pro grams accompanied by line by line expla nations of each command are featured throughout the book and illustrate the les sons taught in the text The last chapter contains 12 routines designed to dramati cally increase productivity when using the AutoLtSP language Those routines are also available on an optional diskette AutoLiSP in Plain English A Practical Guide for Non Programmers is available for 27 95 from Ventana Press P O Box 2468 Chapel Hill NC 27514 CIRCLE 80 ON FREE INFORMATION CARD COMPLETE GUIDE TO RS232 AND PARALLEL CONNECTIONS by Martin D Seyer This guide presents a unique approach to connecting computers and peripherals It uses tutorial modules that are designed to illustrate virtually any possible connec tion using serial and parallel interfaces The reader learns to connect sc
124. ation with a light emitting diode LED You ll learn to identify passive and active components understand concepts common to all electronic circuits For Anyone Interested in Electronics The Contemporary Electronics Series is designed for anyone from hobbyist to professional It s for you if you re looking for new fields of interest if you re a teacher who wants an update in con temporary circuilts a manager or supervisor in an electronics plant a doctor an engineer a chemist who finds electronics playing an increasingly important role in your work It s even for electronics engineers or technicians who feel their training needs freshening up It s the quickest most convenient probably least expensive way to SUR doit And the E only one that gives a you hands on experience 15 Day No Risk Trial To order your first module without risk send the card today Examine it for 15 days under the terms of the order form and see how the Contemporary Electronics Series gets you into today s electronics If card has been used write us for ordering information ang T a J ag no io 3 a a iis a McGraw Hill Continuing Education Center 3939 Wisconsin Ave Washington D C 20016 AN HL 6861 AYVANVE wo HANDS ON ELECTRONICS POPULAR ELECTRONICS NO MYTHS AND MISINTERPRETATIONS W radio amateurs sometimes toss around facts figures numbers
125. ay to express digi tal logic operations mathematically Boolean equations can be written to precisely describe how a logic Circuit operates which can help you to de sign such circuits Boolean algebra also provides a way to minimize the number of gates needed In a logic circuit to simplify circuit Gesign That lowers overall cost and can help re duce power consumption Also the equations can show at a glance what is going on in a logic circuit to aid you in troubleshooting As I ve said in previous articles don t let terms like Boolean equation mathematical expression or al BOOLEAN ALGEBRA and LOGIC CIRCUITS BY LOUIS E FRENZEL JR gebra scare you Once you leam the jargon and the few simple fundamen tals presented here even complex cir cuits will be easy for you So get ready for a digital logic refresher then we will have some fun writing the Boolean equations of a circuit and creating a circuit from the equations Review of Digital Logic Circuits At one time or another you probably learned how basic logic circuits work If not the following brief summary will bring you up to date The review is also for those of you who need a re fresher The three basic logic gates are the inverter AND gate and or gate Two other widely used gates the NAND and the nor are often derived from those basic gate circuits All of the gate circuits process binary numbers made up of 0 s and 1
126. ays wel come Write to Marc Ellis Antique Ra dios C O Popular Electronics 500 B Bi County Blvd Farmingdale NY 11735 First aid kits are fine for some emergen cies But what if you were choking Having a heart attack Or a stroke This kit would be useless Cali the Red Cross We ll teach you and your employees how to save a life From work safety to CPR you can count on the Red Cross We ll help Will you mis American Red Cross A Puget Sareta of Tra Putecamor FREQUENCY COUNTER Continued from page 61 _ measurec the initial readout will be the previous frequency that was latched in the counters Wait for two or more count periods for the circuit to stabilize on the new frequency Op tionally the reset switch S2 may be pressed to reset the display to 00 and then released The display is basically jitter free and all digits are significant If the frequen cy itself is somewhat unstable D1 may vary by one or two counts Notes The input signal voltage must not overshoot the 5V to ground limits and rise and fall times may not exceed 10 nanoseconds Integrated circuit U3 provides those safeguards so do not be tempted to apply random signals directly to Ul pin 12 For special circum stances knowledgeable builders may substitute other signal Conditioning Cir cuits for the CA3130 U3 Do not sub stitute a ICM7207 for the newer ICM7207A used in the circuit and use only the 5 24288 MHz crysta
127. b volume control and FM AM and power switches partially obscures each The highly readable dial was no longer visible and sliding the radio into the case inevitably meant that volume station or band selection had to be read justed Despite its generally sturdy design the Action AM FM radio is by no means rug ged It may be weather resistant but the directions note that the headphones arent and that the radio itself is vulnerable to salt water or salt spray But in our exposure to the 7 1990 its price performance ratio seemed a positive one If we found ourselves in need of a radio say on a trip or during a general power outage this GE model would fill the bill nicely A smal marvel of technology of the kind we ve come to take for granted this receiver is a worthy successor to the tiny portables of decades past CIRCLE 39 ON FREE INFORMATION CARD the years we ve formulated the informal rule of thumb The more simple the micro chip watch the more complicated it is to set This imepiece is not an exception to the rule We re not really sure what the problem was although the directions printed on the watch packaging may be at the root but the first SMWSS we tried to set refused to follow the sequence outlined A trio of case mounted buttons control all of the watch s functions Because of the need tor a reasonably waterproof casing the but tons are a trifle difticult to manipulate The rigid pla
128. c idea How about a contest where you readers submit photos and descrip tions of your most messed up radios The one judged to be the best worst that is would be restored in the col umn and then returned to the owner Let me know what you think but hold your entries It will be several months before I d consider doing that Mike Schulsinger Springfield OH wrote to correct a boo boo made in the September column referred to the broadcast band dial of the 7 232 as covering a range of 55 170 kilo hertz the range is really 550 1700 kilo hertz Thanks for the correction Mike Waltons Reruns finally received the 78232 comment that was hoping someone would send It comes from Bill Morris 13901 Oakridge Dr Carmel IN 46032 Some years ago had seen a Zenith set that looked very much like mine used as a recurring prop in a TV situation Comedy series wanted to mention it in the column but Couldn t quite remember the series name Bill writes that the series was The Waltons so keep an eye open for reruns in your area You may be lucky enough fo spot the Zenith too Bill included quite a want list of sets and parts and l ll see if can fit them all in Please contact him if you can help He d like to locate a Zenith Transo ceanic Model 7G605 1942 model servicing information an owner s man ual door assembly and AM wave magnet for a Transoceanic Model 1000 1957 model Fisher 800B re ceiver antenna
129. cations include interfacing the microcomputer to printers plotters mo dems networks and instrumentation and communicating with signal conditioning and control systems The board has two independent RS 422A communications ports each with its own base address and interrupt selection codes Either channel can be set as COM 1 COM 2 or any other desired base ad dress interrupt level combination The DUAL 422 s design is based around the INS 16450 UART giving it compatibil ity with both the INTEL 8250 UART and IBM asynchronous card Communications parameters such as 5 6 7 or 8 data bits and even Odd or no parity check modes are software selectable by the user The board plugs directly into any unused half or full size IBM PC XT AT expansion board slot It is connected to external serial busses through the board s two 9 pin D connectors The DUAL 422 Interface Board costs 260 00 the 9 pin D connector costs 12 00 and RS 422 cable costs 25 00 For further information contact MetraByte Corp 440 Myles Standish Blvd Taunton MA 02780 CIRCLE 78 ON FREE INFORMATION CARD CAR STEREOS Jensen s three top of the line autosound re ceivers feature sleek Styling and upgraded electronics Model SJS 7000 a full featured mini chas sis has a backlit LCD display 24 station presets 12 AM 12 FM and separate bass and treble
130. cessories New Panasonic multi line key business tele phone systems from 675 AIS SATEL LITE INC 106 N 7th St G Perkasie PA 18944 215 453 1400 SATELLITE TV FREE CATALOG Systems Upgrades Houston Uniden Chapparal etc SAVE SKYVISION 2008 Collegeway Fergus Falls MN 56537 218 739 5231 BUSINESS OPPORTUNITIES MAKE 250 000 yearly in IBM s Computer Color Monitor Repairs Details U S A 1 00 Canada 2 00 U S Funds Middle East Europa South Pacific Etc 8 00 RANDALL DATA DISPLAY PRODUCTS Box 2168 H Van Nuys CA 91404 U S A MAKE WITH YOUR COMPUTER Simple instruc tions and programs Complete package 5 00 GSATT Box 1165 Holly Springs GA 30142 CATALOG hobby broadcasting HAM CB Cable TV Transmitters Amplifiers Bugging Devices Computers More PANAXIS Box 130 F1 Para dise CA 95967 PHOTOCOPIER REPAIR High profit area For ex panding electronic repair business Photocopier owners ihese interested in full or moonlighting em ployment in the Field Troubleshooting tech tips parts markup more Illustrated 34 00 5615 Deer Creek Drive Ferndale WA 98248 CABLE TV CONVERTERS CABLE TV CONVERTERS Scientific Atlanta Jer rold Oak Zenith Hamlin Many others New VIDEO HOPPER The Copy Killer Visa M C and Amex 1 800 826 7623 B amp B inc 10517 Upton Circle Bloomington MN 55431 HIGH TECH ELECTRONICS SCRAM
131. cessors When Word For Word cannot make a format translation it will print out a list of the non translata ble locations so that the user can step right to the problem s and key in the correct format command s Fig 3 A check mark appears adjacent to the selected source and target formats Word For Word can be either com mand line or menu driven Command line is what is usually called the expert mode meaning a single line of com mands gets the computer to do a se ries of steps For example with Word For Word the command line WFW WS XY3 SAMPLE TST SAMPLE TXT is all that it takes to convert a WordStar file called SAMPLE TXT to a XyWrite file called SAMPLE TXT But you can also use menu driven commands until you become an ex pert or if you use the program so infre quently that you cant remember the translation commands The program comes up with the menu shown in Fig 2 Both sides of the screen are identical listing those Fi Fiji s o LEE TEE EEN F B fia Seer PEES Lares ane Temi iimis E b CEEE p Pi day ia tar ima Fig 4 So that you aon t get bored or think something s gone wrong if the translation takes several seconds Word For Word keeps vou entertained with a screen display of the translator s progress word processors that you selected during the initial installation Figure 2 shows Only part of the total As shown in Fig 3 checkmarks indi cate the source and t
132. ciation behind it For More information Contact ISCET 2708 W Berry Ft Worth TX 76109 817 921 9101 LEARN VCR CLEANING MAINTENANGE REPAIR EARN UP TO 1000 A WEEK WORKING WO Knowledge of Electronics Necessary NO Special Toots or Equipment OF THE 1990 S IF you are able to work with common small hand tools IF you possess average mechanical ability and have a VCR on which to practice and learn then we can teach YOU VCR maintenance and repair FACT up to 90 of ALL VCR malfunctions are due to simple MECHANICAL or ELECTRO MECHANICAL breakdowns FACT over 77 million VCRs in use today nationwide Average VCR needs cleaning maintenance or repair every 12 to 18 months VIEJO s 400 PAGE TRAINING MANUAL over 500 photos and illustrations AND COMPANION VIOEO TRAINING TAPE REVEALS THE SECRETS OF VCR MAINTENANCE AND REPAIR REAL WORLD IN FORMATION THAT IS NOT AVAILABLE ELSEWHERE ALSO INCLUDES ALL THE INFO YOU LL NEED REGARDING THE BUSINESS SIDE OF RUNNING A SUCCESSFUL SERVICE BUSINESS FREE INFORMATION CALL TOLL FREE 1 800 537 0589 Or write to Viejo Publications 217 E 86th St Dept HO New York NY 10028 CIRCLE 21 ON FREE INFORMATION CARD 6861 AYVNNVS HANDS ON ELECTRONICS POPULAR ELECTRONICS GRAPHER BAS Continued from page 64 bit that means that each graph must occupy 89 600 8 11 200 bytes of the computer s random access memory Based on the above calculatio
133. coils for an Echo phone EC 2 any Zenith shortwave receiver of the 1960 s and he wouldn t mind locating a 78232 either Criticism Accepted George Bidwell La Jolla CA wrote to remind me that still haven t discussed the reader com ments received in response to the col umns on the Crosley 50 January and February 1988 issues At the time postponed the discussion on that one tube regenerative receiver there was such a backlog of reader mail that the Continued on page 102 686 AYVANVE 8 Q3 HANDS ON ELECTRONICS POPULAR ELECTRONICS d UNUSUAL USES FOR TRANSDUCERS his months Circus starts the new year off with a number of solid state piezo transducer circuits Those critters can be heard chirping their lit tle hearts out in just about every kind of equipment that uses an electronic sounder We wake up to the beep beep sound of our digital clock Then as we get into our automobile a beep re minds us to buckle up And on through the day we hear a beep here a chirp there directing our attention from one place to another With ail of the racket created by the piezo sounders you d think there s nothing else they can do Well it s just not so Fixed Frequency Generator The cir cuit shown in Fig 1 is self oscillating in it a piezo element is used as the fre Quency determining Component The circuit produces a tone Output that can be used as an encoding signal for remote control or any
134. d nets covered inthis section Irom the manulacnurer please circle the vent s code number on the Free frformation Card TALKING SECURITY SYSTEM The Dicon 9000 wireless security system verbally instructs the user on how to pro gram and test the system It also vocally reports which sensor has triggered an alarm verifies that transmitters are within receiving range and reports when trans mitter or console backup batteries require replacement Easily installed by consumers the sys tem fully integrates security fire medical and other emergency monitoring using a variety of sensing devices with miniature transmitters The central console is about the size of a telephone answering machine it has a built in automatic telephone dialer that is Capable of calling eight local or long distance numbers and relaying an emer gency message in the user s Own voice if an emergency occurs the console de termines whether a Security fire or medi cal alarm has been triggered It will auto matically place an emergency call to the appropriate pre programmed number ornum bers An electronic voice announces to the answering party Medical Emergency or Fire Emergency as appropriate then de livers the user s Own message Each mes Sage is repeated three times before the console hangs up and dials the next emer gency number Codes rather than conventional keys are used to arm and disarm the sof
135. d LeBlanc ONT Henry Loewer OH Tom Manley ONT Paul Brouilette IL Tom Laskowski IN Richard Eckman CA Ontario DX Association PO Box 161 Station A Willowdale ONT Canada M2N 5S8 North American SW Association 45 Wildflower Rd Levittown PA 19057 DX Listening By Don Jensen language publication called the Uk rainian DX Review Summary in 1982 The problem for small Soviet clubs is the lack of copying equipment Xerox type machines are not for public use Most bulletins are simply typed in lim ited numbers although computer printers are becoming available Some active listener clubs are the DX Circle Leningrad founded over two years ago by three SWL s from that city and a newer organization the Soviet DX Club which has published a bul letin called World DX News since mid 1987 While those bulletins surely would be of interest to U S and Canadian SWLS so far they are intended for Soviet lis teners and are written entirely in Rus sian In the future though look for greater contacts between DX hob byists in the USSR and the West A Fine Romansch On shortwove one can hear ail sorts of obscure lan guages and dialects from the Eskimo Inukitut Canadian Broadcasting Commissions Northem Quebec Ser vice to Pidgin the National Broad casting Commission of Papua New Guinea It is interesting to note as you tune This gentleman is not only a shortwave listener and a license
136. d all potential problems caused by human error during the instru ments manufacture Such problems plague other telephone manufacturers who rely on individual workers to solder wires into place correctly time after te dious time With one mistake an entire unit can malfunction Thanks to Swisstel technology and design we offer consum Tower of Power PARSEC INDOOR FM ANTENNA LS 4 Manufactured by Parsec of Delaware Ltd 400 W 9th St Wilmington DE 19801 Price 59 95 New York where GIZMO does its test ing can be an FM listener s nightmare There are few problems associated with receiving the big powerful signals at the center of the dial But the various non profit educational ethnic and low power stations mostly at the lower end of the dial are like ghost radio stations They exist they offer unique programming but often they re more heard about than heard At certain locations and times of the day the stations may come in clearly but it seldom lasts Most often they disappear in a burst of static to be replaced by some higher powered neighboring signal Or at least that s been our experience and not just in New York when depend ing on the standard wall mounted simple dipole antenna tor FM reception Parsee of Delaware Ltd a company that specializes in FM antennas manutac tures three different units that promise to deliver superior performance The Beam Booster an FM Dish and the LS 4
137. d ham radio oper ator 9IMC but is also the chief engi neer for Radio Nepal Readers who have received QSL s from this exotic Asian station have Krishna B Khatry to thank for those replies the SW bands the many different and varied lingos of the world Consider Romansch for instance Along with French Italian and Swiss German it is one of the four official languages of Switzerland You won t find it among the 200 name list of principal languages of the world languages spoken by more than a million persons There are more people in West Africa some 2 million who speak ljaw than there are Swiss about 50 000 who consider Ro mansch their mother tongue And each census shows that the number of Romansch speaking persons is de creasing In the eastern canton of Grau bunden less than half of the popula tion now can speak the language Few visitors to the ski resorts of St Moritz even realize that the native language of the region is Romansch not the commonly heard Swiss German Romansch linguists say is probably the closest living language to the an cient Latin vemacular spoken during the time of the Roman Empire Clearly Switzerland s curious fourth lan guage is dying Curious SWL s can get a brief sample of Romansch on Swiss Radio Intema tional SRI notes Harold Sellers writing in the Ontario DX Association s bulletin DX Ontario on Tuesdays and Fri days at 0315 UTC on 6 135 9 725
138. d on the screen The result of that is that no points will appear on the screen when the program is run That would be the first place to look for mis takes if your graphs do not appear as you expect them to The variable YS in line 7050 is assign ed a value to be used as the title of the graph s Y axis and the variable XS of line 7100 is used for the title of the X axis Similarly the program has two lines associated with the main title 7130 and 7140 and those lines assign values to variables T and T2S To modify the four fabels to fif your own graphs merely change the string values to whatever text you would like to see on the graph Because the pro gram automatically centers the title and axis labels there is no need to pad the strings with extra spaces When entering the variables be care ful not to exceed the maximum al lowable lengths the Y axis label can be up to 18 characters long while the other three strings can be up to 60 characters in length The last thing you must do before Grapher can plot your functions is to type into the program the functions you want to plot To do that you need to enter each function as a subroutine one starting at line 8000 and one at 9000 Your subroutines should always retum a value in the variable Y for every value of X that is used by the routine that is every value of X that is between XMIN and XMAX In Listing 1 Function 1 is a simple sine wave with an am
139. d to hold a flashlight at almost any angle for video taping or projecting the images BOLT ANO WING NUT CLAMPS AT X AND Y FLASHLIGHT CLAMPS GROOVE Fig 5 Shown here are construction details for a typical experimental mount for a flashlight Such an arrangement allows a flashlight to be used with either a projection unit or a video camera OROINARY MIRROR ee OPENING ROUNO TUBE FITS ON TOP OF PROJECTION LENS Fig 6 When projecting the image onto a wall screen the tube is used to hold a mirror at a 45 degree angle securely in place a collar mounted to the assembly and the whole thing glued to a corrugated cardboard panel When thoroughly dry one or two slits are cut and a rubber band provides the friction to hold the lens Details of the best way to hold the panel above the kaleidoscope are difficult to give frequently use corru gated cardboard for the box Try using a small slide projector as the light source The slide projector is mounted onarack as shown in Fig 4 so that the light is emitted at a 45 degree angle into the apex of the kaleidoscope Trial and error with the lens at several positions and angles may be needed to optimize the conditions For short projection distances have used a TRANSLUCENT OR FROSTEO PLASTIC KALEIOOSCOPE TUBE Fig 7 When video taping only a rela tively small amount of light is required The light should be diffused That can be accompli
140. de of the electrical box cord and clamped it to the electrical box The wires from the autotransform er were passed into the box to begin the wiring of the box In Fig 1 as in all electrical circuits the white wires are ground and connect to the silvered screw terminals on the AC outlet The black wire it s electrically hot from the autotransformer goes to the fuse The red wire from the wiper terminal is also hot and connects to the brass screw terminal on the outlet The Juice is On powered up the autotransformer assembly after the fuse was installed The original unit called for a 5 ampere fuse so I used a fuse rated at 5 amperes however a fuse that has a lower current rating can be used A voltage check at the AC outlet indicated an output O to 140 volts AC as the control knob was moved through its range F More than just a Christmas tree bulb saver the autotransformer is used here to uncover a failing part in an old relic a Hallicrafters SX 38B shortwave receiver The first task designated to the au totransformer was to discover a fault in an antique tube design Hailicrafters SX 38 B shortwave receiver The re ceiver operation was intermittent but the trouble never lasted long enough to locate the fault Voltage was ap plied and cranked the autotransform er up to 127 volts AC when the fault occurred and held The problem was then traced to a defective wax paper capacitor A used autotran
141. degree to qualify but vou do need an FCC License No Need to Quit Your Job or Go To School This proven course is easy fast and low cost GUARANTEED PASS You get vour FCC License or money refunded Send for FREE facts now MAIL COUPON TODAY pareten e ee a m m ttt et COMMAND PRODUCTIONS FCC LICENSE TRAINING Dept 203 i P O Box 2824 San Francisco CA 94126 Please rush FREE details immediately l NAME ADDRESS on ae cee st a Includes antenna rechargeable battery charger adaptor amp belt chp Full range of optional accessones available Covers 27 54 MHz 108 174 MHz 406 512 MHz and 800 950 MHz Scan Banks and 5 Search Banks 25 Day Satisfaction Guarantee Full Refund if not Satisfied No Frequencies cut out s Size 2 x 5y x ly wt 12 oz AR900 Total Price Freight Prepaid Express Stupping Optional i COMMUNICATIONS 10707 E 106th St Indpls IN 46256 Toll Free 800 445 7717 Visa and MasterCard ee COD slightly higher In Indiana 317 849 2570 Collect FAX 317 849 8794 CIRCLE 17 ON FREE INFORMATION CARD 6861 AYVNNVE O J The Electronic Industries Association Consumer Electronics Group has recently completed the first in a series of videocassette training tapes EIA CEG ANNOUNCES COMPLETION OF NEW BASIC CAR AUDIO INSTALLATION VIDEO TAPE If you are thinking of cashing in on the prof tion facility covering basic as well as specialized
142. demodulated RF signal that ap pears at R4 to op amp U Op amp U a provides 10 dB of gain to the 490 Hz signal from R4 Op amp U b further amplifies and shapes the 490 Hz signal into squarewave pulses To do that resistors R5 and R set the voltage gain of Ul a to 40 dB 100 times Resistors R7 R9 R12 and R13 fix the quiescent DC output voltage at pins 1 and 7 to 2 5 volts Resistor R10 allows a test probe to sample the 490 Hz tone at pin 1 A ferrite bead con nected in series with R10 and located at TP1 and C9 block any RF current that may be present Another ferrite bead connected across the opposite end of C9 keeps RF current from reaching any test probes connected to Circuit ground Capacitor C10 cou ples the 490 Hz signal from pin 7 of U b to pin 3 of U2 an LM567 PLL tone decoder Resistor R16 divides pin 7 s output voltage decreasing the trans mitter s range but increasing the re ceiver s immunity to interference from other transmitters using the 49 MHz band Integrated circuit U2 contains cir cuits that can be set to detect a specif ic signal frequency when applied to its input at pin 3 Resistors R17 and R18 and capacitor C14 set the detection frequency to 490 Hz Capacitors C11 and C12 fix the circuits bandwidth to 1 LEDI U4 less than 100 Hz Pull up resistor R19 keeps output pin 8 high until a signal is decoded at which time pin 8 goes low Upon going low pin 8 grounds the cathode of
143. dheld scanners and ham trans ceivers for instance Handheld units will do most everything that the larger ta ble models will do But there is one area where they are lacking at least for some applications recently bought a handheld two meter ham transceiver which decid ed to use as a mobile rig It has one drawback though The audio output and the tiny little speaker work just fine in a relatively quiet environment but there is nowhere near enough sound coming out of the little rig to overcome vehicle noise and road noise for mobile applications What could do The first thought to come to mind was to build a small amplifier and speaker unit to be mounted somewhere in my small automobile Bad idea the car is too t cramped already Then another thought struck simply mount some kind of switch and jumpers in the existing radio tape player so could use the audio ampli fier and speakers already in the car that was another bad idea The car s radio tape player is miniaturized and permanently mounted Putting a switch and input wiring into the unit would be a big job Finally arrived at the perfect solution Simply input the handheld s audio into the existing tape player at the same place that a cas sette tape does via the tape head All that is required is to place a small coil Of wire in an audio cassette tape body The small coil must be mounted so that it fits snugly against the tape head in the tape
144. e HH 505 with 5 watts of power and four channels in Low Band The crystal controlled radios are adapt able to radio common carrier and to sys tems with all standard ElIA subaudible CTCSS tones two tone sequential and various other signalling formats All mod els Carry a 2 year limited warranty The suggested retail prices for models HH 464 D2 and HH 464 D4 are 569 00 and 615 00 respectively Models HH 154 and HH 156 cost 459 00 and 550 00 respectively Model HH 505 sells for 549 00 For further information contact Regency Land Mobile Inc 7707 Records St Indianapolis IN 46226 CIRCLE 74 ON FREE INFORMATION CARD PORTABLE OSCILLOSCOPE Tektronix Model 2247A portable oscillo scope aimed at the digital design and field service markets features a counter timer automatic rise fall time and propagation delay measurements and other extended measurement capabilities The 100 MHz 4 channel scope provides auto setup on screen cursors and up to 20 pre pro grammed measurements The unit features 11 automatic voltage and time measurements In addition to rise fall time and propagation delay measure ments the 2246A s built in counter Atimer pro vides delta time gated counter measure ments and frequency ratio measurements The oscilloscope offers several gated meas urements that allow the user to choose por tions of the waveform for closer analysis Users can also make measurements on NOTHING
145. e Sound Activated Decoder the piezo transducer performs double duty in that it operates as a sound pickup device and a frequency selective filter PARTS LIST FOR THE SOUND ACTIVATED DECODER UI LM324 guad op amp integrated circuit DI D2 1N914 general purpose small signal diode RI R2 R7 10 000 ohm ta watt 5 ESISTI R3I 25 000 ohm potentiometer R4 4700 ohm i watt 5 resistor R5 R6 2200 ohm t watt 5 resistor R 270 000 ohm Ya watt 5 resistor Cl 220 pF 25 WVDC electrolytic Capacitor C2 47 pF 25 WYDC electrolytic capacitor Cm 7 uF 25 WVDC electrolytic capacitor C40 l pF cerumic dise capacitor BZl Piczo fixed frequency transducer Radio Shack 273 064 or similar Printed circuit or perfboard materials enclosure IC sockets battery and battery holder wine solder hardware etc In band audible tones reaching the transducer s surface cause the trans ducer to vibrate in step with the incom ing sound wave The regenerative action of the circuit then causes the signal to be amplified to a 1 to 2 volt level The output of U1 a is fed to Ut b where the signal is doubled The boosted signal is then fed across a dual diode rectifier circuit to the input of a voltage follower consisting of U1 c only The circuits output can be used to activate optocouplers drive relay cir cuits or to control almost any DC op erated circuit The DC signal at the output of Ul c varie
146. e advantage of the beam steering capability of the an tenna to null out the competition and the DX is yours By the way remember the days when CB ers souped up their 5 watt rigs to get out better A typical modi fication boosted the power to an illegal 7 watts That change wasn t even a single S unit Not only that they typically did not modify the modulator so the percentage of modulation went down as well sadly we ve come to the end of the space allotted to us for this month but be sure to tune in next time In the meantime if you have any tips com ments or suggestions for this Column write to Ham Radio Popular Elec tronics 500 B Bi County Blvd Farm ingdale NY 11735 AUDIO COUPLER Continued from page 65 flame Solder a 10 ohm resistor to one end of the coil Before soldering wrap 3 or 4 tums of the bumed enamel wire around the resistor lead Solder the other end of the resistor fo one lead of the wire or cable that will exit the car tridge It would be a good idea to con nect the inner conductor of the cable to the resistor leaving the shield con ductor for the other end of the coil That will protect your scanner handi talkie etc in the event that the coil should get scuffed and make contact with grounded metal objects Solder the other end of the coil to the other wire lead Finishing Up You should now have a coil and resistor connected in series see Fig 1
147. e at most libraries Figure 8 shows the signal of the RF transmitter as seen on a spectrum analyzer As required by FCC regula tions Part 15 the bandwidth is less than 10 kHz E 6861 AYYNNYT gt A HANDS ON ELECTRONICS POPULAR ELECTRONICS amp pe BUILD THE SPEEDI WATT Here s an easy to build circuit that can be used as an electronic speed control for electric drills or fans as a power controller for electric blankets or soldering irons or as a lamp dimmer and for much much more Ook around your home and you will probably find a number of AC powered appliances that could pro vide improved service to you and your family with the use a speed or power controller We ve put an electronic controller together that we call speedi Watt that is ideal for that pur pose Speedi Watt is cheap to build compact in size and best of all it is very easy to put together As a bonus speedi Watt incorporates elec tromagnetic interference EMI sup pression circuitry That means that you will not be plagued by those her ringbone TV pattems that more elec trically noisy units produce The Speedi Watt is an easy to make Circuit module to which you will need to add a knob a three wire power cord a three terminal AC plug and matching AC socket and a suitable plastic case The whole project should go together in about one evening The resulting dimmer and speed control is suitable for lamps fans or univer
148. e case with metallic hard ware but secured with a dab of epoxy or some super glue The idea is to avoid having any exposed metal work on the surface of the plastic case When you have completed the wir ing switch your multimeter to the low ohms range and check the continuity of the ground and neutral wires from the AC plug to the AC socket Check also that there is no resistance be tween hot neutral and ground for both the AC line socket and plug If all is Ok your Speedi Watt dimmer is ready for set up and use Test and Adjustment Now connect a table lamp and plug the dimmer into a wall AC outlet You should be able to smoothly control the lamp brightness over the potentiometer s whole range With that accomplished you can if you wish set the minimum brightness of the lamp by adjusting trim potentiom eter R3 That is a trial and error process though and you should not make any adjustments to the circuit while the AC voltage is applied fs G JANUARY 1989 Toshiba Facsimile Machine pg Swisstel Responds pg Parsec Indoor FM Antenna pg Video Cut Update pg Smith Corona Electronic Typewriter pg GE Action AM FM Headset Radio pers PG Kenwood Automatic Turntable pg 6 Sports Time Diver s Watch pg GIZMO BYTES Electronic Cooking Timer pg Murata Personal Fax Machine pg Olympia Electronic Typewriter pg Videocassette Organizer pg Satellite TV Receiver Decoder pg Can
149. e is the 78232 now stripped of its finish Much to my surprise and delight the grain was not photographic but really in the wood just waiting to be brought out by an application of stain Antique Radio By Marc Ellis finish and reassess the situation hoped that once cleaned up the cabinet would take stain nicely so that a presentable replacement finish could be applied Being grainless it would lack the beauty of the old one But it would at least be fresh and new providing an attractive setting in which to install the restored chassis used a methylene chloride based chemical stripper the kind that ap plies as a heavy gel so that it will stick to the wood surface and do its work without dripping off That stuff takes off old paint or vamish coatings as quickly as anything know And it s pretty nasty if you get it on your hands It s not caustic like lye or acid but will defi nitely sting bum and redden the skin find it difficult to strip fumiture while wearing gloves so try to work near a water tap By rinsing my hands fre quently can avoid most of the ill effects it s also wise to use that type of stripper outside or in a well ventilated area While not noxious the fumes are definitely not good for you and can leave you with an unpleasant hang over like feeling the next moming Under the Sludge That type of chemical stripper tums the old finish to a kind of gummy sludge The idea is t
150. e light pulse that produces long range visibillty yet the Strobe requires very little ener gy input Basic Strobe Circuit A strobe circuit has four basic parts See Fig 1 The first is the Dower supply which must be ca pable of producing about 300 volts from a 9 volt battery That high voltage is required to sustain the arc within the lamp after triggering Second we need a capacitor to store energy The luminescence pro vided by the Strobe is directly related to the value of the capacitor or to the amount of energy that the ca pacitor can store Third we need a triggering cir cuit to produce a very high volt age pulse to ignite the lamp A typical ignition pulse has an am plitude of 4000 volts and is sev eral microseconds in duration The trigger pulse is capacitively coupled to the Xenon gas inside the lamp When enough atoms are ionized by the pulse and if ar Now vou can launch a model rocket on the darkest night and find it in a flash no matter where it lands the capacitor has enough charge on it the gas fully conducts Light output begins after conduction and con tinues until the charge on the capoci tor drops to about 50 volts The lamp shuts itself off at that point to renew the cycle after the voltage builds up again Last we need a Xenon flash lamp one is available from the supplier given in the Parts List There are several different shapes and designs of flash lam
151. e pari om 3 Ft dual RCA color coded 50 50 ea stereo cords ea SAER Oe PRAECED DRLE MORSE ptss A rna ttita J eae to EMTEMT T a ON ISSUE DURING S PRECEDING AAt o npani S TO m PLUG N POWER WALL SUPPLY r z COMMODORE KEYBOARD A TOTALNO COPIES Ner Pram Run 120 694 5 41 svat 78 Amps 2 99 E tr oe C16 4 Plugs PAIO AM 7 Aati 1 ps LJ r F bo ea 12VDC 12 Amps 2 95 ea 2 hp Suter pean _ __ trud ender voqwested 1i 23 863 29 117 e TOTAL PAID ANOA MEQUESTED CIRCULATION 0 H am ef LORI eet Ol se aman on area aa lil 4 FANS TERMS Minimun order 10 00 ae ES COMPLIMENTARY AND OTHER f AEE COPIE 2 041 115V 3 amp 4 6 00 N J residents 6 sales tax added E TOTAL DISTRIBUTION Jum of C one D 58 250 61 053 24V 3 amp 4 6 00 Please call for shipping charges ia Lid kid t yt TEON see tale ores CARANA GOAS IE rning 6 620 10 848 220V 3 amp 4 5 00 2 Return trom toma Agneta 55 824 0 211 Wane 19 Freeman St Newark New Jersey 07105 AAE AS masid equal ag Ptrl rua own sa Aj 120 694 122 11 IN DSOR 1 certify thet the ststements made by me above are correct and complete PS Pere 3526 Ox 1985 vpn ANB TITUS Lg EDITOR PUBLISHER GLSINESS MANAGER R f 25 4 VAC 300 Amp 1 95 DISTRIBUTORS CIRCLE 24 ON FREE INFORMATION CARD 230V 1 5V Amp 12V 2 5 Amp w 800 645 9060 201 344 5700 Fax 201 344 3282 6861 AYVNNVS oS W HANDS ON ELECTRONICS POPU
152. e used Price 899 CIRCLE 45 ON FREE INFORMATION CARD Compact Disc Player In its announcement of new CD players Sharp Electronics Corp Sharp Plaza Mahwah NJ 07430 asserts that the new models are for digital purists But for many consumers the most interesting feature of the new DX C5000 Compact Disc Player will probably be its six dise changer The player can store up to 32 songs in memory controlled via the front panel or by wireless remote A digital display indicates the disc track and program number being played The DX C5000 also offers continuous and repeat play and a memory back up that Stores an entire CD magazine s memory programs even while changing functions The purists we imagine will be interested in the system s double over sampling digital filters Price 399 95 CIRCLE 56 ON FREE INFORMATION CARD Gizmo Bytes integrated 35mm Camera Canon Checkbook Recorder Sharp CD Player 6864 AYVANYS GIZMO Page9 Gizmo Bytes Pf anal HANDS ON ELECTRONICS POPULAR ELECTRONICS 56 Page 10 GIZMO Cher Er Li vik t Las mT Portable Co aie Wireless Headphones Wireless listening is a technology that remains Controversial some Consumers like existing wireless systems while others wouldn t touch them with a ten foot Speaker connection cord Datawave Inc 19611 Ventura Blvd 2nd A Tarzana CA 91356 is hoping its new Privare Waves Wireless Headph
153. e without affecting the PLL s operation Following U2 is the 18 dB octave fil ter containing U3 which has a gain of one for the desired signal frequencies The filter is followed by the final stage U4 which has a gain of 10 The adapter is ideally powered from the tuner or receiver it is built into so we had to make its input voltage require ments non critical The solution is to use a 12 volt 3 terminal regulator that en ables the circuit to be powered from any 15 to 30 volt supply The three op amp IC s and the PLL are all biased to half the supply volt age by a voltage divider consisting of two 10 000 ohm resistors which is de coupled by a 4 7 uF capacitor The center of the voltage divider is con nected to pin 3 of each op amp and the PLL PCB Assembly The printed circuit board for the project see Fig 3 mea sures just 3 x 2 Ya inch and will help ease assembly if made Point to point assembly can be used but will be a bit difficult to perform accurately No special points need to be watch ed when installing the parts on the board except that component polar ities must be correct see Fig 4 Note also that Ul has a different orientation to U2 U3 and U4 When assembly and soldering are finished check your work carefully and then connect a DC supply of be tween 15 and 30 volts Now check the voltage at the output of the 3 terminal regulator at pin 7 of the TLO71 op amps and at pin 10 of the PLL
154. earing the program s variables and displaying one screen of instructions Then in lines 1280 1320 the user is al lowed to gracefully exit the program if they have not modified the print values in tines 7000 7160 or if they have not entered the functions they wish to plot as subroutines starting at lines 8000 and 9000 In the next section of the program from line 1350 to line 1700 both the program variables and the screen are initialized This section takes care of drawing and labeling the graph s axes displaying the titles of the axes and displaying the title of the graph as a whole The last section of code the part that handies the actual graphing of the functions is Contained in lines 1710 1900 An outer FOR NEXT loop which begins on line 1750 is used to step through each of the two functions in turn An inner FOR NEXT loop begins on line 1760 and its purpose is to step through each pixel or dot on the X axis from the minimum X value XMIN to the maximum value XMAX More Words Grapher s charts do not fill the entire PC screen but rather use an area that is 160 pixels high by 560 pixels long for a total of 160 x 560 89 6000 pixels Because the PC uses a method of dis playing graphics known as bit map ing every pixel is represented by a Continued on page 100 hat modern semiconductor technology has done to mini aturize electronic devices in recent years is quite amazing Take small han
155. eck Continued on page 26 HITACHI SCOPES AT DISCOUNT PRICES i sia y 212 OC to 40MHz DC to 100MHz tases 379 Dusi Channel Delayed Sweep CAT Readout List 560 Save 181 Sweep Time 20MHz Dual Trace Oscilloscope Ye alt Magnifier Autoranging Ail Hitachi scopes include probes schematics Compact Size Trigger Lock 1060 1 285 2mV Sensitivity and Hitachi s 3 year guaranty on parts and tabor Many accessories available lor all V 425 List 995 PRICE SAVE ImV sens Delayed Sweep DC Offael Vert Mode Trigger EA Im sens DC Oftsei Vert Mode Trigger Alt Mag 36 E _ im sens Delayed Sweep DC Offaet Alt Mag pE my sens Delayed Sweep CRT Readoul _2m sens Delayed Sweep CAT Readout Cursor Meas _ im sens Deleyed Sweep CAT Readout DYM Counter Im sens Delevan Swany Curtor Meas OYM Counter 11004 100MHZ 1150 150MHz 35MHz Dual Trace Oscilloscope SCOPE PROBES r P 1 6SMHz 12 10 19 95 J P 2 100MMz 1x 10x 23 06 5 accessories oes ohm input lt a 1252 6 CAT e im Sensitivity OKV Acceleration Voltage 10ns Rise Time m X Y Operations 2 Axis a Delayed Triggering Sweep Toy Quality scopes at a very vaasonabis price Contains sil desired features Two 1x 10x probes diagrams and manual Two year Quarantes Digital LCR Meter I ce iis nd Higi j n aian Werner Teater LC 1800 135 55 CM 1500A 138 05 DC Accuracy T Reads Volts
156. ed list price of 2795 00 For further information write on company letterhead to Tektronix Port able Test Instruments Division P O Box 1700 Beaverton OR 97077 or call 1 800 426 2200 CIRCLE 75 ON FREE INFORMATION CARD WRIST STRAP CHECKER Wrist straps often fail to provide a constant path from the wearer to ground Such fail ures Can be caused by a loose Strap oil or creams on the skin open resistors in the molded cord poor contact of snaps from the band to the cord or poor grounding of the strap to an earth ground Wescorp s WSC 110 Wrist Strap Checker is designed to assure the wrist Strap wearer of continuity from the banana plug at one end to the wearer s hand at the other To check for continuity the wearer Simply piugs it in at the banana jack or Clips it on the post or Snap provided with the unit and touches the contact bar on the face of the instrument A series of indi cators include a high reading light over 10 megohms series resistance a low read ing light under 1 0 megohms resistance and a pass light plus audible signal to indicate satisfactory Operation A low bat tery light indicates when to change the 9 volt battery The WSC 110 Wrist Strap Checker costs 85 00 For more information contact Wescorp 144 South Whisman Rd Moun tain View CA 94041 Tel 800 537 7828 415 969 7717 in California CIRCLE 76 ON FREE INFORMATION CARD
157. egas Kit found its place in a Christmas dec orated window in a home Next to a moving mechanical Santa Clause the LED display was the most stared at item in the window Children and adults were fascinated by the varying light patterns presented by the 64 LEDs The display can find its place any where inside the house too It ll perk up a child s room Set between parallel mirrors it has an Infinity Mirror effect that makes it suitable in any room The Vegas Kit is a project for begin ners and gadgeteers who like novel and unusual items to assemble and use The actual number of applica tions is unlimited You can purchase the Vegas Kit Order No TSM 99 for 130 00 You can contact the TSM headquarters at 2065 Boston Post Road Larchmont NY 10538 for the TSM distributor nearest you Give a Friend A Hands On Experience for Christmas Does fighting the crowds at Christmas short circuit your holiday fun Don t blow a fuse this year for the friend who shares your love of project oriented electronics or a youngster who may need only a spark to ignite a life long interest give a gift subscription to Hands On Electronics Because when you give him Hands On Electronics you re giving him valuable Hands On experience month after month of challenging construction projects including complete plans for testing equipment electronic worksavers for home and car add ons and modifications for h
158. en in the review of the Digital Voice Re cord Playback Module in the October 1988 issue was incorrect The correct number for the kit s distributor the Tapto Corporation is 1 800 876 8001 Editor CASIO CLARIFICATION In the September 1988 installment of Gizmo the review of the Casio JE 3 desk top calcu lator contains some terms ano Fr 5 4 and cut which were foreign to me at first Casio is my favorite manufacturer and wish still had my old FX 27 with the blue nixie tube display I ll buy the batteries rather than strain my eyes on most LCD displays In any case if understand Casio cor rectly the rnp rounding off works like this F merely gives you answers without any rounding off up to 12 digits 5 4 should give rounded off answers and cur should en able you to select how many digits you want behind the decimal point it shouldn t just limit the user to two as stated in the article S G Caseyville IL ANTIQUE RADIO REVAMP enjoy reading your column Ellis on Antique Radio Last year came across an old table model Emerson 149 The unit was in good condition and contained tubes 6A7 6D6 6Q7 25L6 and 25Z5 and a ballast tube in a metal case After cleaning it up switched it on The tubes lit up and there was a low hum coming from the electromagnetic speaker When I replaced the can filters with two 47 yF 150 volt tubular c
159. en mag netism and electricity The history of magnetism from the dis covery of the loadstone to scientific pio neers ranging from Hyppolyte Pixii through Joseph Henry Wilheim Weber James Clerk Maxwell and Nikola Tesla is covered The book defines magnetism and geomagne tism It explains natural magnetic phenom ena such as the Northern Lights and mag netic effects on the weather It covers fer romagnetic paramagnetic and diamagnetic materials and how they are used E The book also describes the ways mag netism is used in homes and industry It illustrates DC circuits and introduces basic semiconductors coils and electromagnets basic AC circuits and transformers are cov ered as well The book discusses how mag netism is used in everything from doorbells to particle accelerators Some simple experiments will underscore the principles learned from the text Those include a compass an electromagnetic re lay a galvanometer a transformer and an electric lock The projects presented an electric motor a steam engine and an elec tromagnetic repulsion coil are fully illus trated and contain complete parts lists Understanding Magnetism Magnets Elec tromagnets and Superconducting Magnets is available for 10 95 from Tab Books Inc Biue Ridge Summit PA 17294 0850 Tel 1 800 233 1128 CIRCLE 98 ON FREE INFORMATION CARD HANDBOOK OF VIDEO CAMERA SERVICING AND TROUBLESHOOTING TECHNIQUES by F
160. er Essentially it was a diode with an added terminal that was used as and was called a gate Thanks to the SCR small voltages could control large voltages and not through relays that had only two steady states You could now conirol a full range of voltages As time and science progressed new applications were discovered for that versatile device and we re glad to of fer a range of them here SCR Tester This handy little unit will give you a visual indication is a one evening project and is easy to throw together Once you ve got it you can check the operation of all those possi ble duds in your junkbox and maybe throw some of them into the scrap heap Figure 1 shows a 3 amp 50 volt SCR and a test circuit A fixed resistor can be used for M Points G gate and K cathode are temporary connections so that they can easily be opened If M is a fixed resistor of a few hundred ohms when K is closed the lamp doesn t light When G is also closed the lamp lights to its full intensity The lamp remains lit even if G is opened again But when K is opened even mo mentarily the lamp does not light again when K is closed It does so when G is closed That illustrates the Think Tank on and off operation of the SCR lf Ri is of a higher value about 50 000 ohms you can place a meter at G to show the gate current I A small gate current flows that rises as you reduce the value of M At some given va
161. er the phone This unique product is manufactured and sold exclusively by LT Sound and is not available through dealers Call or write for Free Brochure and Demo Record LT Sound Dept PE 9 7980 LT Parkway Lithonia GA 30058 404 482 4724 For 24 hour Phone Demo Call 404 482 2485 Manufactured and Sold Exclusively by LT Sound Employers Willing workers available now at as little as 4 your usual cost This is your chance to get help you ve needed but thought you couldn t afford No business too large or too small Call your private industry council or write National Alliance of Business PO Box 7207 Washington D C 20044 A Pubic Service of a Thus Pubkcabon 2 Coui NO MASTER NO CAMERA NO FILM NO DEVELOPER DIRECT ETCH dry transfers make quality circuit boards fast without formal artwork A new Master Assortment includes over 4000 donuts from 050 to 250 and 118 trace lines from 014 to 125 It also contains all sizes of through hole and surface mount devices including DIP TO DIN D and edge card connectors SO SOL PLCC flatpacks SOT s 2 terminal tubular and flat SMD s The Master Assortment has 69 cut apart dry transfer sheets with complete instructions Works with all common etchants DE 973 Master Assortment 69 pattern sheets 34 95 Add 2 00 shipping NJ and CA residents also add sales tax DATAK Corp 3117 Paterson Plank Rd N Bergen NJ 07047 CIRCLE 19 ON FREE INF
162. erhaps your children are playing outdoors and you would like an easy way to call them in This article describes a wireless transmitter re ceiver combination called the Personal Pocket Pager that allows you to page beep someone from a distance of up to about 100 feet When activated the transmitter sends out an amplitude modulated AM 49 890 MHz RF carrier The re ceiver detects amplifies and de codes the RF signal which in tum activates a piezo beeper buzzer The receiver is small enough to carry in a pocket or sit on your workbench The transmitter is also small and fits easily into a pocket for quick access The Transmitter Figure 1 shows a schematic diagram of the transmitter circuit A 7555 CMOS oscillator timer Ul generates a 490 Hz squarewave Resistors RM R3 and capacitor C3 de termine the squarewave s frequency Capacitor C2 and L3 prevent RF cur rents from reaching the trigger input pin 2 of Ul at the same time 490 Hz signals pass unattenuated The 490 Hz Output of Ul at pin 3 is used to drive a crystal oscillator circuit built around G1 which generates the 49 890 MHz RF carrier signal Capacitor C5 bypasses RF Current to ground placing transistor A in a common base configuration Resistors R4 R set Qi s quiescent DC emitter current to about 7 milliamperes MA inductor U is used to tune Capacitors Shown here is the Pocket Pager s complete ly assembled transmitter which should
163. et radio includ ing digital audio and video and the evolu tion of the amateur satellite program Mastering Packet Radio The Hands on Guide costs 12 95 and is available at bookstores computer Stores electronics distributors or from Howard W Sams amp Company 4300 West 62nd St Indianapo lis IN 46268 Tel 800 428 SAMS CIRCLE 95 ON FREE INFORMATION CARD BOB MIDDLETON S HANDBOOK OF ELECTRONIC TIME SAVERS AND SHORTCUTS by Robert G Middleton Packed with dozens of little known tricks of the trade new testing techniques and time saving shortcuts this 378 page hand book will make it easier to troubleshoot tele vision radio CB tape recorder intercom audio CCTV telephone and digitally con trolled equipment The book explains how DC voltages can be added or subtracted with a voltmeter how a digital voltmeter temperature probe can be especially useful in analyzing digital IC temperature signatures and how a DC voltmeter can be converted into a high performance dynamic ohmmeter that automatically measures the internal resis tance of live circuits It describes how to use a DC voltage monitor as a DC current monitor make a sensitive test for amplifier distortion with a DC voltmeter and meas ure DC voltages in very high impedance Circuitry using a two DVM method that draws no current from the circuitry under test There are instructions for building a sim ple voltage controlled audio oscil
164. et that delivers more than merely adequate sound According to GE this is an action radio weather resistant and sturdy enough to withstand the active lifestyles of music listeners of the 1990 s making it a product only slightly ahead of its ime The diminutive receiver is sturdily de signed with headphone jack and battery compartment for the 7 1990 s single AAA cell power source protected by Hexible vinyl covers Its trio of controls in yellow lies flat against the case Anyone who has struggled with mini radio tuning will appreciate one refine ment in this unit The AM FM dial is among the most easily read we ve seen on a midget radio The two broadcast bands are clearly separated horizontally and a vertical thin red line makes the visual as pect of tuning in a station precise and easy for anyone with normal vision The notched nickel sized station selection thumb wheel ts easily manipulated If our experience is any guide users of the Ac tion radio won t have to worry much about the slightly smaller volume wheel With a new battery even at the lowest audio setting the 7 1990 delivered plenty of decibels Besides the simple directions the radio s package includes a booklet warning against listening through the headset at excessive volume and including guidelines for traffic safety That advice is summed up with the slogan use your head when you use your headset CIRCLE 66 ON F
165. ete your sound system add the remote control compact disk player cassette deck and any of our fine speakers and headphones Technical excellence Do it yourself pride That s what we promise That s what you get Heath Company brings you a wide range of innovative electronic products each backed by our 40 year reputation for excellence in design quality and durability Heath s new hi tech audio components are just a few of the fine products you ll see in the Heathkit catalog Discover 108 pages packed with TVs VCRs computers test instruments radio control vehicles and so much more For your FREE copy call 24 hours a day TOLL FREE 1 800 44 HEATH 1 800 444 3284 PS ar iy ee Heath Company ii CIRCLE 23 ON FREE INFORMATION CARD
166. ets them slide out freely during the engine s ejection phase and they unroll quicker when in the air The finished model s weight is an im portant consideration in engine selec tion To launch successfully the model must be less than the maximum lift weight MLW of the engine type se lected Weight can really creep up on you as all dieters know Our model called the Phoenix weighed 11 6 ounces with the engine and Strobe installed After it was painted the paint added 1 9 ounces That put total weight at 13 5 ounces very close to the MLW of the engine we used Table 1 is a listing of some rocket engine combinations that will lift off with the Strobe onboard Each model was selected to provide a reasonable weight margin and a body size large enough to hold a 9 volt battery The weight margin is what s left over for the Strobe paint battery and so forth The rockets are sold in kit form and man ufactured by Estes Industries Other de signs may work provided that you use lightweight batteries and build the rocket and Strobe using minimal weight methods Multiple strobes add a very interest ing touch We used up to six flash lamps strung in parallel all operating from the same power supply The light output appears to be equally divided among multiple lamps if they are all of the same type To get the same bright ness per lamp you ll have to increase the value of C7 see Fig 4 For in stance with 3 lamp
167. ever put glue or cement on the contact surface the wiper will fail to make electrical con tact and the unit will not work properly The epoxy set in 24 hours and the bump was gone The next consideration was the broken Bakelite parts One mounting leg of the autotransformer was gone broken off and lost forever However the rest of the base was good so decided that the remaining two legs were sufficient to hold the autotrans former to a breadboard If necessary could have used epoxy to cement the entire base to the board A plastic tab that was used to secure the cover to 0 140VAC ADJUSTABLE fuse holder and AC ouflet and passed the line cord to the outside was broken beyond repair That was not a total loss because was not satisfied with the two terminal AC outlet used in the original unit wanted a three ter minal outlet and a strong contact sur face in the outlet to grab the prongs of the AC plug So discarded the plastic piece and covered the opening in the cylindrical housing with a piece of sheet metal cut from a 2 pound coffee can The price of the can was certainly right The section had cut from it had almost the same radius as the metal shield and its indented ribs common to coffee cans made it very rigid drilled a hole through it and inserted a grommet in it fo protect the insulation of the wires to be passed through it The metal was painted black before in stallation and
168. f coffee The line transformer 11 the full wave rectifier a bridge circuit and SCM are rated for the maximum current and voltage needed Use a 12 6 volt trans former capable of delivering three to five amps During maximum charge resistor M and diode D1 triggers SCM so the full rate is there The voltage across R and R3 is relatively low so D2 doesnt conduct that keeps SCR2 off The voltage at which SCR2 conducts is set by potentiometer R When D2 starts passing gate current to SCR2 the SCR tums on moving di ode D1 negative The voltage for DA drawn through M drops almost to zero That keeps SCM from triggering The effect is slow and the triggering angle D2 R4 1N4739 2209 BATTERY of SCM is reduced as voltage rises You can put a limiting resistor meter or fuse at R2 Frank Zabo Palo Alto CA Great idea Frank many a snowy morning I ve needed just such a charger for my own car Hey Does it really snow in Palo Alto Keep an eye out for your copy of the Fips book It s on the way Code Practice Oscillator m really not a monster and really got a boot out of it when my son expressed an interest in amateur radio While was pleased told my wife that any thing even a code practice os cillator would be better than blasting rock n roll It seems that today s kids really dont need a volume control on their amplifiers They blast em till the windows rattle But
169. f fuss Low in cost it uses just a few readily available inte grated circuits Before we describe the Adapter cir cuit let s briefly talk about FM subcar rier transmissions They have no effect on standard FM mono and stereo radi os Also they are fully compatible with This story first appeared in Silicon Chip Australia January 1988 reprinted here with permission all existing FM radios whether stereo or mono In fact unknown to the great mass Of FM listeners such transmissions have been going on for some time 67kHz INPUT FROM FM DEMODULATOR AUDIO OUTPUT Fig 1 This klock diagram shows the four circuit funcrions of the SCA Adapter The corresponding functions are also marked on the circuii diagram in Fig 2 BY JOHN CLARKE AND LEO SIMPSON This simple adapter circuit fits in your FM tuner and lets you tap into hidden FM transmissions But while all FM radios are presently unaffected they are capable of pick ing up the subcarrier transmissions With the adaltion of an adapter such as the one we ll describe here they will be able to detect the hidden audio signals The SCA Adapter prototype was built on a compact printed circuit board accommodating three low cost op amps a phase locked loop IC a 3 terminal regulator and a hand ful of resistors and capacitors How it Works Figure 1 shows a block diagram of our circuit The 67 kHz sig nal present at the output of the FM detec
170. f range next value 1790 PY 172 Y YMIN 160 YMAX YMIN 1800 PX 76 X XMIN 560 XMAX XMIN 1810 IF X XMIN THEN LINE PX PY PX PY ELSE LINE PX PY 1820 NEXT X 1830 NEXT ML 1840 1850 INS INKEYS IF INS lt gt THEN GOTO 1850 1860 INS INKEYS IF INS 1880 END 1890 1900 7000 7010 7020 YMIN 7030 YMAX 1 5 1 5 minimum y value maximum y value THEN GOTO 1860 1870 IF INS lt gt E AND INS lt gt e THEN 1850 push E to exit loop 22 22 22 PLACE CONSTANT VALUES HERE 22222s2e2s s 7040 place y axis title below 18 characters max 7050 YS THIS IS THE Y AXIS 7060 7070 XMIN 360 7080 XMAX 360 minimum x value maximum x value 7090 place x axis lable below 60 characters max 7100 XS THIS IS THE GRAPH S X AXIS 7110 7120 place two title lines below 60 characters max 7130 T1S THIS IS THE FIRST TITLE LINE OF THE GRAPH 7140 T2S 7150 7160 RETURN 2170 7180 And this is the second title line 8000 a 2 PLACE FUNCTION 1 BELOW s s sz 2 25 8010 8020 Y SIN X P1 180 8030 8040 RETURN 8050 8060 9000 ous eeuzuze PLACE FUNCTION 2 BELOW s2 8222 2222222 2 9010 9020 Y 1 2 SIN X PI 180 30 PI 180 9030 9040 RETURN will also change other labels shown on the screen We ll describe how to make those modifications a littie later
171. f some data FactCard 85 concerning the 4514 IC states in Features that the 4514 is a Piug in replacement for MC14514 SPEAKERS AND COMPONENTS EMINENCE cir M PIONEER Ce EMINENCE i MADEIN 2870 290 125 12 POLY WOOFER Super duty 40 oz magnet Polypropylene cone 100 watts RMS 145 watts max 4 8 ohm compatible 6 ohm 2 voice coil 1 3 4 up 3680 3450 MC 14515 That is far from the truth To make the data complete and true it should include the 4515 That is because according to specs when the chip is selected the output of the 4514 goes HIGH and when the 4515 is selected the output goes LOW It s some thing like Saying that they are the same breed but different sexes C A D Aurora CO A SIZABLE MISTAKE While building the Speech Processor from the October 1988 issue of Hands on Elec tronics discovered that the board size is wrong First made a transparent copy at 5 4 inches as the article said Following the parts placement diagram aligned each chip over the corresponding chip diagrams But my copy that Complied with the directions in the article was too big reduced the size from 5 a inches to 4 s inches and every thing lined up correctly S P Chicago IL You are Correct Due to a reproduction er ror the board that was prepared for publi cation and measured for the article was roughly 20 oversized The proper dimen sion is
172. from the top and a On the project bench or under your Christmas tree this troubleshooting device from the vacuum tube era is just as important today few screws and then gently slid the meta protective shell off After clean ing the case found repainting was not necessary Inspection revealed that some plas tic parts were broken and some of the Bakelite pieces were still inside the unit One of the leads to the transformer coil was yanked a bit and the copper wire that was wound on the foroidal core was stretched That caused the wiper contact at the top of the unit where the selected AC voltage is tapped to ride roughly over the top of the coil Also the power cord had been cut off near its entry point to the unit Everything else looked very good Even the S5 ampere fuse was in good shape There appeared to be no short cuts in the manufacturer s construction techniques The unit was rigidly built with solid Bakelite parts hooked up a power cord and gave the autotransformer the acid test AC power Without a load connected the autotransformer took the volfage with out any smoke In fact almost no heat was detected so far so good A volt meter connected to the autotrans former s output jack showed that the output could be varied from 0 to 140 4 volts when the input was rated at 115 1 volts AC the AC power line was low that day Next added a two photoflood bank of lights and the au totransforme
173. g in the Danish Shortwave Clubs International s Short Wave News Listening to foreign stations has not been a crime since the death of Joseph Stalin says igor Sannikov but neither was SWL ing encouraged be cause some westem stations engage in what he cails ideological warfare in 1982 some Russian SW enthusiasts sought to have DX ing recognized by the Radio Sport Federation as a part of the amateur radio hobby but the re quest was rejected However with to day s official policies of peristroika and glasnost more Soviet citizens are discovering SWL ing Still Sannikov estimates there are only your 100 active SWL s in the entire USSR with its population of 280 million That s mostly due to a previous lack of publicity about DX ing as a hobby That too is changing Sannikov says that in Lithuania for example there already have been two articles pub lished on the listening hobby Soviet SWL s also have been asked to partici pate in DX ing programs aired by Radio Tashkent and Radio Vilnius Most Soviet listeners belong to the Radio Budapest SW Club Hungary he notes but that there are some local clubs developing within Russia As ear ly as the 1970 s club bulletins were published by two small organizations known as Baitika DX Club and DX Club 77 There also was an English Credits Harold Sellers ONT Jack Jones MS Alan Laves TX Ivan Grishin ONT Paul Buer FL E
174. generally sounding bet ter add up to two reasons why that indoor FM antenna is worth an examination Parsec s FM Dish introduced to the market last August uses a three step am Continued on page 6 GIZMO Page 3 49 HANDS ON ELECTRONICS POPULAR ELECTRONICS CIRCLE 64 ON FREE INFORMATION CARD Letter Quality SMITH CORONA ELECTRONIC TYPEWRITER XL 2500 Manufac tured by Smith Corona Corp 65 Locust Ave New Canaan CT 06840 Price 229 Word processing laser printing letter quality computer printers what many of us learned in high school typing courses often seems as outmoded today as some Skill learned in the past century But to borrow Mark Twain s well known quote reports of the death of the typewriter are greatly exaggerated In fact contemporary electronic type writers have borrowed a great deal from both word processors and computers And as any but the most dedicated computerist will admit there are times when sitting down to a typewriter keyboard makes a lot more sense than firing up the PC printer combo If the typewriter is on its last legs no body s told Smith Corona which intro duced a new executive line of five type writers in three different categories earlier this year The XL 2500 is the top of the Smith Corona line of electronic type writers and a fairly Convincing argument for the continuing utility of that century old communications tool The XL 2500 offers a numbe
175. ger current for the SCR 24 volt transformer and lower rated lamps Then you can ground one pole of the lamp circuit or the center tap of the transformer The two capacitors shown are used as interference sup pressors for SCM The values of the ca pacitors are not critical and they can vary somewhat from what s shown but be sure they have a 5 to 1 kilovolt rat ing hope you like it and that it eams me a copy of the Fips book Fred Bergmann Chicago IL Okay Fred I ve got good news for you The Fips book is on its way to you now Enjoy Okay guys that s it for this month send your schematics with complete descriptions please to Think Tank Popular Electronics 500 B Bi County Blvd Farmingdale NY 11735 If your idea or circuit is a good one there might be a free copy of the Fips book in your future a i 20 Programs ae a a ee ee ee ee a a a eS SS ee SSS SSS SSS SS SERS Se eS PE ES SSS Se Bea ees eS eee Ss Kam L e 7 BP173 COMPUTER MUSK PROJECTS your home compuler to produce electronic music a BP135 SECRETS OF THE COMMODORE 64 5 75 Masses of useful info and program mung lps not found in any user s manual BP130 MICRO IN TERFACING CIRCUITS BOOK 1 5 75 Practical add ons transtorm your computer mito control of measure ment equiprent P183 AN INTRO DUCTION TO CP M 6 95 To tun and use rams opeta
176. ght drying the pic ture looked quite a bit different The stripper had definitely removed quite a bit of the old stain resulting in a pale splotchy appearance A new coat of stain would definitely be required possibly with a preliminary bleach to even out the variations in color inten sity l Il report on my progress next month several readers have written me in teresting letters during the course of the Zenith restoration and this seems like a good time to catch up with them So let s open the mailbag 78232 Clones One of the first com munications received was from John W White Il who says he has a Zenith 6 233 set that s very similar to my 78232 The cabinet on his was warped so he had to discard most of it But he enjoys the set so much that he keeps the bare chassis on a bedside table for evening listening John doesn t miss the cabinet too much because he likes to construction of Dan Damrow s Crosley 50 replica The fabricated parts for the coils and book condenser are in the foreground Compare the front of Dan s replica left with a similar shot of an actual Crosley 50 right Note the remarkable resemblance between the two watch the glow of the tubes at night Can anyone help John with a sche matic for a National Dobro Amplifier Model 6107A It was built by Webster Electric of Racine WI and uses the fol lowing tubes one 5Z3 two 2A3 s a 79 and a 56 He d probably also be inte
177. h for Beginners is available for 51 00 from Prentice Hall Inc College Di vision Englewood Cliffs NJ 07632 CIRCLE 99 ON FREE INFORMATION CARD THE AUTOCAD PRODUCTIVITY BOOK Second Edition by A Ted Schaefer and James L Brittain Productivity is the key word here Read ers learn to work smarter by using satisfaction job security and productivity in the process The AutoCAD Productivity Book hetps professionals tap the subtleties beneath the surface of AutoCAD that can make it a powerful new tool with more speed power and performance It also details how to achieve company wide linkage and integration of AutoCAD with engineering sales purchasing manufacturing and desk top publishing specific design needs The tutorial section aimed mainly at novices and intermediate users dgives step by step directions on us ing macros and the powerful AutoLISP pro gram creating and modifying screen and tablet menus and automating drawings This second edition contains two added chap ters on how to customize AutoCAD Re lease 9 s new pop up menus and on tips and tricks that boost speed and drawing power In addition many sophisticated AutoLISP routines have been included in the AutoCAD Productivity Library section The 70 carefully selected AutoLISP routines and time saving macros that are presented in that section illustrate the features and power of customization giving users m
178. h plastic coated templates displaying commands and a users manual costs 79 00 For more information contact PC Template P O Box 9273 Glendale CA 91206 Tel 1 800 451 6086 CIRCLE 71 ON FREE INFORMATION CARD DESOLDERING GUN Xuron s WickGun desoldering system re moves solder from PC boards and other electronic devices 3 to 5 times faster than the conventional use of braid The tool makes the dispensing positioning and cutting of desoidering braid a one handed operation The WickGun accurately dispenses the desired length of desoldering braid When heat is added with a soldering iron the melted solder is drawn up into the exposed braid The solder impregnated braid is eas ily cut off by squeezing the trigger The desoldered area is left clean and free of contaminants such as finger oils That im proves future solderability The WickGun also acts as a heat shield to prevent burned fingers The unit is made of Static dissipative ma terials in keeping with current ESD control practices Easy loading replacement braid cartridges are available in 15 foot lengths in sizes 1 through 4 The Cutting blades are also replaceable The WickGun has a suggested list price of 39 95 The replacement braid cartridges cost 4 95 each for sizes 1 through 3 and 5 25 for size 4 For more information con tact Xuron Corporation Saco Industrial Park 60 Industrial Park Road Saco ME 04072 CIRCLE 72 ON FREE INFORMATION CA
179. he bar it took a call to the company s toll free service number to discover what we were doing wrong According to Toshiba facsimile trans mission via telephone lines works like this The originating fax scans the docu ment and converts the information into a data stream representing the black and white elements of the original That is sent via the phone line to a receiver in the receiving facsimile unit that records the image line by line creating an exact du plicate or picture of the transmitted document However it works fax is faster and often cheaper than other hard copy communica trons methods For an obvious example it s a good deal cheaper to make a tour minute long distance call to fax some doc uments than to send the same information via an overnight express service The 3300 s delay send function even allows the user to set the machine to take advantage of lower telephone rates that are in effect during certain hours of the night Fax owners are also finding out that just as with standard mail and telephones there s a certain tendency toward frivolous or unwanted fax use In some parts of the country unsolicited sales promotion liter ature is transmitted to unsuspecting fac simile owners whose fax numbers have turned up on lists circulating among sales personnel in the area But the fax revolution is undoubtedly here to stay When and i prices ever come way down the era of electronic mail on
180. he bead stays in place and then solder the lead to the board Install a second ferrite bead over a inch length of hookup wire to form TP2 Bend the end of the lead into a ring to secure the ferrite bead in place and connected the other end with the ferrite bead installed on the printed circuit board transmitter Remove the frequency counter and attach an audio ampli fier soeaker to TPA receiver Using a small screwdriver adjust the core of T1 receiver and the core of U1 transmitter until the top of each core is even with the top of its housing A rushing noise and possibly the 490 Hz tone should be heard Alternately ad just L1 and T1 for the strongest reception of the 490 Hz tone Next place the transmitter at the fringe of its range and tune 11 receiver for the best re ception Disconnect all test equipment and power and reinsert U2 A second harmonic of the transmit ters signal may be detected on an FM receiver tuned to about 100 MHz If so minimize that signal by carefully ad justing Li FERRITE BEAD gt PARTS LIST FOR THE RF RECEIVER ALERT BEEPER SEMICONDUCTORS UI LM358 dual op amp integrated circuit U2 LM567 tone decoder integrated circuit U3 7555 CMOS oscillator timer integrated circuit U4 78L05 low power 5 volt regulator integrated circuit Q MPSH11 ECG229 TCG229 or SK3246 229 NPN RF silicon transistor Q2 2N3904 general purpose NPN silicon transistor
181. he audio signal is converted to a digital signal and processed for sound eftects Then the system converts the signal back to clean clear analog That feature creates theater like sound with the addition of a rear Speaker System and the user can select any of six Surround modes Theater hall club concert hall studio or stereoplex The SA R530 features separate rear speaker amplification a power rating of 100 watts per channel and a seven band electronic graphic equalizer that stores ten EQ curves in memory tor instant push button recall Price 850 CIRCLE 50 ON FREE INFORMATION CARD Gizm o Bytes LANUARY 1988 EO CO GEN MOD EED MED SS 5 Electronic Reminding Calendar agg puia Sle a MIFIT TY gt Z G gt D lt A V Receiver z re GIZMO Page 11 57 Gizmo B ytes hls oe Prenatal Soundshare Sy for the Fam Dynamic Stereophone HANDS ON ELECTRONICS POPULAR ELECTRONICS 58 Page 12 GIZMO Decorator Ultrasonic Humidifier It s about time some manufacturer offered a decorator line of home humidi tiers which is why the new Ultrasonic Humidifier 1844 from Soundesign Corp Harborside Financial Center 400 Plaza Two Jersey City NJ 07311 didn t surprise us According to the product release the 1844 is aimed at consumers who want the benefits of an ultrasonic humidifier without sacrificing on style Soundesign gave it a white Eu
182. he flight sequence of the rocket along with a cutaway showing its engine components and their function IF STROBE MOVES CG BACKWARO OF ORIGINAL SPOT ADD COUNTERBALANCING WEIGHT TO NOSE OR MOVE PROBE FORWARD 4m m l BAD iF STROBE MOVES CG FORWARO OF ORIGINAL SPOT ROCKET WILL FLY FINE NO CORRECTIONS NEEDED NO PROBLEM CENTER OF GRAVITY OF ROCKET WITH ENGINE AND RECOVERY SYSTEM INSTALLED BEFORE INSTALLATION OF STROBE CG Fig 6 If the electronics are forward of the model s center of gravity the rocket should fly fine with the added weight around 20 000 flashes That s over 20 hours continuous at a high flash rate and represents many rocket flights To get the best efficiency it s neces sary to keep C4 close to ON see Fig 2 That ensures a reservoir of current to draw from as switches Usually Continued on page 96 6861 AHYNNYT Lo G3 HANDS ON ELECTRONICS POPULAR ELECTRONICS ww D though new to some countries subcarrier transmissions on FM broadcasts have been made for years They are referred to as Subsidiary Communications Author ized transmissions or SCA They are based on a 67 kHz subcarrier that is placed on a stations main FM cartier It s even possible to have multiple sub carriers some carrying digital data and others carrying audio So yOu can receive such broad casts we present the SCA Adapter that can be hooked into most FM tun ers with a minimum o
183. he various logic gates starting with the inputs and building the equa tion a step at a time A couple of ex amples will illustrate the process Refer to the circuit in Fig 12 Note that the input variables are labelled The output is designated G Our job is to write the expression for G in terms of the input variables It s really not as complicated as it sounds i o G AB C DEF Fig 12 You end up with a sum of products expression for this circuit after analysis To begin you start with the variables at the inputs to each of the circuits on the left Write the expression for the out put of each circuit For example the output of AND gate 1 is simply AB The output of the inverter 2 is not C The output of AND gate 3 is DEF The outputs of gates 1 and 3 and inverter 2 form the inputs to or gate 4 To complete the expression simply or together each of the inputs to gate 4 The output expression G then be comes AB C DEF Take a look at the expression we just derived You often hear an expression like that referred to as a sum of prod ucts In this case the products are the ANDed variables AB and DEF The sum of course refers to the oring together of each of the products A slightly more complex circuit is shown in Fig 13 Still the evaluation pro cess is the same Work your way through the circuit from left to right writ ing the output expression for each gate The output of gate 1 is A1 K as sho
184. hons under CPM you need this book D BP104 ELEC TRONIC SCIENCE PROJECTS 5 75 Simple lo complex a group of projects with a strongly screntihc flavor See the ER Spectrum amp wr Ixa BP126 20 PRO GRAMS FOR THE ZX 5 75 Alt rams run on both il ae aa Include tlow charns and mio on how lo madity to uN on other computers PC P104 ELECTRONICS BUILD of a arcul demonstrator and shows a vanety of Name City aeta Mus 6 95 Shows how to use Many circuits Mostly jar SPECTRUM amp 16K ZX81 AND LEARN 9 95 starts off with construction details ficuns for experimenters Addi2ss ___State BP176 TV DXING FOR THE ENTHUS gon Iree AST 7 95 Practical authorilative intro to this unusual aspect of elec troncs 8V2 x 11 im 144 pp Secrets of the An inlra duc lion Camputer COMMODORE 64 1a Programming Terminology the ATAA taptaned e00 800 IL TERT 3 se l 1 fs 4 _ 8P143 INTAO TO PROGRAMMING THE ATARI 600800 XL 5 95 Perfect compe ment to the Atan users manual Even shows how to use animaled graptucs BP131 MICAO IN TERFACING CIACLUITS BOOK 2 5 75 interfacing sound and speech generators temperaiure and optical sensors motor control lers and more a teow te Dow ge f thew to Got Yow Hiectronic Bruene Projecta Frejocta BP127 HOW TO DE SIGN ELECTRONIC PROJECTS 5 75 How lo use slanda
185. i fi computers radio and TV He ll get all the how to he needs to build exciting useful projects like these a touch light dimmer a traveler s theft alarm an economy NiCd battery charger a voice synthesizer a wave form generator the ultimate burglar alarm a stereo graphic equalizer and many many more PLUS testbench tips and techniques circuit design electronics fundamentals book reviews and new product news including our new 2 page Gizmo section regular columns on computers scanners dx ing ham and antique radio the list goes on and on SAVE MONEY A great gift to receive Hands On Electronics is also a great gift for you to give The Special Holiday Rate saves you 11 00 off the newsstand price on each gift You can save another 11 00 when you start or extend your own subscription at the same time It s our thank you for sharing the Hands On experience with a friend this Christmas Send no money unless you prefer We ll be glad to bill you in January Next Year Just take a brief moment to go over your gift list and make sure you haven t forgotten anyone who might appreciate the Hands On experience Then write the names on the attached Gift Certificate and mail it back in the postage paid reply envelope we ll take it from there Your friends will receive a handsome gift announcement card signed with your name j
186. iare under penalty of perjury that all products purchased now and in the future wiil only be used on cable TV systems with proper authorization trom ilocal officials of Cable company Officials in accordarce with all applicable federal and state laws FEDERAL AND VARIOUS STATE LAWS PROVIDE FOR SUBSTANTIAL CRIMINAL AND CIVIL PENALTIES FOR UNAUTHORIZED USE Dated Signed Pacific Cable Company Inc 7325 RESEDA BLVD DEPT H 1 RESEDA CA 91335 818 716 5914 No Collect Calls 818 716 5140 Copyright 1987 PACIFIC CABLE CO INC 686 AHYVNNVE n 7 gt _ Electronics Library T _ AutoCAD as more than just an electronic Beginning intermediate and advanced drawing board and increase their personal users learn how to tailor AutoCAD to their the history of the theones presented A discussion of the essence of higher mathe matics and its possible applications in phys ics and engineering is followed by exam ples involving specific physical problems within those disciplines The 560 page book contains an exten sive section on two mathematical trends that expand and generalize the classical differential and integral calculus complex numbers and functions of a complex vari able and generalized functions Finally there is a discussion of scientific trends that use higher mathematics intended to arouse the reader s curiosity and to encourage fur ther study Higher Mat
187. ifiers come in three basic power levels all of which are called kilowatt in advertisements 600 watt CW 1000 watts and 1500 watts Let s see if punning a power am plifier is worth it in your case and which power level is best for you Assume that you have a 250 watt HF transceiver A 600 watt linear also called 1200 watts PEP is little more than 2 1 increase so it is about 3 aB That means that a station at the other end will Just about hear an S unit change If you were S6 before you might be 7 now But if you bought a 1000 watt linear then there would be a two S unit change And that begins to be worthwhile Now consider what happens if you own a 100 watt transceiver for one of Continued on page 101 NEW FREQUENCIES tlooks as though the FCC is respond ing to frequency congestion in the Business Radio Service by considering the possibilities of adding 12 new channels for use in the VHF high band 152 to 162 MHz Another pos sibility the FCC is thinking about in order to open up new frequencies in the Business Radio Service BRS is to create new channels offset 15 kHz above and below existing Business Ra dio frequencies in the 152 to 162 MHz portion of the spectrum BRS channels presently exist on 151 655 151 685 and 151 715 MHz under such a new plan if approved that portion of the BRS al locations would expand to become 151 64 151 695 151 67 151 685 151 70 151 715
188. ig 20A With two inputs there are four possible input combinations We want the out put to be a binary 1 when D is equal to1 Fig 20 A truth table A must be generated from a circuit B before deriving the Boolean equation and E is equal to 0 All other input states produce a binary 0 output The truth table shows that set of conditions Now to derive the Boolean expres sion from the truth table we look at the output column F and note where bin ary 1 s occur Next we look at the input states that produce that output Then we write an expression that is the prod uct of the inout variables For example in the truth table of Fig 20A the equa tion becomes F DE We write the D because a binary 1 ap pears in the D column We write E because a zero exists in the E column That simple equation of course can be implemented with a single two in put AND gate An inverter is be needed to produce E if only the E input is avail able The resulting circuit appears in Fig 20B Now let s take a more complex ex ample Suppose that we want to de velop a simple circuit for comparing two bits We would like the output of the circuit to be binary 1 when the two bits are equal and binary 0 when they are different That is described in the truth table shown in Fig 21A The two inputs are X and Y therefore the four possible input combinations are listed We want the output Z to be binary 1 when the bits are alike So we wr
189. ights are given in ounces Weight w Engine MLW Weight Margin 8 1 14 5 9 3 9 8 4 1 3 9 8 4 1 3 8 10 6 2 47 10 5 3 47 10 5 3 3 1 10 6 9 5 9 14 8 1 5 9 10 4 1 3 4 8 46 2 7 8 4 6 2 8 8 5 2 Courtesy of Estes industries Material used by permission around the lamp affords additional breakage protection Plug the open end with a tapered balsa or plastic plug to preserve the rockets aero dynamic sleekness Use of a short stur dy flash lamp cushioned in Silicone may work fine as it did with our model The parachute s size must be in creased to compensate for the added weight 40 square inches of parachute area per ounce of weight is recom mended All told our rocket weighed 13 5 ounces sc 540 square inches of chute area was needed We replaced the 18 inch chute that came with the model with two 24 inch ones That gave about 900 square inches which gently delivers the model to Earth lf you need to use more than one chute attach each chute s shroud lines to a snap swivel which can be found at tackle shops Those handy little gizmos reduce the chance of the line tangling which can lead to disas ter and enables you to clip on or re move chutes in a jiffy More than one parachute means you will have to pack each carefully Try not to wind the lines too tightly around the chutes and use plenty of flame proof recovery wadding between the chutes and en gine Dusting the chutes with plain tal cum powder l
190. ime atter Time operates on two AA size batteries included and can be mounted on stove or refrigerator with a built in magnet As with all the products it distributes Ham macher Schlemmer offers an unconditional guarantee Price 37 50 CIRCLE 51 ON FREE INFORMATION CARD Electronic Typewriter A long established manufacturer in the contemporary typewriter industry Olympia has a new moniker and a new line of personal typewriters Now called AEG Olympia inc 3140 Rt 22 Box 22 Somerville NJ 08876 the company has rolled out the 500 series including the XL 505 Electronic Typewriter the 505 offers a 5 000 character editing memory a 50 000 word spell check feature automatic lift off Correction memory and automatic word delete plus automatic centering Carriage return underlining paragraph indent and decimal tabulation The typewriter can use a variety of Olympia printwheels Price 289 CIRCLE 47 ON FREE INFORMATION CARD Integrated Singlte Step 35mm Camera At its market introduction in September the new Mirai ntegrared Single Step 35mm Camera was dubbed the world s most advanced camera incorporating the broadest range of photographic capabilities currently available in any single camera Although technology moves fast nowadays the Mirai from Ricoh Consumer Products Group 155 Passaic Ave Fairtield NJ 07009 is still on the cutting edge of photographic development The camera which even lo
191. immediately you will be eligible for our Bonus Book Plan with savings of up to 80 off publishers prices Club News Bulletins 14 times per year you will receive the Book Club News describ ing all the current selections mains alternates extras plus bonus offers and special sales with hundreds of titles to choose from Automatic Order If you want the Main Selection do nothing and it will be sent to you automatically If you prefer another selection or no book at all simply indicate your choice on the reply form provided As a member you agree to purchase at least 3 books within the next 12 months and may resign at any time thereafter Ironclad No Risk Guarantee If not satisfied with your books return them within 10 days without obligation Exceptional Quality All books are quality publishers editions especially selected by our Editorial Board All books are hardcover unless numbers are followed by a P for paperback Publishers Prices Shown 1988 ELECTRONICS BOOK CLUB Blue Ridge Summit PA 17294 0810 FREE when you join 15 Easy Electronic Projects From Delton T Horn Projects you can build some unique some old favorites from the author s vast treasury of elec tronics know how E ectroncs Book Ciue Biue Ridge Summit PA 17294 0810 Please accept my membership in the Electronics Book Club and send the 5 volumes listed below pius my FREE copy of Delton T Horn s All Time Favorite Electronic
192. impartial For many years Herb was in the radio and television industry He started out as the technician who lit the fuse to ignite a pyrotechnic device in an ascending rocket for the Captain Midnight show in the early fifties He then went to Station WNYE at Brooklyn Technical High School where he spent most of his time at the FM station as an engineer Herb enjoyed the inquisitive mind of the J Students at the high school and thus began his free lance writing career so that he could reach out to the many others who shared the hunger for electronics project building ideas When he retired from the radio Station Herb went to work for Radio Electronics our sister publication as an associate editor He was more than what his title indicated Herb was an inspiration to the entire company especially to the editors of both magazines He set up our photographic studio so that project and product photos would be of the quality re quired for our publications Herb leaves behind a magnificent family Nancy his wife is a beautiful person whose comments from time to time contributed to the contents of his articles and this magazine She is blessed with an uncanny hearing ability that assisted Herb in rating high fidelity head phones for many years Celia his eldest child in an accomplished author Her science fiction book is a win ner Larry is first entering the business world after an outstanding college career He is a superb compu
193. inary 0 appears at the input and the variable itself is used when a binary 1 state occurs The other two conditions that pro duce a binary 1 output are ABC and ABC Finally the output expression is built by oring together the three input conditions that cause a binary 1 to ap pear p D ABC ABC ABC The corresponding circuit is shown in Fig 22B That procedure works regardless of the number of inputs used As the number of inputs increases the Boolean expressions become far more complex As it tums out most of the larger more complex networks can be simplified by the use of Boolean rules In the next installment we will intro duce the Boolean rules and show you ways to tum complex circuits into sim pler ones But first another exercise problem can be found on page 94 Why not tum there now to check your understand ing The answers to all of problems in this month s installment can be found there a Continued on page 94 6861 AYVONVS d O HANDS ON ELECTRONICS POPULAR ELECTRONICS TSM VEGAS KIT he TSM Vegas Kit TSM 99 is a fes tive light display When as sembled the Vegas Kit is a fascinating hypnotic lighting device which can be both relaxing and amusing A long se quence of changing light patterns gives the display a dancing quality that appears to have motion and depth A speed control can be set to suit the mood of the observer The two board kit holds the light emitting d
194. indeed 4 s inches 2 18 WOOFER 100 oz magnet 3 voice Coll 250 watts RMS 350 watts max 8 ohm 30 Hz Made in U S A 100 WATTS resonant frequency 22 2700 Hz RMS response Efficiency 95 dB 1W 1M Paper cone treated accordian surround Net wt 29 Ibs 290 200 9880 8950 a U PIONGER HORN TWEETER Exponential horn design Mylar dome 3 x 3 j 1800 20 000Hz response 35 watts RMS 50 watts max 270 050 650 590 1 9 10 up 3 WAY 100 WATT CROSSOVER t34 12 dB octave rolloff 800 Hz 5000 Hz 8 ohm 100 watts RMS 260 210 1250 995 9 10 up 8 30 am 6 00 pm EST Monday Friday Mail order orders exceeding 5 ibs CIRCLE 16 ON FREE INFORMATION CARD customers please call for shipping estimate on EMINENCE 6861 AHYYNNYTF wn MICROCOMPUTER MARKETING COUNCIL JDR Microdevices 30 DAY MONEY BACK GUARANTEE 1 YEAR WARRANTY ON ALL PRODUCTS TOLL FREE TECHNICAL SUPPORT e COMPLETE CUSTOMER SATISFACTION SUPERIOR SERVICE FRIENOLY KNOWLEOGEABLE SALES STAFF EPROMS SIZE SPEED 1024x8 450ns 204828 450ns 20488 350ns 40968 450ns 409628 250ns 819228 250ns 192x8 450ns 819228 250ns 8192x8 200ns 8192x8 350ns 16384x8 250ns 16384x8 200ns 32768x8 250ns 32768x8 250ns 3276828 200ns 6553618 250ns 65536x8 250ns 131072x8 200ns CO PROCESSORS 8087 5 MHz 99 95 8087 2 8 MHz 159 95 8087 1 10 MHz 229 95 80267 6 MHz 179 95 80287 8 6 MHz 249 95 80287 10 10 MHz 309 9
195. into your computer enter Listing 1 and immediately save the program to disk to protect yourself in case of a system crash After loading the pro gt PRINT MIDS YS I1 1 PRINT USING PRINT T1S PRINT T2S PRINT XS print y axis lable lable y axis loop RER HE S I gram and typing iN RUN GNC RETURN you should see a page of text appear on the screen In it are instructions on how to use the program For testing pur poses disregard the waming about making modifications and press the space bar to continue if you have entered the program correctly you should see the text page replaced with a graph carrying the very technical sounding title THIS IS THE FIRST TITLE LINE OF THE GRAPH followed by another title line The title lines are a good example of the program s frills When using the pro gram you will replace those lines with the title of your particular graph You LISTING 1 continued 1620 NEXT I 1630 1640 JS STRS XMAX 1650 DX XMAX XMIN 10 1660 FOR I 0 TO 8 STEP 2 1670 J XMIN I DX 1680 LOCATE 23 7 I 7 PRINT USING 1690 NEXT I 1700 LOCATE 23 81 LEN JS gt PRINT JS lable x axis loop J 1710 kkkkkk MAIN PLOTTING SECTION 888 XRRRRRAARR ARR H 1720 1730 SX XMAX XMIN 560 1740 1750 FOR ML 1 TO 2 1760 FOR X XMIN TO XMAX STEP SX 1770 IF ML 1 THEN GOSUB 8000 ELSE GOSUB 9000 1780 IF Y lt YMIN OR Y gt YMAX THEN 1820 out o
196. iodes on one board eight radials of red and green LEDs eight LEDs per radial and all the elec tronics on the other board The circuit board contains a diode bridge for rec tifying 9 volts AC Its output is passed through two 5 volt regulators Two pre programmed ROMs contain the light ing sequences and are used to control 16 switching transistors Construction The light display goes together with a minimum of trouble By following the simple instructions the two boards can be wired quickly Con necting the LEDs may take some effort because there are 64 of them that s 132 solder connections Each LED has a series Current limiting resistor which ERA REN oy This is the circuit board that contains the brains for the Vegas Kit Two pre programmed ROMs marked X and Y provide almost 800 different patterns CIRCLE 35 ON FREE INFORMATION CARD It s a star burst cartwheel chase light it s everything 64 LEDs can do to entertain means an additional 132 solder con nections Get past that phase and the rest is a piece of cake A ribbon cable is supplied with the kit to use as long jumpers and for inter connecting the two boards Unfor tunately the individual wires were stranded discarded the cable and used one from my junk box that was a bit more colorful and had solid wire The solid wire would help me avoid twisting and pre soldering of the wire ends and the trouble of fitting the pro ces
197. is an or gate followed by an inverter The output is binary 0 if at least one of the inputs is binary 1 Otherwise the output is binary 1 The NOT oR Circuit shown in Fig 5A Clearly illustrates the circuit s function but usually one of the symbols in Fig 5B or 5C is more often used The truth table shows the possible input and output states IC nor gates are available with 2 3 4 5 8 and 13 inputs Expressing Logic Mathematically To begin using Boolean algebra we need to find some way to express the basic logic operations using mathe matical expressions Lets take a look at ways of expressing inversion AND OR NAND and Nor Operations As you leam the basic rules keep in mind that the binary signals to be pro cessed by the logic circuits are known as variables Variables are signals that can change value Binary variables can have one of two values those val ues are 0 and 1 Variables are usually given names to distinguish them from one another Letters of the alphabet are the most common although numerous other al pha or alphanumeric names are also used Usually signals are given some variable name mnemonic that is sim ply a shorthand way of referring fo the Fig 4 A NAND gate is nothing more than an inverted AND B Its output ts the compliment of an AND gate s C OUTPUT Fig 5 A NOR gate is nothing more than an inverted or B Its output is the compliment of an OR gate s
198. ite a binary 1 when both bits are 0 and when both bits are 1 The remaining input states produce a binary 0 output INPUTS OUTPUT Fig 21 The truth table A generates a sum of products equation for circuit B Now we can write the equation for the circuit We took at the output col umn and note the places where the binary 1 s occur Then we write an AND ed expression using the inputs The first binary 1 output occurs if X O and Y 0 Therefore the equation for that state is Z XY The other binary 1 output occurs when X 1and Y 1 Therefore the input ex pression is Z XY To complete the Boolean expression we simply or the two AND expressions together That is because the output becomes binary 1 under either con dition The resulting output expression Z XY XY The resulting circuit is illustrated in Fig 24B Let s take it one step further and de velop a more complex circuit Sup pose we have three inputs and the desired outputs are indicated by the binary 1 s in the truth table of Fig 22A To deveiop the output expression for a m B B 8 aS a 0 1 1 1 1 Fig 22 The conditions for a binary output A must be ORed together to produce the Boolean equation B the truth table write an AND expression using the input variable for each place where a binary 1 appears in the output The first AND expression is ABC The vari able with the not sign is used when a b
199. ith a felt tipped pen For example pins 1 of U U2 and U3 are located in holes 19G 10F and 37F respectively It s a good idea to use sockets as the author did for the IC s aside from making IC re placement easier doing so also pre vents possible damage to those parts during soldering After the sockets have been mounted in the proper locations install the jumper connections designated J guided by Fig 3 The horizontal jum pers may be bare wire all others should be insulated to prevent shorts Next begin installing the support com ponents starting with the resistors then the capacitors and finally the crystal XTALI Solder extra long color coded wires to the board for the off board compo nents Then as the positions of the off board components are established with respect to the case cut the wires to the proper length and solder them to the components If you suspect that the wires will interfere with IC installa tion insert the IC s before soldering the wires to the off board components Enclosure Any suitable case may be drafted to house the finished circuit Mount the power supply terminals or jack the input jack the switches St D4 b a f 03 0201 d e O06 D5 D7 Fig 3 Here is the parts placement diagram for the author s prototype of the lO MHz Frequency Counter It was assembled on a universal printed circuit board Note that the display is not shown in the layout However by following the con
200. its are connected by a single conductor and that the cathodes of all segments of any one digit are connected to a common terminal Thats accom plished by a printed circuit within the display and limits the number of wires or traces needed to operate the dis 6861 AHYYNNYT 5 HANDS ON ELECTRONICS POPULAR ELECTRONICS ao 5V XTALI 5 5 24288 MHz T TEMP JUMPER o oO SEE TEXT 7 23 27 Lux COMMON Fig 1 The 10 MHz Frequency Counter consists of UI an ICM7208 seyven decade counter U2 an ICM7207 oscillator controller and U3 a CA3130 biFET op amp The display for the circuit can be any seven digit seven segment common cathode multiplexed unit play Such units may be salvaged from an appropriate old calculator or pur chased from electronic surplus stores A multiplexed display can also be fabricated from discrete seven seg ment display modules as shown in Fig 2 More display modules can be add ed as needed Duplicating the display shown in Fig 2 is easy simply connect all like pins in parallel as shown For example pin 1 of the first seven seg ment unit which for this particular display is segment a is connected to pin 1 of all the other modules Pin 3 is the common cathode connection it is not connected to the other pin 3 ter minals in the set which is used as the digit driver DI D7 input Note that for the display modules s dp 6 f ac TO
201. its in the ever growing car audio service business tools needed for the installation business the troubleshooting service installation and This informative videotape is also an excellent removal of car audio products is a large non com aid to the electronics technician in that it gives petitive profit center for your service facility This the correct procedure for removing and replacing thirty minute video introduces you to the ever any car radio from the dashboard of any car increasing complex world of car stereo installa and shows the installer s salesperson s and cus tion It guides the new installer or owner in the tomer s role in the installation and sale of car correct layout and design of a car stereo installa audio products KEY TOPICS COVERED J for installing car audio equipment The technical resources available for information about specific types of vehicles dashboard dis mantling speaker sizes and antenna locations Speaker wiring types found in the automobile Common and floating ground systems how to differentiate Proper wiring procedures used in the car IN THIS VIDEO The design and layout of a Car Stereo installa tion center Basic and specialized tools needed for car audio installation work Safety in the shop How to treat the cus tomer s car from pre instal lation checkout to demon strating to the customer the completed job The proper
202. l parts in the machines increas M A CHRONICLE OF CONSUMER ELECTRONICS R CIRCLE 63 ON FREE INFORMATION CARD ing their reliability and bringing down their cost Then in 1981 the International Telegraph and Telephone Consultative Committee adopted a set of standards that made it possible tor most units regardless of manutacturer or Country of origin to communicate with each other Suddenly the tax machine was the hot new business and communications tool Today there are about 30 manulacturers of the units and some 100 models on the market The Toshiba Facsimile Machine 3300 is arepresentative example of the units that are gaining favor with all kinds of busi nesses institutions and professionals GIZMO s encounter with the 3300 makes clear the reasons for the explosive growth in fax use Once the simple protocol ot usage is understood that machine is extra ordinarily easy to Operate If a person can use a telephone and a copying machine he or she can use a fax Outfitted with a telephone handset that GIZMO Page 1 VOLUME 2 NUMBER 1 6861 AHYNNYF 4 HANDS ON ELECTRONICS POPULAR ELECTRONICS includes a keypad the 3300 also incorpo rates a Second phone keypad and can memorize 30 fax numbers dedicated fac simile transmussion phone lines and an other 30 non fax numbers Other telephone features include last number re dial speed dialing from memory handset volume control on h
203. l speaker Getting Started For your first experi ment suggest that you use a 4 inch speaker that has a well suspended cone The speaker cone is expected to bear the weight of the mirrors and the mount which may result in severe dis tortion if the speaker Cone is not rug ged enough The mirrors are ideally of front sur faced thin glass or plastic Front sur faced mirrors are available ina variety of sizes and thicknesses To help deter mine mirror size it is suggest that you build an experimental unit using fe flective foil Many art stcres sell reflec tive foil by the foot It is easily peeled from its substrate and transferred to a piece of very smooth cardboard or Generate eye catching patterns that change in cadence with an audio signal with this sound activated kaleidoscope BY DR DON H ANDERSON i Fata Shown here is the projection lens mounted in a cardboard tube ready for installa tion on a cloth covered cardboard base plastic sheeting The surface that holds the reflective foil should be as free from defects as possible because the film will bring out any the defects in the surface Because the unit is to be experimen tal its assembly need not be super crit ical The mirrors angled at 60 are mounted on a thin aluminum piate which Is then mounted on a small pa per cylinder That assembly is then glued to the cone of the speaker For particles crumpled bits of alumi nu
204. l specified You can use the Counter to perform 5 Poste Sevae STATEMENT OF OWNERSHIP MANAGEMENT AND CIRCULATION pia TITLE OF PUBLICATION HANDS ON ELECTRONICS J FREQUENCY OF ISSUE MONTHLY 4 TE MAILING ALDATSS OF ENOAR 00 B BI COUNTY BLVD FARMINGDALE N Y 1 s COMPLI VE LING ADDGESS OF THe hta RTT AS OF GONEF AL BUSINESS OFFICES OE THE PUBLISHER Yur anaro 500 B BI COUNTY BLVD FARMINGDALE N Y 1 Puke WAMES AND COMPLETE MAILING ADOMESS OF PUBLISHER EDITOR AND MANAGING EDITOR Tres item MUST NOT 00 dient PUBLISHER Nome end Compin Mading Adorer LARRY STECKLER 500 B BI COUNTY BLVD FARMINGDALE N Y Assembled on a universal printed circuit board the Counter requires several jumper wires to complete the circuit paths numerous functions including Mea sure the input and output frequencies of digital devices measure the speed of motor shafts precisely adjust the output of signal generators set audio signals to the exact pitch determine Computes Grade 5VDC 3 Amps 12VDC 6 Amps SVDC 0 5 Ames REGULATED LINEAR POWER SUPPLY 24 ea Bench Style Great for Hobtiests Plug in WALL the exact values of RC timing compo nents and measure any frequency between 1 Hz and 10 MHz its a sure bet that once you ve used your Counter for a while you won t be able to get along without it zy MAGNAVOX AMBER PC MONITOR 12 Tube TTL Level Digital VIDEO 20 MHz Bandwid
205. lator that permits the use of a tape recorder as a DC voltage monitor automatic internal resistance ohmmeters and modified emit ter followers with zero insertion loss The book discusses controlled timbre tests and digital logic troubleshooting ground rules with examples of oscilloscope applications it describes a simple arrangement for us ing a tape recorder as a digital data memory storage unit and cites the causes of circuit loading when a meter is applied in a comparatively high resistance circuit With step by step instructions and de tailed illustrations the handbook is easy to use It presents quick tests and testing tips professional advice on how to get the most from new electronic test equipment and new ways to use conventional test equip ment Many new servicing techniques were specially developed for this book Bob Middleton s Handbook of Electronic Time Savers and Shortcuts is available for 16 95 from Prentice Hall Business and Professional Publishing Englewood Cliffs NJ 07632 CIRCLE 99 ON FREE INFORMATION CARD UNDERSTANDING MAGNETISM Magnets Electromagnets and Superconducting Magnets by Robert Wood While scientists try to decipher its myster ies people are using magnetism every day unaware of the scope of its influence on their lives That invisible force of attraction is one of the fundamental forces in the uni verse This book examines magnetic phe nomena and the relationship betwe
206. le The Personal Facsimile M1200 from Murata Business Systems 4801 Spring Valley Rd Dallas TX 75244 incorporates the functions of a telephone facsimile machine and a copier into a unit weighing less than ten pounds Its telephone features a keypad offering all standard phone features and the M1200 s automatic manual receive lets the fax operate either manually or automatically eliminating the need for a dedicated phone line In transmission the machine ofters normal and fine print resolutions and is compatible with both group 3 and group 2 fax machines Murata calls the M1200 an affordable alternative to comparable equipment for first time and low volume users Price 899 95 CIRCLE 46 ON FREE INFORMATION CARD Electronic Cooking Timer Experienced cooks know that a big part of meal preparation is timing specifically getting everything onto the table at the proper time Hammacher Schlemmer 147 E 57th St New York NY 10022 distributes the Time after Time Electronic Cooking Timer that the firm calls the only five course culin ary timer on the market The device uses five individual timers to synchronize the preparation of up to five different parts of a meal After entering the cooking time of each tood the unit s electronic processor calculates a schedule an alarm and LED signal alert the cook to begin dking each of the items After all foods have been cooked an alarm sounds and the meal is ready to be served The T
207. lows users to greatly re duce the number of key strokes needed for even the most complex and seldom mastered WordPerfect functions The pack age also includes 50 pre formatted page style setups and a guide to WordPerfect s keystrokes The system offers mnemonic key strokes that are named for every WordPerfect Com mand P for print BOX for box line draw ings etc allowing even novices to ad vance quickly through word processing com mands without constantly referring to the manual More than half of the macros fea ture pop up tips prompts and instructions PerfectPal version 5 0 commands include moving copying text in two key strokes one stroke tab sets pre set sorts and fonts easy merge and simplified math and desk top publishing All those and more are accom plished in one or two keystrokes instead of struggling through layers of menus Other complex tasks including columns cross references and lists are also pre coded Pop up instructions help the user master setting up tables of contents indexes book chapters and graphic images PerfectPal can automatically map the key board with special science or math Signs or foreign language Characters With one macro it can Change the keyboard to Span ish for example and back to English again with another macro Specific routines for the legal profession are also included The PerfectPal package including two system disks two 3 by 18 inc
208. lue of l the SCR begins to conduct and the lamp lights Using a standard 3 amp 50 volt SCR con duction begins at an of perhaps about 0 5 mA 12V RI 27082 50K SEE TEXT Fig 1 The SCR Tester which provides a visual indication ts simply a voltage source an indicator lamp and a resistor through which gate current is supplied You can make an additional test by supplying the current from an adijusta ble voltage source enabling you to determine the SCR s turn off point Close K then temporarily close G Re duce the anode to cathode supply to about 2 0 volts retum to 12 volts and note that the lamp remains lit Further reduce the supply to about 1 0 volt and repeat the check You ll find a point where if the supply is reduced under the holding level the SCR won t con duct when full voltage is retumed It has reverted to the off condition Brian Conklin Enid OK Thanks Brian That s a nice piece of work and know that you re going to enjoy the Fips book It s on the way Simple Burglar Alarm Parents usu ally dont have a lot of respect for the abilities of their kids I m in high school and heard dad saying at the dinner By Byron G Wels table that if he d get a burglar alarm for his store he could cut down on the cost of his insurance premiums Being an electronics hobbyist offered to build him one got a Thats a good boy look and the matter was dis mi
209. m es a cassette you may be able to use a thin flat wire that can be routed so that it exits the tape player opening without foo much stress Now drill a small hole in the cassette cartridge right behind the metal tab so that the tiny wires from the coil can pass through it into the body of the cartridge Remove the enamel coating at the coil ends by passing them through a Continued on page 101 6861 AYVNNVS HANDS ON ELECTRONICS POPULAR ELECTRONICS Oo Oo a t Sound Activated aleidoscopes have been popular for ages and over the yearn a wide variety of kaleidoscopes have been developed Most have de pended on rotation of either the mir rors Or particles imaged in them to provide a multiplicity of changing pat tems In the 1950 s a kaleidoscope in which the particles were caused to move in cadence with music was shown on television The Sound Acti vated Kaleidoscope described in this article accomplishes the same ihing using readily availiable materials The kaleidoscope can be built to be viewed directly and sound be it from radio tape recorder or the human voice can be used to move the pari cles It can also be coupled to a musi cal instrument through a contact microphone I ve had the greatest success when coupled the kaleidosccape to an elec tric organ and projected the image of the moving particles on a screen in front of the organist The heart of that unit was a smal
210. m foil either plain or colored like florists use works well Bits of plastic Insulation from some brightly colored wire can be used Another alternative provided you are located in an area of low humidity is to use the brightly colored particles sprinkles that are used as cake and cookie decorations high humidity would cause the sprin kles to bond together Construction Begin construction by cutting two pieces of cardboard or plastic to about 2 by 3 inches Be sure they are the same length and wid th they ll be used to form the reflecting surfaces in the kaleidoscope Apply the foil to the cardboard or plastic Use thin transparent plastic film to provide the window area Be sure that the film is stiff enough to hold the mirrors in position after cementing without buckling The clear film is the window through which the display will be pho tographed If you use a video Camera If you make a projection unit the win dow will be used fo illuminate the par ticles For assembly a support can be made by gluing two pieces of comu gated cardboard together with the corrugations at right angles The win dow material is cut about inch wider than the mirror panels but of equal length Refer to Fig 1 As shown one of the mirror panels is pinned to establish the spacing of the parts during cement ing Pinning the window material down as shown in Fig 2 allows the two mir ror panels to be properly ananged Tw
211. m to have more color bands than resistors do Are they read as microhenry or millinenry Incidentiy to make the RF Sniffer more sensitive replace the telescoping antenna cut an 8 inch length of 75 ohm coax and remove the vinyl sleeve the outer braid and the center conductor wire so that ail that is SARE Volume 6 No 1 January 1989 Steckler EHF CET Editor In Chief amp Publisher Art Kleiman editorial director Julian S Martin KA2GUN editor Cari Laron WB2SLR managing editor Robert A Young associate editor Herb Friedman W2ZLF associate editor John J Yacono associate editor Brian C Fenton associate editor Byron G Wels K2AVB associate editor Teri Scaduto assistant editor Kathryn Campbell editorial assistant Ruby M Yee production director Karen S Tucker production manager Robert A W Lowndes editorial associate Marcella Amoroso production assistant Andre Duzant technical illustrator injae Lee assistant illustrator Jacqueline P Cheeseboro circulation director Nancy Estrada manager HOE Bookstore BUSINESS AND EDITORIAL OFFICES Gernsback Publications inc 500 B Bi County Boulevard Farmingdale NY 11735 516 293 3000 President Larry Steckler Vice president Cathy Steckler Cover photography by Diversified Photo Services Composition by Mates Graphics Advertising Sales Offices listed on page 106 Hands i Electronica HERO Ropulei Electronics ISSN ters zaen Posteo
212. me by identifying the start of the primary and secondary windings Connect the start of each winding as indicated in Fig 2 When in doubt you may make a simple power indicator from a NE 2 neon lamp and a 220 000 ohm half watt resistor connected in series Con nect the lamp to the cathode of D2 and the lamp will glow much more brightly when the right combination of winding polarity is connected The Flash Lamp Circuit Previously we mentioned that there is a rela tionship between lamp luminance and the size of the main capacitor A unit rated at 33 uF will provide 2 watt seconds W S of light output With our Circuit the flash rate is adjustable from one every 30 seconds to one every 4 seconds using R4 You may want to experiment with different capacitor values to obtain the desired light out put at the desired flash rate For instance a 10 F capacitor in gt h 6 8K R4 1K C2 01 4 2200RF INg148 1 6 CO4584 R2 10K u 10 330pF a a1 i 0 130 12 6 Our Circuit will produce about 3 of the maximum attainable light level while providing a rate of nearly one flash per second at R4 s maximum setting That rate would be better suited to night photography of the flight sequence A slower brighter flash is ideal for re covering the rocket in the daytime when visibility of the flash is at its worst A long battery life at a slow flash rate is possible by setting R4 to mini mum We strongly rec
213. mputer fun damentals right up to writing practical pro grams to control specific robotic operations using NRI s Robotic Programming Language software included in your course Your success is assured by your personal NRI instructor whose expertise and personal guidance are always available to you whenever you need a helping hand along the way Get training you can build a career on send for your FREE catalog today See for yourself how NRI s breakthrough train ing can put you at the heart of the robotics revolution Send today for NRI s big 00 page fullcolor catalog that gives you all the details about NRI s exciting new training in Robotics Technology plus training in computer elec tronics TV video audio servicing electronic music technology security electronics and other growing hightech career fields If the coupon is missing write to NRI School of Electronics McGraw Hill Continuing Educa tion Center 3939 Wisconsin Avenue Washington DC 20016 ca iy E i B ii McGraw Hill Continuing Education Center ane 3939 Wisconsin Avenue Washington DC 20016 For career courses approved under GI Bill check for details v Check one catalog only Robotics Technology Computers and Microprocessors Io Security Flectronics 4 Flectrone Music Digital Electronics Servicing TV Video Audio Serving J Communications Electronics CJ Telephone Servicing _ Data Communications
214. ms smoke gas water detection BP65 SINGLE IC PROJECTS 5 75 All projects iN this DOok are based on one IC and are swnple lo construct Great way to get Started with C s SORRY No orders accepted Number of books ordered C outside of USA and Canada 4 00 7 50 pre Equrvaternt BP198 AN INTAO DUCTION TO ANTENNA THEORY 6 95 Basic concepts relevant to receiving and transmitiing antennas BPBS INTERNA TIONAL TRANSISTOR EQUIVALENTS 7 50 Locales possible substitutes tor a popular user onented selection of modern transistors Japa nese European and Amencan types BP49 POPULAR ELECTRONIC PROJ ECTS 5 95 A collection of wide range of electromc proyects and arcurts tor the exper mente Total price of merchandise Sales Tax New York State Residents only Shipping see chart All payments must be in U S funds Lema a a a eB EE OE BEBE ee EEE Eee ee ee ee ee eee ee eee eee eee ee Total Enclosed BP146 THE PRE BASIC BOOK 6 95 A book on the BASIC programming tor those who have not yet bought a Compuler as wel as those who have Irouble learning how to program lectronics Paperback Books _ BP239 GETTING THE MOST FROM YOUR MUTLIMETER 5 95 Covers basics of analog and digital meters Methods ol component lesing inciudes transistors thyrtsiors resisiors capacitors and olher acte and passive devices Elec tranic 25
215. my wife didn t like the constant beep beep beeping as she called it and she offen caught the kid prac ticing and grinning at her at the same time and wished she knew what he was saying This Circuit simple as it is solved the problem In Fig 5 Capacitor C1 charges through resistor M and when the gate level established by potentiometer R2 is high enough the SCR is triggered Current flows through the SCR and ear phones discharging C1 The anode voltage and current drop to a low TD AC DUTLET HDT NEUTRAL SEE TEXT Fig 4 This Battery Charger provides a heavy charge to depleted batteries which diminishes as the battery advances toward full charge level so the SCR stops conducting and the cycle is repeated Resistor R2 lets the gate potential across C1 to be ad justed which changes the frequency or tone R1 A acd p O gt Fig 5 Shown here is the Code Practice Oscillator which consists of only five components feeding 8 ohm headphones Use a pair of eight ohm earphones The telegraph key goes right into the B line a nine volt battery All is quiet around the house now Building this oscillator for my son has demonstrated that l m a doting father my wife now greets me at the door with a kiss instead of a scowl and I m sav ing a fortune on aspirin Thomas Dickinson Sioux Falls SD Okay Tom You re also saving a for tune a small one on your free cop
216. n 27 Trans World 105 15 United Electronic Supply 17 21 Viejo Publications 99 24 Windsor 103 ADVERTISING SALES OFFICE Gernsback Publications Inc 500 B Bi County Bivd Farmingdale NY 11735 516 293 3000 President Larry Steckler Vice President Cathy Steckler For Advertising ONLY 516 293 3000 Larry Steckler publisher Artine Fishman advertising director Christina Estrada advertising assistant Shelli Weinman advertising associate Lisa Strassman credit manager SALES OFFICES EAST SOUTHEAST Becky Akers Pattis 3M 310 Madison Ave Suite 1804 New York NY 10017 212 953 2121 MIDWEST PACIFIC Joe Shere 1507 Bonnie Doone Terrace Corona Del Mar CA 92625 714 760 8697 SCANNER SCENE Continued from page 93 way Department in Polk County FL has a repeater with the output on 159 135 MHz The input receive frequency that s 159 045 MHZ is just a mere 5 kHz away from one of those frequencies 156 05 MHz The repeater manages to pick up illegal maritime transmissions on 156 05 MHz and repeats them slightly distorted on 1599 135 MHz That results in no small amount of fishing boat chatter being blasted throughout the county thanks to the powerful High way Department repeater Looks like its probably worth putting your scanner into the search scan mode between 156 025 and 156 25 MHz to see if any of that activity is go ing on within
217. n SCR When low level audio ts pres ent across T1 SCM is not triggered into conduction A louder signal however triggers the SCR so that the lamp lights and follows the sounds Since SCM is operated by an alternating current the rectifier moves out of the ava lanche condition when gate current is low If you scale the circuit down to use 12 volts or any other lower voltage cur rent has to come from a line trans former A DC supply can t be used or SCM continues to conduct once it is triggered to the on condition Variable resistor R3 lets you adjust the power reaching transformer T1 so that with normal operating volume SCM trig gers again and again except during quiet passages When building such a Circuit safety must be kept in mind A breakdown in Ti could slap the line voltage into your audio system and with many of the amplifier circuits you just cannot ground T1 A low rated fuse should be included in the live half of the line con nector A safer way to do things is with Continued on page 106 SING WITH THE WORLD S BEST BANDS A virtually Unlimited supply of Backgrounds The Thompson Vocal Eliminator can remove most or virtually all of a lead vocal froma standard stereo record or CD and leave most of the background untouched Record with your voice or perform five with the backgrounds Used in Professional Performance yet connects easily to a home component stereo Mot an equalizer We can prove it works ov
218. n order to make a massive attack on a Zenith dial Well George agree with you The Crosley is a good subject and the let ters I ve received about it including your Own long one were very interest ing indeed And finally their time has REPRINT BOOKSTORE O 106 Radio Electronics back issues 1986 Write in issues desired O 105 Radio Electronics back issues 1985 Jan 85 not available Write in issues desired O 104 Radio Electronics back issues 1984 December 1984 issue is not available Write in issues desired O 103 Radio Electronics back issues 1983 5 50 Jan Feb May are not available Write in issues desired O 102 Radio Electronics back issues 1982 Jan Feb is not available Write in issues desired O 153 Etch your own PC boards O 154 How to Repair VCR s O 155 IBM Typewriter to Computer O 125 Radio Electronics Annual 1985 O 126 Radio Electronics Annual 1986 O 156 How to Make PC Boards O 157 Alt About Kits B B o B B B 3 75 4 25 5 25 5 75 2 158 Electro importing Co Catalog 1918 5 95 159 Low Frequency Receiving Techniques Building and using VLF Antennas 160 New ideas 42 Circuits 161 Descrambling Feb 1984 162 Build Your Own Satellite TV Receiver 7 00 163 Receiving Satellite TV O 164 Modern Electrics April 1908 O 165 How to Repair CD Disc Players O 166 Collected Works of Mohammed Ullyses fips 62 pages April Fools Collection O 167 Designing With
219. nal F See Fig 16 HO X A B CKD ENF Fig 16 The product of sums expression shown was used to generate this circuit Exercise problems Here are a cou ple of problems for you to practice on 4 Write the output expression of the circuit shown in Fig 17 2 Draw the logic diagram corre sponding to the expression M F G H J K L Assume no inverted signals are avail Fig 17 Write the equation for the circuit Truth Tables You have already seen how truth tables are used to define alll possible Combinations of inputs and Outputs for the various logic elements Truth tables however can also be used to describe larger more com plex logic circuits The nice thing about a truth table is that it gives you a com plete picture of what s going on in the Circuit for any set of input states Developing a truth table for any log ic Circuit is relatively easy All you have to do is write out all the possible input states and for each one compute the output state for every gate in the circuit until the final output is derived Let s take a couple of simple examples to show how you can evaluate the output state for a given set of inputs Take a look at the circuit shown in Fig 18A Where N is the number of in 6861 AYVNNVS j j HANDS ON ELECTRONICS POPULAR ELECTRONICS J o j INPUTS i Oe a OG o2O _2 6 amp oq OO OG OUTPUTS 2E INVERTER 2 GATE 3 G
220. nal load connected to SO Varying the setting of potentiometer R2 alters the phase timing of the trig ger pulses fed to the Triac and so alters the average power level fed to the load Resistor R5 and capacitor C3 form a snubber network across the Triac to protect it from back EMF voltages generated by inductive loads each time the Triac turns off Inductor Li a 50 H Choke and ca pacitor C4 form an interference sup pression filter Some of those essential components are often not incorpo rated in usual domestic light dimmer circuits BY LEO SIMPSON Wiring It Up You Could use a printed circuit board as the author did but for you to make just one etched board would be time consuming All that is needed is a perfboard and point to point wiring to interconnect and mount the components Should you plan to make several Samant 2 INCHES Fig 2 The same size foil pattern is how n here for those who wish to use a printed circuit board A perfboard circuit would operate just as well The circuit board was mounted in a plastic case to make a handy speed control The power cords are anchored with cord grip grommets A larger plastic case is required to mount an AC outlet socket on the case instead of the power cord 6861 AYVNNVS a an HANDS ON ELECTRONICS POPULAR ELECTRONICS units printed circuit board con struction is the way to go The single sided copper clad board is small measuring only 1 x 2i
221. nches You can make several from the standard size sheets available at most electronics stores Use the same size foil pattem shown in Fig 2 and mount parts on it using Fig 3 as a guide Since the circuit is electrically hot a plastic shaft unit is recommended for potentiometer R2 to minimize the pos siblility of shock If you cannot locate a plastic shaft potentiometer use epoxy to secure the knob to the potentiome ter shaft do not use the set screw Note that the board is designed to accommodate the special potenti ometer switch unit that the author used in the original prototype That unit may be difficult to find in this country It is perfectly acceptable to mount any 500K potentiometer switch combina tion on the case instead of the board and use leads to connect the parts Suitable units are available from Mouser Electronics 2401 Highway 287 North Mansfield TX 76063 and many other distributors C3 OUT Fig 3 The completed printed circuit board with all the parts in place is shown here You may have trouble finding the brass screw terminals so solder leads directly to the board from the power cords The bottom terminal was not used Choke Lt can be fabricated by winding 35 50 turns of No 18 20 enameled wire on a t inch OD out side diameter toroidal core If you wish you Can also use a J W Miller M5248 heavy duty hash choke avail able from Mouser and others that is a 68 H 5 amp unit but
222. nclined to wonder if automatic operation is all that labor saving the KD 67F s simple to use primary controls won us over After a while the prospect of lifting a tone arm off its stand and putting it on the edge of a record seemed like time consuming drud gery The music search system also turned out to be something more than window dressing But we wish that the department that designed the turntable s cover had got ten together with the designers of the man ual search system The semi translucent cover makes it impossible to visually cue up a cut While we experimented with shining a tlashlight beam onto the LP we finally deferred to reality and opened the cover when we wanted to skip a selection At least the search operation can be oper ated with one hand Selecting record size each time the power goes on seemed less than handy We also mourn the passing of manual pitch control Some of our favorite tunes sound better speeded up just a tad This turntable lacks that opuon But One indisputable advantage emer ged after our use of the unit Records picked up significantly less dust and visi ble residue than on our usual turntable Like tens of thousands of other audio slobs who listen to music in less than climate controlled conditions we ve gotten used to picking little mats of fuzzy lint off the Stylus before and after each record With this Kenwood linear drive turntable that became a hygienic ritual of the
223. nd showing correct date and day within 10 minutes of breaking it out of the package However as we discovered inad vertently later that same day we d man aged to unknowingly set the timepiece s alarm function Perhaps the least likable aspect of this budget priced watch was its so called one year warranty A close reading of the tiny type outlining the offer revealed that it would cost 3 95 10 offset the cost of handling to send it to the NDQ Service Center In any event repairs wouldn t be on the agenda Instead a replacement watch not necessarily the same mode but ot equal value and similar appearance will be sent to the warranty holder A 4 charge to replace a 9 95 watch would seem to be poor marketing arithmetic But a warranty and repairs aren t really the point with today s extraordinarily low priced electronic timepieces Those are really disposable watches timepieces the consumer can wear without worry and dis card with impunity Time may be money but keeping track of it has seldom been so cheap especially not at 150 feet under walter a 6864 AYVNNVS GIZMO Page 7 53 Gizmo Bytes Videocassette Organizer Electronic Cooking Timer Olympia Electronic Typewriter HANDS ON ELECTRONICS POPULAR ELECTRONICS 54 Page 8 GIZMC Satellite TV Receiver Decoder If you re considering getting into satellite TV reception but aren t interested in investing in a deluxe system
224. nection scheme outlined in Fig 2 almost any common cathode display can be used with the circuit PARTS LIST FOR THE 10 MHZ FREQUENCY COUNTER SEMICONDUCTORS LI ICM T2708 seven decade counter integrated circuit U2 ICM 72074 oscillator controller integrated circuit U3 CA3130 FET op amp integrated circuit RESISTORS All resistors are 4 watts 5 units unless otherwise noted RI 500 ohm R2 10 000 ohm R3 10 mezohm R4 33 4 ohm R5 3304 ohm R6 megohm R7 4700 ohm R8 470 000 ohm R9 2200 ohm Cl See text C2 22 pF ceramie disc CI 0 22 uF ceramic disc C4 l uF 50 WYDC subminiature electrolytic Ji Miniature closed circuit phono jack Sl Single pole double throw toggle switch 52 Single pole single throw momentary contact pushbutton switch ATALI 35 24288 MHz crystal Universal printed circuit board seven digit seven segment common cathode multiplexed LED display see text enclosure IC sockets power source see text wire solder J1 and 2 and the display on the front panel of the case The circuit board may be trimmed to about 5 inches long to keep case size ata minimum Use a nibbling tool to cut an open ing for the display but do not secure the display to the case until wires from the board have been connected If a trimmer Capacitor is used for C1 as will be discussed later drill a hole at the proper location to allow for any adjust
225. ng Calendar Not necessarily a new product but one that s proved its staying power the Electronic Reminding Calendar trom Hammacher Schlemmer 147 E 57th St New York NY 10022 can be programmed to signal special dates annual events or important deadlines The reminder is delivered with flashing LED lights which can be set for up to three days before the important date What the catalog calls its patented 60 year memory can store as many as 2000 different dates The calender also shows time and date and allows the review of all events entered into memory Two AA size batteries provide memory backup the calendar itself plugs into a standard wall outlet Price 79 95 CIRCLE 40 ON FREE INFORMATION CARD A V Receiver Does anyone own just a TV stereo and VCR anymore Our impression is that American consumers have moved on to the more elaborate home audio video entertainment center A new top of the line A V Receiver SA R530 from Tech nics One Panasonic Way Secaucus NJ 07094 is geared to that development with features designed to further integrate home electronic entertainment The unit includes a remote control with learning capability that Can serve as a central command unit over other infrared remote control video equipment The 103 function remote can learn the major Commands of most VCRs TVs and wireless infrared cable control boxes A major audio feature is a built in digital Dolby surround system through which t
226. nings and much more BP1S2 4ANTRO TO Z 90 MACHINE CODE 5 95 programs up your hey may be harder 10 wnle dul it s worth leaming how Some demo programs are included Wuality Paperbacks 5 Borni feed Crystal Sei wohor daaar BP12 DESIGN amp MAKE YOUR OWN PC BOARDS 5 75 Ev eryiting you need fo know belore you make panled citcut boards for your projects BP182 MIDi PROJ ECTS 6 95 Detads of how to inlertace many popular home computers with MID music sysioems 0 01 to 5 00 5 01 to 10 00 10 01 to 20 00 20 01 to 30 00 30 01 to 40 00 40 01 to 50 00 50 01 and above PCP102 INTRODUCING DIGITAL AUDIO 9 95 CD DAT and sampling Whal is involved in the cagrta pan of audo signais Principles and practices P195 INTRODUCTION TO SATELLITE TY 9 95 A definihve introduction to the subject written lor the professional engineer electromcs enthusiast or others who wan to know more betore they Duy amp x 10 CHECK OFF THE BOOKS YOU WANT SHIPPING CHARGES IN USA AND CANADA 1 25 2 00 3 00 5 00 6 00 of digital auto techniques X BP105 ANTENNA PROJECTS 5 50 Practical radio antenna designs that deliver good pertormance and are rer atively simple and inexpensive 10 Duid amp BPS6 ELEC TRONIC SECURITY DEVICES 5 50 Three basc sections Switch actvaled alarms intrared amp ultrasonic sys le
227. nnels numbered from 101 to 180 Scanner Market AOR scanners got their name after the callsign of the company s founder JATAOR AOR has brought out no less than three new scanners within the past few months giving it a well deserved place in the array of monitoring equipment avail able to monitoring enthusiasts of North America The AR 900 handheld scanner offers com plete public service band coverage and features a priority channel BNC anten na connector backlit LCD display there are lockouts a scan delay and other standard features along with recharge able batteries an AC adaptoricharger and two antennas all for a suggested retail price of 299 The latest entry from AOR is their AR 900 handheld scanner a small unit that offers complete public ser vice band coverage including 27 to 54 MHz 208 to 174 MHz 406 to 512 MHz and the hot new high interest 830 to 950 MHz band The AR 900 can operate on channels in 12 5 25 and 30 kHz increments Twenty five front panel keys allow programming of five banks of 20 channels for a total of 100 channels All information is retained in three state of the art permanent memories that won t get amnesia even if the batteries are removed or become drained Other features of the unit include a priority channel BNC antenna con nector and a backlit LCD display with 22 separate prompts to aid in pro gramming and to show the status of channels Of course the
228. not function properly if a black back ground is used For video purposes use either a neutral gray or a pale blue background If you have some light color spray paint available use it and see for yourself what works to your satis faction For video work illumination of the particles is done from above with the camera mounted on a tripod at an angle determined by the optics of the A mirror mounted atop the cardboard tube ata 45 degree angle and fitted over the projection lens allows the kaleidoscope images to be projected on a wall screen particular video Camera Here again what you have available dictates what you can do have close up lens attachments for my video camera and find that a lens with about a 2 inch focal length is quite satisfactory for use with a kaleidoscope The usual kaleidoscope pattern owes much of its fascination to the completely unpredictable patterns that come and go on the screen pre fer a variety of patterns that are com pletely unpredictable for certain applications but for demonstration purposes a pre recorded program is frequently desirable For video taping a defusion panel con sisting of frosted clear plastic can be fitted over the viewing window of the kaleidoscope lam currently building a unit that will project the pattern on the ceiling of a bedroom which is the easiest mode of projection Combined with soothing music it may have some therapeutic value For eithe
229. ns we see it turns out that the old cliche is wrong As far as Grapher is con cemed a picture is not worth simply a thousand words a picture is worth 5 600 words Printing Graphs If you would like to send the graphs you generate with the program to your computer s printer you can do so using the PC s lt SHIFT gt lt PRINT SCREEN gt keystroke sequence However because the graphs are dis played on the high resolution screen of the PC you must execute the Graphics Com file before you enter BASIC The graphics program will cause the picture to be rotated by 90 before being sent to the printer fo ac count for the differing aspect ratios That file which can be found on one of the DOS disks that came with your computer gives the computer the in telligence to use lt SHIFT gt lt PRINT SCREEN gt for graphics as well as text screens For more information on using that com mand please consult your DOS refer ence manual E TABLE 1 PROGRAM BREAKDOWN 1000 1040 and define Pi 1060 1280 1300 1320 Display instructions Wait for key press If E is pressed end the program Clear variables set to 80 column text mode clear screen 1370 Place computer in high resolution graphics mode and Clear screen 1380 1420 Draw horizontal and vertical axis 1440 Get graph values from subroutine 1460 1560 1580 1690 Label the axis Print graph and axis titles 1730 Calculate the horizontal step size
230. ny similar low cost single or dual op amp will work for U1 a Sound Activated Decoder fuming our attention to Fig 3 we see a piezo transducer performing double duty in that it operates as a sound pickup de vice as well as a frequency selective filter Transducer BZ1 is connected to op amp a just as in the previous cir cuit but with one notable exception a gain control potentiometer R3 has been added By controlling the gain of the op amps the oscillator circuit can be transformed into a sensitive and fre quency selective tone decoder cir cuit With the gain of Ul a set just below the point of self oscillation the trans ducer becomes sensitive to acous tically coupled audio tones that occur at or near its resonant frequency The circuits operation is compara ble to an early and popular type of radio receiver in which regeneration was used to achieve super high gains using relatively low gain amplifying vacuum tubes Regeneration is ob tained by adding a controllable positive feedback path between the receiver s input and Output circuitry And it was the gain obtained via re generation in receivers of the 1920s that tumed a simple one tube set into a world wide receiving station EAS 2 2K C2 RE 4 a 2 2K Cl R 220 10K 6 12V Lava 4 LM324 9 8 10 1 ca D1 R8 o CONTROL 1N914 220K DC Ah a OUT D2 C3 h ingt R 4 7 Fig 3 In th
231. o remove as much as possible with a broad putty knife being careful not to scratch the wood surface as you work The remains of the sludge are then mopped up with a cloth moistened in solvent leaving behind a clean as a whistle surface As soon as began the first mop up operation received a very pleasant surprise A beautiful wood grain pat tem was being exposed the grain was real after all What had looked prior to stripping like an almost bare grainless wood surface was really a layer of old vamish decomposed and whitened in some way by the effects of the explosion Working a little more enthusi astically now quickly removed the rest of the old finish Stripping may be a smelly messy job but it really doesn t take long to complete even for a large cabinet like this one had noticed too late by the way that the recommended mop up sol vent for the particular stripper was using was lacquer thinner didn t have any handy but made do with mineral spirits instead That worked fairly well but tended to leave behind little grains of solid sludge Those remaining grains were easily brushed off once the cab inet had dried but assume that they would have been dissolved and re moved during mop up had used the correct solvent When had finished with the cab inet still damp from stripper and sol vent it looked almost as if could apply the new finish without re stain ing But after ovemi
232. o build unlimited micro processor I O circuits Only 249 00 CLAYTRONICS Box 7293 Vallejo CA 94590 707 544 9903 PC boards made to order Details SASE Function Generator plans 3 50 Includes semiconductor bonus GALLIUM JUNCTION 540 C N E North gate Way Suite 542 Seattle WA 98125 PROJECTION TV Convert your TV to project 7 foot picture Easy Results comparable to 2 500 proj ectors Plans and 8 lens 24 95 Professional systems available Illustrated catalog FREE MAC ROCOMA 15HE Main Street Washington Crossing PA 18977 Creditcard orders 24 HRS 215 736 3979 PROGRAMMABLE CONTROLLERS POCKET CONTROLLER Versatile low cost pro grammable Digital Controller Designed for technician experimenter student anyone that deals with electronics Battery operated ow 69 95 For literature call 800 533 7159 in C 791 8220 or write Pocket Controller Company Box 232 Semour CT 06483 MASTERCARD AND VISA are now accepted for payment of your advertising Simply complete the form on this page of the Market Center and we will bill you ooo RADAR SPEED GUNS AND SYSTEMS i oe D Professional units for clocking speeds in skiing car amp boat racing etc starting at 269 used 350 reconditioned Mov ing and stationary units available with dual displays All units are road tested and have 30 day warranties Catalog 1 Complete line of TV ac
233. o pieces of masking tape placed along the bottom and top edges serve as a temporary support during the ce menting process Place a small amount of five minute epoxy cement along the joints Be careful that the cement does not get on the mirrored surfaces The first coat must be solid and completely dry be fore the second coat Is applied Doing Oe ee TRANSPARENT f FRONT WINDOW PINS CORRUGATED CAROBOARD TEMPORARY MOUNT DURING CEMENTING Pen ats sp aan not orioa sa bie mirrors or reflective foil Plastic sheeting or smooth cardboard 4 inch thick Clear plastic rigid thickness not critical White glue 5 minute epoxy cement Flat black spray paint Stereo amplifier optional see text A small slide projector or halogen flashlight i ojector lens or simple tens 4 to 6 _ inch focal length V jeo camera extension microphone Note ms a mirrors are WOODEN SUPPORT ANGLE ABOUT 45 DEGREES PROJECTOR LENS OR SIMPLE LENS IN A CARDBOARO TUBE LENS MOUNT SLIPS IN THIS CARDBOARD TUBE RUBBER BAND ENLARGMENT FOR SUPPORT ON BASE PLATE BASE PLATE TWO LAYERS OF CORRUGATED BOARD SMALL SLIDE PROJECTOR KALEIDOSCOPE UNIT HANDS ON ELECTRONICS POPULAR ELECTRONICS the joint between the base plate and the cylinder When all joints are set you can put particles into the kaleidoscope unit and test it with a small radio You ll find that the load of the kaleidoscope re
234. o telecommunications shows readers how to use their computers mo dems and telephones for at home shop ping and research and to get up to the minute financial travel and entertainment information It traces the development of telecommunications from the telegraph to i CATION i MUNIE ALET r JOHN C SANS JR the high speed digitai equipment in use today Communications technology includ ing micro to mainframe links local area net works multi user systems telephone switching techniques and error detection and correction is explained in clear text and with numerous illustrations The book details the basic components comprising personal computer communications sys tems terminais modems Serial interface cables and telephones Continued on page 12 EXPAND YOUR CAREER HORIZONS aaa ELECTRONICS EDUCATION OF TOMORROW TODAY E gcion jte of TORY pg LABORA gp TRAIN The CIE Microprocessor Trainer helps you to learn how circuits with microprocessors function in computers the handy reply coupon or card below to Cleveland Institute of Electronics Microprocessor Technology Satellite Communications 1776 East 17th Street Cleveland Ohio 44114 Robotics Wherever you want to go in electronics Start first with CIE m ggm AHO 104 Why CIE Because we re the leader in teaching i World Headquarters electronics through independent study Consider this We teach aver 25 000
235. oks dif ferent from conventional 35mm units includes a computer controtled autofocus lens built in motor drive and flash units automatic exposure capabilities motorized manual and macro focusing and a super high speed shutter The flash system alerts the user to underexposure before the picture is taken The Mirai lens is a variable tocus type rather than a conventional zoom lens Among its advan tages when combined with the camera s constant automatic refocusing ca pabilities is an unusually long focal range rated by Ricoh at 4 1 An exclusive programmed automatic backlight control metering system allows the camera to automatically increase or decrease the exposure in variable amounts to handle extreme contrast Another special feature of the Mirai is a special sensor film transport system using a double infrared system to read the film s perfora tions with a choice between continuous advance at two frames per second or single shot advanee The entire unit weights 33 ounces Price 795 CIRCLE 43 ON FREE INFORMATION CARD Checkbook Recorder A big trend in consumer electronics is getting personal with the Customers A recent example is the Personal Money Manger Checkbook Recorder from Canon U S A Inc One Canon Plaza Lake Success NY 11042 The calculator provides balancing calculations with transaction history storage function tor checking accounts and charge accounts The Checkbook Recorder can keep
236. om manuscript the typing of the same word twice in a row The beep sounds when the same word is repeated Finally Wordfind will reposition the type writer s print wheel under the incorrect word if the user has keyed in letters faster than the XL 2500 can print them Al though we re not particularly fast typists we regularly outran the machine s printing speed when the automatic return was en gaged There s a limitation to that too however As the owner s manual explains changing pitch in the middle of a line or using the half space feature deletes correc ton memory Standard typewriter features have been Streamlined and expanded with the XL 2500 Spacing between lines the user can select single double or one and a half Spacing pitch selection ten characters per inch Pica or twelve characters per inch Elite and automatic centering and return are all set or engaged by pressing the code key located on the bottom of the keyboard and one of the top row of keys each Clearly designated by a guide printed Just above the keyboard Enhanced fea tures that are engaged in the same manner are page end signal another beep and subscript and superscript clearly a feature borrowed from word processing pro grams One drawback ts that spacing must be reset each time the typewriter is turned On an easy enough adjustment but One that the novice XL 2500 user is likely to forget at least at first One design aspect
237. ommend the use of a 9 volt nickel cadmium Ni Cad rechargeable battery to save on bot tery costs An alkaline battery can also be used Regular carbon batteries work poorly because of their inability to supply the current needed for the Strobe circuit The average current consumption of the Strobe at 9 volts was measured at 230 mA at the max imum flash rate setting and 45 mA at the minimum setting Nickel cadmium batteries give a slower maximum flash rate because of their lower voltage The triggering circuit uses an inter esting trick See Fig 4 A small trans former T2 is grounded via an SCR connected to its primary When SCRI switches on the charge on C quickly travels through T2 s primary and the SCR to ground That induces a high voltage pulse in Tis secondary wind ing which ignites FL A simple and inexpensive trigger circuit kicks on SCRI when the charge on C7 is high enough to sustain the arc inside FU A voltage divider consisting of R and 300V TO HIGH VOLTAGE FLASHLAMP CIRCUIT ca 8V 330 1 02 E 1 6 04584 9 8 yen wo a SEE E 1 6 004584 ee TEXT 1 6C 04584 R5 EIK e DENOTES START OF WINOING _ Fig 2 Shown here is the schematic diagram of the PWM power supply for the Rocket Strobe which produces 300 volts from a 9 volt battery 18 i 12 mm mm A 1 5 PRI USE 2 CONNECT SEC SECONDARY 3 USE HERE FEED we 4 6 LEA
238. on Cassette ts inserted a flashing green light mounted in the shift lock key indicates mismatched ribbons and cas settes The company says that the correc tion cassette tor the XL 2500 and companion models is the first drop in correction cassette for a portable elec tronic typewriter The shift lock lnght in addition to indi cating that upper case letters are engaged flashes when the typewriter cover is not closed properly or the typewriter has re ceived an incorrect command That tea tures powers of interpretation however are fairly limited Perhaps it was merely our brief experience with the typewriter but the light seemed to fiash at least once every time we used the machine for rea sons we that couldn t discern The manual merely says that the cover should be prop erly closed or the space bar touched to stop flashing light Once we knew our way around it the keyboard was comfortable to use and had a fairly firm touch And the finished prod uct the typed page could stand com parison with pages issuing from type writers costing hundreds of dollars more Whether this lightweight machine which makes extensive use of plastic parts would give the years of use expected from more expensive typewriters is an open question Even today plastic has its du rability limitations Equipped with a snap in place cover and a bottom mounted carrying handle the XL 2500 s cord wraps neatly around a b
239. on Checkbook Recorder pg Integrated 35mm Camera _ pg Sharp CD Player pg oO O OO O oo OO O S VHS Compatible Monitor pg Integrated Answering System pg 10 pg 10 Quartz Halogen Video Light pg 10 Portable Computer Videocassette Labeling System pg 10 Wireless Headphones pg 10 A V Receiver pg 11 Electronic Reminding Calender pg 11 Phone Call Accounting System pg 11 Squelch Telephone Accessory pg 11 AM FM Stereo Receiver pg 12 Decorator Ultrasonic Humidifier ver pg 12 Dynamic Stereophone pg Prenatal Soundshare System pg a 7 Hu ite iid A ths a T dr e SOP g e Feaees Fax to the Max TOSHIBA FACSIMILE MACHINE 3300 Manufactured by Toshiba America Inc Telecommunication Systems Division 9740 Irvine Blvd irvine CA 92718 Price 1 995 95 In the world of consumer electronics the 1980 s might carry the designation decade of the facsimile machine Since 1981 the use of facsimile transmission de vices has increased dramatically By some estimates there are about two and a half million of those devices currently in use around the globe In the U S alone an estimated one and a half million ma chines will be in use by 1990 A decades old technology facsimile transmission took off as a result of a cou ple of factors In the early part of this decade digital microprocessors replaced mechanica
240. on of ST ducer with a resonance frequency of 2500 Hz was used in the circuit see the Parts List any piezo unit should work as long as the values of C3 and R2 are selected to tune to the transducer s op erating frequency With power on and S1 in the B posi tion adjust R2 for the loudest tone out put The circuit should be tuned to the resonance frequency of the trans ducer In that position the circuit can be used as an acoustical or tone sig nal encoder Next switch to the A position and aim an on frequency au dible tone toward the transducer the LED should light indicating a de coded signal The LED can be replaced by an op tocoupler or relay to control just about anything that s electrically operated A single op amp audio amplifier can be added between the transducer and U to detect weak audio tones Use the Ul a amplifier circuit shown in Fig 4 and select M and R8 to set the amp s gain as needed E EE BeanFCC LICENSED ELECTRONIC TECHNICIAN y i raged C ge j 5 E pA si Learn at home in spare time ee e H No previous experience needed No costly School No commuting to class The Original Home Study course pre pares vou for the FCC Commercial Radio telephone License This valuable license is vour ticket to thousands of exciting jobs in Communications Radio TV Micro wave Computers Radar Avionics and more You don t need a college
241. ones WH 100 can please both groups The company says that the Private Waves system relies on radio frequency transmission rather than infrared technology In contrast to other so called wireless headphones Private Waves offers range and sound quality both more sophisticated and flexible to a distance of 75 feet A compact transmitter is Connected to the audio out or headphone jack of aTV VCR stereo or CD player The lightweight receiver three and a half ounces clips to the listener s belt shirt pocket or other item of clothing Miniature headphones plug into the mini receiver and are powered by two AAA size alkaline batteries good for about 50 hours Price 99 95 CIRCLE 58 ON FREE INFORMATION CARD Videocassette Labeling System Drowning in a sea of uncertainly identified video tapes To transform your cassette collection into a file instead of a pile Discwasher Inc 4310 Transworld Rd Schiller Park IL 60176 has introduced its Professional Video Cassetie Labeling System Labels are inserted into see through plastic label sleeves that adhere to the spine of the cassette Discwasher thinks the system will put an end to the video heartbreak of label build up which the company calls a sticky problem The basic Video Cassette Labeling System includes 5 double sided paper labels and five label sleeves for both VHS and Beta tape cases Price 3 99 CIRCLE 41 ON FREE INFORMATION CARD Integrated Answe
242. ontrol ele PARTS LIST FOR SPEEDI WATT RESISTORS R1I 2200 ohm Va watt fixed resistor R2 500 000 ohm potentiometer PC mount optional includes switch S1 R3 2 megohm trimmer potentiometer PC mount R4 10 000 ohm Y watt fixed resistor R5 1000 ohm 1 4 watt fixed resistor CAPACITATORS Cl 047 p F 400 W VDC Mylar or ceramic capacitor C2 047 wF 100 to 400 WVDC Mylar or ceramic capacitor CI 033 F AE WY DC Mylar or ceramic capacitor C4 _01 pF 200 WVDC Mylar or ceramic Capacitor ADDITIONAL PARTS AND MATERIALS Di Diac 27 37 volt A0 volt nominal 50 mA Teccor HT 32 or equivalent L JI S0 H choke 4 amps sce text PL I Plug 4 terminal AG power type Ol Triac 200 volts AC 4 amps GE type CIOSRI or better SI SPST switch part of potentiometer R2 SOl Jack 3 terminal AC power tyre Plastic utility box with plastic lid 5 x OPA x Pain plastic knob 3 6 ieet of 3 wire rubber covenal AC power cord 2 power cord grip grommets two way insulated terminal block solder wire hardware decals epoxy cte ment it feeds current to capacitor C1 and to a second changing network consisting of resistor R4 and capacitor C2 When the voltage across C2 rises above about 30 volts either polarity the Diac D1 breaks over and delivers a trigger pulse to the gate of the Triac TM That causes the Triac to turn on and apply the full power line voltage to the exter
243. ook dialing tone pulse dialing selection adjustable ringer and even a digitized music on hold se lection A back up battery system pro tects the memory function against power failures At the front of the 3300 a roll of ther mal paper is inserted into a covered com partment Received transmissions are printed on that paper when the unit is used as a low volume copying machine the thermal paper is also used for reproduc tions To use as a copier the original docu ment is inserted into a slot in the rear top of the unit and the start button is engaged just as if the document was to be transmit ted However when the 3300 is not com municating with another fax the unit copies the inserted document onto the ther mal paper lt can even make enlargements The 3300 wasn t the most efficient or fast est copter we d ever used but sitting right there on the desk it was extremely handy A manual automatic control allows that fax machine to be used both as a com bination telephone fax transmission unit or for unattended receiving of documents Set to manual telephone calls can be re ceived in the usual way If the high pitched tone that signals facsimile transmission is heard when the receiver is picked up a press of the start button will put the 3300 into the fax mode during which no con versations can be carried out via the hand set When sending the start button activates the fax signal tone E
244. ore insight into AutoCAD s powerful programming lan guage Novices are strongly advised to read the tutorial section thoroughly before delv ing too deeply into the AutoCAD Produc tivity Library The AutoCAD Productivity Book Second Edition is available for 39 95 from Ven tana Press P O Box 2468 Chapel Hill NC 27515 CIRCLE 80 ON FREE INFORMATION CARD SS lt e s e s E RS 232 o Switchable Lines 9 LED indicators jumpers Patch Termina Pioneer Laser Disc Player Compact Size 1 2 MW Helium Neon Laser Laser Power Supply ore hgh amp AN 29 95 RN 2 Front Surface Mirrors THIS MONTH ONLY ei SEND FOR FREE CATALOG ITT PUSH BUTTON ITT MDPL series 3 4 X 1 2 gray rectangular key Hi cap S P S T N O Push to i ciose PIEZO WARNING DEVICE Murata Erie PKB8 4A0 gh pitched audibie alarm Operates on pm 3 20 Vde 20 ma pe 1 high x 7 8 dia ra Two 1 2 Voice Coil Actuated Oscillating Mirrors One Beam Splitter Rated 0 1 amp iy ai P C board mount ai i at 25 amp car s py eal Vetecto wr es L CAT PBZ 84 1 75 each i Mini Gear Reduction Motor AC Line ELTEC a A n olling Electronics CAT i mse each XENON TUBE Assorted Switches Fan Solenoid 400 ONDITIONER r 6 THESE UNITS ARE OEM MODELS AND Ermina r PC or
245. ores of devices together computers modems terminals and printers are covered The book s methodical approach offers the reader a profile that can be used to analyze a port on a device and determine its Compatibility with other devices The reader can easily and quickly connect any number of different devices together by sim ply filling out the port profiles for those devices and following the straightforward steps and tools provided in the book Pinouts for over 300 serial Computers and peripherals supplied by the vendors are included in one appendix Cable dia grams for serial connectors printer and terminal escape Sequences connection symptoms and solutions steps for connec tion rules for cable design and intelligent modem commands are included in some of the other useful appendices Complete Guide to RS232 and Parallel Con nections is available for 27 95 in softcover or 42 00 in hardcover from Prentice Hall Inc College Division Englewood Cliffs NJ 07632 CIRCLE 99 ON FREE INFORMATION CARD USING MS DOS by Kris Jamsa Time is a limited and valuable commodity these days With that in mind this guide to MS DOS aims to quickly teach the most effective thus time saving use of comput ers Rather than getting bogged down with long words in even longer chapters the book is arranged in individual lesson plans that can be easily completed in 15 minutes at the computer That is
246. past Win a few lose a few would seem to be the lesson of GIZMO s tests While we could have done without the turntable s sensitivity in picking up skips on some older records we were delighted by the end of discernible surface noise and the disappearance of stylus lint Music search worked well but linear tracking doesn t accommodate the flexibility embodied tn manual pitch adjustment Maybe the best guide to making a deci sion about linear tracking is the condition of the potential buyer s record collection Is the consumer considering jettisoning the entire viny library tor new copies At that point to our way of thinking the switch to CD would be on the agenda If compact disc proponents are right con sumers won t be faced with those kinds of quandaries for very much longer Until then the KD 67F clearly rates as an op tion worth having al PARSEC ANTENNA Continued from page 3 plification process according to the coni pany Besides the Gallum Arsenide Field Effect Transistor the unit features elec tronic tuning and a circular element that can be aimed to focus clearly on one FM signal thereby increasing signal strength another 3 dB anu eliminating multipath distortion It s a serious FM antenna of fered at the equally serious suggested re tail price of 219 95 For consumers this side of fanatical regarding FM reception the LS 4 may be just the ticket iis Budget Time NDQ SPORT
247. player The wires from the ends of the coil are then connected to the audio output of the scanner handi talkie of any other au dio device that needs a little more power Construction You ll need to find an old cassette tape held together with small screws Also the cassette car tridge must have a small flat metal tab with foam or felt on it normally used to press the tape against the tape head as opposed to the type that only has a piece of thick foam glued to the car tridge body Hunt for a bargain since Build The AUDIO COUPLER Add an audio input to any cassette deck without altering the unit in any way BY GREGORY R MCINTIRE e a a FROM d m el L1 SEE TEXT are an 3 Fig 1 The terminals to the unit should be connected to the appropriate plug for the device you wish to amplify a 2 tes feeb This is the proper position for the coil PARTS LIST FOR THE AUDIO COUPLER L J AW tums of No 36 or 40 enameled wire RJ l0 ohm Ya watl resistor Cussette lape housing see text fast dry ing epoxy cement shielded audio cable phone plug if necessary te you won t need the tape itself I found cassette tapes at three for a dollar at the local discount store To begin the metal tab will be used to mount the coil Next take the car tridge apart and throw out the tape and little rollers etc If there is a small flat metal piate behind the metal tab throw it away too Next remove
248. ple use XyWrite the word processor of choice for maga zine editors Why is it the word pro cessor of choice for editors Because its text files are pure ASCII They are read directly by our typesetting com puter and its files can be read by any program that reads pure ASCII files and that s a very large list of software Computer Bits By Herb Friedman inet ferent oa P ae F a oh ris r eget ji E aaah soul outa Peres mile Hoe oe oe nice ace PT F b inm ak aia prec mah mmr e aak ons bn yates priait 5 ii a the magji y e CTE welll oF ani apir ek eee pair iia ol me cad AG el Sf ki ieee eve 1 tt be Te el AKI N joe ree ied he ee el apm teria pesmmrertlh toed imi Pete ann am ami thik ree Stee oe F faji sd eek e it Peres Leh prih bb ppt M Peden aimi tel mmie rg Slo Pot imme jl Le el i ai i dna al ow Farii canes aA al E beme a hii mhii a ee E Fig 1 A WordStar file read on a different word processor will produce a sereen of what resembles hieroglyphics as will most documents that were prepared on non ASCII word processors But if try to read an author s disk that was written in WordStar get the hi eroglyphics shown in Fig 1 which is caused by WordStar having the high bit set While there are several programs that strip the high bit to create read able text from WordStar files a strip per doesn t untangle WordStar s fo
249. plitude of one and a phase angle of zero Function 2 is also a sinewave but with an amplitude of 1 2 and a 30 phase angle Please keep in mind that BASIC assumes all angles are in radians Because the varlabie X is in degrees the ratio m 180 is used to Convert degrees into radians fe amp 6861 ABVNNVE HANDS ON ELECTRONICS POPULAR ELECTRONICS oO a THIS I THE FIRST TITLE LINE OF THE GRAPH 1 50 1 20 u m G I i S r 3 fo e eD SE i 1 50 360 8 216 8 72 8 And this is the second title line WAV 72 0 216 0 360 THIS I THE GRAPH S X AXIS Fig 1 The two sinewaves shown here are the default functions To display your own functions and label the axis modify grapher as described in the text EXPONENTIAL FUNCTIONS 10 89 9 00 8 00 11 0 6 00 5 00 4 00 3 00 t2 B0 1 00 0 00 0 08 1 me Deam o cS MV ref As an example of how to modify the program to use other functions Fig 2 shows another set of plots generated by Grapher the rising and falling ex ponential functions Listing 2 shows the modifications necessary to to gener ate that graph Keep in mind that the functions de scribed by the subroutines don t have to be just one line long they just have to retum a single value of Y for every value of X in the range from XMIN to XMAX For example the subroutine For the second example 3 8 in seconds 2 TIME Fig 2
250. procedure The cost of the videocassette is 30 00 Use the order form below to order yours now Send to EIA CEG Department PS PO Box 19100 Washington D C 20036 Basic Car Audio Installation Quantity Amount Total Enclosed Videocassette 4 5 ee ts 30 00 each VHS O BETA O Continued from page 68 should be somewhat diffused Diffu sion can be accomplished using a small piece of frosted plastic held in the top of the kaleidoscope between the flashlight and the particles in the tube If you wish you can take a small piece of clear plastic and roughen it with fine sandpaper The diffusion me dium is held on a triangular tube that just slips about 4 inch into the top of the kaleidoscope tube The tube is then heid in position with a slightly larger strip of cardboard glued around it See Fig 7 You may want to try is to convert the unit for use with a video camera That requires Only a few changes in the unit but you ll need to do a little engineer ing to mount the light source for proper illumination The fleeting images of the kaleidoscope can be captured on video tape and the programs re played with the assurance that it will be what is planned For video taping or projecting the image it is desirable to use two speakers one speaker is used as the audio source while the other is used to produce the changing patterns of the kaleidoscope The automatic exposure control of the typical home video camera does
251. ps We shall use a small straight type in our Strobe Size and Weight In order to be suc cessfully lofted our Strobe needs to be small efficient and light Weight and size saving is accomplished by mini aturizing the power supply Surplus electronics suppliers often have cam era electronic flash boards left over from manufacturing overruns Those boards contain tiny transformers that are capable of producing hundreds of volts from a battery powered driver Circuit Suitable transformers are also available from the supplier given in the Parts List To drive them with maximum effi ciency we use a hex FET and a pulse width modulator PWM cir cuit That Combination results in maximum power Output from the smallest size and weight unit while providing an adjustable flash rate Strobe Circuit Description Referring to Fig 2 gate U1 a one sixth of a CD4584 CMOS Schmitt trigger is configured as an oscillator With the values shown the oscillator Operates at 6 kHz You may need to experiment with different frequencies by using the different values of C1 and Mto obtain maximum output if you use 6861 AHYNNYT N HANDS ON ELECTRONICS POPULAR ELECTRONICS CAPACITOR COMMON OUTPUT Fig l Here is a block diagram of the basic strobe circuit which consists of a power supply storage device the capacitor triggering circuit and a Xenon flash lamp a transformer other than the one spec
252. r ested in a cabinet for his Zenith Con tact him at RD 3 Box 217 Claysville PA 15323 Frank De Stasi has another set very similar to mine a Zenith 98262 By a strange Coincidence his is also a bare chassis job Like John he doesnt allow the lack of a cabinet to keep him from enjoying the radio But if you can sup ply a cabinet for Frank s set write him at 769 Sybil Ave San Leandro CA 94577 Frank enclosed a schematic of the set which has a larger speaker than mine and a couple of extra tubes Frank s set also boasts a motor tuning drive that allows him to go from one end of the dial to the other in seconds And since the tuning dials on those radios are geared way down for good vemier action imagine that the motor drive comes in very handy Frank tells me that he purchased the 95262 schematic and many others from Howard W Sams amp Co Photofact Tech Services PO Box 7092 Indi anapolis IN 46206 He reports that they can come up with schematics for many antique radios for a price of 1 00 per copy and a 2 50 handling charge assume the latter is a per order rather than per copy fee Helping Hands John Fitzgerald Mid dleton WI informed me that a copy of the 7 232 s schematic can be found in Supreme Publications Most Often Needed 1926 1938 Radio Diagrams on page 228 That useful book as well as many of the other Supreme pub lications is available as a reprint Write ARS Enterprises
253. r of auto matic correction features Perhaps the most impressive is Smith Corona s trade marked Spell Right electronic diction ary That built in lexicon ofters 50 000 words and on those new models will catch word redundancies and beginning of sentence capitalization mistakes When an incorrectly spelled word is typed an audio signal is heard Perhaps unfortunately for users who aren t good spellers the Spell Right fea 50 Page 4 GiIZMO ture doesn t supply the correct spelling Instead once the typist has erased the mis spelled word and typed in a correction the function checks the new letter combina tion Presumably with really difticult to spell words and in the absence of a con ventional dictionary this signal erase new spelling sequence could continue for quite some time Errors the electronic dic tionary can identify include misspellings transposition of letters repeating the same letters unintended space between letters and character omissions In using the XL 2500 we found it slightly disconcerting that proper names in particular would set off the misspelling signal Smith Corona apparently antici pated that reaction the Spell Right func tion can be disengaged by pressing the code key and the D key marked with a book symbol designating the electronic dictionary feature The XL 2500 s redundancy check can help eliminate a typing mistake especially common tn transcription and retyping fr
254. r video taping or proj ection you will need to hold the speaker invariably level That can be accomplished by mounting the speaker in a piece of inch plywood The plywood in turn has three threaded bolts long enough to serve as feet have built many variations of the unit described in this article since built the first one in the early 1960 s am always looking for improvements and would be very pleased to hear from anyone who has improvements or re finements to suggest Write to me in care of Popular Electronics 500 8 Bi County Bivd Farmingdale NY 1 1735 The advent of the video camera has given me a renewed interest in build ing variations to take advantage of this exciting technique F You Can Be PS CEATIFIED The International Society Of Certified Electronics Technicians offers permanent certification by administering the CET exam with the FCC recognized communi cations option for 20 A second exam on FCC regulations for a 10 fee is re quired for a Radiotelephone License Upon passing technicians receive both a permanent Radiotelephone Operator Cer ieee and a CET Certificate issued by ISCET Offers License Renewal ISCET has developed a program for regis tration of those who currently hold a valid Radiotelephone Operator License By sending a completed application a photocopy of your FCC License and 10 your license will be renewed with the assurance of a recognized national tech nicians asso
255. r worked well with a 300 watt load The variable voltage tap worked well throughout most of the 6861 AYVNNVS bo 3 HANDS ON ELECTRONICS POPULAR ELECTRONICS N oO AUTO TRANSFORM Fi 5A 1 BLACK HOT alaco NEUTRAL TI7VAC i WHITE GREEN GROUND S01 S02 CONNECTEO IN PARALLEL Fig I Here ts the wiring diagram for the modified autotransformer The original fuse holder was reused The power Switch and two terminal outlet were discarded Colored insulated wires black hot red variable AC and white neutral were attached to the short leads on the stripped autotransformer to assist in goof proofing the final wiring range was too chicken fo take the flood lamps above 130 volts The re sults of the tests convinced me that the autotransformer was worth sprucing up and using Fixing Up began by fixing a bump on the tapped coil where the 1 17 volt AC power line is connected That was easy to do Every time tried to push it down and glue it in place the tums popped back up again That tech nique was not working so tied a thin Here s the autotransformer ripe for leather shoelace to the tap point and repair With a little effort it turned out added some weights until the weight to be a worthwhile test bench tool was heavy enough to hold the bump down applied some epoxy to the sides of the turns so that when the weight was removed the turns re mained in place Do not
256. rank Heverly By the end of this book readers will be expert in the repair and alignment of to day s single tube video cameras and in how to build a profitable TV camera Service busi ness Complete operational data details the inner workings of video cameras The step by step techniques needed to troubleshoot and service a wide range of video cameras are accompanied by over 400 charts dia grams illustrations and photographs The handbook shows how video cam eras work how to accurately pinpoint the trouble when they malfunction how to re move re install align and adjust the pick up tube and how to deal with Customers Beginning with a basic description of every type of design of today s video Cameras and how they work the book goes on to 16 95 from Prentice Hall Inc Business describe in full detail the individual parts circuits and Components that Comprise video Cameras There are hundreds of short cuts for troubleshooting repair and align ment Also included are listings of Sources for test equipment special tools and addi tional reference material as well as a glos sary of terms and abbreviations Handbook of Video Camera Servicing and Troubleshooting Techniques is available for and Professional Division Englewood Cliffs NJ 07632 CIRCLE 99 ON FREE INFORMATION CARD _ HIGHER MATH FOR BEGINNERS by Ya B Zeidovich and I M Yaglom This introductory text book written by a
257. ransformer T1 make the circuit into a Harley RF os cillator Capacitor C4 is non critical but it does improve performance by providing an RF current path around transistor Al for the discharge from the T1 C6 tank circuit Capacitor C1 couples the antenna to the primary of T1 From there the received signals are used to drive the base of QI through T1 s secondary and capacitor C2 which affects Q1 s DC bias rate Because of that the circuit oscillates at two frequencies simulta neously 49 890 MHz and 450 kHz Dur ing each 49 890 MHz cycle before RF oscillation begins 1 acts like a high gain RF amplifier greatly magnifying the antenna s signal Once amplified the signal Causes an increase in the average DC emitter current of Q1 and that in turn in creases the voltage drop across re sistor R4 So amplitude variations in the P 6861 AYYNNYF WO HANDS ON ELECTRONICS POPULAR ELECTRONICS C2 L3 200pF 50H 1 METER WHIP ANTENNA R5 49 89MHz 3 3K 4 0 1 c5 RG ULEN EE San 2200 L C7 bP 180pF u IFI O47uH Era ua SHIELD L4 S1 TO C8 50uH 6 15 VOLTS DC 50LH Fig 1 The transmitter is built around a 7555 CMOS oscillatoritimer Ul whose frequen cy is dependent upon the values of resistors RI R3 and capacitor C3 and is designed to generate a 490 H2 squarewave output antennas signal result in voltage varia tions across R4 Capacitor C7 couples the
258. rd cr cml elements to make custom electronic prop acts BP92 CRYSTAL SET CONSTAUCTION 5 50 A varety of crystal radio receivers lor me expenmenier and hobbyist BP106 MODEAN OP AMP PROJECTS 5 00 Includes a Shoe Timer AF Signal Gen Mike Pre amp Scratch Fiter and much more BP185 ELEC TRONIC SYNTHESISER CONSTRUCTION 5 95 Shows how to build a monophonic syn thesiza section by section Replaces BPBI1 ELECTRONIC TECHNOLOGY TODAY INC PO Box 240 Massapequa Park NY 11762 0240 GREAT PAPERBACKS AT SPECIAL PRICES PCP103 PRACTICAL MIDI HANDBOOK 9 95 Explains what MIDI the Musical Digtal interiace can do and how can put to work sS Keyboards drum machines sequencers miers guitars ard computer music BP148 COMPUTER TECHNOLOGY EX PLAINED 5 50 Explanations for comput er lems otten encountered A dictionary lor computer lingo BP110 HOW TO GET YOUR ELEC TRONIC PROJECTS WORKING 5 75 How to find the fauils in your projects repair Ihem and get them worung co BPS9 SECOND BOOK FOR CMOS IC PROJECTS 5 50 Muti ators ampiners triggers amp gales Special devices inciuding reac thon timer simple electronic organ and more pte P1 89 RADIO S FIRST TWO DECADES vpe RFTD RADIO S FIRST TWO DECADES 3 50 This story of tados early days makes tor fascmaling reading Spark gap transmwtiers K s begin
259. re are lock outs a scan delay and other standard features along with rechargeable bat teries an AC adaptor charger and two antennas The unit has a sug gested retail price of 299 For more information write to the sole American source for those units Ace Communi cations a subsidiary of AOR 10707 East 196 Street Indianapolis IN 46256 Fishy Business A newsy note from Alex W Mcllwain Lakeland FL clues us into some strange goings on that are probably nationwide in scope Alex reports that some of the newer VHF FM marine band radios provide their owners with channels designated as 1 to 5 and 60 to 64 The 10 frequen cies that correspond to those channel numbers are spaced at 25 kHz incre ments between 156 025 and 156 25 MHZ The problem is that even though transceivers using those frequencies are sold for use in the U S the 10 chan nels are for simplex use in overseas areas and arent permitted for mar itime use in American waters Alex observes that the temptation to use those forbidden frequencies in American waters has apparently proven too much for some boat owners seeking uncrowded yakking frequencies In fact he points out that some frequencies among that group are set aside by the FCC for police and other public service purposes In Alex s own area illegal maritime use of those channels hasn t been with out strange consequences The High Continued on page 106 6861 AYVNNVE re 7
260. receiving range of your station Cellular Reception Several readers have written to share the news that re ception on the factory omitted 800 MHz cellular channels is easily accom plished on the Uniden Bearcat BC 200 205XLT All you do is program in frequencies exactly 21 7 MHz above the cellular channels and you re in business via the IF image reception method To search the 870 to 896 MHz band set your BC 200 205XLT to search 891 7 MHz through 917 7 MHz Once again we ve reached the end of the space allotted to us for the month but be sure to tune us in next month when we ll present another as sortment of scanner tidbits In the meantime be sure to send your scan ner related comments questions tips loggings and suggestions to Scanner Scene Popular Electronics 500 B Bi County Boulevard Farmingdale NY 11735 POPULAR ELECTRONICS HANDS ON ELECTRONICS 1988 EDITORIAL INDEX FREE COUPON Return this FREE coupon together with a No 10 business size envelope on which your name and address appear and to which you have affixed a 22 cent postage stamp and we will send you a copy of the POPULAR ELECTRONICS HANDS ON ELECTRONICS 1988 EDITORIAL INDEX This is a limited offer so act today THIS FREE OFFER EXPIRES APRIL 30 1989 AFTER APRIL 30 1989 THERE WILL BE A 1 00 CHARGE THINK TANK Continued from page 27 SPEAKER Fig 7 This light control circuit uses the audio out of your stereo to provide trig
261. ring System Yet another product deemed ideal for the first time buyer this one oftered by Northwestern Bell Phones 9394 W Dodge Rd Suite 100 Omaha NE 68114 is the Favorite Messenger Integrated Answering System with voice activated recording beeperless remote operation ten number memory last number redial automatic toll saver and lighted keypad Desk or wall mountable the Favorite Messenger is sold with a one year warranty and is hearing aid compatible Price 149 99 CIRCLE 55 ON FREE INFORMATION CARD Quartz Halogen Video Light Let there be light remains a useful adage even in the world of low light camcorders Arkon 11627 Clark St Suite 101 Arcadia CA 91006 is marketing a compact lightweight Can Cool Quariz Halogen Video Light CL SOO that makes it possible for camcorders to produce protessional looking results under low lighting conditions Fabricated of aircraft alloy aluminum and weighing five ounces the Cam Cool will run continuously for 45 minutes with power from a standard 6 5 amp hour 2 volt battery There s also an eight foot power cord equipped with a car lighter DC adapter The Cam Cool also features a 180 degree self locking bracket for what Arkon calls precise bounce lighting Price 69 95 CIRCLE 54 ON FREE INFORMATION CARD Portable Computer If you ve been looking tor a personal computer that takes advantage of the best desktop and portable computers have
262. rmatting codes for such things as boldface indent underline etc Just as with virtually any other word pro cessor would still have to muck my way through to change all the page formatting Commands to the com mands of my word processor and on a large document that might take an hour or more pme H ier eek lime Lem Foe Diaping iia ia TATI AE aL ne machi Eii 1 Seog Reinke 1 8 R ei bmg ii 1A TEETE flees ae i memi bb ea vain Cl igen et ie i l ja Fig 2 Word For Word can be command line or menu driven This is the opening menu You page down for more formats The Electronic Rosetta What was needed to untangle the incom patibilities of word processors was an Electronic Rosetta Stone something that could translate one word pro cessed document including the page formatting commands into the format used by another word pro cessor That meant for example that if were translating a Multimate text file into a XyWrite file the Multimate page formatting commands would automatically be converted to Xy Write commands thereby saving me an hour or so of dull boring manual format conversions Well we now have an Electronic Rosetta Stone It s called Word For Word Design Software Inc 1275 West Roosevelt Rd West Chicago IL 60185 and it translates both the text and the major formatting features such as line spacing tabs boldface underline etc of the most popular word pro
263. rned wither 90 days from recept with a COpy of your mvorce PRICES SUBJECT TO CHAM wirnourT NOTICE tenenan a CIRCLE 10 ON FREE INFORMATION CARD izpace GIZMO Volume 6 No 1 JANUARY 1989 COMBINED WIT ti Popular Electronics CONSTRUCTION Rocket Strobe find that model rocket even at night or in tall weeds Subcarrier Adapter connects to your FM tuner to uncover hidden FM transmissions Personal Pocket Pager keep in touch at home or work with this personal paging system Build the Speedi Watt a power controller for almost anything electronic Build a 10 MHz Frequency Counter for those times when multimeter readings just won t do Build the Audio Coupler add an audio input to any cassette deck without modifying the unit Sound Activated Kaleidoscope makes patterns that seem to dance to Speedi watt page 44 the music FEATURES GRAPHER BAS turns abstract equations into tangible graphs Salvaging An Autotransformer they re just as useful today as they were yesterday E Z Math getting acquainted with Boolean algebra HANDS ON REPORTS TSM Vegas Kit for Christmas and all year round SPECIAL COLUMNS Think Tank SCR projects Antique Radio cabinet refinishing Circuit Circus unusual uses for transducers Computer Bits an electronic Rosetta stone DX Listening glasnost and DX ing Ham Radio myths and misinterpretations Scanner Scene new frequencies
264. ropean styled exterior and says that as a result it s attractive enough to be used anywhere in the home The unit can vaporize the contents of its two gallon tank in as little as twenty hours and broadcasts cool water vapor mist via a 360 degree rotation nozzle Both mist intensity and the humidity level can be adjusted Once the desired humidity level is reached the 1844 shuts off automatically The unit also turns off if it tips over or whenever the water level is low An LED indicator tells the user when a tank refill is needed there s also an audible signal that can be used when desired Price 89 95 CIRCLE 59 ON FREE INFORMATION CARD Prenatal Soundshare System This may be the product that makes born electronic consumers out of the next veneration of babies From nfant Technology Inc P O Box U Stanford CA 94309 the Listen Baby Prenatal Soundshare System 1s described in a company brochure as consisting of a stereo speaker pack hand held microphone and heart shaped dual listening adapter The theory seems to be that mom dad and siblings can not only listen in on but also bill and coo to the unborn child Infant Technology supplies what it dubs Infant Age Music but points out that expectant parents can make their own tapes at least suggesting that the child will recognize moni s voice The booklet s two page list of additional reading and clinical references bolsters the case for Listen Bab
265. rs They cover a wide range of subjects from Triac circuit replacement guides to flip flops Schmitt triggers Thyristor circuits Opto so lator Coupler selection and replacement All are Clearly explained with typical circuit ap plications WANT TO EXPAND your knowledge of electronics Do it the easy way by Studying the Electronics Fact Cards Do you travel to and from your job each day Drop a handful of cards in your pocket before you leave and the bus becomes a schoolroom At home you can build some of the projects and not only have fun building and using them but learn how they work at the same time YOU LL BE AMAZED both at how rapidly you learn with these cards and how easy it is to understand These new cards are available right now Don t miss out Send your check or money order today FACTCARDS Facts at your fingertips for Experimenters and Project Builders Please send one copy of FACTCARDS at 3 50 Shipping 1 00 U S and Canada only CJ Please send copies of FACTCARDS Total cost is sum of copy price and First Class postage and handling cost multiplied by number of card sets ordered Please print Name Street Address City State Zip Allow 6 8 weeks for the material to arrive Detach and mail today HANDS ON BOOKSTORE P O Box 4079 Farmingdale NY 11735 All Payment must be in US Funds HAM RADIO _ Continued from page 92 oo those 60 watt solid state
266. s Binary 0 and binary 1 are represented by voltage levels For example a binary 0 may be indicated with zero volts ground while a binary 1 may be indicated by 5 volts The Inverter An inverter is a logic element with a single input and a sin gle output As its name implies it inver ts an input signal A binary 0 input produces a 1 output A 1 input gener ates a 0 output The inverter always produces an output that is the comple ment of the input Complement here means opposite or reverse You will also hear the inverter referred to as a NOT gate The logic symbol for an inverter is shown in Fig 1 The triangle represents Don t let logic gates bar your ability to experiment with circuits INPUT OUTPUT Fig 1 The simple inverter A is shown here with its little four entry truth table a buffer a circuit that directly passes a binary digit onto the next circuit with out Changing the value The circle at the output indicates inversion So the digit passes through the buffer and is inverted at the gate s output Note that the input and output are labelled with letters All logic signals are given a name or designation Here A is the in put and B is the output Also shown in Fig 1 is a table that shows all possible combinations of in puts and outputs The input A can be either a 0 or The table shows the state of the output B for each input state Such a table is called a truth table Truth table
267. s C7 would need to be three times larger to provide each lamp with a high brightness but the total light output would be tripled Increase C to 0 1 wF when using more than one lamp in parallel The higher capacitance causes a greater charge to be dumped across T1 s pri mary and hence a larger secondary current which guarantees the ignition of all lamps Construction Well by now you are an expert on power supplies strobes rockets and aerodynamics so let s roll up our sleeves and get to work You may make a PC board or wire the electronics on perfboard which we did A universal printed circuit board worked fine As you assemble the circuit be mindful of the need to minimize weight Use just enough sol der to make a good joint Trim away excess space on your mounting board Wherever possible use miniature components A Ni Cad battery wiil save you quite a bit of weight 1 25 ounces vs almost 2 ounces for an al kaline unit The Ni Cad gives a good 15 minutes of flashing at high rate and over 1 hour on slow The power supply layout is not crit ical but you must pay attention to the high voltage output of the trigger transformer That little guy puts out over 4 000 volts and while it does not look too dangerous it packs quite a nasty wallop Dress the secondary leads away from other components a half inch is recommended The wires leading to capacitor C7 and the trigger trans former should be short and
268. s On Electronics 1 112 Hands On Electronics 2 113 Hands On Electronics 3 114 Hands On Electronics 4 115 Hands On Electronics 5 115A Hands On Electronics 6 O 116A Hands On Electronics Jan Feb 86 O 1168 Hands On Electronics Mar Apr aay el O 116C Hands On Electronics May Jun 86 O 1160 Hands On Electronics Jul Aug 86 O 116E Hands On Electronics Sep Oct 86 O 116K Hands On Electronics Nov 86 4 O 116L Hands On Electronics Dec 86 4 O 117 Hands On Electronics 1987 back issues Write in issues desired O 118 Hands On Electronics 1988 back issues Write in issues desired O 150 TV Descrambler O EH87 Experimenters Handbook O 152 8 Bail Satellite TV Antenna O 108 Radio Electronics 1988 back issues 3 00 Write in issues desired______S O 107 Radio Electronics back issues 1987 3 25 O O O O O O O O O O O O O O a gg88g8g8g8gg8g2zzgzg22228222228 peger To order any of the items indicated above check otf the ones you want Complete the order form below include your payment check or money order DO NOT SEND CASH and mail to Popular Electronics Reprint De partment P O Box 4079 Farmingdale NY 11735 Please allow 4 6 weeks for delivery couple of months into the restoration just as had begun to dissect the dial assembly to make the necessary re pairs George lost his patience He accused me writing tongue in cheek hope of evading a good subject the Crosley i
269. s and differences and the advan tages and disadvantages of each The DOS section has an introduction to its basic fea tures and proceeds to commands system configuration and advanced DOS features For the OS 2 user the book explores multi tasking the program selector and other OS 2 features Hardware specifics are also covered in detail with the emphasis on how things work Memory 80286 specifics interrupts disk drives keyboard video and printers are described Using the Models 50 amp 60 costs 21 95 it is available from Osborne McGraw Hill 2600 Tenth Street Berkeley CA 94710 CIRCLE 96 ON FREE INFORMATION CARD THE ROBOT BUILDER S BONANZA 99 INEXPENSIVE ROBOTICS PROJECTS by Gordon McComb This educational yet fun book takes a modu lar cookbook approach to robot building it offers a unique collection of fully tested project modules that can be mixed and matched in countless combinations The reader s imagination is the other ingredient required for the creation of highly intelli gent one of a kind working robots The projects which include all the infor mation needed to construct the basic build ing blocks of any personal robot are geared to novice and intermediate robotics enthusi asts Included are various modules for the body and frame power and locomotion ap pendages facial features navigation and electronic control The reader can combine v
270. s are used to show what s going on inside a logic circuit AND Gate An anb gate is a logic cir cuit with two or more inputs and a sin gle output The output is a binary 1 if all inputs are binary 1 Otherwise the out put is binary 0 The ano gate is often called a coincidence circuit because the output will be binary 1 only when all inputs are simultaneously all binary 1 The logic symbol for a two input AND gate is shown in Fig 2A The inputs are A and B the output is C The shape of the symbol designates its function An alternate symbol is given in Fig 2B The box designates the circuit while the ampersand amp indicates the gate s function The truth table for a two input AND gate is shown in Fig 2C There are al ways 2N possible input combinations where N is the number of inputs With two inputs there are 22 4 different combinations They are listed in the truth table along with the result ing outputs Note that the only time the output C is 1 is when both inputs are 1 Keep in mind that an AND gate may Fig 2 This two input AND gate A can be drawn as shown in B The truth table for all its possible states is shown in C lt x N 0 1 1 1 1 Fig 3 For a change this OR gate A is shown with three inputs instead of two An alternative symbol is shown in B while the elements truth table is shown in C have more than two inputs Integrated Circuit AND gates typically
271. s from zero to over six volts depending on the input signal level One unusual application for the Sound Activated Decoder would be R8 100K 1 4 on M324 10K C3 47 R3 10K 1 3 11 PARTS LIST FOR THE LOW FREQUENCY CRYSTAL FILTER UI LMIM quad op amp integrated circuit R1 47 000 ohm s watt 55 resistor R2 R5 10 000 ohm watt 5 resistor R R7 2200 ohm s watt 5 resistor RE I X 00 obm 4 watl 5 resistor Ci C2 1 F ceramic dise capacitor C3 47 nF 16 WVDC electrolytic capacitor C See text BA I Piezo transducer Radio Shack 273 073 or similar Printed circuit or perfboard materials enclosure IC sockets battery and battery holder wire solder hardware 6 12V 1 4 LM324 OUTPUT Fig 4 In this circuit the piezo transducer functions like a low frequency quartz crystal in a narrow band crystal filter circuit in extremely high noise environments where normal broadband micro phone pickup would be useless Be cause piezo transducers respond only to frequencies within a very narrow bandwidth little if any of the noise would get through the transducer Low Frequency Crystal Filter Another interesting job that the piezo transducer can perform is to function like a super low frequency quarz crystal in a narrow band crystal filter Circuit The circuit shown in Fig 4 is the piezo equivalent of a super selecti
272. s with jumpers fo the alternate strips Rain falling on the board reduces Circuit resistance until gate Current trig gers the SCR That sounds the little sol id state buzzer which remains on until the water dries or S1 is opened Resistor S1 12V De BZ1 D1 s R2 Seal 6802 BUZZER SENSOR SEE TEXT SCR1 R1 C1068681 1K H Fig 3 A printed circuit board etched so as to form interweaving but electrically separate traces ts used as a Rain Detec tor sensor Which when bridged by water droplets causes BZI to sound R2 provides sufficient current to keep SCM conducting You can also use the circuit to operate a sump pump when water reaches a given level by con necting a sensitive relay to the circuit in place of the buzzer With the same technique you could hook it to a motor and use it for anything from clos ing windows automatically if it rains to raising a convertible top on a car the joining surfaces connected a wire to each and thence to a battery and bell He put an aspirin tablet between the tacks and accomplished just about the same thing After all he explained aspirin manufacturers all boast about how fast their tablets dis solve John McFee Denver CO got a wooden spring type clothespin and put a metal thumb tack at each of Digital Triple Power Supply Okay John one and only one Fips book Your son will just have to read yours My young son a real smart al
273. sal motor loads up to 500 watts or approximately 4 amperes at 117 volts AC By universal motors we mean AC motors with brushes such as those used in electric drills food mix ers and sewing machines Circuit Details Speedi Watt s sche matic diagram is essentially a typical dimmer circuit that uses a phase con trolled Triac TRI as the power contro element A Triac is a high power switching device developed by Gen eral Electric about 25 years ago It is similar in function to a silicon con trolled rectifier SCR or thyristor This story first appeared in Silicon Chip Australia December 1987 reprinted here with permission In effect an SCR is a bipolar switch that can operate at AC frequencies up to 400 Hz Like a silicon controlled rectifier it is non conducting until it re ceives a trigger voltage between its gate and the anode electrode MT1 When that happens it switches into conduction and remains that way until the voltage reverses in polarity or the current dies away to zero The difference between a Triac and an SCR is that while an SCR will only work with one voltage polarity the Tri ac will work with both It can conduct on both half cycles of an AC wave form It can be made to control the AC power fed to a load merely by being made to conduct early or late in each successive AC half cycle such a method of power control is referred to as phase control because the timing of the gate trigger p
274. sducer pinout shown in Fig 2 you should have little trouble in con necting any transducer to the circuit The outer ring of the piezo element is usually connected to circuit ground The large inner circle serves as the driven area and the small elongated DRIVE IN RED WIRE FEEDBACK GROUND COMMON BLUE WIRE BLACK WIRE Fig 2 Here is the pinout diagram for the three terminal piezo transducer The outer ring is usually connected to ground the large inner circle is the driven area and the elongated section is the feedback PARTS LIST FOR THE FIXED FREQUENCY GENERATOR WI LM324 quad op amp integrated circuit RI 10 000 ohm 4a watt 5 resistor R2 R3 2700 ohm t4 wait 5 resistor R4 t7 OO0 ohim watt 5 resistor R5 1000 ohm s watt 5 resistor Cl O aF ceramic dist capacitor BZ Piczo fixed frequency transducer Radio Shack 273 064 or similar Printed circuit or perfboard materials enclosure IC sockets battery and battery holder wire solder hardware el section supplies the feedback signal Resistor R5 sets BZ1s Output volume level That level can be increased by decreasing R5 say to 470 ohms To decrease the volume increase R5 to about 2 2K Or so Resistors R2 and R3 set the bias for Op amp Us positive input pin 3 to half of the supply voltage level That allows for a maximum voltage swing at Us output Although a quad op amp is specified in the Parts List almost a
275. sed and published than Herb One of Herb s greatest loves was to sit at his workbench and produce one and two transistor projects that any one can build in a single evening As the state of the art advanced Herb would build single chip projects as a concession to current trends but he kept the projects simple Herb always envisioned a kid as he would call a teenager building one of his projects Thus he was concerned that the cost was low the parts were easily obtainable and that the circuit was not Critical the project had to work when powered up Herb acquired test equipment to build an extensive consumer electronics testing laboratory He did consid erable product testing in the seventies and became well known to U S European and Japanese audio man ufacturers Many years ago when it was popular to quote extremely small intermodulation figures Herb ceased doing so because he knew once the numbers fell below a few percent they were meaningless The audio indus try followed suit a year later His private testing laboratory was the first to be capable of testing citizen band radios for magazine reviews He JANUARY 1989 Popular Electronics began in 1968 and was ready for the CB boom he predicted in the early seventies Herb made it a practice to test products for magazine reviews Only manufac turers made offers for his service but he turned them down for fear of compromising his reputation for being
276. sed ends into the small drilled holes in the printed circuit board Power Supply Confusion There was some confusion generated by the kit instructions in regards to the power supply required to operate the Vegas Kit On the first page of the instructions it was indicated that a 12 volt DC 1 am pere power supply not included was required to power the unit The circuit board however indicated that a 9 12 volt AC 1 ampere power source was required That made more sense since a diode bridge circuit was included on the circuit board Somewhat later in the instructions two sentences cleared up the confusion Yes a 12 volt AC supply was required however in its place a 12 volt DC supply can be used provided it is connected across filter capacitor C2 on the circuit board No further mention was made about 9 volt sources With those options open a tele phone step down transformer nor mally used to power the lights in a home phone was used to provide the AC power The transformer was rated at 8 5 volts AC and most probably rated less than 1 ampere but decid ed to use it anyway It did do the job although it was warm to the touch after The LEDs are arranged in a cartwheel fashion with four radii of red LEDs and four radii of green LEDs The colors of the radii alternate one hour s use Once the power was applied to the Vegas Kit the LED dis play started and amazed those who saw it Looks Great The assembled V
277. sformer may be hard to find when you are looking for one Mouser Electronics sells them in different sizes and configurations One unit listed in their catalog is a Staco Variable Transformer catalog No 563 3PN501 which sells for 125 98 it is comparable to the unit found In a few weeks Christmas will be here and the autotransformer wil be put to work on the Christmas tree s lights Those miniature bulb sets last much longer when the voltage is down to about 105 volts 6861 AYVNNVS J w HANDS ON ELECTRONICS POPULAR ELECTRONICS J gt f you have followed this math series you know that we ve spent a lot of time covering the math related to basic electrical principles and elec tronic fundamentals In this month s in stallment we ll head out in another direction for a change of pace We will discuss a type of math used with Gigital logic circuits That math is known as Boolean algebra What s Boolean for Boolean al gebra is a collection of simple mathe matical procedures used to represent and express the logical operations that go on in a digital circuit Boolean algebra is very similar to standard al gebra The primary difference is that unlike standard algebra in which vari ables can be any value in Boolean algebra only the values O and 1 are recognized Besides that most of the basic rules of working with algebraic expressions apply The big benefit of Boolean algebra is that it provides a w
278. shed by placing a piece of frost ed plastic between the flashlight and the particles in the tube flashlight containing a high intensity halogen bulb with satisfactory results A typical experimental mount is shown in Fig 5 That mount or a similar ar rangement of your own design allows the flashlight to be used with either the projection unit or for video taping If you wish to project the image onto a wall screen see Fig 6 the tube is used to hold a simple mirror taken from an old purse at a 45 degree an gle When video taping only a rela tively small amount of light is needed It Continued on page 99 A adventure inside a flea market in the next state uncovered an item that will be very useful at home this Christmas was on the trail for a few table top antique radios circa 1940 s when Came upon an old auto transformer commonly called a Variac which is a trade name An au totransformer can take line voltage and vary it at its output from zero to 140 volts AC The unit found was an import that was sold by Radio Shack in the late 1950 s it had been dropped and slightly damaged The deep dust and dirt covering parts of it did not bother me that s the easiest thing to take care of bought the gadget for three dollars the seller drove a hard bargain and took my prize home The Story Deepens The following weekend had a chance to scrutinize the autotransformer removed the large control knob
279. sing On line information services such as bulletin board systems information utilities includ ing CompuServe and The Source and many electronic mail Services The Complete Communications Handbook is available for 12 95 from Wordware Pub lishing Inc 1506 Capital Avenue Plano TX 75074 CIRCLE 81 ON FREE INFORMATION CARD MASTERING PACKET RADIO The Hands on Guide by Dave Ingram K4TWJ Packet radio the technique of breaking down information into small pieces pack ets and transmitting them over amateur radio is a rapidly expanding field This eaSy to understand guide to packeting is intended to put amateur radio enthusiasts on the cutting edge of the digital communi cations revolution The book examines packet radio tech nology and capabilities from simple con cepts to more technical subjects It offers precise explanations of what packet is how it works why it is uSed and the hardware involved Readers will learn about the roles of home computers and data communiCa tions terminals and how to set up their own packet Stations Masieri Packet Badin Pie Wark non ibe Information is included on packet net works bulletin boards HF linking concepts Oscar satellites and electronic mail There is a Survey of amateur equipment for packet radio and tips for newcomers and veteran amateur radio enthusiasts alike on being a good packeteer Finally the author looks ahead to the future of pack
280. sing Figs 2 and 3 as a guide to polarity Use proper precautions to minimize static and install Qi The 300 volt output may be tested with a neon lamp Resistor R4 varies the brightness of the lamp somewhat THINK TANK 53 PAGES OVER 130 PROJECTS SIMPLE EASY TO BUILD AND USEFUL IDEAS FOR YOUR HOME HOBBY CAR Put together the strobe section of the circuit see Fig 4 keeping in mind the high voltage output of T2 Once you have all the parts assembled if is a good idea to give the finished board and components several light coats of an insulating spray to prevent shorts and high voltage arcing A product such as Acrylic Coating which has a dielectric strength of 2 000 volts per 001 inch or other material for coating printed circuit boards works well Don t coat R4 or it wont work anymore Also dont spray anything on the flash lamp although you may insulate the ends to prevent arcing outside the flash tube Testing Before installing the elec tronics in the rocket and gluing every thing down check to see that the Strobe is operating correctly With a 9 volt input and using the parts spec ified you should see a flash every 4 seconds on the high setting and about every 30 seconds on the lowest setting of R4 You ll note the first flash takes quite a while to appear usu ally about 10 15 seconds on high and a few minutes on low The reason for that is that C7 the large electrolytic that
281. sors to keep heat and air conditioning at ideal levels a remote controlled commercial killer for the TV and voice activated transmitters and relays Before getting into project building there is a Simple but thorough introduction to how remote control and automation sys tems actually work Advice on Safety pre cautions finding parts substitution of com ponents and techniques for customization is also presented in the first few chapters Then for each device the author supplies complete instructions wiring diagrams and illustrations 62 Home Remote Control and Automation Projects is available for 12 95 from Tab Books Inc Blue Ridge Summit PA 17294 0850 Tel 1 800 233 1128 CIRCLE 98 ON FREE INFORMATION CARD Official 1934 SHORT WAVE MANUAL simple high performance old a time shortwave radios All of the secrets are here the circuit diagrams parts layout coil Specifications con Struction details operation hints and much more This is a compilation of shortwave construction articles from Short Wave Craft magazines published in the 20 s amp 30 s It s wall to wall how to Included are circuit diagrams photo graphs and design secrets of all short wave receivers being manufactured in 1934 including some of the most fa mous SW 3 the SW 5 Thrill Box the deForest KR 1 the Hammurland Comet Pro
282. ssed worked up the enclosed circuit See Fig 2 but dad was too busy to go over it with me so built it and installed it in the store He didn t have time for it until he heard the bell go off and sud denly he became interested figured that any crook would come through the front door one way or an other so put a switch mat under the carpeting just inside the front door The alarm circuit is connected to the SCR anode and gate Pressure on the mat closes the contacts of the mat switch which applies current to the SCR gate causing it to conduct With the SCR conducting a path to ground is provided through BZ1 a to 2 volt bell and SCM causing BZ1 to sound The bell continues to sound even if the crook steps off the mat To tum the alarm off you have to man ually throw switch S1 to break the cir cuit During the day when customers are going in and out simply open the switch and the alarm is disabled until you throw the switch on again to arm the circuit CONTACT MAT 12V D1 1N4001 SCR C10681 Fig 2 This Burglar Alarm circuit con sists of a mat switch which when stepped on triggers SCRI used diode Di to protect the SCR from back voltage from the bell wind ing As the vibrating contacts of the bell open the circuit opens Resistor R3 maintains a steady current through the SCR keeping it from going back to the off state You really dont need R2 if leakage in the
283. st perfeet curve and indented ribs for reinforcement A hole was drilled through it Once the shield was complete it was sprayed with a flat black paint After drying a grommet was installed The leads of the evlindrical winding were too short Colored leads a red a black and a white were added to make wiring easy and goof proof The splices were soldered and black plastic tape was used to insulate the splices Electrical Work The autotransformer was secured to the board with wood screws A 4 in square electrical box and a face plate for one duplex outlet with toggle switch was installed on the installed a new three wire power Here s the autotransformer mounted on the board with the electrical box mounted and wired Note that the fuse holder is easy to reach for fuse replacement board about one inch away Two of the box s circular knockouts were re moved and cable clamps were in stalled A third knockout was removed and the original fuse holder was in stalled The knockout hole was foo large for the fuse holder so an over sized washer was placed on each side of the hole and the fuse holder was installed through them Should you wish to do that do not over tighten the nut because the plastic fuse holder breaks easily If you can t find washers of the right size cut out two squares of aluminum and drill a hole in the center of each One of them should be sized to fit neatly on the inside and one on the outsi
284. stic casing appears to be a single piece that includes the wrist strap into which the timepiece is placed and sealed beneath the plastic crystal We finally used the eraser end of a pencil and pushed hard Otherwise the casing successfully resisted finger pressure The directions are straightforward and step by step unfortunately the SMWS8 acted as if it hadn t read the instructions When we pressed button C to set the time or in the nomenclature of the direc tions to enter the desired mode and then pressed B the seconds did not begin flashing Instead the watch ap peared to go into the stopwatch funcuon not our desired mode At that point we felt completely lost Directions tor these watches always assume the user will go through the outlined sequence with com plete success There never seems to be any guidance on how to abort a maneuver and return to the starting point with a clean slate The watch finally was set by an associ ate who seems to have a knack for such tasks a terribly imprecise and non tech nological factor to depend upon When we asked him what he d done he wasn t able tO Say Patience would seem to be the key The second SMWS amp NDQ Marketing sent to us followed the sequence outlined on the package s instructions to the letter Instead of the half hour of ineffectual poking and pressing we d gone through with the first watch the second was set and keeping time a
285. stors are vertically mounted on the board due to tight spacing A cno O e SEE TEXT LEDI On the transmiter circuit solder one lead of the antenna loading coil L2 to the printed circuit board and attach the other lead to the base of the whip antenna Tuning The following alignment pro cedure uses a frequency counter and an amplifier speaker with an auxiliary or microphone input jack All test points are referenced to the circuit board ground Temporarily remove U2 receiver from its socket Apply power to the transmitter and receiver circuits Adjust trimmer potentiometer R18 for 490 Hz while measuring the frequency at TP2 receiver Similarly adjust R3 for 490 Hz while measuring the frequency at TM BZ1 V re H N fury i ie SEND b K cie _s a C2 Fig 6 Assemble the receiver printed circuit board using this layout diagram as a guide Note the locations of the two ferrite beads and be sure not to leave them out and Fig 7A for construction details is made by bending a inch 180 de gree loop in one lead of resistor R Install and solder the resistor onto the printed circuit board so that the loop is accessible with a test probe similarly make two test points on re ceiver s printed circuit board see Fig 6 for their locations Test point TPA see Fig 7B is made by inserting a ferrite bead over one lead of resistor R10 Make a ring in the lead so that t
286. table carefully so that you understand exactly what is going on in each column Lets take one more example to be sure you know how to develop the truth table from a given logic circuit Refer to Fig 19A That circuit has four dif ferent inputs therefore it will have 24 16 possible input combinations Those are the four bit binary numbers 0000 decimal 0 through 1 1 11 decimal 15 They are illustrated in the truth table shown in Fig 19B The remaining columns in the truth table are the output of gate 1 A B the output of gate 2 C D and the final output F Again using the input states develop the output for gate 1 and then gate 2 Those are or gates and so produce a binary 1 output when either or both inputs are binary 1 For gates 1 and 2 simply search through the table for those rows where binary 1s occur at the inputs of the gates and record binary 1 s in the cor responding output column Once you have done that for both gates you will have the inputs to gate 3 Gate 3 is an AND gate so its Output is 1 when the output columns for gates 1 and 2 are both binary 1 Again look through all of the columns in the truth table to be sure you understand how they apply to the Circuit Exercise Problem Io see if you can do this yourself try the following prob lem 3 Draw the circuit for the Boolean ex pression Z2 Y VW X VX Assume only the inputs V W X and Y are available Develop the truth table
287. tage of assembly you come to a full understanding and apprecia tion of the microprocessor technology that makes today s robotics applications possible But that s just the beginning You go on to use your computer to pro gram and control a diverse array of robotic systems you create with NRIs remarkable Robotic Discovery Kits automation systems programmed by you to do the types of operations and tasks per formed in today s industrial environments Tasks such as plotting polar coordinates to create graphic displays of numeric data sorting different size objects and routing these objects to separate containers even performing a preprogrammed sequence of operations again and again just as robots now do on manufacturing lines Nothing is left out nothing is left to chance You get everything you need the skills the con fidence and the equipment to feel completely at home with today s robotics technology Step by step you get the training you need to move into robotics fast You need no previous experience to succeed with NRI training because NRI takes you from electronics basics all the way up to the state of the art in robotics technology You train from the ground up first gaining a working eles if i electronic circuits and components as you experiment with your NRI Discovery Lab and professional digital multimeter Rapidly theory becomes understanding as you move on to digital logic co
288. ter 1 260 210 3 way 100 watt crossover 2 260 255 50 watt L pads 1 260 300 terminal and 1 260 340 woodgrain grill cloth Recommended cabinet volume 3 1 cu ft Cabinet Kit Available 260 390 19 95 each 7395 gt Save Over 7 wr 1000 s a each 15 day money back guarantee 10 00 minimum order We accept Mastercard Visa Discover and C O D orders 24 hour shipping Shipping charge UPS chart rate 2 50 minimum charge Hours 07 0 E TOLL FREE 1 800 338 0531 have a Dumont handheld FM radio receiver it is a type DH300 Model N33H from Ham marlund Mfg Co Inc in Marshill NC I ve written to that company but didn t get an answer Can anyone help me find a sche matic diagram and any other information on that receiver Ernest Wurfer 741 San Diego Ave Sunnyvale CA 94086 Perhaps you can help me just recently got my hands on a Lewytt RC77 GRC9 U S Army Corps Field Radio with no manual It s a trans ceiver tube type radio I m not sure how old itis I m looking for the correct operating volt age and of course a manual for it Andrew Bowlby 4700 Highland Ave Downers Grove IL 60515 CHECK YOUR FACTS Having just purchased my first copy of Popu lar Electronics can truthfully say that it seems to be a good publication for anyone who enjoys working or playing in electronics i m writing to point out some information that is inaccurate due to the omission o
289. ter in the radio to be modified is first fed to a 67 kHz bandpass filter and then to a phase locked loop de noted PLL which recovers the audio on the 67 kHz subcarrier The audio output of the PLL is then passed through a low pass filter which attenuates frequencies above 6 kHz at the rate of 18 dB octave Another 12 MODULATED FM INPUT 7 C19 220pF R3 10K TWIN TEE FILTER J 7kHz BAND PASS FILTER GND FROM RECEIVER Fig 2 The circuit for the SCA Adapter is basically a PLL with input and output filter stages dB octave low pass filter stage com pletes the conditioning of the signal before it is passed to an extemal audio amplifier Figure 2 shows the complete circuit Op amp U and its associated com ponents Comprise the 67 kHz band pass filter A twin T network comprised of four 1100 ohm resistors and four 0 0022 uF capacitors is connected in the feedback network of the op amp PLL DEMDDULATOR GAIN 1 That gives some gain at 67 kHz and heavy attenuation for frequencies above and below that frequency An additional passive filter at the in put to the twin T network containing a 220 pF capacitor and a 10 000 ohm resistor provides some additional roll off for frequencies below 67 kHz In practice the bandpass filter ac tion covers a frequency range of about 10 kHz above and below the 67 18dB OCTAVE LOW PASS FILTER 15V 30V FROM RECEIVER 12V OUT 12dB OCTAVE 6kHz
290. ter programmer and has had articles published in several consumer magazines will miss Herb The entire staff will miss Herb Our readers especially the emerging experimenters will miss Herb Adieu Herb Friedman oA Julian S Martin HT E REPAIR TROUBLE ELECTRONIC CIRCU UTS practical probies al f it yourselter solving guide te home elec Flectrici ty Electronics I a ery ren electronics a a Peas Ta bole 1962 2753 _ 23 95 22 95 101 SOLDERLESS BREADBOARDING MHE PROJECTS f MASTER es Ie COOKBOOK 2985 24 95 1199P 18 95 AMCORDER CA ANDBOOK Beyond the Transistor 198 Giectsanica Projecta aaa u a osm SO quart gm 2801P 12 95 2887 16 95 AMATEUR RADIO 2965 24 95 1939P 19 95 TEST PMG VOLA OWN DICROSUU OF ELECTRONS SPEAKER SYSTEM ath prajer ve PTOS ies i 2900 36 95 1964P 12 95 diet S a using THE TRIGGERED SWEEP OSCRLOSCOPE aar i oa 2853 23 95 22 95 2831 SELECT 5 BOOKS for only 3 95 values to 132 70 and get a Free Gift 1625P 16 95 Electronics projects all at up to 50 off publishers prices ideas the latest technology Membership Benefits Big Savings in addition to this introductory offer you keep saving substantially with members prices of up to 50 off the publishers prices Bonus Books Starting
291. tereo Converter Full Feature Descrambler Compatible MISCELLANEOUS 129 95 ECONO 3V Mini Code 89 95 ECONO 3V Mini Code Vari Sync 89 95 ECONO 3V Mini Code Vari Sync Plus Uk re 119 95 OAK Sine wave Anti Jammer Kit 39 95 JERROLD 400 amp 450 Handheld Transmitters 529 95 HAMLIN MLD 1200 Channels 2 0r 3 599 95 NEW ITEMS Scientific Atlanta SA 3 129 95 GENERAL INSTRUMENTS VCU Amplified Video Switch Signal Amplifier 44 59 95 UNITED ELECTRONIC SUPPLY P O BOX 1206H e ELGIN ILLINOIS 60121 312 697 0600 CIRCLE 15 ON FREE INFORMATION CARD 6861 AYVNNVS J HANDS ON ELECTRONICS POPULAR ELECTRONICS aah ce 9 95 each with snap lock For more infor mation contact Curtis Manufacturing Com pany Inc 30 Fitzgerald Drive Jaffrey NH 03452 CIRCLE 73 ON FREE INFORMATION CARD TWO WAY PORTABLE RADIOS The Regency Pius HH Series of die cast two way portable radios are durable and dependable yet lightweight With die cast metal mainframes the portables are rug ged under working conditions The HH Series is available in three bands In UHF the HH 464 D2 and HH 464 D4 have four watts of power and two or four channel capability In VHF High Band the HH 154 and the HH 156 feature 4 or 6 watts of power switchable to 1 watt and up to six channel capability The se ries is rounded out by th
292. th ASTEC POWER EOOTOR Nome and Complore Miading Adar Saicorsel Birector 7 TRANSFORMER SUPPLY KLE IMAN 500 B BI COUNTY BLVD FARMINGDALE N Y 11735 te ETE Mame gard comple re Maing ae N i Quantity Pricing Available MODEL AA12690 i JULIAN S MARTIN 500 8 BI COUNTY HLVD ARMINGDALE N Y 11723 95 gaa on Sea TUE Tad IO E wt Sv se a 9 5 VDC 1 Amp 3 00 weur 49 DUTPUT oning pererat or mare of tatal om outi o gt POTS inta Re fo net Te o Doin rA df ESAn BY E POIRE ux DOS case EPEAN fas coer can cs 2 j 19 VAC 300 MA 1 50 1 15V 3 0 Amp 5V 10 Amp aa t Puhhi rd y a monger fll ovgesietian sit aame gmd wdd Bult NA ce ING ADDRESS Tae 50 60 HZ t2 5 UN REG i SERNSEACK PUBLICATIONS TRC 506 5 RiT nty blvd Farmingdale WY Ta 14 VDC 200 MA 1 00 113 WATT MAX 12V 0 25 Amp LAWRENCE ITELELE I 305 6 Bi County Blvd Farmingdale NY TT7 _ a SS T Fy HEAVY DUTY MOTOR COMMORDORE fe KNOWN BONDHOL DERS MORTGAGES AND OTHER steun ty nor Loras OWNING OF NOLOING PLMCENT OR MORE Oe FOF AL an Heavy duty ceversible gyal 64 CARTRIDGES AMOUNT OF BONDS MORTGAGES OF OTHER SECUR shaft 12 volt P M OC Motor Dragons Den Simen Basic f sai aii 2 95 ea Ideal fer Rebets amp Tels etc 1 50 ea Vidazzies ABE Vice Espa TOY MOTORS PATCH CORDS x FOR COMPLE TION BY HONPAOF TOPGANIZA A TIONS AUTHOR eb T MAIL AT SPECIAL AA ISe rwn 6 tol2 voc On The put ond Morera tetas n f eae ta
293. that we didn t like was the placement of the code and margin set keys to the left of the space bar The left margin is selected by moving the print element to the desired margin location and pressing the margin set key The right mar gin is set in the same manner except that its necessary to depress the code key When first using the XL 2500 occasion ally a finger would slip as it stretched to engage the code key or hit the space bar and we found ourselves with a new left margin when the print element moved to the next line We also had some minor problems with the tab set Although a beep is supposed to confirm cach setting our test model had a balky key which didn t always register the desired tabulation setting Pressing hard or repeatedly brought a confusing two beeps and only occasionally set the tab The lift off correction system however worked smoothly and cleanly The cor rect key to the right of the space bar lifts off a single character The WordEraser key lifts off an entire word with a single keystroke Continuous pressure on the cor rect key will erase up to an entire line Even when erasing bold face words which the XL 2500 creates by repeating and blackening the letters typed after the bold face function is engaged the re moval was clean and complete Another new feature of this machine is Smith Corona s Right Ribbon System It the wrong combination of ribbon and correcti
294. the small metal tab that the foam pad is glued to and wrap one layer of mask ing tape or any thin adhesive type tape around the foam or felt pad The purpose of that is to cover the sharp edges of the attached metal piece Next wind between 200 and 400 turns of no 36 or no 40 enameled wire around the tab and pad It takes about about 1 feet of wire That wire is very fine and very easy to break so be careful a You can salvage some out of an oid speaker ear phone a small toy motor or even a small audio transformer It may not be necessary to use wire as small as used Larger wire may require more turns though and there is not a whole lot of room for the coil if it is too large After the coil is wound ap ply a small amount of quick drying ep oxy cement to hold the coil in its place Next prepare a length of two lead wire or shielded cable by connecting a phone plug on one end and tinning the leads on the other With a small file saw or hot knife cut a small notch in the cassette cartridge in a spot where the wire can enter exit the cartridge without interference from the tape player Also it should be located so that when the tape cartridge is plugged into the tape player the ca ble will protrude from the end of the cartridge that is closest to the player opening Most automobile tape play ers that have seen leave one end of the cassette sticking out in the open If your tape player completely consu
295. these de vices and they all work just great I m sure your s will too _ P O BOX716DEPT HO AMHERST NH 03031 AMAZING SCIENTIFIC amp ELECTRONIC PLANS Build Yoursett All Parts Available in Stock LC7 BURNING CUTTING CO LASER 20 4 RUB4 PORTABLE LASER RAY PISTOL Mi Of TCCI 3 SEPARATE TESLA coll PLANS TO 1 5 MEV oN t0G1 ION RAY GUN 0 0 GRAI GRAVITY GENERATOR 0 EMLI ELECTRO MAGNET COIL GUN LAUNCHER SA a KITS With All Necessary Plans MFT3K FM VOICE TRANSMITTER 3 MI RANGE 49 50 VWPM7K TELEPHONE TRANSMITTER 3 Mt RANGE 39 50 BTC3K 250 000 VOLT 10 14 SPARK TESLA COIL 249 40 LHC2K SIMULATED MULTICOLOR LASER TH 50 8LSIK 100 000 WATT BLASTER DEFENSE DEVICE we ai TM1K 100 000 VOLT 20 AFFECTIVE RANGE INTIMIDATOR 69 50 PSP4K TIME VARIANT SHOCK WAVE PISTOL 59 50 STAIK ALL NEW SPACE AGE ACTIVE PLASMA SABER 59 50 MYPIK SEE IN DARK KIT 99 50 PTGIK SPECTACULAR PLASMA TORNADO GENERATOR 149 50 ASSEMBLED All Necessary TCIO 50 000 Yor WORLD S SMALLEST TESLA COIL 54 50 Da 1MW HeNe VISIBLE REO LASER GUN 2435 50 TAT30 AUTO TELEPHONE EECOROING DEVICE aisi GVP10 SEE IN TOTAL DARKNESS IR VIEWER 344 f LESTIO SNOOPER PHONE INFINITY TRANSMITTER IPG70 INVISIBLE PAIN FIELO GENERATOR MUTLI MODE 74 50 e CATALOG CONTAINING ce ie OF ate PLUS HUNDREDS MORE AVAILABLE FOR 1 00 OR USE OUR PHONE FOR ORDERS ONLY 603 673 4730 PLEASE INCLUDE 3 00 PH
296. track of every transaction with its description items dates and amounts once the user enters the data A trio of search functions provide easy verification of transactions and a security function provides financial confidentiality The unit features a two line twelve digit display including AM PM designations and month and day display Up to 90 separate transactions can be stored in its three memory banks and up to a dozen description items like house rent car loan utilities telephone food etc can be stored Power comes from a single lithium battery and the recorder comes equipped with a case and pen Price 32 95 CIRCLE 53 ON FREE INFORMATION CARD S VHS Compatible TV Monitor Receiver Super VHS users are in luck Yamaha Electronics Corp U S A 6660 Or angethorpe Ave Buena Park CA 90620 has introduced a 27 inch S VHS Compatible Television Monitor Receiver YM 270S in addition to the two S VHS monitor receivers already offered by the company The new YM 270S features a flat square picture tube automatic color correction 142 channel PLL synthesized tuning MTS on screen channel display a stereo amplifier two video Inputs and monitor and TV Outputs Other features include a clock last channel memory seven day memory retention black level retention and peak white suppressor and stereo wide circuitry that is said to expand the stereo image beyond the screen and cabinet when the YM 270S s own speakers ar
297. tware based system Authorized visitors can be provided with a temporary visitor code Different monitoring and alarm modes are used when the occupants are at home or away Up to four separate security zones can be created allowing selective monitor ing of sensors There is an instant panic alarm for emergencies The Dicon 9000 s digital signal coding system and sensors are made with surface mount components resulting in compact size and improved quality and reliability It is designed so that even close neighbors can use it without interfering with each other s systems The basic Dicon 9000 package consists of the console two magnetic window door switches with transmitters a speaker siren with a 50 foot cord an AC power adapter a modular telephone cord an extended range antenna and window decals Op tional accessories full function remote con trols infrared motion detectors personal or medical emergency pendants smoke alarms additional window and door switches and indoor sirens and a weather proof outdoor siren are available Tem perature sensors and propane natural gas detectors will be available in late 1988 The Dicon 9000 package including all hardware and installation materials and an Operator s manual with diagrams of sug gested sensor placement costs 494 00 For additional information contact Dicon Systems Inc 631 Executive Drive Willow brook IL 60521 1 800 387 2
298. u work out the arithmetic for voltage decibels aB 20 log Vi V2 we find that 60 dB is a ratio of 1000 In other words a report of 60 dB over S9 means that other station was one thou sand times louder than an extremely strong signal Perhaps what he really meant was By Joseph J Carr K4IPV power decibels which means that the other guy was a real blazing blow torch 60 dB over S9 means 1 000 000 times as much signal power at the re ceiver s antenna terminals as an S9 sig nal Surely such a signal qualifies as a long range death ray The Pentagon should take note So what is an S9 signal According to some manufacturers an S9 signal is a 50 nV signalacross the 50 ohm in put Others require a 100 uV signal across a 50 ohm input to make the meter deflect to S9 In other words there is at least a 21 ratio between voltage levels that supposedly qualify as S9 The S unit is traditionally given the subjective definition of being the mini mum signal level change that an ap preciable number of standard grade A average listeners can per ceive whatever that means or whoever that person is As a result the usual definition makes each S unit worth a 6 cB change in voltage level or a 3 dB change in power level which is the same thing mathe matically A 3 dB power change has a ratio of 2 1 In other words if you dou ble the RF output power from your rig the S meter at a distant station will in cre
299. uilt in rack at the back of the machine Plastic construction shows its positive as pect in that this really is a portable ma chine as much so as a briefcase or book bag An exceptionally good machine tor student use or for the use of someone who types regularly if not all the time the XL 2500 is easy to get used to and loaded with features that reveal their utility with use It s a well thought out hybrid of word pro ceSsing functions and traditional type writer features Radio Lilliputian ACTION AM FM HEADSET RADIO 7 1990 Manufactured by General Electric Co Audio Communica tions Products I 455 P O Box 1976 Indianapolis IN 46026 Price 26 95 The continuing miniaturization of con sumer electronic products has its market ing roots in the introduction three decades ago of the transistor radio Hailed at the time tor both its portability and its small size the battery powered cigar box sized radios were a first step on the road that has led to complete music systems small enough to slip into a coat pocket While our attention these days is focused on other more glamorous prod ucts the garden variety portable radio is still shrinking The recently introduced Action AM FM Headset Radio 7 1990 from General Electric is a bright blue and yellow palm size package But within its Y2 inch thick 314 by 1 inch case is an AM FM radio worthy of the name Clear reception produces impressive listening on a heads
300. ulses is varied with respect to the phase of the AC waveform PLI Slew a ho et F _NEUTRAL GROUNO The device used to generate the trigger pulses is the Diac D1 also de veloped by General Electric at the same time as the Triac A Diac is re ferred to as a breakdown diode be cause if is non conducting at all voltages up to its breakover point When the breakover point is reached it breaks down to the conducting state It remains in that state until the voltage reverses in polarity or the cur rent dies away to zero The Diac is used in conjunction with a capacitor to deliver a pulse of cur rent to the gate of a Triac Now look at the complete circuit of Fig 1 Note that the Speedi Watt circuit works at 1 17 volt AC power line poten tial In other words the whole thing is inherently lethal if you touch any part of the circuit while it is connected to the AC power line Don t worry though when it is correctly as sembied it is completely safe Fig 1 The circuit for Speedi Watt is a standard light dimmer with components for RFI suppression and a snubber network The latter consists of resistor RS and capacitor C3 which reduce the counter EMF caused by the load at SO The hot lead of the AC line connects to a single pole switch Si and then to resistor M which feeds two potentiom eters R2 and R3 which are both wired as variable resistors in parallel Potenti ometer R2 is Soeedi Watt s c
301. useful instrument can be put together for about 40 by anyone who is reasonably adept at soidering Circuit Operation Figure 1 shows the schematic diagram of the 10 MHz Fre quency Counter The circuit consists of an ICM7208 seven decade counter LN an ICM7207A oscillator controller U2 and a CA3130 bIFET Op amp U3 Integrated circuit Ui counts Input signals decodes them to 7 segment format and oufputs signals that are used to drive a 7 digit display Integrated circuit U2 provides the fiming for Ut while U3 conditions the input signal to provide a suitable waveform for input to Ul The 5 24288 MHz crystal frequency is divided by U2 to produce a 1280 MHz multiclexing signal at pin 12 of U2 That signal is input to Ut at pin 16 and is used to scan the display digits in sequence The cathodes of each digit are taken to ground several times each second activating any segments of the digits whose anodes are high as the result of decoding by U The crystal frequency is further divided to pro Counter Need a frequency counter that won t cost a mini This hobbyist grade instrument is just the ticket for budding techs ona tight budget PAUL AMAN duce a short store pulse at pin 2 of U2 foillowec after about 0 4 millise conds by a short reset pulse at pin 14 of U2 The frequency of the pulses is determined by the state of U2 pin 11 When pin 11 of U2 is taken to ground through Si the pulses
302. ust a little more time than tuning in a hard to receive FM station We used the LS 4 with both a six year old stereo receiver and a brand new Onkyo quartz synthesized tuner amplifier TX 850 While results were short of mi raculous the improvement in reception was noticeable in both units Across the spectrum reception was crisper and better modulated that was particularly evident with the older receiver The antenna s gain control was a usetul secondary adjustment that seldom failed to tighten and brighten a station s sound The LS 4 didn t seem particularly effective at drawing in hard to receive FM signals Lower powered stations con tinued to elude tuning their reception ap parently depending more on atmospheric One to visit our facility in New Jersey and test as many Swisstels as they would like We are convinced that once you test a Swisstel fairly and accurately you will love the phone Peter Buckles x VIDEO CUT UPDATE Our October report on the Video Cut 10 neglected to mention that the Dot Line Corp 11916 Valerio St N Hollywood CA 91605 as well as Photo Systems Inc distributes the product in the United States The Video Cut 20 a companion product to the Video Cut 10 has a sug gested retail price of 2 349 50 not 2 200 as GIZMO reported conditions than on anything within the lis tener s power to improve Set on its base the LS 4 is an om nidirectional antenna Parsec also advises
303. ust before Christmas And all through the new year they ll remember and appreciate your thoughtful gift of Hands On experience So don t blow a fuse take it easy and enjoy the holidays Give Christmas gifts of Hands On Electronics 6861 AHYNNYT e HANDS ON ELECTRONICS POPULAR ELECTRONICS N CABINET REFINISHING ast month we completed the res toration of a Zenith Model 78232 shutter dial chassis that was begun in the August issue certainly enjoyed doing the work and hope that you all enjoyed reading about it Unfor tunately the set s cabinet also requires quite a bit of attention And cabinet refinishing is my least favorite radio restoration activity The radio was damaged in a small but violent gas furnace explosion while it was pos sessed by its previous owner which is the only reason he was willing to sell it Besides blowing out the speaker cone which has since been repaired and charring the grille cloth the explo sion also Completely ruined the finish on the 7 232 s cabinet It looked as if it had been almost vaporized exposing a rough light colored wood surface The wood seemed virtually grainless suggesting that the grain had been a photographic one as was common in sets of that era and was lost along with the finish Down to Basics That was discourag ing but obviously the only thing to do was to strip off the remains of the old Shown her
304. ve crystal filter In a typical crystal filter circuit the crystal s intemal capacitance is elec tronically canceled to keep unwanted and out of band signals from getting through and showing up at the filter s output Internal capacitance normally runs in the low picofarad range for crystals and in the 20 to 30 000 pF range for the piezo transducers In a quarz circuit a small trimmer capacitor is used to tweak out the ca pacitance effect but to use the same approach for the piezo filter you d need to gang at least 100 broadcast band tuning capacitors together to achieve the same effect With our piezo transducer Circuit op amp a doubles the level of the input signal That magnified signal is fed to one leg of BZ1 while at the same time being fed to the inverting input of Ul b Op amp Ut1 b with a voltage gain of one inverts the signal s wave form which is next fed through capac itor C and then to the other side of the piezo element If the value of C equals the intemal capacitance of the piezo elemert the transducer s capacitance effect is canceled out Several piezo trans ducers come with a list of their elec trical characteristics including their intemal capacitance figure If the in formation isn t available it can be de termined with the aid of a capaci tance decade box or a capacitance meter Continued on page 97 6861 AYVNNVS io oi HANDS ON ELECTRONICS POPULAR ELECTRONICS a
305. ven in the auto receive mode a voice monitor function allows the sender to talk to the 3300 user before sending the facsimile message In that mode the send er s voice is heard over the unit s monitor speaker Setup requires connection to the phone line with a modular jack and connection to either a three prong electrical outlet or to a Standard outlet with an adapter The machine is readied for use with a function keypad located under the 3300 s LCD dis play The LCD display by the way can be set to show information in either English or French using the function keypad A reset button and a paper jam bar complete the unit s top mounted controls At the back of the machine a volume dial adjusts the loudness of the monitor speaker Gizmo is published by Gernsback Publica tions Inc 500 B Bi County Blvd Farm ingdale NY 11735 Senior Writer George Arthur Copyright 1989 by Gernsback Publications Gizmo is a registered trade mark All rights reserved 48 Page 2 GIZMO The LCD display guides the user through each setup step Selecting dialing mode time and date setting each docu ment sent carries this information as well as the name of the sending party business or company facsimile resolution and contrast LCD contrast ring delay auto receive mode elapsed time alarm a sig nal goes off every three minutes to help keep track of time especially for long distance transmissions or calls and a
306. very 4 6 weeks give you a handle on subjects like optoelec tronics robotics integrated circuits lasers fiber optics and more Each Concept Module goes right to the heart of the matter You waste no time on extraneous material or outdated history It sa fast efficient and lively learning experience a non traditional approach to the most modern of subject matter Unique Interactive Instruction With each module you receive a McGraw Hill Action Audio Cassette Each tape is a dynamic discussion that drives home the key facts about the subject Your learning With your first module you get this solderless breadboarding system You ll use it through out the series to build elec tronic circuits and bring concepts to life experience is reinforced through interaction with vividly illustrated text audio cassettes and actual electronic experiments Indexed binders preserve backup material notes and tapes for convenient referral Perform Experiments in Contemporary Electronics Throughout your series lab oratory experiments reinforce every significant point This essential experience dynamic hands on demonstrations of theory in practice lt t will help you master principles that apply all Wi the way up to tomorrow s latest VLSI Very Large Scale Integrated circuitry In your very first module you ll use integrated circuits to build a digital oscillator verifying its oper
307. was missing Can anyone advise me on where to find one Ron Fite 1205 East 25th St San Bernardino CA 92404 V PIONEER AA MOTOROLA 6 x 9 COAXIAL SPEAKERS Super buyout Made in Japan by Pioneer tor GM Upgrade auto sound system 6 x 9 woofer 24 cone tweeter 35 watts RMS 50 watts max 12 RMS oz magnet Dust cover Sold in pairs 8 Ibs pair Limited quantities s4450 1195 6 prs up 1 5 prs 300 220 290 098 15 WOOFER 60 watts RMS 90 watts max 14 voice coll 8 ohm 25 2500 Hz response 20 o2 magnet paper cone with poly foam surround 93 dB 1W 1M Sensitivity Net weight 7 Ibs 2895 7 Any Oty WOODGRAIN GRILL CLOTH Authentic woodgrain print design cloth 36 x 60 595 Per Yard 290 160 260 340 lt n Fy ars LXPress 340 E First St Dayton OH 45402 Local 1 513 222 0173 FAX 513 222 4644 100 WATTS __ 10 WOOFER USA Super duty 34 0z magnet 2 voice Coil Paper cone treated accordian surround 100 watts RMS 140 watts max 8 ohm 70Hz resonant frequency response 45 4000 Hz Net weight 8 Ibs 3150 D M PIONCEN oo 1 3 4 up 7 7 12 3 WAY 100 WATT SYSTEM i Pioneer design engineers carefully evaluated the performance characteris tics of this speaker systems to ensure the best full range frequency response System Includes 1 290 125 poly woofer 1 280 045 heavy duty 5 midrange 1 270 035 4 soft dome twee
308. wn We use parentheses in this case to show the separation between the M B A1 K J Al K J Al K DS Ba Fig 13 The output of one gate becomes the input of the next in this circuit two variables yet they are written ad jacent to one another to indicate a product or AND function Next the output of gate is ored with the input of J The resulting output from gate 2 is Ai K J That becomes one of the inputs to AND gate 3 That expression is anped with input B to produce the final output ex pression M B A K J Again parentheses are used to keep the variables separated and to ensure the correct logical operation is ex pressed Take a look at the example in Fig 14 Again the procedure is to develop the Output expressions of the input gates z W X YW xX Fig 14 You end up with a product of sums expression for this circuit after analysis then work your way from left to right to create the output The output from gate 1 is W X Y The output of gate 2 is W X Those two outputs become the inputs to AND gate 3 We create the final out put expression Z by simply ANDing to gether the two expressions The result is Z2 W X Y W X You might hear that kind of expression called a product of sums Generating a Circuit From Equa tions Now lets consider the process of drawing the logic circuit corre sponding to a given Boolean expres sion Let s start
309. y In our limited experi ence the kid will be hearing and making lots of noise later on without tapping into his or her nine months of guaranteed peace and quiet Price 60 CIRCLE 61 ON FREE INFORMATION CARD AM FM Stereo Receiver Moderation 1s usually considered a virtue but in stereo component design that value seems to have fallen by the wayside Yamaha Electronics Corp USA 6660 Orangethorpe Ave Buena Park CA 90620 however is offering a new AM FM stereo receiver described as delivering moderate power with high dynamic power low impedance drive capability The RX SOOU Stereo Receiver with remote control is rated at 5O watts RMS per channel and features circuitry de signed to assure that the unit will reproduce digital sources with full fidelity and that it can be used with multiple speaker systems The RX 500U features direct PLL F count digital synthesis tuning with sixteen station random access pre sets auto seek and manual up down tuning The receiver s infrared remote permits input source and station selection and volume control Dual tape monitor inputs and an independent record out selector are also features of the new model Price 379 CIRCLE 62 ON FREE INFORMATION CARD Moving Coil Dynamic Stereophone Stereo headsets are fairly mundane products but a new model introduced by Signet 4701 Hudson Dr Stow OH 44224 as described in a new product release sounds downright exotic The Moving Coil
310. y of the Fips book Hope you enjoy it Automatic Lights My family has been planning a week s vacation for several months and didnt want to tip our being away to any unwanted vis itors We planned to stop newspaper and mail deliveries and did all the right things Still the house would be completely dark at night One of my neighbors had installed a series of timers that would automatically turn lights on and off at night and one eve ning he invited me over to check out the system We stood across the street and watched as lights blinked on and off inside his home at random making the place look like a pinball machine didnt want that so built this circuit See Fig 6 which is controlled by a light dependent resistor LDR R3 that tums On one living room lamp when the room is dark Period It s enough to make a would be burglar suspect that somebody is in the house When the sun comes up the light goes out it s just enough but not too much Since potentiometer M acts as a sensitivity control almost any LDR is suitable for the task The one we Chose has a resistance of about 1megohm in the dark When light falls on it the resis tance drops to a mere few hundred ohms R2 5 6K LOAD 6 V fae SCR ua ECQ5401 ae Fig 6 The Automatic Light circuit is controlled by an LDR which has a high resistance in darkness and a low re sistance when exposed to light When light reaches the LDR the
311. year parts and labor warranty as well as a tree update of the call cost chip in the event that phone rates change The company says the TA 100B was designed specifically for small businesses and self employed individuals but we know some parents of teenagers who might be more than a little interested in the device Price 449 CIRCLE 52 ON FREE INFORMATION CARD Squelch Telephone Accessory A news release trom Effective Solutions 14902 Preston Rd Suite 212 310 Dallas TX 75240 announces that the firm s Squelch Telephone Accessory was granted a U S patent last year and that they are the only company manufacturing this product under the patent The product in question is described as an easy tO use accessory which provides automatic control of extension telephones By plugging in an extension phone via the accessory the user is assured that the second instrument will not interfere with calls on a directly connected phone If you use a modem or facsimile Effective Solutions says the Squelch allows the extension to be used when the fax or modem is off but automatically protects a transmission in progress Connecting an answering machine via the device assures that the phone s answerer automatically takes priority over the machine when a directly connected phone is picked up A pair of LEDs provide veritica tion of correct installation Price 9 95 15 CIRCLE 42 ON FREE INFORMATION CARD Electronic Remindi

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