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Vol 10 - American Radio History

1. 4026 decade counter LED 1 DL 750 7 segment common cathode display or equivalent Q1 through Q7 2N4401 transistors R1 500 000 ohm linear taper potentiometer R2 100 000 ohm linear taper potentiometer R3 10 000 ohm watt resistor R4 through R11 1 000 ohm watt resistors 1 S2 SPST momentary contact switches omitting the last gate section Like wise the input can be enabled low by returning the biasing resistor to the positive supply and applying a negative going signal PARTS LIST FOR DO IT YOURSELF DELAY C1 see table D1 1N4148 diode D2 small LED IC1 4001A or 4011A quad NAND gate Q1 2N4401 R1 47 000 to 56 000 ohm watt resistor R2 see table OPTIONAL OUTPUT OUTPUT LED INDICATOR VOLUME X 55 THE ROBOT EYE TTL A useful chip at home with both TTL and CMOS logic is the type 555 timer which can be used both in the mono stable and astable or free running modes In the mono stable mode shown here timing RC can run from 1000 ohms to over 1 megohm and 0 001 uF to over 100 uF A combination of 2 2 uF and 220K ohms gave a delay interval of about one second The Robot Eye can thus extend from a tiny wink to an intent gaze RI The type 555 timer can not only see but hear as this sound pick up circuit shows It is most apt in picking up sudden sharp sounds A type MPS A13 Darlington transistor provides gain to cause triggering action Wi
2. Figure 4 The complete PVC coil form with L1 L2 and L3 Note that LI is wound at the bottom of L2 VOLUME X 43 a Figure 5 Notice the cemented areas of coil L3 inside the foam with two fiber washers at each end of the coil area holes at the top and off center of the rod holes to hold the wire or metal commutator Wind the first 12 turns in the 1 inch space above the brass commutator rod Then close wind the rest of L2 to a total of 72 turns Start at the top of the coil form and wind 12 turns of number 24 or 26 enameled wire for L2 Tap the coil 1 2 4 8 and 12 turns Fig 9 The six position rotary SW2 will switch in the various coil taps Place a piece of scotch tape over the coil lead to hold the coil in place Twist the wire without cutting it to make each coil tap Try to keep them on the right side close to the PC board Tinn the tap and coil ends after the coil is cemented in place with a dab of clear rubber silicone cement Start L1 about inches away from the bottom side of L2 Wind L1 with a total of 27 turns of number 24 or 26 enameled wire Hold the coil in place at several points with tape until cement or coil dop is applied All coils are close wound except the top of L2 which straddles the metal commutator rod Mounting L3 L3 is mounted on the brass wood dowel piece inside the large coil area Insert the brass end of the dowel through coil form and place a fiber or plastic washer over it Push
3. PROGRAMMED MUSIC may be 1 and 5 Hz use slower tempos for chime like PARTS LIST FOR EVEN ODDS C1 0 47 to 2 2 uF electrolytic capacitor 15 VDC C2 50 to 100 uF electrolytic capacitor 15 VDC D1 through D10 1N4148 diodes 1C1 4017 decade counter Q1 through Q4 2N4401 transistors LED 1 DL 750 7 segment common cathode display or equivalent R1 500 000 ohm watt resistor R2 100 000 ohm watt resistor R3 1 000 ohm Yz watt resistor R4 560 ohm watt resistor R5 R6 R7 R8 1 000 ohm watt resistors S1 SPDT momentary contact pushbutton switch TO LED Qi RS PINS 1 8 4 2 PARTS LIST FOR PROGRAMMED MUSIC C1 C2 0 1 uF ceramic capacitors 15 VDC C3 1 000 uF electrolytic capacitor 25 VDC D1 hrough D10 1N4148 diodes IC1 4017 decade counter IC2 555 timer R1 through R10 1 000 to 100 000 ohm 2 watt resistors see text R11 4 700 ohm V watt resistor SPKR 8 ohm PM type speaker T1 audio output transformer 1000 ohm center tapped primary 8 ohm secondary Radio Shack 273 1380 or equivalent Mi 14 ki Mitith no a r Tc m PROGRAMMED MUSIC OUTPUT 20 a O D ILJU 7 3 i SEQUENCER HO O 3 1495 R4 D4 2 4 13 6 5 124 6 7 8 TWO TONE ALARM When this circuit is triggered into acti n itis hard to ignore for very long A 555 timer is Operated in the astable free running mode with its output powering booth a loudspeaker and
4. The front panel was made up of a piece of scrap hard masonite with two coats of black car enamel paint sprayed on it The rear chassis may be cut from pine or composition board Cut both panels to the correct dimensions Fig 10 Drill all holes in the front panel with different size bits The speaker hole may be one large one or several small holes representing a circle Drill all holes before painting the front panel ver with a ground strip separating the audio and RF amp scone section Layout both the RF and audio section on the M PC board Fig 7 Double check the PC wiring after being placed on the foil side Make sure the layout wiring is not loose on the board Notice that the audio output connections are at the bottom of the board The RF regeneration circuit is placed at the top of i connects to the PC board After the board has been etched drill all holes for parts and connections Now the entire board may be tinned for better connections Mounting The Parts First mount the 8 pin IC audio output socket Mark terminal 1 on the top side and bottom side of the board for terminal reference Be careful in soldering small IC socket prongs to PC wiring to prevent overlapping excess solder Mount each component and solder each terminal Watch for correct polarity of electrolytic capacitors and the varactor diode Fig 8 The tuning control R3 regeneration R5 and volume control R7 can be connected together
5. SS 4 2 Un 3260P 14 95 Tee SECOND EDITION INDI STRIAL 3258 Courts as 2 27 95 3632 33212 516 95 18 95 Your most complete source for electronics books for over 25 years NR TE F TR ara gt 4 i t los Tronas BUND YOUR EN and OWN 80435 PC Pg gt Repatrs AMD SAVE A SUNDLE Aad ocr a Y E 3 3241P 16 95 3279 36 95 Counts as 2 HOME Desigring Seling and Testin A ELECTR RIGAL Your Dan Speaker System ALARMS aie Al sud Kd aknal a 3414 39 95 3628 26 95 Counts as 2 3072P 16 95 3374P 16 95 Counts as 2 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 immediately you will be eligible for our Bonus Book Plan with savings of up to 80 off publishers prices Club News Bulletins 15 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 scores 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 preter another selection or no book at all simply indicate your choice on the reply form provided You will have at least 10 days to decide As a mem ber you agree to purchase at least 3 books within the next 12 months and may r
6. 2 8 Tau ER E hat A Ea A a yas Mato Fai The transmitter of AM radio station WBNO in Bryon Ohio is said to be the first using photovoltaic power A combination of 800 modules containing 33 600 cells produce 15 kilowatts peak and delivers 128 volts DC to the station Sixty lead acid cells are kept effectively charged by this system reliable coverage over a much larger area High locations permit a greater separation between relay stations of a point to point system and more economical operation TV and FM broadcast signals can be picked up and rebroadcast from high locations to obtain extended and better coverage into remote areas Marine beacons buoys and other navigation equipment can be powered with solar cells and associated batteries A number of railway signaling systems are now powered with photovoltaics PN JUNCTION N SILICON P SILICON elie EIGHT PHOTONS SS Figure 1 A load connected between the N and P junctions will receive current flow when light photons hit the N junction Basic Operation The basic solar cell is a semiconductor diode Most often it is made of pure silicon properly doped to obtain a PN junction as seen in Figure 1 The N type silicon is doped with phosphorus while the P type silicon is doped with boron The N silicon has free electrons while the P silicon has free moving positive VOLUME X 65 charges called holes At the PN junction region the charges neutra
7. 74188 s BO to B7 outputs are all at logic O levels To program a logic 1 at any one of 256 memory locations an internal fuse must be blown By applying power that is well over the normal operating voltage internal fuses can easily be opened Here in Figure 5 this over voltage is 12V So that you don t destroy adjacent fuses from high current a 330 ohm resistor is placed in series with the arm of the rotary switch To allow the insertion and removal of the programmed IC a 16 pin IC socket should be used The power required by the programmer is quite unique but not impossible to find Surplus mail order houses sell inexpensive DC power supplies that deliver 5VDC as well as 12VDC with a current of about 50mA When wiring the circuit just verify the polarity and level of each output with a volt meter Then connect the appropriate voltages in place Once your programmer in complete check the wiring and inspect for solder bridges When all 74188 PROGRAMMABLE READ ONLY MEMORY PINOUT 32 WORDS 8 BITS WORDS DATA OUTPUT DATA OUTPUT DATA OUTPUT DATA OUTPUT DATA OUTPUT DATA OUTPUT DATA OUTPUT GND Oo IO VI DB OO N SUPPLY VOLTAGE OUTPUT ENABLE INPUT D4 16 INPUT D3 8 INPUT D2 4 INPUT D1 2 INPUT DO 1 DATA OUTPUT B7 FIGURE 4 36 ELECTRONICS HANDBOOK seeme connections have been inspected for problems the time has come to program the logic data onto the non volatile memory of the 741
8. A Ampere hours Peak Sun Hours 9 6 4 2 4 Amperes Allowing a 25 safety factor the solar system should be capable of delivering an average Current lav of Average Current 2 4 0 25 x 2 4 lav 3 amperes if the transceiver operates at 12 volts the rating of the solar panel should be about 14 volts at 3 amperes In this arrangement on an average basis the ampere hours delivered by the solar panel would be 12 3 x 4 while the average demand of the transceiver would be 9 6 ampere hours A solar cell consists of two types of silicon semi conductor material separated by a junction Half the solar cell is made up of material designated type N This semiconductor material tends to attract and hold electrons The other half of the cell contains type P material which has a surplus of electrons and is willing to give them over to the N substance More on this later Think of the silicon atom as having four protuberances It is the atom s nature to want to hook up with other silicon atoms rather than having its appendages flapping idly These arms of the silicon atom are in reality electrons surrounding the silicon nucleus The electrons don t swarm about the 68 ELECTRONICS HANDBOOK nucleus as often depicted instead each electron occupies an energy shell The closer to the atom s core the electron is located the lower its energy and the more stable it is Each shell will accommodate a specific number of e
9. Allabout Books Dept H Box 14155 Fremont CA 94539 V10 P O Box 5148 N Branch N J 08876 O Yes Enter my subscription 4 issues ONLY 15 00 Canada 18 00 Forelgn Postage add 8 00 U S Funds O Payment enclosed Payable to C amp E Hobby Handbooks PLEASE PRINT NAME ADDRESS CITY STATE VOLUME X 17 DESIGN YOUR OWN OP AMP CIRCUITS By William R Hoffman From its introduction almost two decades ago the simple lowly operational amplifier op amp has probably become the most used functional analog circuit block in semiconductor history From that first IC circuit called the 709 has come all of todays analog semiconductor circuits from high performance low noise preamplifiers to large high power amplifier stages The basic circuit usually composed of a differential input stage followed by one or more voltage gain stages and ending with a push pull output circuit configuration can be made to do almost anything from analog amplifiers and filters to digital comparator functions And because of the universal availability and low cost as well as simplicity of designing with them even the home experimenter can successfully create a large variety of circuit functions with only a pencil and paper and pocket calculator SOME BASIC INFORMATION o begin with lets look at some of the op amp s own design work characteristics so we can learn some basic Their inputs
10. SOLDER FIGURE SA Added Assembly Instructions lf you choose to assemble the compass using a home brewed PC Board or by purchasing the complete kit from Suncoast Technologies there are a few things you must be made aware of All resistors must be installed and soldered while standing on end See Figure 5A By placing components on end precious PC Board space is saved And at 50 a square inch you can appreciate this saving Diode D1 is another component that must be soldered on end Unlike the resistors diodes have a polarity and they must be installed in a certain way If not the compass just won t work Figur64 shows the proper installation procedure for D1 Note that the banded end of the diode is facing downward Also it s installed with the body towards the 7805 voltage regulator 101 funds and or Money orders onl 40 ELECTRONICS HANDBOOK THE FOLLOWING ARE AVAILABLE FROM SUNCOAST TECHNOLOGIES P O BOX 5835 SPRING HILL FL 34606 Complete Compass kit containing Compass Sensor PC Board Programmed 74188 Resistors and LEDs Less Plastic Housing 24 00 Available separately Compass Sensor 15 00 PC Board 5 00 Programmed 74188 3 00 Please add 2 50 Shipping Handling for all U S orders and 3 50 Shipping Handling for Canadian orders Payable In U S Florida residents must Include Sales Tax DIODE D1 ALSO STANDS ON END PC BOARD SOLDER INSERT DIODE D1 WITH ITS BANDED END FAC
11. Transistors How Radio Recelvers Pull In Slgnals Cathode Ray Tubes Explalned How Capacitors Work Using Magnetism In Electronics and much much morel Of course we can t make you a master electrician ovemight But we can show you the fundamentals of repalr plus malntenance tips TRY A FEW ISSUES AND EVALUATE OUR e HOW TO DO IT HELP Tips and pointers that add up to money saved For example tuning up your tape player all about radios whys and hows of tumtables care and feeding of speakers e EXCITING DISCOVERIES Whatever your particular Interest In electronics you ll be entering a word of discovery In the pages of the ELECTRONICS HANDBOOK No other training shows you how to troubleshoot and service computers like NRI NEW 386sx 20 MHz MINI KOTOR NEW 40 MEG TOWER COMPUTER High resolution HARD DISK DRIVE Features 32 bit 80386sx nonglare 12 TIL You instal this CPU 1 meg RAM 64K ROM monochrome 40 meg IDE 1 2 meg high density floppy monitor with tilt hard disk drive disk drive and swivel base inte nally for greater data storage capacity SOFTWARE DISCOVERY LAB Train with MS DOS GW BASIC and popular Microsoft Works applications software Complete breadboarding system lets you design and modify circuits diagnose and repair faults DIGITAL MULTIMETER Professional test instrument for quick and easy measurements DIGITAL LOGIC PROBE Simplifies analyzing digital circuit op
12. We also said that according to Ohm s Law V IxR or we could say the voltage drop across a resistor is equal to the resistance times the current through it If Ohm s Law is the most important then the second most important concept in electricity is Kirchhoff s Voltage Law which states The sum of all the voltage rises and drops around a Closed loop circuit will equal zero Don t be intimidated This isn t Electricity 101 If you never remember the name Kirchhoff again it s really 62 ELECTRONICS HANDBOOK not that important The important thing is the concept If we look at our circuit in Figure 5 with the switch closed we see that the battery supplies 1 5 volts That is a voltage rise We calculated in Part that the Current in the circuit was 015 amperes 15 mA according to engineering notation If we use Ohm s Law to multiply the current through the resistor times the resistance we find that there is 1 5 volts dropped across the resistor If we note the polarities of the battery and the voltage dropped across the resistor we will see that they are opposite or oppose each other If we add them algebraically the sum is zero Kirchhoff would be proud of us This may not seem like it s very profound in a simple circuit but it comes in very handy a little later on So let s look at another simple circuit SWITCH FUSE O l 7 5mA R1 1 5V 100 OHMS 5 CELE V 75VOLTS R2 100 OHMS V 75VOLTS Figure 6
13. and chances are you ll find yourself rubbing shoulders with scientists and engineers from nearby Cal Tech and the Jet Propulsion Laboratory It s not the ambiance of the place that attracts these guys it s the bargain priced electronic components For those of us who can t make it out to Pasadena the next best thing is to have a copy of the C amp H Sales catalog on hand Most of the material sold by C amp H falls into the category of new surpius and the selection is enormous Consider the following partial list of items motors accelerometers transducers wave guides solenoids timers hand tools optics meters valves synchros semiconductors magnets differentials gyros pressure gauges and relays Prices are great For example Swiss made Erem pliers which list for over 50 are just 10 95 You can get a free copy of this great catalog by writing to C amp H Sales P O Box 5356 Pasadena CA 91117 9988 VOLUME X 85 ROLYN OPTICS The new 127 page catalog from Rolyn Optics is a treasure trove of precision optical components that will be a welcome addition to the data library of the advanced experimenter as well as the professional engineer Whether you re planning to build a telescope an enlarger a microscope a copier a spectroscope or some other optical instrument you can find all the parts you ll need in this catalog Rolyn sells simple and compound lenses of all kinds prisms beamsplitters glass blanks fused S
14. counterweight in certain applica tions Shaft couplings and universal joints are discussed in Chapter Six Belt drives chain drives and pulleys are explained in Chapter Seven which for most readers will be the most important chapter of the book This chapter is augmented by an extensive set of center distance tables which make the design of belt driven systems easy Chapter Eight is all about shafts and bearings Chapter Nine deals with techniques for the damping or elimination of vibration and the book ends with a final chapter on elements of robotic design To sum up the Design and Application of Small Standardized Components is a 784 page handbook of practical mechanical design You don t have to be a mechanical engineer to under stand it and you won t go broke buying it since the price is just 7 95 soft cover or 12 95 hard cover This book is available from Educational Products P O Box 606 Mineola NY 11501 THE BEGINNER S GUIDE TO RADIO CONTROL SPORTS FLYING By Douglas R Pratt The flying of radio controlled model airplanes dates back to at A A ii least the 1940 s and possibly earlier Back in those days you not only built your own airplane you built the transmitting and receiving equipment as well and you had to have a ham license to use the equipment Things have changed considerably since then Factory built transmitters and receivers are readily available and you don t need a ham lic
15. sitting in your car or boat take the adapter plug and insert it into the cigarette lignter Holding the compass parallel to the ground press SW and note which LED lights This indicates the direction the compass is being held Another option that you might want to consider if using the cigarette lighter adapter is the permanent removal of switch SW1 because when the engine of the car or boat is turned off voltage to the vehicle s cigarette lighter will be cut off thus removing power from the compass Just remember to place a jumper wire between the two SW1 PC Board holes VOLUME X 39 Testing When the PC Board is inspected under strong light to ensure that there are no solder splashes or bridges take a 9 volt alkaline battery and connect it to the provided clip Facing a known direction hold the compass in parallel to the ground Press SW1 and note the lighting of the appropriate LED Slowly spin around and check for the advancement of the LEDs as they light and extinguish in the proper sequence If the north LED doesn t light double check to see if the device was inserted in the proper direction If no LED lights check to see if a positive 5 volts is present at pin 16 of IC1 Also check for proper grounding of IC1 s pin 8 If no voltage is present check IC1 for proper insertion and finally check diode D1 It might be open or reversed on the board TO SAVE BOARD SPACE SOLDER ALL RESISTORS STANDING ON END PC BOARD
16. there are two one marked or non things about them necessary for us to do our inverting and the other marked or inverting is 9 volts F G1 B1 Ground m E s B2 9 volts E B Fig 1 A is AC operated power supply for op amp circuits Fl is a 4A fuse Tl is a small 120V to 12V power transformer rated at 100mA or more with a center tapped secondary Dl to D4 are small silicon diodes rated at 1A with at least 50V PIV Cl and C2 are 470 uF 16V capacitors For the battery supply B simply connect two 9V carbon zinc transistor radio batteries as shown 18 ELECTRONICS HANDBOOK eda where we apply the Signal or reference input into the IC If we choose the non inverting input then the output will have the same phase as the input VOLTAGE FOLLOWER GAIN 1 Output voltage input voltage OUTPUT IMPEDANCE about 5k ohm depending on op amp used However if we go into the inverting input then our Output will be an inversion of the input signal Both can be used and each has aspecific application Note that the input impedance for the non inverting input is very high very little current is used from the source signal to produce an output On the other hand the inverting input because it is where the feedback is applied from the op amp s output has an impedance near zero ohms Therefore an input resistor must always be used to protect the source of
17. 1 a es Badiiy Oiber 19 1577 ar 194 B kia timer allows the The Event user to count down the amount of time remaining in a given event This counter can be set from one second to 99 minutes It counts off the time in 1 10th second increments The timer can be suspended at any time When restarted the timer begins from the suspended value The user also has the option of having an audible alarm sound when the event has counted down to 00 00 The Event counter comes in handy for timing speeches and presentations or code practice The large display makes it easy to read the remaining time from across large rooms The Lap timer allows the user to keep track of event times within a total amount of time Perfect for auto racing sporting events or laboratory experiments The counter increments in 1 10second intervals The function keys control the counting of both the lap time and the total time The space bar of the PC can be used as a convenient way to controi the lap time The large number display makes it easy to read and record time results as they happen The U S Time Zone Display provides a quick way to get the time across the country This display provides a means to check the time in a remote part of the country you are planning to cail or make schedule arrangements The time can be displayed in both 12 hour and 24 hour modes continuously being updated on They Pte Diteleg
18. 111 MONS KENG aa E E O MES O KES KES KS KS Publisher Editorial 4 Build Your Own The Future Of From The Editor s Electronic Compass 33 Solar Energy 64 Desk 6 Build A Vario New Products Parade 8 Coupler Receiver 41 Solid State Update 80 New Book Reviews 12 Expert Guide To Project Construction Quickie Design OpAmp Building de anal 47 Curiosity Detector 83 CircullS 0n ohte 18 i Understanding Catalog Corner 84 Crystal Oscillators es 26 Basic Electricity ae es 59 CIRCUIT 19 Crystal Controlled TTL FRAGMENTS Tape Player Code Oscillator Buraler Alarm Super Signal Booster Jome A eR Double Feature Water Level Detector Power Mike Amplifier Automatic Turnoff Negative Power Supply Pusheon Push off Home Intercom System Touch Control Mini Digital Roullette Mag Tape Anp Basic Pulse Maker Do It Yourself Delay Even Odds Telephone Voice ve 2295 The Robot Eye TTL Programmed Music ERT TEL esrenras IC TESTBENCH 73 The Robot Ear L Two Tone Alarm The Waveshaper LED Adds Luster A Switch With WORKBENCH 52 Positive Into Negative A Memory sonni nennet voi PROJECTS CMOS Logic al For RF 2 ELECTRONICS HANDBOOK SELECT 5 BOOKS for only 425 we ao
19. COIL PARTS LIST FOR CODE PRACTICE OSCILLATOR C1 001uf Capacitor IC1 4011 CMOS Quad 2 input NAND Gate R1 1 500 000 ohm Watt Resistor R2 1 000 000 or 2 000 000 ohm Potentiometer R3 10 000 ohm Watt Resistor R4 5000 ohm Audio Taper Potentiometer Q1 2N3903 NPN Transistor or Equivalent S1 Code Practice Key T1 Audio Output Transformer 1000 ohm center tapped primary 8 ohm secondary Radio Shack 273 1380 SP1 8 ohm watt speaker VOLUME X 75 DOUBLE FEATURE The versatile quad op amp LM 3900 or MC 3401 can easily be persuaded to deliver two different PARTS LIST FOR DOUBLE FEATURE waveforms from two of its sections reserving the C1 001 or 01 uF ceramic capacitor other two for mixing or amplification purposes IC1 LM 3900 or MC 3401 op amp Section one is an integrator furnishing a fine R1 R4 1 000 000 ohm Y2 watt resistor triangular waveform the other unit supplies a sguare R2 R3 100 000 ohm Y2 watt resistor wave signal Adjusting R6 varies both freguency and R5 120 000 ohm watt resistor duty cycle symmetry of the two waveforms AC1 16200 0o0 ohimy lingartzper potehtiomerss value of 001 uF will give a frequency of about 1 kHz while 01 uF will be close to 100 Hz This circuit can save you Steps time and without bothering with extra house wiring Or you can electricity When you leave a room and turn out the use the circuit to help kee
20. Fig 1 Actually these vario coupler parts cost less than a buck fifty plus the coil wire The 3 inch PVC pipe coupling can be picked up at most plumbing supply stores This makes a very sturdy coil form The foam ball disc brass tubing and wooden dowel can be found at most hobby stores Even the front panel and bottom chassis are made of scrap masonite and wood pieces Although this all wave receiver may take a little time to build it will take you back on a nostalgia trip to the early days of radio and it s worth every minute of it E ack in the late twenties and early thirties the OWN VARIO R RECEIVER By Homer L Davidson The Circuit The allwave receiver should operate from the broadcast band down to the 20 meter band The circuit consists of a FET regenerative transistor and a low power audio IC Fig 2 C1 is switched directly to the main coil of the shortwave bands and switched to the primary coil L1 for broadcast operation Coil L2 and C2 tune the entire bands SW2 switches in the different tapped coil windings of L2 Varactor diode VD1 provides adequate bandspread tuning or Station separation L3 provides feedback operation when rotated This movable coil helps in regeneration control and separating stations The main regenera tion is controlled by R5 The entire receiver circuit is constructed on a single PC board C8 picks up the weak audio signal and is fed to the volume control R7 Isolation capac
21. The other two control wires should be twisted together and soldered into the PC board Either mark the center terminal wire or check it out with the ohmmeter Make the coil tap connection short and direct as possible to SW2 Mount 1C1 LM 386 after all soldering is completed Check the dot on top of IC to match with the dotonPC board Solder in Q1 by using a heat sink or the long nose pliers to dissipate the heat from the soldering iron Although the MPF 102 FET transistor is quite hardy it is prudent to protect the terminals from excess heat Likewise use the pliers to dissipate the heat when soldering in the varactor diode VD1 Solder C1 directly to the antenna post Run the capacitor wire to the center switch terminal Fig 9 Connect the hookup wire to the top side of L2 and RF side of L1 Solder the 9 volt battery clip with the red wire to B and black wire to common ground Make sure the ground post and all ground connection ties in each control variable tuning capacitor SW2 and PC the board The coil terminals of L2 and L3 are brought a out high to correspond with the coil connections Use MER larger PC terminal connections for all wiring that 238 ga hae VARIO it COUPLER OM FIGURE 8 ge u ll AS A ar A IA a n Figure 8 Back side view of receiver with antenna capacitor C1 soldered to the antenna post terminal Testing After all wiring is completed check all connections once again It s a little disheartening
22. a component or conductor If all the current flows through all of the components what would happen if the wire became disconnected from the battery or if the filament of the lamp burnt out Obviously there would no longer bea path for current to flow and all of the current would stop Remember we must have a complete circuit or circle for current to flow in This is called an open circuit SWITCH 1 5V RESISTANCE 100 OHMS D CELL Figure 5 Series circuit In Figure 5 we have the same circuit but now we have added a switch and a fuse Both of these are used to create open circuits The switch is there so you can turn the lamp on and off by interrupting the flow of current to it The fuse is a safety device It is constructed in such a way that if the current exceeds its rated value the internal link will melt and create an open circuit so that current can no longer flow When the circuit is originally designed we determine the maximum current we would ever want to flow and choose a fuse with a current rating slightly higher than that If the current ever reaches that level the internal link melts and current stops KIRCHHOFF S LAW IT ALL ADDS UP TO NOTHING Let s talk about voltage In Part we said that when voltage is supplied by a battery or other power source called a voitage rise we labelled it E and if we were talking about a voltage drop across a resistor or other device we labelled it V
23. a dual polarity power supply For low current applications it may be easier to construct this negative power supply using one IC rather than rectifying from the power line or transformer 1C1 operates in an astable mode with essentially square wave output at pin 3 C2 C3 D1 and D2 form a full wave voltage doubler circuit which produces approximately minus 14 volts with no load at the negative output terminal The circuit will deliver 12 volts into a load of 1000 ohms NEGATIVE OUTPUT VOLTAGE PARTS LIST FOR NEGATIVE POWER SUPPLY C1 01 uF ceramic capacitor 15 VDC C2 C3 C4 15 uF electrolytic capacitor 25 VDC D1 D2 1N4148 diode TOUCH CONTROL Have you ever been in an office building where the elevator up down buttons aren t switches at all but work by touch You can build a similar touch control Circuit using a 555 timer IC The circuit shown Operates an LED but you can easily modify it to control a doorbell or any other device 1C1 is connected as a one shot or monostable multivibrator with the trigger input pin 2 wired to a high impedance network When the input terminal is touched by a finger stray AC voltage pickup is impressed upon pin 2 of C1 causing it to trigger This Causes pin 3 to go positive and provides forward bias to Q1 which illuminates the LED R2 and C2 IC1 555 timer R1 1 000 ohm watt resistor R2 10 000 ohm watt resistor determine the time interval that LED 1 is i
24. and 120 ns settling time to 0 1 The AD827 s superior DC performance makes it Suitable for buffering fast 8 and 10 bit analog to digital converters With 5V supplies the AD827 has 2 mV of maximum offset voltage guaranteed and a typical open loop gain of 3 500 with a 500 ohm load With 15V supplies the cpen loop gain increases to 5 500 with a 1 000 ohm load and the maximum input offset voltage is 4 mV Data sheets are available from Analog Devices Literature Center 70 Shawmut Rd Canton MA 02021 1990 RF Products Selector Guide E Cross Reference VOLUME X 81 HIGH SPEED A D CONVERTERS Analog Devices new high speed ECL compatible AD9060 the industry s fastest 10 bit analog to digital converter ADC guarantees encoding rates up to 75 million samples per second MSPS Its TTL compatible counterpart the AD9020 provides encoding rates as high as 60 MSPS The analog input voltage is established by a pair of external reference voltages nominally 1 75V The typical analog input bandwidth is 175 MHz Maximum input bias current is 1 mA The AD9020 requires a 5V supply while the AD9060 requires a These two new analog to digital converters are well suited to such applications as high speed instrumentation professional video medical imaging spectrum analysis and radar Track and hold circuitry and external trimming are not required to achieve rated performance Contact Analog Devices Literature Center
25. as bug eyed and downright crazy over great new project ideas as they are And guess they re right ELECTRONICS HANDBOOK thinks of you who dig electronics as the last of a special breed It s more than Just the do it yourself angle it s also the spirit of adventure In this pre packaged deodorized world building your own stereo system shortwave receiver darkroom timer or CB outfit is like constructing a fine tuned little universe all your own And when it all works perfectly it really takes you to another world ELECTRONICS HANDBOOK knows the kinds of projects ON you like and we bring em e to you by the truckload oo 72 ELECTRONICS HANDBOOK ARN ELECTRONICS G o Witcheg O n Of course we can t make you a master electrician overnight But we can show you the fundamentals of repair plus maintenance tips IF YOU RE NEW TO ELECTRONICS YOU GET A BASIC COURSE lt gives you a complete ground floor lowdown on a variety of important electronic subjects For example Understanding Transistors How Radio Receivers Pull in Signals Cathode Ray Tubes Explained How Capacitors Work Using Magnetism in Electronics and much much more TRY A FEW ISSUES AND EVALUATE OUR HOW TO DO IT HELP Tips and pointers that add up to money saved For example tuning up your tape player all about radios whys and hows of turntables care and feeding of speakers e EX
26. attach the com ponents plug it in and use it cuts will make repair easy and efficient Learn money saving maintenance tricks and repair techniques You ll feel confident about troubleshooting problems You ll know when to call for ser vice and when you can fix equip NENNIR AEAN ss FREE Circuit Layouts on Acetate a P mf d f a e ETA TR ment yourself Timely supplements offer you brand new projects and up to date information Experts in their fields work out new and interesting assembly instructions for one evening projects and keep you on top of whats new Your knowledge of electronics please send me The Modern Electronics Manual MONEYBACK YES for only 49 95 plus 5 00 shipping and handling GUARANTEE There s no risk in trying The Modern Electronics Manual to see if it s right for you If you are not delighted simply return the Lunderstand that if am not completely delighted may lt j return the manual within 15 days and receive a prompt E refund Updates will be sent 4 5 times a year they are up to 120 pages each and cost 25 per page Cancel anytime en nd gt ee O Visa MasterCard Check enclosed Bill me grows continuously You ll benefit from the manual after the LS Card __ Ema latest developments and ideas be able to IS day trial period EA oi nat
27. before the word is caution Integrated Circuits are extremely sensitive devices and require very special handling A eS VOLUME X THE WAVESHAPER This little circuit illustrates the principle behind multi kilobuck laboratory style waveform synthe sizers as well as some of the more advanced music synthesizers Into J1 you should feed a square wave signal swinging from ground to almost 5 volts The input signal s frequency should be ten times that of the desired output Adjusting potentiometers R1 through R10 will enable you to literally design the shape of the output waveform If you can get hold of 5V la an oscilloscope use it to observe the effect of R1 through R10 on the output At the same time feed the output to an audio amp so that you can hear the changes in timbre that occur as the waveshape IS altered Capacitor C5 can be used to smooth out the chunky shape of the output With a 10 kHz input start with a value of 0 1uF for C5 and experiment Make sure at least one potentiometer is set to maximum resistance and that at least one is set to minimum This guarantees a full 1 volt peak to peak output TYPICAL OUTPUT WAVEFORM yA NORMAL O L 4 J2 gt irs OUTPUT C5 OPTIONAL NOTE OUTPUT FREQUENCY INPUT FREQUENCY 10 PARTS LIST FOR THE WAVESHAPER C1 C2 C3 0 01 uF ceramic disc capacitor 35 VDC C4 0 5 uF mylar capacitor 35 VDC C5 see text IC 1 4017 CMOS decade cou
28. brings us a collection of easy to build projects designed to add new features and enjoyment to a TV VCR or stereo system The roster of projects consists of 22 items tunable notch filter audio delay line equalizer noise reducer low voltage power amplifier two watt audio ampli fier four watt audio amplifier rear speaker ambience amplifier bass boost filter stereo audio control VU meter audio power meter stereo simulator infrared audio transmitter and receiver surround sound decoder VCR AC controller stereo adapter for TV 14 ELECTRONICS HANDBOOK tone controller stereo audio switch and various power supply circuits to power the projects presented In addition to the projects there are chapters on TV and VCR theory assembly tips reading schematic diagrams making printed circuit boards and soldering The book is thus a self contained introduction to project building that will appeal to the beginner as well as the more experienced hobbyist Most projects require only two or three integrated circuits and a handful of other components so you can assemble them quickly and inexpensively PCB layouts accompany most of the projects Customize Your Home Enter tainment System is an excellent book of projects reasonably priced at 15 95 Order from TAB Books Inc Blue Ridge Summit PA 17214 9988 or your local bookstore DESIGN AND APPLICATION OF SMALL STANDARDIZED COMPONENTS By the Staff of Stoc
29. expect you to pay the full retail price discounts are virtually unheard of Therefore it was a Surprise to us when we received the new Products International catalog and found that almost every piece of test gear was being sold at discount prices The typical discount seems to be about 10 15 which means that you could end up saving hundreds of dollars in your next scope counter or EPROM programmer Products International is an authorized distributor for such test equipment manufacturers as Simpson B amp K Precision Beckman Hitachi Kenwood Leader Fluke Carlo Gavazzi EKO A W Sperry Hameg Systron Donner VIZ and American Reliance As you can see their product line is truly international and it includes scopes DMMs frequency counters signal generators power supplies and more Write to Products International 8931 Brookville Rd Silver Spring MD 20910 TIME MOTION TOOLS Regardless of whether you are involved in electronics professionally or just as a hobbyist you soon learn the value of good tools With the right tools your work is accomplished quickly cleanly and professionally without them the job seems to take forever and the results are often disappointing Finding the kind of tools you need can be a tricky business Of course you can obtain some of the tools you need from the local hardware or department store but you won t find everything there The special tools necessary for electronic assembly and re
30. it is suggested that you write to Linear Technology at the following address and ask for Application Note 12 Linear Technology Corporation 1630 McCarthy Blvd Milipitas CA 95035 7487 Circuits A D are typical gate oscillators which as you Can see require only a minimum number of parts These gate oscillators are worth mentioning because they work so well If you have ever worked with gate oscillators you know how temperamental they can be Usually their operation is intermittent or they fail to oscillate or you spend all day tuning the all too familiar trimmer capacitor trying to get them to oscillate There are even cases where substituting one chip manufacture s IC for another will cause the circuit to fail to oscillate q a 10mMHz 11117 0 25 nF TL demas e telianalsifio ots FREQUENCY GENERATOR 100KH2 Mino 14 11110 of 8 741330 10KHZ e lalia saltanaltiltol 91 8 741390 7413390 68pF 74L890 ME 1437 44 14 680 68pF L LL 5 VOLTS 1 00H22 7 edits 1932 1110 91 8 74LS90 POSTE 5 VOLTS 74 8590 Gate Oscillators There may be the oddball occasion in which one of these circuits fails to operate It is therefore suggested that you test the oscillator in your Circuit before you incorporate it into your design Even though this problem occasionally happens these gated oscillator circuits are so easy to build and require so few parts that you will find you
31. no effect on its suspectibility to inductive coupling Also you may have wondered whether a shield would be as effective against a magnetic field as it is against an electric field The answer is no Aluminum which is so effective as an electric shield begins to be effective against magnetic fields only at higher frequencies above 100 kHz At the important frequency of 60 Hz aluminum is useless In order to obtain better magnetic shielding your shield must be a feromag netic substance such as steel Because it is harder to machine than aluminum steel is rarely used by hobbyists even though its magnetic shielding properties are superior to those of aluminum At 60 Hz however even steel is only partially effective shielding effectiveness increases with frequency Special magnetic alloys such as Mu Metal are necessary at low frequencies All things considered serial manner Resistance and inductance on the power lines can create unwanted ground noise 50 ELECTRONICS HANDBOOK 1 magnetic shielding is more difficult than electric shielding Wiring Problems So far we ve dealt with stray pickup from a more or less familiar viewpoint familiar at least in the sense that whenever noise problems occur the first thing to be blamed is some mysterious invisible field Very often however the trouble is the handiwork of amore mundane villain your circuit s electrical wiring Figure 5 shows a serial power distribution
32. of 0 45 volts there is maximum power delivered to the load As shown in Figure 2 almost maximum current flows A reduction in the load resistance below this value results in very little change in current In fact the solar cell can be short circuited and there will be no damage or significant increase in the load current This condition too is shown in Figure 2 with the same 66 ELECTRONICS HANDBOOK current present from right above the knee of the curve over to the zero voltage value In practice then the voltage produced by a single silicon solar cell is between 0 4 and 0 45 volts The size and shape of the cell has nothing to do with this value The level of the output current as a function of a given light intensity is related directly to the cell area regardless of the shape of the cell be it circular semicircular rectangular or any other configuration Under the illumination of 1 sun a typical 3 inch diameter solar cell will produce an output current of 1 2 amperes at a voltage of 0 45 A similar 2 4 inch diameter cell about half of the area of the previous one will provide an output current of 550 milli amperes The efficiency of a solar cell is the ratio of the electrical power output over the light power unit Efficiency ee 100 Efficiency is important and determines the electrical power output that can be obtained for a cell of a given size The greater the efficiency the more power that can be obtained wi
33. one sun out of millions of suns a sun 93 million miles away which always has powered the earth All forms of life are dependent on the sun Many millions of years ago fossil fuels coal natural gas petroleum were created by chemical reactions stimulated by the sun These fossil fuels are difficult to get to imported at great expense increasingly taxed and just plain running out Now today we are turning to the sun to provide for us the basic stuff of life energy The sun shines down at about 138 watts per hour per square foot of area on this planet This energy is a gift free ours for the taking Some day we may have satellites revolving in space collecting solar radiation before it is deflected by the atmosphere These solar absorbing extraplanetary devices may then radio signal the captured energy back to a welcoming mother earth A gleaming glittering satellite wings effortlessly through the expanse of outer space performing a multitude of tasks Meanwhile a desert well pumps hundreds of gallons of water daily changing an arid wasteland into an oasis What do they have in common They re both solar powered Solar power by photovoltaic cells is a space age technology which has come into its own on our planet Let s take a look at this workhorse of space now established on terra firma and see how it performs its magic 64 ELECTRONICS HANDBOOK v 0 EN ii TE i ja a eT Photoelectri
34. ote SAAMA ols C3 4 7Mfd disc capacitor R4 2 7 ohm resistor C4 25Mfd disc capacitor Mi C5 05Mfd disc capacitor 1 S2 SPDT single pole double throw switches C6 100Mfd disc capacitor Voc see instructions for Max Vcc on IC package MAG TAPE AMP From time to time surplus dealers offer complete tape or cassette mechanisms everything ready to go except for the electronics and at rock bottom prices of 10 15 or 20 Often all the mechanism needs is this equalized tape head preamplifier Though the power supply is rated at 15 VDC almost optimum results will be Obtained with supply voltages as low as 7 VDC Two Ordinary 9 volt transistor radio batteries will power the preamp for many hours As with all these projects the 7411C is internally compensated and no special wiring practices are needed the preamp can be built in just about any TAPE enclosure PARTS LIST FOR MAG TAPE AMP C1 22 uF electrolytic capacitor 25 VDC or better C2 0 005 uF disc capacitor 25 VDC or better C1 1Mfd disc capacitor OUTPUT C3 0 01 uF capacitor 25 VDC or better IC1 Type 741 opamp i O05 uF R1 100 ohms watt resistor R2 100 000 ohms watt resistor VOLUME X 77 EVEN ODDS The continued versatility of the 4017 counter and DL 750 digital display is demonstrated in this Odd Even or Coin Toss simulator As an added feature the
35. output is 74188 COMPASS PROGRAM COMPASS HEADINGS BINARY INPUT D3 D2 D1 DO NORTH SOUTH EAST WEST NORTHEAST NORTHWEST SOUTHEAST SOUTHWEST NOTE 74188 OUTPUT 1 74188 OUTPUT BO B1 B2 B3 B4 B5 B6 B7 OOOOOO O OO 000O0O 0000000 OOO 20000 LED ON 0 LED OFF TABLE 2 34 ELECTRONICS HANDBOOK i re 5V R5 R8 1K SLEREET DUEIBEDUDP ARE REVEVUSA LED 1 8 a NORTH TO COMPASS SENSOR EAST jam NORTH EAST WEST WEST NORTHEAST 5V NORTHWEST SOUTHEAST SOUTHWEST 101 R9 R12 V 74188 i 1K gt 5V SW1 px IC2 ze a 1N4001 9 VOLTS GND FIGURE 3 VOLUME X 35 then wired to pins 10 to 13 pin 14 is tied to a logic 1 level of the 74188 ROM chip The output terminals BO to B7 are programmed in such a way as to placea logic 1 at the output pin that will light the appropriate LED When connected to an LED whose cathode leg is wired to ground a difference of potential between the two terminals is present This voltage difference will light the appropriate LED COMPASS DATA OUTPUT HEADINGS NORTH SOUTH EAST WEST NORTHEAST NORTHWEST SOUTHEAST SOUTHWEST O O O E A O LED OUTPUT ON LOGIC 0 LEVEL TABLE 1 Seeing that the 74188 is a device that makes use of an open collector output eight loading resistors in the range of 1K ohm must be connected to each output leg The other side of the resistors are shorted together an
36. raising capital dealing with lawyers setting up a production line marketing the product and running the business What he doesn t cover you can find by reading the books listed in the extensive bibliography I think this is a terrific book and a good value too Whether you have a specific invention in mind Or are just Curious about inventing in general inventing Creating and Selling Your Ideas is a book you ought to read The price is 15 95 and the publisher is TAB Books Inc Blue Ridge Summit PA 17214 9988 THE EMPLOYMENT MAZE By Paul Dombroski David Hage and Dennis Hage As America entered the twen tieth century most of its working citizens were self employed They were farmers or shopkeepers or lawyers or a hundred other things and they were their own bosses Today on the threshold of the twenty first century the situation has reversed itself big corpora tions and big government dominate the economic land scape and most people work for someone else Under such conditions the key to success may not lie in working hard but in working someplace else Paul Dombroski personnel manager at an electronics firm in the southwest along with associates David and Dennis Hage has written a book that will enable the ambitious job seeker to find the kind of job he wants The author advocates establishing a network of influential friends to help in the job search since the choicest job openings are o
37. say that the compass sensor is facing North The Hall effect Sensor 3 will deliver a ground or logic 0 to pin 3 of the device If the anode lead of an LED were connected to this pin while the cathode had a positive 5 volts on it The LED will light Indicating a heading of NORTH The same would hold true if the compass was facing West But this time the Hall effect Sensor 4 will place a ground on the anode of another LED while the output of Sensor 1 will go high So if a number of LEDs were placed in an 8 point circle pattern we can easily indicate the standard compass headings just by lighting the appropriate LED How It Works Figures 2 and 3 show the schematic diagram for our Electronic Compass As you can see the compass TO IC1 5V PIN 11 PIN 10 PIN 13 PIN 12 GND WEST NORTH BOTTOM VIEW FIGURE 2 The 74188 1C1 is a Programmable Read Only Memory 32 words 8 bit word See Figure 4 When programmed the chip can easily create a situation that will eliminate the lighting of two LEDs to indicate intermediate compass headings such as north east south west etc The 74188 senses the dual input from the Dinsmore compass sensor then lights the one and only one LED that corresponds with this data Table 2 shows the internal programming of the 74188 The Binary output from the Dinsmore sensor is weighted 1 2 4 8 Here we will indicate this as DO D1 D2 and D3 respectively The sensor data
38. the Reset may zero the display first although there is statistically little or no effect upon subsequent outcomes When the switch is released the counter holds on one number which is displayed until reset or new counts arrive If a Zero appears on the display it may be assumed that the Bank takes all wagers thus keeping the system in fresh batteries Medium scale integrated circuits like the 555 timer are all very fine but it is instructive to know how to make do with simple gates The following circuit employing a single type 4011 quad NAND or 4001 quad NOR provides a hold in delay ranging from at least one second down to 20 milliseconds In operation when a positive potential is applied to the input the output follows immediately operating a relay or some other properly interfaced component When the input is removed the output continues high for a period determined by the RC time constants The polarity of the output may be reversed by C1 R1 R2 Time 1K 100K 1K 10K 100K 1K 100K 1Meg 0 1 uF 0 1 uF 0 2 uF 0 2 uF 0 2 uF 1 0 uF 1 0 uF 1 0 uF MINI DIGITAL ROULETTE DO IT YOURSELF DELAY 00 14 mSec 13 00 mSec 00 30 mSec 02 70 mSec 25 00 mSec 01 30 mSec 00 12 mSec 01 10 seconds PARTS LIST FOR MINI DIGITAL ROULETTE C1 0 47 to 2 2 uF electrolytic capacitor 15 VDC C2 100 uF electrolytic capacitor 15 VDC D1 D2 1N4148 or 1N914 diode 1C1 4011 quad NAND gate IC2
39. the answers and see how you did Betcha nobody does them Okay now have you all convinced that the rest of this is going to be pure math Right No We ll try to MULTIPLIER TOLERANCE engineering notation for right now is to understand the resistor color code VIOLET AND THE BAD BOYS Resistors and less often capacitors use a code consisting of bands or dots for caps of color on the component to indicate the value of the component We learned in Part that resistors are the components which have the property of resistance built into them Resistance is that property which opposes the flow of Current in a circuit and is measured in ohms The colored bands on a resistor give us the value of resistance and the tolerance of the resistor The tolerance is an indication in percent of precisely how the resistor was manufactured If it has a ten percent tolerance the actual value of the resistor will be within plus or minus ten percent of the value given by the colored bands on it Figure 3 shows a resistor its bands and the corresponding values of the color code The mnemonic used to remember the color code or at least the one that is printable is Bad Boys Race Our Young Girls But Violet Generally Wins Good Stuff Figure 3 shows how the first letter of each word of the mnemonic represents a color and its value Note that the first two bands give the first two digits the third gives a multiplier which corresponds t
40. the dowel clear through L3 form and place another washer on the opposite end These washers keep the coil centered and prevent rubbing on the ooil form Leave 1 4 inch of metal tubing stick out the rear end Fig 6 Rotate L3 from the opening so the coil ends can be cut off and soldered to the metal tubing pieces then solder each coil end to the brass tubing Double check the coil continuity at the brass ends with an ohmmeter Center the coil and cement the coil foam to the rod area with rubber silicone cement Let the cement dry before rotating L3 The commutator pieces can be made up of number 14 copper wire or brass strips Letz wire also works well here Cut two pieces of Letz wire 10 inches long 44 ELECTRONICS HANDBOOK Wrap the wire through the small hole twice leaving 1 inches to connect to the metal rod Tinn the Letz wire and solder to the metal rod end Cut the wire leads off as close as possible to PC board The other end will tie into the PC board FIGURE 6 Figure 6 The PC wiring layed out ona 2 4 4 piece cut from a larger PC board The PC Board Cut the PC board 2x4 from larger PC stock The audio circuit was placed at the bottom of the board 4 co TAE e z EA z i a aa l e o li JD Se la E A E E a q alt canes 4 A ar cas ore mite A i Figure 7 Mount all parts in respective holes and solder each component as mounted the board and components tied to it Chassis Construction
41. the input signal The only other rule to remember is that the input voltage must NEVER exceed the supply voltages going to the op amp from the power supply not even for a fraction of a second or the circuit will be damaged and the IC will fail completely The op amp has only one output where as indicated above the signal may be either an inverted or non inverted copy of the input Depending on the feedback resistance the op amp can also have CURRENT TO VOLTAGE CONVERTER R1 FOR EXAMPLE if R1 1k ohm the output is 1V per ImA of input current 1V 001A 1 000 1 V out Iin R1 GAIN considerable gain the input signal can be amplified up to many thousands of times and the output NON INVERTING AMPLIFIER Minimum resistor value 1k ohm either resistor To begin with try RI 10k ohm and R2 100k ohm for a gain of 11 impedance is usually low enough that the circuit can put Out many milliamperes of current with voltage swinging from just a little less than the positive supply voltage to just a little less than the negative supply typically 12V from a 15V supply Finally we need to know about the power supply for the circuit Most op amps can run on supply voltages from 4V to 15V with little change of circuit performance And with their high efficiency design they typically consume only a few milli amperes of current making a small unregulated AC supply or ev
42. to an aluminum backing sprayed or dipped To this a thin layer of N type cadmium sulfide is vacuum deposited about 20 microns forming the junction Since the thicknesses involved are on the order of microns very little material is used and consequently little is wasted A transparent conductive grid is applied over the N material and protected by a Mylar covering The material cost is low as is the number of manufacturing steps involved But such a design must maintain a greater surface area Another approach incorporates liquid as the energy converter Dust sized particles of silicon are placed in transparent capillary tubes which are filled with an electrolytic generating fluid Sunlight striking the silicon generates electricity which in turn breaks the electrolyte down to its components probably something like hydrogen bromide and water The decomposed matter is transferred to a fuel cell presumably with a pumping system where upon recombination electricity is generated More than likely the fuel cell is similar in design to the type developed for the Apollo missions The electrolyte is then recycled And so it goes with solar technology It would appear that while progress is slow there are some bright spots on the horizon E ee iene oe telephone style keypad A push of the makes the selection The Reset or Stop occurs Complete plans to build the 80 Tune Computer 2 95 Ul Cus
43. to the opposite side where it combines with migrating holes The same is true for the holes which mistakenly travel to the N section Therefore no current flow is generated by these backward electrons in transit This isn t true of all the atoms but it does occur often enough to reduce the electrons available for useful work The more excited the crowd becomes the more likely it ll happen What could possibly cause this Heat Thermal agitation can and does disrupt the atoms orderly State creating enough havoc to reduce efficiency Impurities other than those purposely introduced can also add to the reluctance of electrons to flow Some atoms are more aggressive than others in fact some are downright explosive when it comes to matching up with other atoms Tenacious atoms accidentally entering into the affair grab the free electrons never to release them Hydrogen is such a culprit as is oxygen It goes without saying that the more electrons disloged and put to work for a given light level the greater the efficiency of the unit More electrons more current produced With all these considerations 460 millivolts is considered a practical figure per cell with the open circuit voltage somewhat higher Attempts are being made to increase this potential thereby increasing efficiency gt 18 AZ A a a x krt A i ar aac t md ri Photovoltaic cell varieties The larger discs are high output cells the smal
44. until cement is applied over the winding Wind 8 turns on each side of the wood dowel Cut out two inch holes in the polystyrene coil form towards the center so the two leads of L3 can be soldered to the metal brass commutator rods Scrape off the enamel at both ends Tin the coil ends and push the wires into the foam material towards the large holes Solder the wire to 1 metal tubing Prepare The Rod Cut off the inch wood dowel to approximately 8 inches longer if the vario coupler sets toward the back of the chassis Cut two 1 inch pieces of brass tubing to fit over the wood dowel The brass tubing and foam disc or ball can be found at most hobby or craft stores Cement the brass tubing at one end and start the other piece about Y inch away at the middle Fig 4 Let the cement set a couple of hours while winding the main coils L1 and L2 Coil Form Preparation Center the large PVC coil form Drill a inch hole through the center and 172 inches down from the top of the plastic pipe for the rod of L3 Drop down 14 inch and drill inch hole to start L2 Drill two more inch ALL TAPS 1 2 4 8 12 TURNS WOUND ABOVE SHAFT OR ROD IN LITZ WIRE FINAL CONSTRUCTION h y TO LEFT SIDE OF WOOD SHAFT FACING THE ROD SPACE LI L2 L1 27 TURNS 24 OR 26 EN WIRE L2 72 TURNS 24 EN WIRE TAP FROM TOP 2 4 8 12 TURNS L3 16 TURNS 22 EN WIRE 8 TURNS ON EACH SIDE OF ROD ON FOAM CIRCLE FIGURE 4
45. watt resistor VOLUMEX 29 NY ANT s ul E Y Cl 3 SWL s SUPER SIGNAL BOOSTER TO RECEIVER LIQUID LEVEL DETECTOR This circuit was designed to alert the automobile owner when the fluid container for the windshield wiper container was nearing empty at which point it will light an LED diode strategically placed on or near the dashboard for convenient observation If you like sound better than visual indicators you Can substitute an 8 ohm speaker in place of the LED All that is required for this adjustment is to remove the 6 9VDC O PROBE 1 PROBE 2 WATER C1 01 Mfd Disc capacitor 1C1 555 timer Integrated Circuit R1 1K ohm resistor watt 30 ELECTRONICS HANDBOOK Pe 555 TIMER 1C1 PARTS LIST FOR LIQUID LEVEL DETECTOR LED light emitting diode or 8 ohm speaker LED and connect one lead of the speaker to pin 3 of the IC chip and connect the other lead of the speaker to ground Be sure that the 330 ohm resistor is still connected to pin 3 to complete the circuit While this circuit is designed primarily to alert you when the liquid is low in your windshield wiper container it can be applied to numerous other liquid containers Let your imagination take over R2 33K ohm resistor watt R3 330 ohm resistor watt 6 to 9VDC power supply ee o a ES Many operational amplifiers operate from
46. 0 u LC7 40 Watt Burning Cutting Laser Plans 20 00 o RUB4 Hi Powered Pulsed Drilting Laser Plans 20 00 amp LGU40 1 to 2mw HeNe Vis Red Laser Gun Assembled 199 00 a 2 LLS1 Laser Lite Show 3 Methods Plans pes 20 00 bad SOSK See In the Dark Kit a rm aten 299 50 EMLIK Electromagnetic Colt Gun Kit ooooococonciocconiconoss 69 50 o MCP1 Hi Velocity Coil Gun Plans oooocoooooooooo 15 00 CW LEV1 Levitating Device Plans ooooooooonocccoccccconnnnos 10 00 FHI __ Electronic Hypnotism Techniques Plans uurnaan 1000 HVM7K 75 000 Volt OC Variable Dutput Lab Source Kit 149 50 ta 0G3K lon Ray Gun Kit project energy without wires 69 50 S 2 NIGIK 12V 115 VAC HI Dut Neg lon Generator Kit 34 50 FF ul EMAIK Telekinelic Enhancer Electric Man Assembled 99 50 2 gt LGSK Lightning Display Globe Kit aces 54 50 5 3 BTCIK Worlds Smallest Tesla Coil KIt oooooooooooooccoo 49 50 BIC3K 250KV Table Top Tesla Coll Kit 249 50 z BTCS 1 5 Million Volls Tesla Coll Plans 20 00 J3 Jacobs Ladder 3 Models Plans 15 00 lt GRAY Anti Gravity Generator Plang 10 00 a PFS20 Plasma Fire Saber Assembled o oooooo 69 50 DPL20 Dancing Plasma to Music and
47. 225 is a full function auto ranging 4 digit multimeter that combines 10 000 count resolu tion true RMS measurement accuracy and a 41 segment analog bar graph display With a simple two button menu selection scheme you can engage the four special measurement modes of Range Lock Probe Hold Relative Mode and Auto Min Wax Other p g re RHOLD PREL MALMEN features include a battery saving Auto Power Down mode and Overload Alert which warns you if the meter input ratings are exceeded The high performance dependable and easy to use Model RMS225 comes complete with test leads protective holster Self resetting fuse and a 3 year warranty 10 ELECTRONICS HANDBOOK mv 9 l For further details contact HMC 33 Springdale Avenue Canton MA 02021 Phone 617 821 1870 FAX 617 821 4133 PROG RARMARUE NS SOLDERING STATION From Contact East a new programmable soldering station that has a tamper proof tempera ture setting quick heat up and increased thermal recovery permitting consistent high quality soldering with less dwell time on multilayered boards and heavy ground planes Temperature can be set on the digital key pad from 400 to 899 F with an accuracy of 0 9 F Once the temperature is set unauthorized personnel cannot change the setting without the programming card The temperature memory system allows the iron to be shut off and turned on without having to reset the iron each time Th
48. 4 INDIANA OUR INDINA BA rM A JAYHAWK 64 IOWA FIGHT SONG 67 LOVE Ya BLUE 68 MICHIGAN STATE FIGHT 69 MINNESOTA HOUSER 70 NITTANY LION 71 NOTRE OAME FIGHT 72 OLE miss 73 ON BRAVE ARMY TEAM 74 ON WISCONSIN T WRECK FROM GA TECH 76 ROLL ON TULANE 34 SAN ANTONIO ROSE 39 SEE THE USA 40 OUT TO THE BALLOAME 41 TIJUANA TAX 42 TWO BITS 42 WADASII CANNONUALL 44 SAINTS QO MANCHING 43 WOODY WOOPECKER 16 ANLVEDENCIH HOMA 17 CAMPTOWN RACES 16 CANOY MAN 19 CHATTANOOAA CHOO CIHOO 70 CLEMENTINE Zi DALLAS THEME 22 Et PASO 23 THE ENTENTAINER 34 JUILY GOULD ET LELLOW 25 FUNERAL MARCH 24 HAVA NAGH AH O Payment enclosed to C amp E Hobby Handbooks PLEASE PRINT v10 NAME ADDRESS CITY STATE ZIP Foreign Postage add 8 00 U S Funds 44 YELLOW NOSE OF TEXAS 47 ACROSS THE FIELO 48 AQGIE WAR HYMH 49 ARKANSAS FIGHT SONG So AE SHANP 81 VOOMEH ROONLI 52 BOW OOWN WASHINGTON FEHR VICTONS FO WASHINGTONA KE SWING TH YEA ALABAMA VOLUME X 71 THE FUN WAY TO LE In case you re not all that familiar with us we re not a publication for electrical engineers and other wizards No way ELECTRONICS HANDBOOK is expressly for people who like to build their own projects and gadgets and maybe get a little knee deep in tape solder and wire clippings in the process In fact we have a sneaking suspicion that our readers like us because they think we re just
49. 70 Shawmut Rd Canton MA 02021 82 ELECTRONICS HANDBOOK LOW POWER QUAD COMPARATORS Maxim Integrated Products new MAX900 and MAX901 high speed quad TTL comparators save board space and consume less than one seventh the power of equivalent single and dual comparator combinations Propagation delays are 8 ns and power consumption is only 18 mW per comparator The MAX900 and MAX901 feature differential inputs and TTL compatible outputs with internal active pullups They can be powered from separate analog and digital supplies or from a single 5 volt supply These comparators will accept input signals that swing to ground in single supply applications Typical uses for the MAX900 and MAX901 include threshold detectors high speed analog to digital and voltage to frequency converters line receivers and high speed data sampling The MAX900 provides a latch enable function the MAX901 does not Contact Maxim Integrated Products 120 San Gabriel Dr Sunnyvale CA 94086 RF POWER MOSFETS Good news for hams and anyone else interested in high power high frequency amplification Motorola has added four high power high gain power MOSFET transistors to its line of second generation RF power FETs The 28 volt MRF141 and 50 volt MRF151 are N channel enhancement mode FETS characterized to 175 MHz with output powers of 150 watts and typical gains at 30 MHz of 22 dB The MRF141G and MRF151G are Gemini push pull packag
50. 76 East 17th Street Cleveland Ohio 44114 216 781 9400 A school of thousands A class of one Since 1934 AFWO6 CRYSTAL OSCILLATORS By Bill Axsen 100kH2 1MHz ALL CRYSTALS PARALLEL RESONANT AT CUT TYPES IM 0 25 uF 68pF OUT Gate Oscillators Those of us who have used crystal oscillator circuits know how useful they can be For those who have not now may be the time to familiarize yourself with these extremely useful circuits With few exceptions crystal oscillators are used in digital or communication equipment They supply a highly stable frequency source which cannot be obtained by LC oscillators at relative bargain prices Crystal oscillators are found in digital watches calculators digital meters and transmitters just to name a few applications The circuits in this article were chosen for the most part because they don t require exotic parts and have a minimum parts count You should be able to find the majority of the parts in your junk box In circuits which do require non standard hobbyist parts a reference will be made in the article where these parts may be obtained With the exception of two frequency generator circuits circuits described in this article were taken 26 ELECTRONICS HANDBOOK from the Linear Technology s Application Note 12 Circuit Techniques for Clock Sources If you are interested in a more in depth explanation of the circuits described
51. 88 SW6 PUSH TO PROGRAM 16 SW1 TO SW4 DO SW5 PROGRAMMED COMPASS HEADINGS HIGH ON D1 4 0 OAO UW Aa UN ive D3 5V 74188 IC TO V SIMULATED BE PROGRAMMED COMPASS INPUT NORTH D2 WEST D3 FIGURE 5 Step By Step Programming of the 74188 To Start place a fresh 74188 chip into the 16 pin IC socket observing the proper orientation of the chip Then turn on the power Using the data input switches SW1 to SW4 apply the following binary code D3 D2 D1 OD 1 1 1 0 This code will simulate the compass NORTH output With the appropriate data applied turn the SW5 to its B4 position Then press SW6 Program Switch for an instant Don t hold SW6 down longer than 2 seconds This will destroy the IC When programmed place DO switch back to its logic 1 position Next let s program SOUTH output by flipping the D1 switch to logic 0 SW5 should be in position BO Press SW6 to program a 1 at this point Return SW2 to logic 1 EAST can be programmed by flipping the D2 switch to logic 0 SW5 should be at position B5 Press SW6 to program Return the data switch to logic 1 Programming WEST can be accomplished by flipping the D3 switch to logic 0 SW6 in position B2 To program press SW6 Return D3 to its logic 1 position NORTH EAST is programmed by flipping both DO and D2 to logic 0 SW5 is in its B7 position Press SW6 to program Return data switches to logic 1 NORTH WEST can be prog
52. A Series circuit with two resistances The circuit in Figure 6 is still a series circuit How do we know Because there is only one path for current and it flows through all of the circuit components In this case however we have two resistances connected end to end Do you remember the old series Christmas tree lights Because all the current flowed through all of the lamps if one burnt out creating an open circuit they all went out Let s consider what the relationships between voltage current and resistance are in this circuit Has the source voltage changed No the battery is still a 1 5 volt cell Has the circuit resistance changed Yes because now instead of one 100 ohm resistor we now have two When two resistors are connected in series we can add their values to get the total resistance so Rr 100 ohms 100 ohms 200 ohms If the resistance in the circuit has been doubled what will happen to the current Right it will be one half what it was before because V R 1 5v 200 ohms 7 5mA Now if we work backwards and multiply the current 7 5mA times each of the resistors 100 ohms we find that each of them has 75 volts dropped across them If we add those voltages up they will equal 1 5v which is the battery voltage Again Kirchhoff would smile approvingly We call this circuit a voltage divider because the source voltage is divided between the two resistors If the resistors were not the same values what would ha
53. AL at cit aap Ee A aba Figure 4 Modern hi density solar panel in a frame Model consists of sixty four square cells producing up to 34 watts of power Photovoltaic Solar Panels A solar photovoltaic panel is the result when many solar cells are mounted in a series parallel arrange ment on a frame Note that the solar panel of Figure 4 consists of 64 square cells The Solarex HE 51 21 inch by 21 inch solar panel provides a peak power capability of 34 watts Its rating is 2 1 amperes at 14 volts nominal The response of the panel is shown in Figure 5 Based on the average insulation in the United States the panel is capable of providing approximately 63 ampere hours of electricity per week 2 8 T 2 A MIN gt oil 1 4 a ESSEER 16 KK SD ai a CURRENT A 4 Has L24 0 D O 3 8 on gt 5 10 15 20 25 VOLTAGE V Figure 5 A performance chart of the solar panel in figure 4 Note that the voltage output remains at a constant nominal 14 volts Complete Power Supply A complete solar power supply Including battery and load is shown in Figure 6 In sunlight the solar panel charges the battery through a blocking diode The load is connected across the battery In darkness and at low light levels the battery supplies the necessary energy to the load on a continuous basis Theoretically the solar panel must be capable of supplying at least the same number of ampere hours to the battery a
54. CITING DISCOVERIES Whatever your particular interest in electronics a you ll be entering a world of on discovery in the pages of the oe ELECTRONICS HANDBOOK X IC TESTBENCH re ee Integrated Circuits digital and linear are where it is at that is the state of the art in electronics technology For the newcomer to this fascinating area of electronics we have tried to select a representative cross section of the digital and linear integrated circuits available on the market and design construction projects around them that not only entertain but educate as well In truth there is no easy way to learn electronic theory at least in a manner that will prepare the individual to cope effectively with the influx of technica applications that are now reaching the home the car and your place of business For those with no prior experience in the construction of electronic projects we strongly suggest that you begin with some of the Transistor projects found elsewhere Circuit Fragments in this magazine By beginning with these simpler projects where construction technique is less critical you will learn by necessity the basics of component arrangement lead trimming or lead dress as it is properly called and the difficult art of translating those funny lines and squiggles on a schematic diagram into a working piece of electronic equipment For those of you who have had experience in building transistor projects
55. DBOOK The control circuitry for this tape player burglar alarm can be easily concealed anywhere inside your automobile since it is not much larger than a regular match box With a little imagination this device can be adapted to other areas of your automobile the hood the trunk doors etc the alarm will be the same C1 100MFd G SER 2 E BLACK BURGLAR ALARM 1 2 3 RED CAR a E da OR EQUIV CAR HORN BUTTON 12VD 1 1 CAR BATTERY PARTS LIST FOR THE TAPE PLAYER BURGLAR ALARM C1 100 Mfd electrolytic capacitor 15VDC or better R1 27K ohms resistor Y watt SCR1 HEP RIZZO or SK3634 ECG5444 25 PIV 5Amp or Equivalent S1 SPST slide switch Alarm off 18AWG STRAND RED TO HORN HEP RIZZO OR EQUIV 25 PIV SAMP 18AWG STRAND GREEN 18AW G STRAND TO TAPE PLAYER CAR STEREO BLACK E Hooo B o o0 18 SPEAKERS POWER MIKE AMPLIFIER A popular accessory to a CB radio is a power microphone This circuit provides an adjustable gain of 1 to 10 which will increase the output of a dynamic microphone for higher modulation levels without shouting The circuit has very low ouput impedance and will drive the microphone input circuit of any CB C1 C2 C3 10 uF electrolytic capacitor 10 VDC 1C1 3900 quad amplifier R1 100 000 ohm audio taper potentiometer R2 10 000 ohm watt resistor PARTS LIST FOR POWER M
56. E DANDY 9 LA MAASEILLAISE 10 MARINE HYMN tf REVEILLE 12 STAAS A STRIPES 13 TAPS 14 WILD BLUE YONOEA 15 ALOUETTE 16 AHLYLU HCIH NOMA 17 CAMPTOWN MACES 18 CANOY MAN 48 CHATTANOOGA CHOO CHOO 70 CLEMENTINE 21 DALLAS Ti E ME 72 EL PASO 73 THE ENTERTAINER 24 JULLY ULOD I EtLOWw 23 FUNERAL MARCH 24 HAVA NAGILAH PLEASE PRINT NAME __ ADDRESS CITY STATE 27 IN HEAVEN IS NO DEEA 29 JIMMY CRACK CORN 29 JINGLE BELLS 30 KING OF ROAD 31 LA CUCARACHA 32 LONE RANGER 33 MODEL T 34 THE OLD GREY MARE 35 POPEYE M RAINDROPS 37 SAILORS HORHPIPE M SAN ANTONIO ROSE 39 SEE THE USA 40 OUT TO THE BALLOAME 41 TIJUAHA TAXI 42 TWO BITS 43 WADASI CANNONUALL 44 SAINTS GO MANCHING 48 WOODY WOOPECKER 44 YELLOW NOSE OF TEXAS AT ACROSS THE FIELD 40 AGGIE WAA HYMN 48 ARKANSAS FIGHT SONO t WE SHANP BI VUOMEN BOUNEN 2 BOW DOWN WASHINGTON O Payment enclosed to C amp E Hobby Handbooks ee ee 0 E a Foreign Postage add 8 00 U S Funds Kea SI BUCKLE DOWN WIHSOCKI 4 CHARGE BS DEAR OLO NEBRASKA U 6 THE EYES OF TEXAS ST ABOVE CAYUGA S WATERS 8 FIGHT ON USC 59 GO NORTHWESTERN 64 HAIL PURDUE 61 HEY LOOK ME OVER 42 HOLD THAT TIGER 63 ILLINOIS LOYALTY 04 INDIANA OUR IN IHA 4 TM A JAYHAWK OWA FIGHT SONG E LOVE YA BLUE 08 MICHIGAN STATE FIGIIT 69 MINNESOTA MOUSER 70 NITTANY LION 74 NOTRE OAME FIGHT 72 OLE MISS 73 ON ANAVE ANMY TEAM 74 OH WISCONSIN TS W
57. IKE AMPLIFIER radio IC1A provides voltage amplification and is adjustable by potentiometer R1 C1B is a buffer amplifier which provides isolation between the amplifier and output terminal The circuit draws about 7 milliamperes from a 9 volt supply and can be powered by an ordinary 9 volt transistor battery R3 220 000 ohm watt resistor R4 100 000 ohm watt resistor R5 1 000 000 ohm watt resistor VOLUME X 53 PUSH ON PUSH OFF This simple circuit enables a single pole single throw pushbutton switch to function in a push on push off manner Closing the switch initiates a flip flop latching action The extra gates of the 4011 quad NAND chip may be used in parallel for greater output loading or in series to provide an alternate on off output to external circuits PARTS LIST FOR PUSH ON PUSH OFF C1 0 1 uF ceramic capacitor 15 VDC D1 D2 small LEDs IC1 4011 A quad NAND gate Q1 Q2 2N4401 R1 27 000 ohm Y2 watt resistor R2 R3 1 000 ohm 4 watt resistors NOTE USE ONE DRIVER NOTE GROUND PINS RESET A PLAY 01 71 FOR EACH LED ELEMENT FREQUENCY 54 ELECTRONICS HANDBOOK 3 5 9 14 OF LEO 01 723 DRIVER Y Os R5S 11 TO DISPLAY SEGMENTS A G OF LEDI The clock input terminal connected via a pushbutton switch to the Basic Pulse Maker and two to nine players select a number Then press the button The input frequency should be 10 Hz or higher and
58. ING DOWN THEN SOLDER FIGURE 6A By taking these simple precautions the Electronic Compass will provide years of dependable service And best of all you can say I built it If you wish to house your compass a metal case is definitely a No No The earth s magnetic field will be interrupted and erroneous reading will result The compass housing should be made only of plastic Boxes of this type are readily available and inexpensive And can be found at any Radio Shack store Whichever troubleshooting or housing technique you use to get your Electronic Compass at the stage of final assembly just remember that the use of a printed circuit board in any project will pay for itselfin no time and will provide trouble free operation for years to come ly PARTS LIST FOR THE ELECTRONIC COMPASS R1 to R12 1K ohms W Resistor IC1 Programmed 74188 ROM IC2 7805 5V Voltage Regulator TO 220 D1 1N4001 Diode LED1 to LED8 Standard Red Light emitting diodes M1 Compass Sensor MISC Plastic Housing Printed Circuit Board 9V Battery Battery Clip 3 At NE a r A A AN a Fi a ma ee JF a s arnt st BUILD YOUR vario coupler coil assembly was used fortuning and feed back operations in the one or two tube shortwave receiver Since these vario coupler units can only be found with antique radio collectors and they cost plenty this tuning coil assembly was made from PVC pipe and a foam disc
59. Knapp Ph D The setting is a cheerless basement laboratory In the dim TTT lio o bhi A aaam _ Tm light we see a strange machine that appears to have been thrown together from junk parts Standing next to the machine a man badly in need of a haircut and shave is busy making adjustments with a screwdriver Oops He must have turned the wrong screw because the machine begins to shake and emit puffs of smoke Before the man can correct his mistake the machine lets out a dying gasp and explodes sending gears and springs flying through the air like shrapnel The man dives beneath a table then peers out Cautiously We see in his soot covered face a mixture of Surprise and stubborn determination and we know that it won t be long before he s built a new version of his silly machine Who is this character anyhow He is a typical inventor as seen through the jaundiced eyes of a Hollywood scripwriter Little wonder then that to many people the word inventor is synonymous with crackpot The first thing Philip Knapp does in his new book is to lay to rest the hackneyed stereotype of the inventor Dr Knapp himself an accomplished inventor with 20 patents and more than 50 inventions to his credit portrays the inventor as a creative problem solver someone more in tune with reality than most of his detractors The author goes on to show us what inventing is really like using some of his own inventions a
60. LY SUBJECT WE TEACH CIE PROVIDES YOU WITH A LEARNING METHOD SO GOOD IT S PATENTED CIE s Auto programmed lessons are a proven learning method for building valuable electronics career skills Each lesson is designed to take you step by step and principle by principle And while all CIE tessons are designed for independent study CIE s instructors are personally available to assist you with just a toll free call The result is practical training the kind of experi ence you can put to work in today s marketplace LEARN BY DOING WITH STATE OF THE ART FACILITIES AND EQUIPMENT in 1969 CIE pioneered the first Electronics Labora tory course and in 1984 the first Mircoprocessor Laboratory course Today no other home study school can match CIE s state of the art equip ment and training And all your laboratory equipment books and lessons are included in your tuition It s all yours to use while you study at home and for on the job after graduation PERSONALIZED TRAINING TO MATCH YOUR BACKGROUND While some of our students have a working knowledge of electronics others are just starting out That s why we ve developed twelve career courses and an A A S Degree program to choose from So even if your not sure which electronics career is best for you CIE can get you started with WHY CHOOSE CIE FOR YOUR TRAINING 150 000 successful graduates from every country around the world Onl
61. OTAPE Learn our technigues and make more money repairing electronic equipment These tapes are packed with much practical information that will save enough of your valuable time to quickly pay for the tapes Bf Learn from an expert what fails why it fails how to find it faster and how t fix it faster Much of this information is available nowhere else These tapes start at the beginning for beginners but cover each f subject so thoroughly that even old pros will learn valuable new techniques and Skills Send payment with order and we will pay shipping Order 14 tapes for 499 95 or send 575 00 for all 16 tapes with this simple invention than any other method including 6 000 vacuum desoldering stations Speed up your repairs and salvage hundreds of good IC s per hour from junk boards REMOVE IC S FASTER THE 7 SECOND IC REMOVER ie How to use a Voltmeter 1 hr 51 min A 39 95 Won t damage IC s or circuit board This is a money making How to use a logic probe and logic putser All about resistors and their failure modes 1 hr All about capacitors and their failure modes 1 hr 28 min All about inductors and their failure modes Part Includes inductors transformers flybacks pinball coils solenoids All about inductors and their failure modes Part il Inciudes Tona AD DAA AIDA 0 4 4s Leia s amp s Os ge Sod OC TG 4 we 39 95 labor saving t
62. RECK FROM GA TECH 76 NOLL OH TULANE H Ute VIC PONT 7a WASHINGTONAEE EWIHA TO YEA ALABAMA V 10 Digital Compass Kit The perfect assembly project for school or for that budding electronic hobbyist The Digital Compass is a hand held device that senses all eight compass headings by lighting the appropriate LED By making use of the highly advanced WN Dinsmore Sensor your compass kit can 4 also provide accurate headings for your car or boat gt Kit comes complete with ALL parts compass sensor PC Board 2x3 5in 4 memory chip and assy instructions Less Housing amp 9V Battery Suncoast Technologies P O Box 5835 Spring Hill FL 34606 ELECTRONICS HANDBOOK 2 Ppt pz VHS VCR Repair Solution Sets II Ill IV V VI Each contains 150 symptoms and cures Cross Reference Chart Free Assistance 11 95 each All six 59 95 Eagle Electronics Box D 52053 Locks Lane Granger IN 46530 CIRCUIT DESIGN SERVICE Reasonable prices No job too small ASAP Line 318 797 2262 8 5 Monday Friday 2 00 for brochure M S Design i P O Box 3522 Shreveport LA 71133 3522 construction of crystal set radios 7 95 ppd USA Allabout Books Dept H Box 14155 Fremont CA 94539 ALL ABOUT METERS A Learn by doing history of the development of electrical meters Build seven simple meters using common hardware ALL ABOUT CRYSTAL SETS Theory and 7 95 ppd USA
63. RODUCTS CO Tools tool kits and electronic test instruments are the featured items in the new catalog from Specialized Products Co Tools run the gamut from screw drivers to soldering irons wrenches to wire wrap guns The one thing that all these tools have in common is that they are useful in electronic assembly and repair work You can select individual tools or if you like buy a custom configured tool kit complete with an attractive carrying case The company offers kits for such specialized repair fields as data communications computer maintenance and telephone installation General purpose kits are available too Prices are reasonable and service is prompt We ve purchased many tools from Specia lized Products by the way so we re speaking from experience You can get a free copy of the latest catalog simply by writing to Specialized Products Co 3131 Premier Dr Irving Texas 75063 VOLUME X 87 A er 2 tl T HIH Ly No ASE a 3 ME bri Hh A sTEREO ARA A pao AL 4 orar ha A SURROUND di MU AIRING Sas M Mo ete A EI x RESERVE YOUR COPIES OF FUTURE ISSUES x ORDER COPIES OF BACK ISSUES x MAIL THIS COUPON FOR DETAILS TO ELECTRONICS HANDBOOK P O BOX 5148 NORTH BRANCH N J 08876 a e i ee See eee eee eee eee eee eee poea t ee FROM Please Print E Address AA DS City amp State SSS ee pi CONSTRUCTIO QUICKIE By Bill Axsen This ts really acho
64. SCILLATOR The former generates a continuous train of pulses whose rate is set by the capacitor in the circuit while the latter will make very good sine waves for testing a high fidelity amplifier for power and distortion WAVESHAPERS Sine or pulse or music waveforms can be altered by the DIFFERENTIATOR or INTEGRATOR circuits The differentiator will create short sharp spikes with each input wave to the circuit while the integrator will take an input waveform and create a sloping ramped version of it Both of these circuits are commonly used in making electronic music or used in creating special musical effects along with the output of an electric guitar or organ MISCELLANEOUS CIRCUITS The CURRENT TO VOLTAGE CONVERTER does just what the name implies makes a value of input current into a specific value of output voltage It can operate a buzzer or light when a photo sensor connected to its input detects darkness or a changing light input For those needing an ADJUST ABLE VOLTAGE SOURCE this circuit can provide an adjustable output which can be anything from just a little bit less than the positive power supply to a little less than the negative supply voltage This will makea good reference to operate a power supply regulator circuit since its output is too low to operate a radio or tape player directly The PEAK DETECTOR is an especially good circuit for those who need to read power or signal levels since it will momentarily h
65. Sounds Assembled 79 50 wi ITM10 100 000 Voit Intimidator up to 20 Assembled 129 50 IPG70 Invisible Pain Field Blasl Wave Gen Assembled 74 50 S a PSPAK Phasor Sonic Blast Wave Pistol Kil 59 50 ze LIST10 Infinity Xmtr Listen In Via Phone Assembled 199 50 Es TAT30 Automatic Tel Recording Device Assembled 24 50 Q Q VWPMTK 3 Mi FM Auto Tel Transmitter Kit naa 49 50 PE FMVIK 3M1 FM Volce Transmitter Kit 00 39 50 HOOIK Homing Tracking Beeper Transmitter Kit 49 50 AMAZING SCIENTIFIC amp ELECTRONIC PRODUCTS VRL2K 3mw Vis Red Laser Diode System Kit 159 50 LLISIK Laser Beam Bounce Listener Kit 199 50 EASY ORDERING PROCEDURE TOLL FREE 1 800 221 1705 or 24 HRS ON 1 603 673 4730 or FAX IT TO 1 603 672 5406 VISA MC CHECK MO IN US FUNDS INCLUDE 10 SHIPPING ORDERS 100 00 amp UP ONLY ADO 10 00 CATALOG 1 00 OR FREE WITH ORDER INFORMATION UNLIMITED P 0 BOX 716 DEPT HB AMHERST NH 03031 ATTACH LABEL HERE NEW ADDRESS HERE PLEASE PRINT NAME ADDRESS VOLUME X 5 FROM THE EDITOR S DESK Ask The Editor He Knows Inscrutable Japanese TV Recently returned from Japan and brought a Japanese model Nintendo and cartridges home with me Now find that their TV s
66. THE FUN WAY TO LEARN ELECTRONICS ELECTRONES HANDBOLTI WPS 36286 EXPERT GUIDE TO BUILDING PROJECTS UNDERSTANDING ELECTRICITY THE FUTURE OF SOLAR ENERGY CRYSTAL OSCILLATORS WORKBENCH PROJECTS DESIGN YOUR OWN OP AMP CIRCUITS IC TESTBENCH Mi e D BUILD PLEF IO ever In case you re not all that familiar with us we re not a publication for electrical engineers and other wizards No way ELECTRONICS HANDBOOK Is expressly for people who like to bulld thelr own projects and gadgets and maybe get a little knee deep In tape solder and wire clippings in the process In fact we have a sneaking suspicion that our readers Ilke us because they think we re Just as bug eyed and downright crazy over great new project ideas as they are And guess they re right ELECTRONICS HANDBOOK thinks of you who dig electronics as the last of a special breed It s more than Just the do t yourself angle It s also the spirit of adventure In this pre packaged deodorlzed world bullding your own stereo system shortwave recelver darkroom timer or CB outfit Is Ilke constructing a fine tuned llttie universe all your own And when It all works perfectly If really takes you to another world IF YOU RE NEW TO ELECTRONICS YOU GET A BASIC COURSE It gives you a Complete ground floor lowdown on a variety of Important electronic subjects For example Understanding
67. VDC C6 25 uF electrolytic capacitor 25 VDC C7 0 01 uF ceramic capacitor 15 VDC D1 through D4 1N4001 diodes 1C1 4011 quad NAND gate 1C2 555 timer R1 500 ohm watt resistor R2 50 000 ohm linear taper potentiometer R3 33 000 ohm watt resistor R4 4 700 ohm watt resistor VOLUME X 57 eas OO vii m llu POSITIVE INTO NEGATIVE 1 CMOS logic of the 4000 Series has sometimes been put down against TTL when speed is involved However the following circuit shows that oscillations of over 5 MHz are quite possible and simple to obtain as well With C 27 pF the following frequencies were obtained with varying R The output at pin 2 is sinusoidal but the buffer shown between pins 7 and 6 reduces frequency shifts from circuit loading PARTS LIST FOR CMOS LOGIC AL FOR RF C1 27 pF mica capacitor 15 VDC 1C1 4009AE hex buffer i R1 see table output L 58 ELECTRONICS HANDBOOK 2V D3 D4 OUTPUT 9V OUTPUT 22V C6 dl CMOS LOGIC AL FOR RF lo BUFFERED OUN PUT 2 freg MHz 6 33 9 30 3 50 2 70 2 00 1 10 ELECTRICITY By Ron C Johnson C E T PART II Whether you are starting out in electronics golf playing the piano or basket weaving the same principles apply Get the basics down cold and you ll be off to a good start From there you can work your way into the more complex stuff with a minimum of problems That s what I did and to
68. VOLUME X 49 effect here In addition a noise voltage Vn which is due to source V appears in series with V2 If Vn is not negligible compared with V2 then we must find ways of minimizing the noise pickup SOURCE LOOP RECEIVER LOOP Figure 4 Figure 4 Magnetic field or inductive coupling requires the existence of two complete current loops Shielding against a magnetic field is difficult in home construction What we have in Figure 4 is asimple transformer which suggests why magnetic coupling is also known as inductive coupling Alternating current h generates a changing magnetic field that induces a voltage in any loop it intersects As Figure 4 shows the two current loops may be completely isolated However points A and B could be connected with no change in the induced noise voltage Therefore as was the case with the electric field we must consider coupling between stages of the same device or between stages of two separate devices Let s examine the factors that cause increased noise coupling 1 an increase in the magnitude of 11 2 adecrease in the separation of the two loops 3 an increase in the frequency of 11 4 orienting the loops so that their planes are parallel and 5 an increase in the area of the receiver loop From the above several HIGH CURRENT CIRCUITRY Figure 5 SWITCHING CIRCUITRY Figure 5 Ground noise can originate in any system where power is distributed in a methods of n
69. Weight is critical in space vehicles so the silicon is only about 4 to 6 mils thick making them extremely fragile A conductive coating is applied to the back to complete the circuit E J i M TE eN ab i a 3 s This water pump miles from a power source draws its electrical power from a bank of solar cells Similar pumps could transform arid deserts into arable productive farmland Solar Cells Galore Silicon solar cells are the most popular and least expensive That s not to say nothing s new under the sun there s plenty happening Silicon cells suffer two drawbacks high cost power ratio watts per dollar and mediocre efficiency Research is traveling a variety of routes seeking a solution to this The efficiency of a typical silicon unit is around 11 If this percentage were raised the price per watt could be reduced But atoms are very selective about the kind of photons they ll absorb Silicon has a preference for long low energy wavelengths This affinity for light in the red to infrared spectrum limits the theoretical efficiency to under 20 Gallium arsenide on the other hand prefers high energy high frequency photons Gallium arsenide technology is newer and not as well developed as silicon but it promises greater rewards Cell efficiency presently exceeds 20 a sizable difference On a one to one basis it would require about twice the surface area of silicon to equal the power of gallium Ma
70. a 1kHz oscillator use R3 100k ohm R4 25k ohm potentiometer And R 1k ohm and C 0 15 uf i it has no voltage gain will allow a very high high impedance source like a transducer of some kind to drive a low impedance load like a meter or a lamp The SUMMING AMPLIFIER and DIFFERENCE AMPLIFIER are both linear like all the others in addition they allow us to add two or more signals together and get an algebraic sum or difference at any given moment these actually perform an arithmetic function for us The METER AMPLIFIER is Just what its name says an amplifier just to drive a meter so that we can measure the level of a signal or compare two signals This can be used with the summing and LOGARITHMIC AMPLIFIER R1 10k ohm R2 ik ohm D1 any small silicon diode For output to operate a meter the input must only be a positive voltage 22 ELECTRONICS HANDBOOK ADJUSTABLE VOLTAGE SOURCE V SET RI R2 1k ohm minimum R3 100k ohm potentiometer D1 D2 any small silicon diodes NOTE V and V should be the same as the op amp power supply difference amplifiers for special functions such as reading the simultaneous output of two stereo channels or with the difference circuit read the separation of the signal a very versatile combina tion The LIMITING AMPLIFIER also does what the name implies limits or clips our signal if it exceeds the circuits set lim
71. at lower temperatures Featuring vacuum and hot air blow functions the SA 600 has a variable temperature range of 660 F 350 C to 840 F 450 C This desirable combination of high vacuum pressure for suction and high heat capacity nozzles contribute to the SA 600 being a performance leader for desolder ing and rework operations The SA 600 is sold through OK Industries authorized distributors at a list price of 557 50 For more information contact OK In dustries Inc 4 Executive Plaza Yonkers N Y 10701 or call 1 800 523 0667 AEA E Se EEE E HANDHELD HOLDERS MFJ Enterprises Inc announ ces the release of new Mobile and Desktop HT Holders for only 9 95 each These handy new MFJ HT holders help you make Sure your handheld stays where you put it in your car or on a Crowded table or desk MFJ 24 has a strip of durable plastic that bends to fit snugly over your car door front seat or other area MFJ 25 stands on your table or desktop They re an economical way to help guard against dropping your expensive HT Both units provide for both large and small HTs For more information contact any MFJ dealer or MFJ Enter prises Inc P O Box 494 Mississippi State MS 39762 or call 601 323 5869 Telex 53 4590 MFJSTKV FAX 601 323 6551 or order toll free at 800 647 1800 VOLUME X 9 NEW PRODUCTS PARADE DIGITAL MULTIMETER Beckman industrials Model RMS
72. bulletin board service at 602 741 3978 300 1200 2400 8 N 1 RF DEVICE SELECTION GUIDE Motorola has announced the availability of its latest RF Selector Guide SG46 D Rev 7 This new version represents the latest and most complete listing of standard semiconductor devices offered by the RF Products Division of Motorola Semiconductor and includes 75 new products A key feature of this new Selector Guide is the updated cross reference which is the most extensive RF transistor cross reference available in the industry today The new Selector Guide lists data for all the RF products manufactured by Motorola including power FETs power bipolar transistors small signal transistors and modules This 82 page reference booklet should be a welcome addition to the bookshelf of anyone interested in RF devices and that includes radio amateurs service personnel and design engineers A free copy of SG46 D is available from Motorola Literature Distribution Center POB 20924 Phoenix AZ 85063 DUAL HIGH SPEED OP AMP The AD827 from Analog Devices is a low cost general purpose dual 50 MHz unity gain bandwidth op amp The device remains stable when driving any Capacitive load and features 85 dB of channel separation between the two amplifiers Close matching between the two channels means that the AD827 will be well suited to multi channel video applications Other important specifications include a high 300 V us slew rate
73. c Beginnings e re not performing any new tricks here just W improving on some old ones Although the photoelectric effect has been known for a century it took the wizardry of solid state electronics to make it a practical reality Many of the pioneers of electronics studied it including such names as Davey and Edison Albert Einstein gave it substance when he penned the photoelectric theory for which he was awarded a Nobel Prize Our first encounter with solar electricity came about thirty five years ago with the introduction of the selenium solar cell manufactured by International Rectifier designated B2M At the time it was considered a breakthrough in that it was within the budget of the hobbyist and relatively efficient in use It powered more than one home built transistor radio despite its minute power capacity of volt at 1 milliampere Thumbing through the pages of electronic periodicals of the time leads one to believe we were in a solar electricity boom which was closer to the truth than many experimenters ever would have suspected Uncle Sam was also building solar powered projects The race for space and the need to power earth orbiting satellites demanded a solar cell capable of supplying their needs in a hostile environment Bell Laboratories obliged Bell having just received the Nobel Prize for the invention of the transistor was exploring the new technology of silicon semiconductors Utilizing their vast kno
74. can have values which range from extremely small to extremely large In order to express these numbers without filling pages with zeros we use a system of numbering called scientific notation In scientific notation we take a number like 2 540 000 volts which is the same as 2 54 1 000 000 volts and express it as 2 54 X 10 volts said in Part that we would get into some circuits ELECTRICAL QUANTITY 254 200 000 volts 00276 Amps 8990 ohms 730 000 watts 00000477 Siemens 000000000012 Farads SCIENTIFIC ENGINEERING NOTATION UNITS 2 542 x108 254 Megavolts 2 76 x 1073 8 99 x 103 7 50 x 109 477 x 10 6 4 77 microSiemens 1 2 x 1011 12 picoFarads For those of you not familiar with this notation our goal is to make a shorter expression of the same number 1 000 000 is the same as 10 When we multiply it by 2 54 we end up with the original number Similarly we can express 00000001579 Amps as 1 579 X 10 Amps An easy rule to remember is that when we converta number to scientific notation we count the number of decimal places we will move the decimal point and use that number as the exponent of ten If we move the decimal to the left in a large number the exponent is positive If we move the decimal to the right in a small number the exponent is negative That is scientific notation In engineering notation we shorten the number even further by using prefixes before
75. certainly significant if VS is also on the order of millivolts At high frequencies the impedance of inductance L increases to become the dominant factor and this gives us even more trouble For example a foot of 22 wire has 4 ohm impedance at 1 MHz and a whopping 40 ohms at 10 MHz Needless to Say high current and high frequency stages and this includes our old friend digital logic can wreak havoc on low level circuits What can be done First current spikes from digital logic may be reduced by bypassing ICs with 1 mfd ceramic capacitors These capacitors are applied as closely as possible to the power pins of the various IC packages Another scheme that is successful at frequencies below 1 MHz is the use of a parallel power distribution system as shown in Figure 6 Since 11 and 2 cannot flow in R or L they produce no troublesome noise In order for this system to work well however the power supply must have a low impedance and use very short wires Summary The key to minimizing noise transmitted through an electromagnetic field lies in separation of the noise source and receiver Keep high voltage and high Current circuitry away from stages that carry low level signals Be especially wary of digital logic one of the worst offenders where noise is concerned because of the magnitude and switching speed of the signals involved When separation has been carried to its practical extreme and noise pickup is still a proble
76. ck resistors Assuming that you cannot change the design of the source and receiver circuits the only practical method of reducing noise from an electric field is to minimize the coupling capacitance Separation of the two stages helps at least an inch or two should intervene between the circuits Separation beyond this distance will reduce pickup still more but the noise level does not drop as quickly as it does over the first inch or so Shielding More effective than separation is the use of a metallic shield when pickup is severe In Figure 2 the two possible methods for shielding are diagrammed Figure 2A shows a conductive metal shieid grounded to source common that completely encloses source Vi Electric field coupling between source V and the shield is symbolized by capacitor C Outside the shield another stray capacitance Cz exists between the shield and the equivalent parallel resistance Rez Rin The rest of the amplifier has been deleted because so far as we are concerned here its only important characteristic is Rin An electric field exists within the shielded enclosure however the field outside the shield is zero everywhere This comes about because at least ideally the entire surface of the shield remains at ground potential Since the external field is zero no energy is transferred across stray capacitance Co In part B of Figure 2 the grounded metallic shield envelops the receiver Energy transfer
77. clocking a 4017 counter Pin 12 of the counter provides a high low output which changes with every five input pulses counted This output is applied via a resistor of from 2 2K to 10K ohms to pin 5 the modulated input of the timer This produces a strident warble that calls immediate attention More mellow but interesting tones can be obtained with the addition of the RC filter shown 0593 ett py Hef pu c 8 10V o UV 10V CLOCK INPUT OUTPUTS m 4 SC o n F tel SPEAKER j YU PARTS LIST FOR TWO TONE ALARM C1 100 uF electrolytic capacitor 25 VDC C2 0 1 uF ceramic capacitor 15 VDC C3 1 uF electrolytic capacitor 25 VDC IC1 555 timer IC2 4017 decade counter R1 R2 4 700 ohm watt resistors R3 10 000 ohm linear taper potentiometer R4 2 200 to 10 000 ohm 2 watt resistor see text SPKR 8 ohm PM type speaker T1 audio output transformer 1000 ohm center tapped primary 8 ohm secondary Radio Shack 273 1380 or equivalent 9V VOLUME X 79 SOLID STATE UPDATE Each month the manufacturers of solid state components release literally hundreds of new devices While we cannot report on all of these we do intend to feature some of these devices that are most likely to interest our readers For further information on any of these solid state components write directly to the manufacturers They can provide you with data sheets and applicati
78. d brought to the 5 volt supply The Electronic Compass was meant to be a hand held device So incorporating a 9 volt battery as the power supply is a must for its operation But by applying 9 volts to an IC that was manufactured to withstand only 5 volts would be a foolhardy proposition So to knock the input voltage down to the needed 5 volt level we have used a 7805 voltage regulator IC2 TO 220 This IC not only limits the output to 5 volts but it also provides a constant voltage to the circuit even if the battery used had another life in a portable radio The only drawback to this circuit is the massive current requirements to light LEDs and to power the 74188 which require about 90mA for normal operation For this reason the Electronic Compass was not meant to be in constant operation For momentary operation SW1 was added Here the spring return button is pushed only when compass headings are required Then released to conserve battery life which by the way should be an alkaline Programming the 74188 PROM The programming of the 74188 requires you to assemble the circuit presented in Figure 5 Here the simulated data output from the compass sensor is delivered to the 74188 s input pins 10 to 13 through four single pole double throw switches The output requiring a logic 1 output can be selected by using a 1 pole 8 position rotary switch 1 pole 10 position will also be satisfactory When purchased the virgin
79. d electronic symbcls Published by CIE exclusively for ous_studerts and alumni Yours free when you request a CIE Course Catalog L you want to learn about electron ics and earn a good income with that knowledge then CIE is your best educational value CIE s reputation as the world leader in home study electronics is based solely on the success of our graduates And we ve earned that reputation with an unconditional commitment to provide our students with the very best electronics training Just ask any of the 150 000 plus graduates of the Cleveland institute of Electronics who are working in high paying positions with aerospace computer medical automotive and communi cation firms throughout the world They ll tell you success didn t come easy but it did come thanks to CIE And today a career in elec tronics offers more opportunities and greater rewards than ever before CIE s COMMITTED TO BEING THE BEST IN ONE A ELECTRONICS JIE isn t another be everything to Peverybody school We teach only one subject and we believe we re the best at what we do Also CIE is accredited by the National Home Study Council And with mpre than a 1 000 gradu ates aoe year we re the largest F a ftudy school specializing wely in electronics CIE has been training career minded students like yourself for nearly 60 years and we re the best at our subject ELECTRONICS BECAUSE IT S THE ON
80. day I m an incredible basket weaver So fasten your seat belts grip your calculator firmly and take a deep breath We now enter the land of mobile Ohm No doubt some of you have wondered why you would want to know about Ohm s Law anyway Though the math is simple and you probably had no trouble with it you may have been building projects for years and never needed to use it Just the same Ohm s Law will help in understanding the concepts to come later Also you may be interested in designing some of your own projects in which case this will all be useful Another electrical law we will talk about in this issue is called Kirchhoff s Voltage Law Again though basic and a bit math oriented this is useful in understanding how circuits work VOLUME X PREFIX SYMBOL MULTIPLIER 1 000 000 000 000000000001 EXPONENT 1 000 000 1 000 001 000001 000000001 Figure 1 Prefixes for engineering notation and some of the components used in them First though we should establish a common numbering system and standard coding for resistors capacitors and other components so that we are talking the same language later on COUNTING LIKE SCIENTISTS AND ENGINEERS In electronics as we said previously mathematics plays an important role in determining the guantities of various parameters We talked about voltage current resistance and power to start with These are all determined with math and
81. decimal point of the display is illuminated for an Odd or Even Low Count 0 1 2 3 or 4 count from the counter Even numered counts 0 is considered even for the sake of symmetry cause the display to present an E while odd numbered counts result in a 0 Segments A D E and F are common to both O and E but they are driven by theclock along with B C and G to stimulate all the segments into random motion Holding down the pushbutton causes C to discharge through R giving an uncertainty period of five or seven seconds depending upon the size of the capacitor chosen Good Luck NOTE ICI PIN14 IS GROUNO PIN 7 Music may be a little optimistic but sequential tones are entirely possible with this circuit and with a little experience simple but recognizable themes can be produced The system combines the 4017 decimal decoder counter with the 555 timer in astable oscillation As the counter steps through its ten outputs a different frequency determining resistor R1 10 which may range from 1K 100K is activated through an isolation diode The input clock frequency notes for an electronic door bell Notes may be made longer by giving succeeding steps like 5 and 6 the same value tunning resistors Rhythm may be accomplished by skipping one or more Outputs For very short themes the next stage can be made to reset the counter Composition anyone 78 ELECTRONICS HANDBOOK
82. e shape of the completed cell Sometimes the edges are cut producing a square or rectangular unit A freshly sliced disc carries saw blade marks on the surface To remove the marks the slab is subjected to chemical processing A sodium hydroxide the same as household lye bath etches the blank to a smooth finish The cell is now ready for processing The disc is submersed into a much weaker 2 sodium hydroxide solution for approximately 30 minutes This diluted bath doesn t etch the wafer s thickness as previously but removes material from between the crystal structure This characteristic of silicon leaves a plane of tetrahydrons Incoming light is reflected off the sides of the pyramids ricocheting its way to the junction The tetrahydron allows the light to enter the cell but reflects very little thus eliminating the need for an anti reflective coating A sulfuric acid rinse neutralizes the alkaline etchant and Cleanses the wafer This process creates the type P semiconductor part of the cell The N type semiconductor is created through a diffusion process Cells are placed in a quartz tube and the system purged with nitrogen The tempera ture is raised to 850 degrees centigrade and a measured amount of gaseous phosphorus acid is injected into the chamber The phosphorous atoms disassociate and actually force themselves into the Surface structure displacing silicon atoms With only three valence electrons it produces the hole
83. e housing iron and cord are made of static dissipative material ideal for static safe areas Resistance to ground is less than 2 ohms and leak voltage is less than 0 6mV Priced at 299 00 hobbyists may find the cost a little steep for their workbench but for the hobbyist who has everything this has to be the ultimate in soldering iron stations The station comes complete with iron holder sponge pro gramming card 50W iron with A1016 tip and operates on a 115VAC 3 wire cord For additional details and or information write or call Contact East 335 Willow Street North Andover MA 01845 508 682 2000 SHORTWAVE AIRCRAFT RECEIVERS From Ramsey Electronics Inc Do It Yourself kits to build a Shortwave Receiver that will tune in the world with a 12 antenna SR 1 27 95 This little Receiver can receive any 2MHz portion from 4 to 11 MHz A true superhet with smooth varactor tuning AGC RF gain control plenty of speaker volume and runs on a 9V battery With SC 1 Shortwave Converter Kit 24 95 it can convert your car radio to two switchable bands each 1MHZ wide tunable on your car radio dial An oppor tunity to add some fun to your drive time Dti Poma E Aircraft Receiver AR 1 24 95 kit lets you listen to exciting aircraft communications Picks up planes up to 100 miles away The AR 1 receives 110 136 MHz AM air band with smooth varactor tuning superhet with AGC ceramic filter adju
84. e on choosing a plane For the beginner a plane that is easy to build and easy to control makes sense You want a plane that is slow and stable not something designed for high speed aerobatics If your flying space is limited an R C helicopter might be the answer On the other hand someone with lots of space who likes peace and quiet might prefer an R C Sailplane With the exception of the Sailplane all planes need an engine of some sort The bigger the plane the bigger the engine required Most beginners start out with an economical 2 stroke engine These are ignited by glow plugs and burn a mixture of methanol nitromethane and oil with methanol being the major constituent Since the fuel is very flammable caution is necessary Diesel and gasoline powered engines are also available In recent years 4 stroke engines have become popular especially with scale modelers who prefer the realistic rumble of a 4 stroke engine to the thin whine of a 2 stroke A large 4 stroke engine may put out 3 horsepower and cost as much as 3 000 Douglas Pratt s book was a pleasure to read and recommend it without hesitation to anyone contemplating the purchase of an R C model plane The Beginner s Guide to Radio Control Sport Flying costs 9 95 and is published by TAB Books Inc Blue Ridge Summit PA 17214 9988 VOLUME X 15 LEARN THE SECRETS OF HOW TO FIX ELECTRONIC EQUIPMENT FASTER ON OUR REPAIR TECHNIQUES ON VIDE
85. e versions each using two die and specified at 175 MHz to deliver 300 watts with typical gains of 14 and 16 dB respectively These high performance RF power MOSFETs will find use whenever high power and high gain are required over wide bandwidths Typical applications include broadband power amplifiers up to 175 MHz solid state transmitters for FM broadcast TV transmitters and translators For data contact Motorola Literature Distribution Center POB 20924 Phoenix AZ 85063 it Hiid E Pray CONSTRUCTION QUICKIE CURIOSITY DETECTOR by Hugh Gordon This interesting little circuit challenges a basic since most of the parts are readily available from the human characteristic curiosity junk box The enclosure can be metal or plastic and To activate the circuit simply point the Detector at the number of things that this circuit can detect is the person to be challenged and press S1 Aloud raspy limited only by the builders imagination tone will be emitted from the speaker as long as S1 is depressed Most victims will respond questioning the source of the sound The rest we leave to the builders imagination S1 should be placed on the back or bottom of the enclosure so that it cannot be seen when you press it The variable resistor is optional and can be placed anywhere on the enclosure It is used to readjust the basic Detector so that it can pick up other subjects Constructio
86. ect at least you ll know that the layout is not to blame The less you tempt fate the better your chances are of building a project that works E VOLUME X 51 WORKBENCE PROJECTS The projects we ve prepared for you in this section are more complicated than those in our Circuit Fragments section but they are less complicated than the ones in our IC Testbench section As with any electronics assembly work be sure you understand how the various parts of the circuit work together and the objective of each component before you start gathering the components together and assembling them As with any project that uses ICs integrated circuits or transistors be careful to observe precautions regarding overheating their leads If possible use sockets instead of soldering directly to their wire leads If you can t do that be sure to protect the IC and transistor leads by using long nose pliers as a heat sink when soldering those leads CRYSTAL CONTROLLED TTL This inexpensive color TV crystal of approximately SARI MIST FOR CRKSTALCONTROLEED Mik 3 58 MHz can readily be persuaded to oscillate in the C1 75 pF mica capacitor 15 VDC following 7404 circuit The resultant waveform can be C2 0 01 uF ceramic capacitor 15 VDC divided down via other popular IC chips such as the IC1 7404 hex inverter R1 1 000 ohm watt resistor 4017 CMOS type XTAL 3 58 MHz crystal color TV carrier type 52 ELECTRONICS HAN
87. ed to one in the southwest The average peak sun hours and the daily load in ampere hours can be used to determine the total current in amperes that must be supplied by the solar system according to the following relationship _Ampere hours per day Amps Peak sun hours As a safety margin the amperes required should be a figure which is at least 20 greater that the above VOLUME X 67 calculation The cavacitv of the batterv is usuallv made substantially greater than the above ampere hour figure Thus the battery should be capable of supplying the necessary power for an extended period of time perhaps a week assuming that illumination at the site could be low because of poor weather conditions extending over such a period of time A Typical Example Assume that a radio transceiver was to be powered by asolar panel On transmit the current demand is 1 ampere on receive 0 1 ampere Over a period of a day 24 hours the intermittent operation of the transmitter involves a total time period of 8hours The receiver is in operation for the remainder of the 24 hour period Consequently the ampere hours Ah drawn by the transmitter and receiver are Transmit 1 x 8 8 Ah Receive 0 1 x 16 1 6 Ah The total demand is 9 6 ampere hours 8 1 6 Assume at the site of the solar panel there are an average of 4 peak sun hours Consequently the current 1 that must be made available by the solar power system becomes
88. electrolytic capacitor 15 VDC C3 2 2 uF electrolytic capacitor 15 VDC C4 50 to 100 uF electrolytic capacitor 25 VDC iC1 741 op amp LED1 small LED Q1 2N4401 transistor R1 500 to 500 000 ohm watt resistor see text R2 R3 4 700 ohm watt resistors R4 500 000 ohm 2 watt resistor R5 10 000 to 50 000 ohm watt resistor R6 100 ohm watt resistor SPKR 8 ohm PM type speaker T1 audio output transformer 1000 ohm center tapped primary 8 ohm secondary Radio Shack 273 1380 or equivalent OPTIONAL SPEAKER POSITIVE INTO NEGATIVE Certain IC chips and other circuit elements often require small negative potentials of small current drain necessitating the construction of bulky transformer operated supplies Operating at 1 KHz or higher frequency the pulse generator shown below drives a voltage doubler circuit furnishing a negative potential approaching that of the positive input supply With a 10 volt input an output of about 9 VDC was measured into a 20 000 ohm load A voltage tripler or quadrupler circuit may also be employed for higher potentials positive or negative as well For loads requiring up to 50 ma the type 555 timer in astable mode is an ideal choice PARTS LIST FOR POSITIVE INTO NEGATIVE C1 0 01 to 0 1 uF ceramic capacitor 15 VDC C2 C5 10 uF electrolytic capacitors 25 VDC C3 10 to 100 uF electrolytic capacitor 25 VDC C4 0 001 uF ceramic capacitor 15
89. en two batteries a very practical way of INVERTING AMPLIFIER R2 RI i R2 GAIN 1 RixR2 R3 R1 R2 Minimum resistor value for either resistor should be 1K ohm For a gain of 10 try R1 10k ohm and R2 100k ohm VOLUME X 19 SUMMING AMPLIFIER R3 R4 R5 Tu V out Vin 1 Vin 2 SET RI R3 R4 R5 R2 1k ohm Minimum value of all resistors lk ohm Typical value of all resistors is 10k ohm except R2 NOTE input impedance of all inputs is equal to input resistor value R3 R4 etc powering them For the circuits described here it we wish to use them continuously a power supply circuit consisting of a transformer some rectifiers and some filter capacitors is shown in Fig 1 Most of the parts necessary can be found in a well stocked experi menter s junk box If not they are readily available from most any electronics parts supplier You should be able to build the power supply for under 15 00 even from brand new parts If you build it just be careful with the input wiring 120V AC can be a shock DIFFERENCE AMPLIFIER R2 Vout Vin2 Vinl R1 R2 R3 R4 at least 10k ohm Typical value for all resistors is 10k ohms 20 ELECTRONICS HANDBOOK hazard Also when wiring the rectifiers and filter capacitors be Sure you get the polarities correct The entire circuit can be built on or in a small sheet metal box with t
90. ense to use them You can still build your own airplane if you wish or you can buy one that s ready to fly Before you even consider buying a plane and an R C control system however suggest that you take a look at Douglas Pratt s new book The Beginners Guide to Radio Control Sport Flying Init you ll find all the information necessary to get started in R C modeling Mr Pratt is special projects director of the Academy of Model Aeronautics the national organization for model fliers He knows a lot about planes and flying and he conveys what he knows with good natured enthu siasm One of the things that the author stresses is the desirability of joining an R C modeler s club For the beginner clubs provide camaraderie as well as free advice from more experienced members In addition clubs carry insurance that protects their members so if you lose control of your plane and it crashes through someones window the insurance company pays the bill Most ot the book is devoted to the technical aspects of R C flying For example the author discusses the operation of transmitters receivers and servos He stresses the importance of periodic testing of the control system to prevent possible disasters in the air And he tells how third order intermo dulation from other nearby transmitters Can Cause you to lose control of your plane Construction tips are sprinkled liberally throughout the book There is even advic
91. ents for a total of 30 mAmps If the battery is supplying 30 mAmps 15 mAmps to each resistor then what will Ohm s Law tell us about the overall resistance of the circuit Rrota V 1 1 5v 30MA 50 ohms The total circuit resistance is 50 ohms one half that of each resistor So we now know that connecting resistors in parallel reduces the total resistance Remember that in series circuits the resistors added together give the sum of the resistors The simple way of determining the equivalent resistance of resistors in parallel is to use conductance Arghh Not more terms Sorry but this one is easy Conductance symbolized by G with units Siemens is the reciprocal of resistance G 1 R and conductances in parallel can be added together like resistances in series After the total conductance is determined we can convert back to resistance by R 1 G so for Figure 7 Gr 1 100 ohms 1 100 ohms 10mS 10mS 20mS converting back Rr 1 G 1 20mS 50 ohms And that s what we determined it was before Enough We can only take so many thrills at one time In Part til we will look at series and parallel circuits together short circuits meters and how they are used and tons of other good stuff Meanwhile back to my basket weaving VOLUME X 63 ANOTHER LOOK AT SOLAR ENERGY Solar energy is an idea whose time has come Solar energy is not only the energy of the future it is the energy of now It is the sun our sun
92. er to the completed circuit the compass can also have frequent use in either your car or boat This device is a Cigarette Lighter Plug See Figure 3A Since the compass utilizes a 7805 voltage FIGURE 3A regulator any DC voltage in the range from 6 to 25 VDC can be used to power the device Car and boat batteries are of the 12 volt variety which present no problems The adapter plug is an inexpensive item that can be purchased at any Radio Shack store or from electronic mail order suppliers When your adapter arrives take a look at Figur4A for a diagram showing the proper wiring Note that one of the two line cord wires has a white stripe on it This stripe called a tracer is used to indicate the positive lead In contrast NO trace obviously is the negative lead WIRE WITH WHITE STRIPE LINE CORD CIGARETTE LIGHTER ADAPTER NOT SUPPLIED WITH KIT WIRE WITH NO STRIPE FIGURE 4A To install the adapter unsolder and carefully remove the 9v battery clip from the board Clean out each hole with a desoldering tool or solid piece of wire if solder somehow flowed inside With our polarity requirements in mind take the adapter s tracer lead insert it into the hole requiring positive voltage and solder it into place The nontracer lead is to be installed and soldered to the remaining hole When complete check the board for any unwanted solder splashes before plugging in the adapter Now
93. eration LESSONS Clear illustrated texts build your understanding sy of computers step by step Only NRI walks you through the step by step assembly of a powerful 386sx computer system you train with and keep giving you the hands on experience you need to work with troubleshoot and service today s most widely used computer systems Only NRI gives you everything you need to start a money making career even a business of your Own Ca computer service No doubt about it The best way to leam to service computers is to actually build a state of the art computer from the keyboard on up Only NRI the leader in career building at home electronics training for more than 75 years gives you that kind of practical real world computer servicing experience Indeed no other training in school on the job anywhere shows you how to troubleshoot and service computers like NRI Get inside the West Coast 386sx computer system and experience all the power and speed of today s computer technology With NRI s exclusive hands on training you actually build and keep the powerful new West Coast 386sx 20 MHz mini tower computer system You start by assembling and testing your computer s 101 key intelligent keyboard move on to test the circuitry of the main logic board install the power supply and 1 2 meg high density floppy disk drive then interface your high resolution monitor What s more you now go on to instal
94. eries of substitution boxes are available RS Series sets resistance CS Series sets Capacitance RCS Series sets both resistance and capacitance and LS Series sets inductance For details contact HMC P O Box 526 Canton MA 02021 617 821 1870 CONTINUOUS LENGTH CABLE TIES Strap Loc Continuous Length Cable Ties reduce the need for stocking many different lengths of cable ties The ties are cut from a spool assembled with a lock and used like any cable tie No special tools are required Waste is dramatically reduced because any excess can be reused Unique features include ability to fasten and bundle large objects separate and space wires and cables fasten through panels and multiple wrapping for extra high tensile strength applications Stainless steel and nylon locking device features low insertion force instant locking and infinite adjustability Strap Loc Conti nuous Length Cable Ties are now available in two new smaller package sizes 250 Ft amp 500 Ft for added convenience and ease of use For more information call or write ADVANCED CABLE ELEC TRONICS CORP P O BOX 1291 Westboro MA 01581 Tel 508 366 0669 ILLUMINATED MAGNIFIER The stylish 8MC Series lamps utilize a 22 watt circline fluores cent tube to cast an even glow on your task for optimum brightness and accuracy lt reduces eyestrain and fatigue by combining the two key factors in aiding vision light a
95. esign 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 Pubiishers Prices Shown 2980P 312 95 GORDON MCONB S TIPS amp TECHNIOHES FOR THE ELECTRONICS HOBBYIST ae 2 2 m AAA 3485 2750P 13 95 be E cag ep A En eS a F a a oa E ectagnics Book Cue ELECTRONICS SKIT BOOR Blue Ridge Summit PA 17294 0810 FIFTH EDIT ON Please accept my membership in the Electronics Book Club and send the 5 volumes listed below billing me 4 95 If not satisfied may return the books within ten days without obli gation and have my membership cancelled agree to purchase at least 3 books at regular Club prices during the next 12 months and may resign any time thereafter A shipping han dling charge and sales tax will be added to all orders 3345 Counts as 2 35 95 2883P 18 95 A a gt Name Address City i State Zip Phone 2800P 16 95 Signature Valid tor new members only Foreign aoplicants will receive specia Staind instructions Canada must remit in US currency This order subject to acceptance by the Electronics Book Club CEHB1091 meee wee ee ee did 2613P 17 95 All books are hardcover unless number is followed Ey a PC for pape
96. for Gebel ive kail fie p tt da EA Hed Wia flle he W pe pe ape og ege ig no 13 ig ii j m ja be 11 24 vou 10 3 FRE 45 H da ER ARA the minute The Cities Around The World time display allows you to keep track of the time anywhere in the world The display can be operated in either 12 hour or 24 hour mode This display can be customized by preparing a text file to substitute specific cities and or call signs in the same geographic areas This display can be extremely helpful in understand ing when international news events are taking place or making schedule arrangements with other stations For readers who are interested Ham Time has a modest price of 24 95 and requires CGA or EGA graphics adapter MS DOS 2 1 or later and 128K memory available in 3 5 or 5 25 inch disks Address questions to ECode Systems Inc 335 West Virginia Phoenix AZ 85003 602 257 1826 ANALOG DIGITAL DMM Soar s 3200 Series 3 digit multimeters combine the features of a state of the art digital multimeter with an analog bar graph display The high resolution 3200 count digital display delivers the resolution of much costlier 4 digit meters for measurements above 2 000 counts The 32 segment bar graph display is ideal for readings that change peaking nulling and observing trends These DMMs are simple to use Just select your function with the handy 8 position rotary switch and test The meter automatically
97. ften filled by personal recommenda tions and referrals He tells how and when to respond to employ ment ads and how to write a resume that will elicit a response from a personnel manager Employment agencies are some times necessary in a job search Mr Dombroski tells how to get the most out of them Once you ve got the attention of a prospective employer you face one last hurdle the job interview How you handle yourself in such an interview is crucial to winning the job you seek Like or not you have to sell yourself and convince the employer that he s found a valuable asset Mr Dombroski offers welcome advice on how to do this VOLUME X 13 NEW BOOK REVIEWS The Employment Maze is a fast paced 136 page book that you can read in an hour or two yet the information it contains could affect the rest of your life Copies may be ordered from Paul Dombroski inc POB 47604 Phoenix AZ 85068 Price is 12 95 plus 2 00 for postage bead n ct a m Class i y Enta He hey y Why p Step e m OT CUSTOMIZE YOUR HOME ENTERTAINMENT SYSTEM By Steve Sokolowski Popular author Isaac Asimov recently marked a milestone in his long career with the publication of his 300th book mention this because it appears as if Steve Sokolowski has his sights set on Dr Asimov s record this is the third book of Steve s to be reviewed this year and it looks like his best to date This time out Steve
98. g the eighties but Iraq s invasion of Kuwait last August shattered their complacency People think more about energy these days and some even dream of generating their own electrical power If you are one of these people this new book by New Zealander Alfred Forbes may interest you The Homebuilt Dynamo is a step by step 182 page guide to the construction of a low voltage 3 phase AC generator and rectifier what we would call an alternator Based on high energy permanent magnets Mr Forbes design is unique in that it develops considerable power at relatively low speed Maximum rate output is 1 000 watts at 740 rpm Depending on the rate of rotation and the manner in which the coil windings are connected together output voltages between 12 and 36 VDC may be produced Power to turn the armature can be obtained from a windmill a water wheel or even a stationary bicycle which is the method employed by the author He uses the power generated to charge a battery and light his home using low voltage fluores cent lamps The book has over 300 illustra tions and is printed on high quality glossy stock Instructions are clear but considerable mecha nical aptitude will be needed to duplicate the author s work The Home Built Dynamo is available for 65 U S from Todd Forbes Publishing P O Box 3919 Auckland New Zealand Price includes airmail delivery INVENTING CREATING AND SELLING YOUR IDEAS By Philip B
99. h internal impedance Rai driving a load R This voltage generator might be anything a VOLUME X 47 Figure 1 Figure 1 Electric field coupling between two adjacent circuits can cause interference problems particularly if a low level stage is close to a moderate level or high level stage transistor op amp logic gate or even an alternator the exact nature of the source is unimportant Nearby we have a second voltage generator Vz with an internal impedance of Rez An amplifier with input impedance equal to Rin is supposed to amplify Ve However electricfield coupling between the two circuits exists through stray capacitance C Now C s capacitance will be very small As an example consider that the capacitance between two closely spaced 22 wires amounts to less than 40 pF per foot of wire Despite the small magnitude of capacitance C however it can result in the appearance of a noise voltage Vn across the amp s input impedance We are in trouble if Vn is a significant fraction of V s magnitude and the situation is hopeless if Vw equals or exceeds Va To see what determines the size of noise voltage Vn note that current from generator V can flow in a complete loop first through Re then through C and finally through Rez and Rin back to source Vi Since Rez is effectively in parallel with Rin and since Vn is developed across this parallel resistance combination we are interested in the equivalent parallel
100. he 1C s you purchase to determine their locations and operating values ACTIVE LOW PASS FILTER C2 C1x2 tar a 6 28 x Cx R AND WHERE Cl Cx 1 4 C2 Cx0 7 GAIN IN BAND 1 For 10kHz filter RI R2 27k ohm C1 1000 pf C2 500 pf ACTIVE HIGH PASS FILTER GAIN in band 1 SET RI R2 R FOR A 100Hz FILTER f 1 RI R2 100k ohm 6 28 x Cx R Cl 02 uf cl ER 1 4 C2 01 ut C2 Cx 0 7 AMPLIFIER CIRCUITS We have a choice of amplifier types Linear INVERTING or NON INVERTING are the basic amplifiers we are mostly familiar with They can amplify weak signals from a pickup cartridge or microphone for use with a stereo or the weak signals from a light sensor to detect when a beam is interrupted the uses are almost endless The only difference between the two is just what their names imply one inverts the signal at its output the other doesn t The VOLTAGE FOLLOWER is a simple variant on the amplifier stage it has no gain but serves to isolate the input signal from whatever is connected as a load The current gain of the amplifier FREE RUNNING MULTIVIBRATOR Rl FOR 100 Hz try RI 150k ohm R2 10k ohm R3 5k ohm Cl Ol uf SET R2 R3 x 2 TP NMAMAAMA 6 28 x RI x Cl R2 or R3 should not be less than 1k ohm VOLUME X 21 FIXED OSCILLATOR C C R1 SET R3 R4 x 10 Rl R 2 C1 Cx2 a eee t 6 28 R C Adjust R4 for steady oscillation For
101. he front and rear panels Remember every squeal is a station Lower the regeneration control until the squeal just about quits Now slowly move the vario coupler coil By adjusting coil L3 and R5 together stations can be tuned in for the loudest volume After a few trips it is easy to tune up the regeneration circuits Switch SW1 to SW or direct connection to L2 when listening to shortwave stations When tuning in broadcast stations switch SW1 to the RF winding L1 Remember shortwave listening is best at night or early morning hours Troubleshooting If by chance no stations can be tuned in check for voltage measurements on the Q1 and IC1 terminals Shut off the switch when the voltage is real low on all terminals Remove IC1 from the socket Now check for correct voltages at Q1 terminals and terminal 6 of IC2 If the voltages are normal suspect IC1 is plugged in backwards or defective Q1 may be checked witha transistor tester or diode test of the DMM With normal voltages click the center terminal of the volume control R7 with a small screwdriver You should hear a click or low hum This indicates the audio section is normal Now check the voltages in the RF and regeneration section Reverse tickler coil leads 5 4 6 when there is no feedback squeal or noise Rotate the vario coupler so the tickler coil is inside the main coil form Connect the antenna coil switch directly SW to the main coil and try once again Accurate
102. he wiring on a couple of terminal strips LIMITER CLIPPER AMPLIFIER 2D1 ZD2 R2 GAIN 1 tar R1 R2 minimum value 1k ohm ZD1 ZD2 set voltage to clip at To start try R1 10k ohm R2 20k ohm ZD1 ZD2 2 2V HELPFUL REMINDERS Some hints Like all good circuit layouts be sure and keep the input and output away from each other This will help prevent oscillation Also if you will be running more than a foot or so of wire from the power supply to the op amp be sure and add some 0 1 uf SOV capacitors from each of the power supply lines to COMPARATOR V supply output high V supply low OUTPUT R1 100k ohm potentiometer Adjust for desired output transition voltage level NOTE V and V should be the same as the op amp power supply ground Do this near the op amp power Supply pins to help prevent any possiblities of oscillation With this in mind let s start looking at some of the op amp circuits DIFFERENTIATOR R2 fx R2 _ 1 To start try fx Cl RI 1k ohm R3 lk ohm R2 10k ohm For a gain of 10 typical Cl 0 1 uf R1 R2 gt 10 LOTS OF CIRCUITS On the following pages are 18 op amp circuits complete with design equations and some suggested circuit component values to help you get started Note that none of the diagrams show any pin numbers or power supply connections since these may change from IC to IC Consult the data sheets which come with t
103. her properly so that it ll work only if you know what each component does to the flow of electricity electrons going through it as well as through the rest of the circuit If you don t understand the circuit thoroughly every part as well as its function read the article again carefully until you do If that s not enough look up words you re not familiar with in a good electronics dictionary Read the teaching articles that we include in every issue of the ELECTRONICS HANDBOOK like the ones on Capacitors and Resistors and Understand ing Schematic Diagrams that we have published in previous issues Another caution is in order even if you ve worked with electronic parts before but haven t handled integrated circuits ICs Be sure to observe these simple precautions Don t mount the IC directly into a circuit or solder its terminals into the circuit Instead do what experienced experimenters do solder an IC socket into the circuit unless you re using a quick assembly experimenters board in which case youll just plug the socket into the board s holes Also don t handle the IC any more than necessary to keep from damaging it with static electricity Most ICs are sold mounted temporarily in a little piece of anti static foam Keep the IC in its foam mount until you re ready to plug it into a socket Finally keep excessive heat away from ICs particularly when putting them into a circuit witha soldering iron an
104. hose in our Workbench Projects and IC Testbench sections If you study them and put several together you will increase your understanding of how all electronic components and circuits work SWL s SUPER SIGNAL BOOSTER Super sensitivity is the feature of this two transistor the preselector output and the receiver with which the shortwave preselector It provides overall gainashigh unit is to be used jas 40 dB from 3 5 30 MHz PARTS LIST FOR SWL S SUPER SIGNAL Diode D1 protects against excess gate voltage BOOSTER Caused by nearby transmitters while Q1 serves as an emitter follower to match the medium output C1 365 pF tunning capacitor impedance of the FET transistor to the low input C2 C3 0 05 uF 25 VDC capacitor limpedance of the receiver C4 470 pF 25 VDC capacitor Since Q1 is a MOSFET type with a gate that s very D1 1N914 diode sensitive to static changes Qt must be handled witha L1 Antenna coil 1 7 5 5 KHz use Miller B 5495A short circuit across all leads until just before power is hit el ss Miller 32886 TESO WNG kes MINGE applied Also a soldering iron must not be applied to 4 RCA 40468 FET transistor Do not substitute Q1 s leads unless they are shorted Q2 2N3394 npn transistor Lts connections are specified in the instructions R4 470 ohm watt resistor supplied with the coil A short length of RG 174U R2 2400 ohm watt resistor coaxial cable should serve as the connection between R3 4700 ohm
105. ide to the theory and application of mecha nical components like pulleys belts gears motors and so on This book was prepared by the Staff of Stock Drive Products a major supplier of small precision mechanical components The purpose of this book is to explain in simple language how best to apply the mechanical components that Stock Drive Products sells Of course the information applies equally well to components from other manufacturers Chapter One is a compendium of useful mechanical data most of it in chart form dealing with such things as conversion factors moments of inertia properties of metals properties of plastics characteristics of finishes and coatings and practical hints for mechanical design Chapter Two is an excellent thorough introduction to the design and application of gears and gear trains Let me point out however that most home projects should probably be constructed with belts chains and pulleys since these are easier for the novice to lash together than a gear train But for those times when you just can t avoid using gears Chapter Two will pull you through Chapter Three is about electri city probably nothing that you don t already know Chapter Four is about motors and here there is likely to be lots that you don t know The treatment of stepper motors is especially thorough Chapter Five deals with spring motors handy devices that can replace an electric motor or a
106. ignal is different from the American signal and my trusted toy won t work on my set Is there a commercially made adapter available or is it possible to make one What is the difference between the signals will appreciate any help you can give me You see several of my cartridges are exclusive to the Japanese market and are unavail able here i e Japanese chess go and Chinese chess Dale Oldfield Pinedale WY According to the references that have checked Dale there is no difference between Japanese and American television signals Both nations use the NTSC method of encoding Assuming that your Nintendo was not damaged in transit the only reasonable explanation for the incompatibility youve experienced is that Japanese frequency assignments for the various channels are ditferent from ours That being the case it may be possible to retune the output of your Nintendo so that it falls on one of the standard American channels Such an adjustment would probably be effected by tweaking a variable capacitor or inductor I d write to Nintendo of Japan and see what they have to say Their U S affiliate may not know anything about the Japanese product Perhaps they will allow you to exchange your Japanese model for an American model if retuning is not possible 6 ELECTRONICS HANDBOOK Got a question or a problem with a project ask The Editor Please remember that The to Editors column is limited to ans
107. ilica and sapphire windows precision first surface mirrors in a variety of shapes optical filters polarizers reticles precision pinholes and slits compound eyepieces focusing tubes iris diaphragms x y tables laser beam expanders mirror and lens mounts and optical tools Bear in mind that these are precision devices and they are priced accordingly i e they re not cheap Rolyn Optics Co 706 Arrow Grand Circle Covina CA 91722 86 ELECTRONICS HANDBOOK JAMECO ELECTRONICS A lot of readers have a terrible time trying to find integrated circuits and other semiconductors for their projects We know this because they write to us with their complaints When they do we refer them to a company like Jameco Electronics Jameco s latest catalog is only about 75 pages long but in those pages you ll find several thousand integrated circuits CMOS TTL op amps memory chips microprocessors and discrete semiconduc tors like transistors and FETs In addition to its huge stock of solid state devices Jameco offers a variety of passive components like resistors Capacitors switches and pots DMMs and other forms of test gear are inciuded too Finally like many other parts suppliers Jameco seils economical PC clones in kit form To get your copy of the Jameco catalog write to Jameco Electronics 1355 Shoreway Rd Belmont CA 94002 PRODUCTS INTERNATIONAL Lots of companies sell electronic test equipment but most
108. is helpful to define two classes of devices noise sources and noise receivers Noise originates at some source and appears in another electronic circuit the receiver Almost anything can be a noise source Some of the more common ones are automobile alternators arcing motors the ever present 60 Hz power line high voltage or high current electronic circuits and digital logic Similarly almost any electronic circuit can be a receiver although high gain low level high impedance stages are often the most susceptible While the source and receiver may belong to two different pieces of equipment they may just as well be different stages of a single piece of equipment Coupling In order to transfer energy from the source to the receiver some form of coupling must exist The two important modes of coupling consist of an electro magnetic field or a common ground impedance between the two circuits in question Consideration of an electromagnetic field is usually broken down into two subcases electric field coupling and magnetic field coupling A high voltage low current circuit radiates energy chiefly through an electric field whereas high current low voltage circuitry radiates predominantly through a magnetic field Most noise sources radiate through both fields but it is easier to deal with one field at a time Let s begin with electric field coupling also known as capacitive coupling In Figure 1 we have voltage source V1 wit
109. it And finally the LOG AMPLIFIER does a very curious thing it converts the linear input signal to a logarithmic one at the output it is the simple basis of a compressor or expander circuit expander as it is shown As it is a positive input signal will come out with a positive expansion it can be used to make a decibel scale reading meter along with the meter amplifier above METER AMPLIFIER CIRCUIT GAIN 1 R1 same as resistance of meter movement D1 D4 any small silicon diodes A INTEGRATOR R2 GAIN 10 SET Rl TO START TRY 1 RI 10k R2 100k 1 C1 0 1 uf R2 Cl R2 R3 T ANALOG FILTERS These are as the name implies filters for cutting off or removing parts of the signal frequencies input to them For example the HIGH PASS FILTER will eliminate low frequency noise or rumble from a stereo system while the LOW PASS FILTER may be used to eliminate hiss or other high frequency noises Both of these filters give a 12 db per octave cutoff response which is quite fast Also by carefully choosing our cutoff values we can use them with multiple stereo amplifiers to create a hi fi bi amplified system with an amplifier each for the tweeters and woofers in our speakers WAVEFORM GENERATORS For those interested in amplifier testing or checking digital circuit functions these are two very useful circuits the FREE RUNNING MULTIVIBRA TOR and the FIXED sinewave O
110. ition battery will have no problem driving the load for long periods of time But on the other hand with a load resistance of 90 ohms as in our compass the current that is needed will be 100mA or 1A An extremely large amount of energy for a carbon battery to deliver But hold on a minute we can increase the current handling of the battery by wiring two batteries in parallel This can be seen in Figure 2B Think back for a moment to those thrilling days of yesteryear school days If two batteries are tied together in parallel the total current is equal to the sum of BOTH sources Or in other words Total current is equal to the current from battery one plus the current from battery two Itotal 11 12 So if we take two 9v battery clips and solder them in parallel as shown in Figure 2B to the provided holes in the pc board and snap a couple of transistor radio batteries in place the current requirements for our Electronic Compass will be easily met without purchasing expensive alkaline substitutes The total driving current of the two batteries will be significantly increased thus providing the power needed by the compass circuit Cigarette Lighter Adapter Power Option When completed the Electronic Compass can be housed in a small PLASTIC box for hand held use Just make sure that you have enough room inside for the batteries However the compass is not restricted to tramping through the woods By adding an inexpensive adapt
111. itor C9 couples VOLUME X 41 ANTENNA c9 VOLUME LM386 v C13 C8 3 i 10 A 5 R6 K sr E 4 24V 4 7K 10 8 1 3V R4 2281 C7 10 R5 50K REGENERATION EARPHONE JACK BANDSPREAD PM R R3 SPK 100K TOP VIEW 9 A 1 BOTTOM VIEW 4 13 12 1 oe si 01 VD1 e DOT et A 5 1617 8 CATHODE ANODE FIGURE 1 Figure 1 The complete circuit ofthe RF regeneration and audio circuits Only two solid state devices are used Q1 and ICI tuning in the sguealing stations The small speaker is the audio signal to pin 3 of the audio output IC1 This out of the circuit when the earphones are in operation little amp can drive a 3 or 4 inch PM speaker with the with J1 The small all wave receiver operates from a 9 loudest signals Earphone reception is best when volt battery e 1 Figure 2 The variable or vario coupler coil L3 construction on a foam disk with rod and metal commutators L3 contains 16 turns of number 22 enamel wire 42 ELECTRONICS HANDBOOK COIL END SOLDERED TO BRASS ROD BRASS ROD 3 FOAM DISC WOOD ROD BRASS ROD HOLE IN FOAM WOOD DOWEL BRASS ROD SLEEVE FIGURE 3 Figure 3 The rotating rod is made up ofa 4 inch wood dowel brass rod and 3 inch foam disc The brass sections are cemented to the wood rod Remodeled Capacitor Aithough the variable capacitor shown in the photo is one of those antique types picked up for 2 00 atan antique radio show there are stil
112. k Drive Products As electronic enthusiasts we share a common interest we like to build things great Rube Goldberg style contraptions with whirring and clicking parts gadgets that amaze our neighbors and cause even the most tolerant spouses to grit their teeth This is our role in life and we play it with PE A A An aaa maa a i _ _ _ _ _ _ _ _a__ _ _a_ _ _ a PP gusto For inspiration we read Electronics Handbook and half a dozen other electronics maga zines which out of courtesy to our publisher shall remain nameless here These magazines provide a vital forum for the dissemination of the new ideas and techniques in the field of electronics However most projects are not strictly electronic devices they have a mechanical structure as well yet can think of no popular periodical that addresses mechanical concepts in the same way that magazines like Electronics Handbook and others treat electronic concepts As a result the mechanical part of a project is often approached with little or no theoretical insight Things are put together in a trial and error fashion from whatever mechanical parts are at hand and it is a testament to human ingenuity that many of these projects work at all As an antidote to the current deplorable state of mechanical knowledge let me recommend the Design and Application of Small Standardized Components an easy to understand gu
113. l Effect type switch thus giving a logic 0 at its associated output pin pin 3 while the others remain at logic 1 If the Compass sensor was pointed to the south the same occurrence would take place but this time the 3 Hall Effect switch would close This closure would f one could look inside the compass sensor he deliver a 0 at the pin 3 output of sensor 3 while all others would remain high 1 This scenario is just great if there were only four compass directions or headings But there are eight So what happens if the sensor s bar magnet is pointing between sensor 1 and 4 If this is the case the output pin on BOTH the 3 and 4 sensor will deliver a logic 0 For example say you were facing North West If LEDs were connected to all four output pins the North and the West LEDs would light Indicating Northwest If you were to make a 180 degree turn the compass sensor would light both the East and South LEDs indicating a heading of Southeast VOLUME X 33 sensor requires only a handful of inexpensive components But to make the compass display all eight headings rather than having a dual output we have included an integrated circuit to the final design SOUTH FIGURE 1 To show the relationship between all eight compass headings and output data take a look at table 1 This listing shows which output pin will deliver a logic 0 for each compass heading For example
114. l a few 365 PF variable capacitors around Look in the junk box old radios flea markets and at antique shows Use the RF section found in the two stage variable capacitor of the older AM tube radio Remove all but three rotor plates of the variable tuning capacitor This is not a new trick as it was done many years ago Rotate the plates completely out of the stator plates Start breaking off the back plate by bending the aluminum plate back and forth Be careful not to damage the stator or remaining rotor plates Remove the remaining piece with a pair of long nose pliers Leave only three remaining rotor plates You can check the total capacity with plates meshed together with 2 capacitor tester if handy The total capacity of the modified tuning capacitor should be between 100 and 145 PF Make sure the rotor plates do not touch the stator plates at any time Vario Coil Construction The inside dimension of the PVC coupling coil form is 3 inches inside and approximately 4 inches outside The tickler coil L3 can be mounted on a 3 diameter round ball cut into or a 3 inch polystyrene disc The disc should be at least 1 inches wide to wind L3 on the edge The disc may be cut from a1 flat piece of foam Drill a inch hole down the center of the disc to accept the tuning rod Fig 3 Make sure the Y inch wood dowel will go through the hole Now wind coil L3 with 16 turns of number 22 enameled wire Hold coil in place with tape
115. l and test a powerful 40 meg IDE hard disk drive today s most wanted computer peripheral included in your course to dramatically increase your computer s data storage capacity while giving you lightning quick data access But that s not all Professional diagnostic hardware and software makes troubleshooting fast and accurate Your NRI training now includes a remarkable diagnostic package that allows you to quickly locate and correct defects in IBM XT AT 80286 80386 and compatible computers You ll use your Ultra X QuickTech diagnostic software to test the system RAM and such peripheral adapters as parallel printer ports video adapters and floppy and hard disk drives You ll go on to use your R A C E R diagnostic card also from Ultra X to identify individual defective RAM chips locate interfacing problems and pinpoint defective support chips This ingenious diagnostic package is just one more way NRI gives you the confidence and the know how for advancement a new career or a money making business of your own DIAGNOSTIC HARDWARE AND SOFTWARE R A C E R plug in diagnostic card and QuickTech menu driven software both from Ultra X give you hands on experience with today s professional Oj 1 A H A m m ag i vs ta E No experience necessary NRI builds it in With NRI you leam at your own pace in your own home No classroom pressures no night school no need to quit your pre
116. le to plant a microphone The Russians used this method to spy on our embassy in Moscow during the early sixties They concealed a cavity resonator he isn t offering a circuit design service Write The Editor C amp E HOBBY HANDBOOKS INC PO Box 5148 North Branch N J 08876 inside the Great Seal of the United States which hung above our ambassador s desk and bom barded the resonator with a beam of microwave radiation whenever they wanted to listen in The beauty of the scheme was that the cavity resonator was a passive device and thus almost impossible to detect dont have any information on microwave eaves dropping but an article entitled Build the Laser Listener by Richard Pearson which appeared in the October 1987 issue of Radio Electronics tells all you need to know about laser eavesdropping Detecting the presence of a transmitter is accomplished by intercepting its signal Profession al spooks rely on expensive scanning receivers for this purpose but all you really need is an ultra sensitive field strength meter capable of being tuned over the frequency range of interest typically 50 to 500 MHz Information Unlimited offers plans and kits for a bug detector that should serve your needs Just as the eighties are remembered as the decade of personal computing it may well be that the nineties will be remember ed as the decade of personal espionage There are shops nowin New Y
117. lectrons The free electrons accumulated in the N material flee through the conductor Since the pumped up electron contains more energy than necessary to occupy its former position shell it can afford to be wasteful in its journey Traveling through the conductor it meets certain amounts of resistance from bumping into electrons and the like This energy is released and can be putto useful work It is Current flow Once reunited with an atom the happy couple try returning to that harmonious section the junction Some Technical Considerations What we ve Created is a wafer of silicon possessing a difference of potential voltage Theoretically the voltage is 650 millivolts in reality it doesn t exist There are a number of reasons for this shortcoming voltage shortfall Let s return to the junction group This lethargic group rests secure with all shells occupied But suppose an agitator were to disrupt their tranquility something that would stir up a ruckus and send the atoms hurrying about The arms valence electrons are now in a more excited state a higher shell level and tend to lose their grip on neighboring atoms which are also rushing about busily However the inciter doesn t arouse the electrons sufficiently to escape just enough to create mass confusion an arriving photon will be absorbed as before But instead of rushing to the N territory there s a good chance the chaos will cause it to stumble
118. lectrons and each oscillates at its respective energy level Atoms like the feeling of being complete Should any shell lack the correct number of electrons the atom is said to have a valence a desire to complete the defective shell The atoms at the junction all having the exact number of electrons vibrating in each of its shells are content to remain its within this junction region that the sun will perform its magic This stable group of electrons in the junction remains at rest unless disturbed Should an energy packet of sunlight a photon invade this clique it s quite possible that it will be absorbed by one of the atoms This boosts one of the electrons to a higher energy level or to a different more remote shell When this occurs the electrons have a tendency to wander off becoming lost These wayward electrons are attracted to their electron hungry neighbors and collect in the N material Here other free agents bustle about satisfying the atom s needs The now deficient atom is bumped from the junction and migrates toward its P type cousin This state of events creates tension between the two factions So much tension in fact that the disloged electrons will do almost anything to get back to the warmth and security of the junction But the laws of quantum like a traffic cop only allow foraone way trip But there is a back door If a conductor is connected from the N to the P materials it forms a tunnel for the e
119. ler discs and crescents have a lower output Rectangles are highly sophisticated cells destined for use in space exploration Silicon Into Photocelis _ Now that you have a fair understanding of the internal workings let s journey with a slab of Silicon observing its metamorphosis from sand to photon converter A solar cell begins life as a silicate much like common sand not yet converting its energy into electrons The silicon is refined with a purity exceeding 99 99 by being placed in a crucible and melted A small amount of boron is added Boron is an atom with five electrons in its outer shell thus making it a donor P type Substance it will Supply the free electrons A small perfectly formed crystal called a seed is touched to the molten surface The solution is held at its melting temperature of 1 420 degrees centigrade controlled to within 2 degrees The seed is rotated inducing a counter rotation in the liquid Individual atoms begin depositing on the seed aligning themselves into a perfectly structured crystal using the seed as a pattern Once the igot is finished it s clamped into a saw an abrasive cutter designed to slice the cylinder into wafers Resembling a bread slicing machine its multiple blades grind away producing all wafers simultaneously Unfortunately this is an extremely wasteful process rendering three fourths of the crystal to dust Wafers 3 inches across and 16 mils thick reveal th
120. lize and with no incident light there is no charge motion The arrival of light rays at the thin N silicon layer permits a penetration of photons to the junction region The light energy forces electrons out of the crystal structure This motion of charges produces an output current when there is a load path connected between the positive P silicon terminal and the negative N silicon terminal The current varies linearly with the amount of light striking the cell and the cross sectional area of the cell The absolute output Current is also a function of the load resistance and the conversion efficiency of the cell If a solar cell is directed toward the sun atnoonona clear day the energy striking that cell will be approximately 100 milliwatts per square centimeter This results in maximum current as demonstrated by the top response curve of Figure 2 Note that a light level of 100 milliwatts per square centimeter is referred to as 1 sun If the light level is reduced to 0 5 sun corresponding to 50 milliwatts per Square centimeter the output current is halved 100 mW cm ul a a ju O VOLTAGE Figure 2 Response of a solar cell Current is reduced in proportion to light intensity One Sun yields 100 milliwatts maximum The open circuit voltage of a silicon cell is approximately 0 57 volts This corresponds to zero output current When the load connected to the cellis of a resistive value that results in a cell voltage
121. lluminated and for the values shown is about 3 seconds The circuit is not fussy about power supply voltage PARTS LIST FOR TOUCH CONTROL C1 0 01 uF ceramic capacitor 15 VDC C2 1 0 uF electrolytic capacitor 15 VDC C3 0 1 uF ceramic capacitor 15 VDC 1C1 555 timer LED1 large LED Q1 2N4401 R1 10 000 000 ohm watt resistor R2 4 700 000 ohm watt resistor R3 R4 4 700 ohm watt resistors R5 470 ohm watt resistor VOLUME X 31 BASIC PULSE MAKER Need a basic square wave generator for all those isolate the oscillator from the effects of circuit digital projects This quad NOR gate 4001A CMOS loading Duty cycles of almost 10 to 1 can be chip which can be easily obtained stands ready todo obtained the job with great simplicity Note the two pots R1 PARTS LIST FOR BASIC PULSE MAKER and R2 These govern both frequency and duty cycle symmetry via diodes D1 and D2 C1 determinesthe C1 0 1 uF capacitor for 11 to 2500 Hz range 0 2 uF overall frequency range A C1 value of 0 1 uF capacitor for 4 to 700 Hz range produces a range of about 11 to 2500 Hz Usinga0 2 D1 D2 1N4148 diode uF value the range is about 4 to 700 Hz The 1C1 4001 A quad NOR gate remaining two gates pins 8 13 act as buffers to R t R2 500 000 ohm linear taper potentiometer R3 1000 ohm resistor 10V E IOV 4OOIA TELEPHONE VOICE The telephone voice effect is usually created by passing a voice sig
122. m put a grounded metallic shield around the noise source or receiver If Signals are being radiated or picked up by wires use shielded coaxial cable Sometimes the shield is allowed to carry current in which case it is grounded at both ends At other times we may prefer that the shield carry no current and it will be grounded at one end or the other but not both The question of whether to ground theshield at one end or two is beyond the scope of this article Since most of you will be building projects from plans rather than designing your own Circuitry the best advice here is that you use the kind of shielded cable specified by the project s designer and wire it exactly as he did To avoid the often disastrous noise problems that may arise when incompatible currents flow through a common ground impedance use a printed circuit board if one is available You can either buy a ready made board or etch your own at home provided the plans are available If for some reason you prefer to use perfboard or wire wrapping techniques to build a project do yourself a favor and copy as closely as possible the layout and wiring of the project s PCB Now it is true that there are a great many circuits that will never cause any trouble no matter how carelessly they are wired Unless you know for certain however that a project is failsafe it pays to be smart and copy the designer s original layout Then if something should go wrong with the proj
123. mp E Hobby Handbooks P O Box 5148 North Branch N J 08876 201 231 1518 Published by C amp E Hobby Handbooks Inc Edi torial and Business address P O Box 5148 North Branch N J 08876 201 231 1518 PERMIS SIONS Material in this publication may not be duplicated or reproduced in any form without permission Requests for permission should be directed to Don Gabree C amp E HOBBY HAND BOOKS INC P O Box 5148 North Branch N J 08876 201 231 1518 EDITORIAL CONTRIBUTIONS must be accom panied by return postage and will be handled with reasonable care however the publisher assumes no responsibility for the return or safety of manu scripts artwork or photographs All contributions should be addressed to PUBLISHER C amp E HOBBY HANDBOOKS P O Box 5148 North Branch N J 08876 AS a service to readers C amp E HOBBY HAND BOOKS publishes available plans and or in formation relating to products techniques of scientific and technological developments Be cause Of possible variances in the quality and condition of materials and workmanship used by readers C amp E HOBBY HANDBOOKS disclaims any responsibility for the safe and proper func tioning of reader built projects based upon or from plans and or information published by C8E HOBBY HANDBOOKS Second Class Entry applied for Copyright 1991 by C amp E HOBBY HANDBOOKS INC LHC2K Visible Simulaled 3 Color Laser KI 44 5
124. mpass be powered by high quality alkaline or lithium batteries While higher in price these premium batteries will be able to handle the current requirements of the project Eveready Kodak See Figure 1Aand the copper top Duracell to namea few will power the compass for months without a battery replacement LIGHT CURRENT FLOW 1 gt 9V BATTERY TO LOAD Goo FIGURE 2A If you re like me you have a junk box full of inexpensive 9v batteries So why not use these Sure you can But you need to put some basic electronic theory into practice Figure 2A illustrates how the current of a common battery flows through the copper interconnecting wires to its destination the load which represents how much power must be delivered by the battery for the normal operation of the circuit It is expressed as RESISTANCE in our case the LOAD is represented by the Electronic Compass By making use of the formula CURRENT I VOLTAGE E RESISTANCE R you can see that if the load resistance increases the current being consumed by the circuit decreases In contrast if the load resistance decreases the current requirements increase BATTERIES FIGURE 2B Figure 2B shows a simple series hookup containing a 9v battery and a Load If the load resistance is in the range of 5000 ohms the current being drawn will be 1 8mA or 0018 Amps I E R 1 9 5000 With a current this low a standard carbon compos
125. n is simple and cost is kept to a minimum PARTS LIST SPKR1 Any small 8 ohm speaker T1 Any small audio transformer S1 Normally open momentary on switch C1 01 mF capacitor D1 Any small signal diode K1 5 12 Volt relay B1 9 Volt battery SPKR1 ELECTRONICS HANDBOOK V10 P O Box 45148 N Branch N J 08876 U Yes Enter my subscription 4 issues ONLY 15 00 Canada 18 00 Foreign Postage add 8 00 U S Funds O Payment enclosed Payable to C amp E Hobby Handbooks PLEASE PRINT NAME ADDRESS ee GI TT LEE STATE VOLUME X 83 THE If you live in a relatively remote area that doesn t have ready sources for electronic parts you can send away to numerous supply houses who have good catalogs of electronic parts and assemblies many of them real bargains Following are several catalogs that we have recently received in the mail with brief descriptions and comments Most of these suppliers send out new catalogs every four to six months with many of the items repeated and new ones added plus some new specials usually on the first couple pages and the last few pages of each issue INFORMATION UNLIMITED The complete Catalog of Amazing and Fasci nating Devices is the name of the new catalog from Information Unlimited and after looking over the contents we think that s a pretty fair assessment The company offers a wide varie
126. nal from a high quality microphone through a bandpass amplifier a device that attenuates the frequencies on both sides of a selected frequency Bandpass amplifiers are also effective at providing mid frequency boost presence as it s called in hi fi terms The center frequency of this bandpass amplifier is determined by the values of C1 C2 C3 R2 R3 and R4 The exact frequency can be determined from the formula shown To start assign a value of 100 000 ohms to R2 and R3 use watt resistors To avoid hum pickup the unit should be assembled in a metal Cabinet Potentiometer R1 serves as the Q control it determines the degree of boost at the center frequency RS connects to the non inverting input of the IC R1 between ground and the inverting input No pin connections are given because the IC is available in many different configurations Of course you could find a carbon microphone button and matching transformer to create the effect naturally but that s not how it s done in the big city bub CIN FARADS IN Hz PARTS LIST FOR TELEPHONE VOICE RIN OHMS C1 C2 C3 C1 equals C2 equals C3 see formula IC1 Type 741 opamp R1 10 000 ohm pot R2 R3 R2 equals R3 see text R4 R4 R2 12 R5 10 000 ohm watt resistor 32 ELECTRONICS HANDBOOK BUILD AN z A m y n i ee 5 _ aie 3 a M aa nan 2 i pet oe D ae eo pean te aes a sche ES s teat ar on an li m Y ps O o
127. nd magnification The contempo rary floating arm lets you position the light source with the touch of a finger and keeps it in place so your hands remain free to perform other tasks The 5 inch crown optical glass lenses are available in 3 diopter 75 magnification and 5 diopter 125 Another option is an 11 diopter 275 lens system with a 3 inch viewing area For precise inspection a 4 power 16 diopter lens system is offered which meets government standard MIL STD 2000 For more details contact HMC 33 Springdale Avenue Canton MA 02021 Phone 617 821 1870 FAX 617 821 4133 VOLUME X 11 NEW CAMCORDER MAINTENANCE AND REPAIR By Holmer L Davidson To most people video equip ment seems delicate and complex Thus whenever a camcorder or VCR fails to operate their first thought is not How can repair this but Where can I find a repair man That s the way felt too until read the new book by Holmer Davidson and learned that a wide variety of common ills can be cured at home using nothing more than a voltmeter a screw driver and some common sense The author begins by intro ducing us to the various video formats such as VHS VHS C 8mm Beta and a handful of derivatives We learn the mecha nical and electronic principles on which these machines operate Lots of good diagrams make the discussion easy to follow Once we understand how these devices work the author discus
128. ng silicon layer exhibits a grain structure which is larger than the thickness of the layer But unlike the pyramids of the crystal it appears that whiskers are growing on the Surface when viewed under a microscope These whiskers add to the surface area available to light The ceramic backing is laced with slots permitting access to the reverse side of the semiconductor The semiconductor is now processed in the usual manner previously described An advantage of this process is its ability to be manufactured in long strips The strip is passed over molten silicon a procedure similar to flow soldering This greatly reduces the silicon loss cutting costs The process is also easily adapted to automated assembly and manufacture There are numerous approaches using a variety of materials including plastics and removable back ing The silicon doping impurities also vary widely with application Here s an interesting approach Two strands of silicon are touched to the surface of molten silicon Capillary action sucks up the liquid filling the gap which can be as wide as 40 mm This does away with the need for support backing since it s rigid enough Still others are trying the thin film approach Here we have low cost and low efficiency 5 hopefully these drawbacks will be offset by improved cost effectiveness The candidate here is cadmium sulfide coupled with copper sulfide on thin film P doped copper sulfide is applied
129. niques and the latest in electronics know how Dozens of practical money saving projects With detailed assembly instruc tions schematics circuit layouts and parts lists you ll build projects in areas ranging from telecommu Build your own Surge Protector gar Function Generator Amplifier gt Convenient easy to access information in one comprehensive source You wont need to search for books magazines and manu facturer s brochures The sturdy three ring binder with index tabs organizes the material so that you ll find what you need quickly Free circuit layouts on acetate save time and improve results The hardest part of many elec tronics jobs is in ihe planning because drawing your own circuit layouts can be time con A aaa La cal reererce nications stereos and computers Electronics ap es SUMING and inaccurate The test and repair tools to radio and mante nology td Modern Electronics Manual pro TV And you wont spend valuable time searching for parts because our Sources of Electronic Compo nents and Supplies provides you with an updated list of local and mail order suppliers Do it yourself repair techniques Professional hints tips and short calm Tact tte seme Manual vides clear acetate circuit layouts for every project Just place the layout over a photosensitive cop per circuit board expose it to light and etch your own printed circuit Then
130. nolic laminates XXXP are much less abrasive than glass epoxy by the way Fast Beat Slow Feet need any information you can provide on a 12 VDC motor speed control ihat could be applied to a tape cassette player am trying to help a group of young people in a clogging club Clog dance music is usually fast and we wish to control the tempo of new tunes while learning them or while teaching new members Can you help am thinking in terms of a chopper style control R T McMillan Huntington WV A friend of mine a retired professor of electrical engineering describes clog dancing as one of the few forms of exercise that you don t have to be a masochist to enjoy Clog dancing which has its origins in the Appalachian region of the United States takes ts name from the distinctive wooden soled clogs that the dancers wear on their feet When the dancers kick up their heels the clogs make a pleasant clattering rhythm as they hit the floor Getting back to the question at hand R T think that the use of a chopper style speed control would in this instance be overly ambitious and expensive All you need to do is insert a 50 or 100 ohm potentiometer in series with the hot power lead running to the motor that turns the capstan and take up reel in your cassette recorder Increase the resistance by rotating the shaft of the pot until the speed has decreased to an acceptable level Needless to say you
131. nter IC2 741 op amp A SWITCH WITH A Here is a switch with unlimited uses When momentary contact switch S1 is pressed the relay will be energized Press S1 again and the relay will be de energized In other words this circuit remembers what state it was in even after S1 is released This type of Circuit can be very handy around the house All unused pins should be grounded 74 ELECTRONICS HANDBOOK J1 J2 phono jack R1 through R10 2 megohm linear taper potentiometer R11 through R20 68K ohm 2 watt resistor 10 R21 R22 15K ohm watt resistor 10 PARTS LIST FOR SWITCH WITH A MEMORY C1 0 1 uF ceramic disc capacitor 15 VDC C2 1 uF electrolytic capacitor 15 VDC 1C1 4069 hex inverter K1 Relay 6 9 VDC 500 ohm coil Radio Shack 275 005 A1 2N4401 R1 R3 10 000 ohm watt resistor R2 91 000 ohm 14 watt resistor S1 SPST momentary contact pushbutton switch li t te CODE PRACTICE OSCILLATOR If you are an Amateur Radio Operator or just want to learn Morse Code a code practice oscillator can be an invaluable tool The code Practice Oscillator is simple to build requires only a few parts and operates over a wide voltage range Two of the gates of the 4011 Quad NAND Gate are used to make a simple oscillator whose frequency Can be changed by adjusting R2 R4 is used to control the volume of the oscillator and Q1 drives speaker SP1 9 12 VOLTS SV RELAY
132. nufacturers are striving for 30 conversion a figure they say is already within reach Let s examine a gallium arsenide solar generator Again we have two semiconductor materials a substrate of N doped GaAs the chemical shorthand for gallium arsenide and P type GaAs with the junction sandwiched between An overcoat of aluminum gallium arsenide A1GaAs about 10 microns thick is vacuum 70 ELECTRONICS HANDBOOK deposited over the P type semiconductor forming one electrical contact Photons pass through the A1GaAs and strike the junction region disloging electrons The free electrons collect in the N type material where they are removed and allowed to flow An approach to increasing the efficiency of A1GaAs is to stack them with silicon cells An AlGaAs cell is placed on top of a silicon unit The entering sunlight strikes the GaAs junction which promptly absorbs the high frequency photons the low energy wavelengths pass through and are absorbed by the silicon wafer The overall performance 11 silicon and 17 GaAs approaches the 30 mark Not a bad gain in efficiency Another way to enhance cell output is multiplying the available light this is usually accomplished by focusing the sun s radiation with parabolic reflectors A concentration of 20 suns isn t uncommon with technology sending that figure soaring up to 1000 The cells are specially manufactured to be mounted onto a heatsink The grid lines are thinner and mo
133. o an exponent of ten and the last band is the tolerance If there is no fourth band the tolerance is assumed to be 20 Sometimes there are five bands on resistors These are usually precision resistors and the extra band the third one is an extra digit to more precisely indicate the value of the resistor For those of you who want to practice determining values from the color code Figure 4 gives several examples with their resistances To practice just cover the right hand column while you figure out the answers and then check to see how you did ONWARD AND UPWARD Let s get on with the good stuff One of the last things we did in Part was set up a simple circuit with a battery wire and a lamp We keep it to a minimum What we really need the calculated how much current was flowing whether it COLOR CODE RED RED ORANGE GOLD GREEN BLUE GOLD GOLD GREY RED RED SILVER BROWN BLACK BROWN ORANGE ORANGE BLUE GOLD YELLOW VIOLET YELLOW SILVER EQUIVALENT RESISTANCE 22 KOHM 5 5 6 OHMS 5 8 2 KOHM 10 100 OHMS 20 33 MEGOHMS 5 470 KOHMS 10 Figure 4 Examples of the color code VOLUME X 61 was within the specs of the lamp and how much power was being dissipated That circuit was called a series circuit because everything was connected end to end All the current in the circuit flowed through all the components Note that whenever we talk about current we Say that it flows through
134. occurs between source V and the grounded shield via Ci The field within the shield is zero since the shield is at ground potential As a result no noise is picked up by the receiver Figure 2A 2 SHIELO Figure 2 A grounded shield is very effective against capacitive coupling The shield may be applied either around the noise source A or around the circuitry where noise is being picked up B Aluminun is a good shield metal as are copper and steel Any metallic sheet makes a good electric shield Aluminum a common cabinet material is excellent at all frequencies A shield may be placed between N l vi yay Ce Figure 3 If there is no common ground connection between the noise source and the i two stages of a single piece of equipment On the other hand a grounded metallic cabinet constitutes a shield between a particular piece of equipment and all noise sources in the outside world The only precaution necessary when shielding is that the shield must be in electrical contact with the circuit s ground Note that this does not necessarily mean an earth ground such as a pipe in the soil Connection to circuit common is all that is ever required At this point you are probably wondering what happens if the source and receiver circuits do not share a common ground connection We can treat this coupling by means of two Stray capacitances as shown in Figure 3 You should be able to see for yourself that the
135. oise reduction are suggested First separate the two loops in particular keep high current stages away from low level stages Second minimize receiver loop area This applies especially to the wiring associated with a receiver stage All wires to ajack a Switch or a potentiometer should be twisted together thus minimizing pick up loop area Third try to minimize the source loop s magnetic field This is most conveniently done by using twisted wires again To see why this is effective imagine taking the source loop stretching it then twisting the wires together The currents in the twisted pair flow in opposite directions and because twisting keeps the two wires in close proximity the magnetic field of one wire cancels that of the other Even better than a twisted pair especially at high frequencies is coaxial cable for most hobbyist requirements however a twisted pair is sufficient to reduce magnetic radiation Finally changing the orientation of the source with respect to the receiver often helps Consider for example the magnetic radiation from a power transformer You may carefully twist the leads but you cannot do anything about the magnetic flux from the transformer coils Usually however some mounting orientation of the transformer will result in minimized pickup in your noise sensitive stage Comparing magnetic coupling with electric coupling one thing you may have noticed is that the impedance of the receiver has
136. old a peak value making it much easier to read This is especially good for those who do tape recording or want to determine the power of their stereo Finally the COMPARATOR will act like a digital circuit changing its output voltage from full negative to full positive when the varying input voltage goes higher than the reference input voltage As a threshold detector it can sense when a certain level of darkness is reached when detected by a photocell or compare two voltages and operate an alarm when something has changed store time R3 Cl i R2 GAIN 1 all resistors are 1k onm minimum D1 D2 any small silicon diodes TO START try for 1 sec hold time R3 100k ohm CI 10 uf R1 10k ohm R2 100k ohm USING THE CIRCUITS As it has already been suggested there are many ways to use these circuit function blocks especially in combinations The possibilities are almost endless Don t be afraid to experiment a circuit failure due to an incorrectly installed part or incorrect wiring should be easily corrected most won t do any harm to the IC which in any case is easily replaced if a failure occurs Good luck a VOLUME X 23 If You re Serious About a Future in Electronics Ensure that sg STUDY COURSE CATALOG AND RECEIVE A FREE 24 PAGE CIE ELECTRONICS SYMBOL HANDBOOK re with the Best Educational Training Available Includes hundreds of the most frequently 4 use
137. om hi ui A jiis AE TMa a a HAM TIME Just when you think that you have seen it all you find that you haven t scratched the surface From ECode Systems Inc we find that they have introduced a digital clock simulator designed primarily but apparently not exclusively for the Ham radio operator that will make life easier around the Radio Shack and appropriately called Ham Time lf you are not into Ham radio you might adapt it to numerous other practical functions in your daily routine such as your photographic darkroom lts versatility will challenge your imagination For the Ham radio operator however the Ham Time is designed for both Desktop and Laptop computers it will let you give function to your idle MS DOS computer In the Radio Shack Ham Time provides the perfect way to check local and GMT quickly The built in time zone displays allow you to quickly determine the time anywhere in the U S A and Canada or for that matter anywhere in the world with a user programmable screen Specifically the Ham Time performs the following functions e Local GMT dual display e Snooze Alarm e U S time zone display e Audible time indicator e Sports Laboratory dual timer e Fully functional alarm clock e Event count down timer e 12 hour or 24 hour modes e Cities of the world time zone display e User programmable time zone display 8 ELECTRONICS HANDBOOK PRODUCTS PARADE hada Duich t
138. on notes at no charge SEMICONDUCTOR DATABASE Each year semiconductor manufacturers intro duce thousands of new devices so many in fact that it s next to impossible for the average person to keep abreast of things To give users a fighting chance Motorola now offers a new version of its Data Disk called the Motorola Electronic Selection Guide This floppy resident database allows designers to rapidly search Motorola s entire line of semicon ductors and select the best device for their application The Motorola Data Disk provides information on over 13 000 Motorola Cs and components in 124 product categories and also cross references 25 000 competitive devices The Data Disk provides a fast easy alternative to the printed selection guide All searchers are performed in under one second and no user marual is required To receive your free disk write Motorola Data Disk Literature Distribution Center POB 20924 Phoenix AZ 85063 Specify IBM format DK101 D or Macintosh format DK201 D 80 ELECTRONICS HANDBOOK TWO AND FOUR MEGABIT STATIC RAMS They say you can never be too thin or too rich to that dubious wisdom we d like to add that you can never have too much memory in your Computer system because no matter how much you ve got you ll soon fill it up Those of you who use computers know what we mean Here s good news for all the memory hungry system designers and computer users out there Cypress Semic
139. onductor now offers a 45 ns 512Kx8 CMOS static RAM SRAM in a 32 pin DIP package that is twice as fast as competitive versions of this device Cypress also offers a 25 ns 256Kx8 CMOS SRAM module in a 60 pin vertical ZIP package Both the CYM1464 512Kx8 and CYM1441 256Kx8 SRAM modules are targeted at high performance high density applications such as high end PCs workstations cache memories digital signal processors and simulators Contact Cypress Semiconductor 3901 N First St San Jose CA 95134 ws m 1111 LOW POWER DUAL OP AMP From Burr Brown comes news of a new dual precision op amp the OPA1013 suitable for appli cations demanding low power and or single supply operation It is intended for portable and battery operated applications in medical and scientific instrumentation test and measurement equipment and industrial control The OPA1013 is fully specified for operation at both 5V and 15V When the device is Operated from a single supply the input common mode range includes ground and the output can swing to within 15 mV of ground Quiescent currentis a low 0 5 mA maximum per amp The OPA1013 is unity gain stable and requires no additional circuitry for overload protection Independent biasing networks ensure freedom from interaction between the two op amps even when the inputs are overdriven in comparator applications Contact Burr Brown Corp P O Box 11400 Tucson AZ 85734 Or use their
140. ool Fits Radio Shack or Ungar soldering irons 39 95 soldering iron not included 39 95 Complete set of 8 desoldering bits Remove 6 thru 40 pin IC s e 39 95 Complete set of 10 desoldering bits Remove 6 thru 64 pin IC s 89 95 114 95 magnetic clutches relays of ali types otherdevices 58 min 39 95 i All about diodes and their failure modes Includes rectifiers How to troubieshoot digital integrated circuits includes micro SCR s Zeners triacs LED S 55 MIN merece pre gt 85 stud 1 39 95 processors what goes wrong and how to find it how to use the All about transistor failure modes 56 min 39 95 best literature on IC s and where to get it 1 hr 45 min 39 95 How to solder like a pro with lots of time saving circuit board Job opportunities and money making opportunities repair techniques including some of the fastest ways to in electronics 45 min POLIS WS SSE EEEE TEE 39 95 change IC s you ever saw 1 hr 30 min 39 95 Troubleshooting and locating component failures 1 hr 10 min 39 95 All about electrical contacts connectors connections and their Power Supplies Linear and Switching 42 min 39 95 failure modes common and uncommon problems symptoms A II E Pie el ne a noo a a eer 39 95 V How to use the oscilloscope to track down digital failures 39 95 Re S E LECTR O N IC S How to read
141. ork and other large cities where spy gadgets of all kinds are openly sold and it s not just the weirdos and PI s who are buying them People from all walks of life apparently feel the need to spy on those around them In most cases when we speak out against the invasion of privacy it s Big Brother who is the villain but I m beginning to feel that Pogo came closer to the truth when he Said We have met the enemy and he is at us Eico 460 Dead at 30 Just by chance picked up your magazine at a drug store last year have since ordered five back issues and have enjoyed them all My reason for writing at this time is to ask for your help have an oscilloscope an Eico 460 which ordered from Allied back in 1960 as a kit lt gave me good service for a long time but now it needs some TLC I d like to know where can get service data for this instrument M M Campbell Woodstock GA At one time Eico was Heath s major competitor but unfortuna tely the company went out of business years ago imagine that any of the major service organiza tions that specialize in test instrument repair could fix your scope but the cost might be prohibitive You might try Tucker Electronics 1717 Reserve St Garland TX 75042 and see how much they charge Perhaps they would sell you a photocopy of the Eico service data If any of our readers have service data for the Eico 460 and are willing to help M M ou
142. other good reason to use a socket whenever possible Qui Don Gabree Publisher WANTED PROJECTS How would you like to find your own home brew projectina future issue of the ELECTRONICS HANDBOOK It could happen It s up to youl Build your project for yourself It should have a real purpose Then if you think that it is good enough to appear in the ELECTRONICS HANDBOOK let us know about it Write us a brief letter describing your project Tell us what the project does Provide us with a legible schematic diagram and a few black and white photographs of the project photos with good contrast are Important After we have read your letter describing your project we ll let you know One way or the other whether we would like to purchase your article describing the project If you would like some Editorial Guidelines send us a S A S E with your request All correspondence should be addressed to C amp E HOBBY HANDBOOKS P O BOX 5148 NORTH BRANCH N J 08876 4 ELECTRONICS HANDBOOK ELECTRONICS HANDBOOK EDITORIAL DIRECTOR Don Gabree SECRETARY TREASURER L M Gabree ASSOCIATE EDITOR Holly Love CONTRIBUTING AUTHORS Homer Davidson Walter Slkonowlz Tony Lee Steve Sokolowski Hugh Gordon William R Gross William R Hoffman Ralph Hubscher Ron C Johnson Joe O Connell Jeff Orthober Glenn Rawlings ISSN 0897 7631 ADVERTISING SALES C a
143. p amp instrumentation am plifier It is a differential amplifier that can amplify DC signals in the microvolt range and is accurate to plus or minus 1 microvolt It has a gain of 1000 and the potentiometer R1 can be used to zero the amplifier Decoupling capacitors must be used with this circuit to ensure stable Operation This amplifier has been used to amplify various transducer voltages such as thermocouples and strain gages 5 VOLTS IC1 LTC1052CN8 INPUT O 7 3 6 3 2 4 c 1M R1 C2 1K 22uF c4 luF PARTS LIST FOR INSTRUMENTATION AMPLIFIER Semiconductors IC1 LTC1052CN8 Linear Technology Chopper Stabilized Amplifier Resistors R1 1 Kilohm Y watt 1 R2 1 Megohm watt 1 R3 10 Megohms watt 5 R4 50 Kilohms 15 turn Pot Capacitors C1 C2 22uF 16WVDC Tantalum C3 C4 1uF Ceramic C5 C6 C7 1uF Metal Film Radio Shack 272 1053 22uF C OUTPUT C7 luF 5 VOLTS R3 10M R4 50K OFFSET ADJUSTMENT POTENTIOMETER SVOLTS Laser Printer I can t believe how easy it is to build my own electronic devices This book shows me how to do it step by step The Modern Electronics Manual Newly revised and enlarged now with more than 550 pages shows you how to successfully build and repair electronic appliances and equipment Useful projects easy to follow repair instructions detailed instructions for correctly using test equipment up to date tech
144. p burglars away With Q1 lights for example this Circuit will sense that the sitting at the window it will turn on house lights when lights are off and will activate the relay coil Use it to the sun goes down R1 and C1 keep the relay in turn off the TV hi fi or another light in another room operation for a minimum of one half second to avoid bouncing of the relay contacts SV R2 a 45 le NC 1 E j i Bi R3 CTI CONTACTS TO TV SET LIGHTS ETC PARTS LIST FOR AUTOMATIC TURN OFF Ci C2 01uF ceramic disc capacitor R1 4 700 000 ohm watt resistor D1 1N914 or 1N4148 R2 R3 1 000 000 ohm watt resistor 1C1 555 timer Relay 6 9 VDC coil with switch contacts rated at Q1 NPN phototransistor FP T 100 or Equivalent 120 VAC 2 amp 76 ELECTRONICS HANDBOOK E 3T Bili integrated circuits and or solid state devices before sensitive so proceed with caution This circuit requires a little more than average skill attempting construction of this circuit A breadboard in construction Therefore it is advisable that the is recommended for the final construction as a experimenter or hobbyist have some experience with permanent device for home use IC s are extremely VCC O 10 11 12 MASTER LISTEN T I mea fl oos PARTS LIST FOR THE HOME INTERCOM SYSTEM IC1 388 1 5W Audio Power Amp C2 Any available capacitor tae
145. pair can only be purchased from a tool specialist for example Time Motion Tools which puts out a full color catalog featuring hundreds of time saving tools for the engineer technician and hobbyist They have hand tools like screwdrivers nut drivers crimpers pliers and wrenches And they ve got power tools like drills heat guns and wire wrap guns To get your catalog write to Time Motion Tools 410 S Douglas St El Segundo CA 90245 SPECIALIZED e 421008 MICRO MARK Although the Micro Mark name is apparently well known among model builders we never heard of the company until a sharp eyed helpful reader brought it to our attention Micro Mark proclaims itself the small tool specialist and the company s catalog makes good on that claim What an extraordinary assortment of small hand and power tools Ever hear of a polypus Probably not unless you happen to be an ear surgeon The polypus looks like a bent pair of scissors about 5 inches long with minuscule crocodile jaws at the end of a slender metal stalk it s obviously intended for surgical manipulation within the ear canal but it strikes us as a useful device for handling small electronic components too Micro Mark also carries small power drills push drills and table saws which should be ideal for PCB work A free copy of this fine catalog is available from Micro Mark 340 Snyder Ave Berkeley Heights NJ 07922 Af z F SPECIALIZED P
146. ppen A ratio of voltages would be dropped across them which would be proportional to the values of the resistors And the total of the two voltage drops would always equal the source voltage SPLITTING THE CURRENT Before we wrap up Part II of this series we have to take a look at parallel circuits Just as the name implies the resistors in a parallel circuit are arranged in a parallel configuration See Figure 7 Although you may not always see them drawn this way if they are in parallel they can be redrawn so that they are parallel to each other because they will be connected together at both ends SWITCH 1 30mA 15mA 1 5V p CELL Figure 7 A Parallel circuit In the circuit in Figure 7 we can see that current will be sourced from the battery and will flow through R which originally was the resistance of our lamp filament Because R is connected directly across the battery which is still 1 5 volts and R is still 100 ohms there should be t V R 1 5v 100 ohms 15mAmps Okay hear all those but s You re saying Why doesn t the current split and some of it flow through E Me oe AS atv 1 Se the other resistance Well you are right The current does split but since R2 is connected directly across R and therefore the same 1 5 volts is also across Ra there will also be 15 mAmps flowing through R2 I fthat is the case then the battery must be sourcing both of those curr
147. previously discussed shielding methods still apply A shield around either circuit connected to that circuit s ground potential is all that is required Before leaving the electric field case let s note that wires may also need shielding ifthey connectto possible receivers or sources When wires exit a particular piece of equipment they may be protected by shielded cable Likewise shielded cable may be used within a single piece of equipment when interstage noise coupling is a problem Often however you can obtain the benefits of a partial shield by simply routing wires closetothe grounded chassis The electric field near the chassis shield is minimal so any pickup by wires is likely to be small As a final precaution keep wiring to low level circuitry separated from high level wiring inductance Now let s turn to the magnetic field and Figure 4 The most important aspect of this is that there are two current loops a source loop and a receiver loop In the source loop generator V drives a current h through load Ri The current flow is in turn responsible for a magnetic field that exists in the vicinity of the source loop The receiver loop consists of generator V2 driving a stage with input impedance Rin Note that no internal resistances are indicated for the voltage generators since such impedances have a negligible receiver electric field coupling may be represented by two stray capacitances Cl and C2
148. rammed by flipping both DO and D3 to logic 0 SW5 should be in position B3 Again press SW6 to program SOUTH EAST is programmed by setting D1 and D2 to logic 0 SW5 should be set to its B6 position Press SW6 to program Final SOUTH WEST can be programmed by applying a logic O level to both D1 and D3 SW5 is placed in its B1 position Press SW6 to program This completes the programming of the 74188 But there is an easier way to get the same results How Consider purchasing a pre programmed PROM from Suncoast Technologies Spring Hill Florida Why not let them do the work why should COMPONENT SIDE FIGURE 7 VOLUME X 37 A AA NS Construction The wiring of the Electronic Compass is relatively simple But the compass does require the use of many polarity sensitive components Such as the LEDs ICs and most of all the compass sensor itself To help minimize the burnout of the fragile Components Figure 6 shows the 1 1 artwork for the circuit board while Figure 7 illustrates the component layout If you follow the layout diagram you should have no problem in the construction of the circuit Just remember to double check all component orientation before soldering All orientation is shown on Figure6 Care must be taken when installing the LEDs in their appropriate holes All LEDs have their cathode leg connected to ground Note that the placement of the LED indicating North is in reverse to all others See Figure 8 Al
149. rback irg and dick ADO EQUIPMENT 3329 29 95 Counis as 2 ENCYCLOPEDIA OF ELECTRONIC CIRCUITS ar 1 ear O ora Fa d ami Y gar pe ae fe JU p hi pm pao pe pm qua ag erm s ng ccm aw aw me por A 1938 60 00 Counts as 3 ew to Test 2925P 9 95 EPA ALAN ELECTRONIC CONVERS ONS mbols and ormulas 3 27 29 95 2865P 14 95 Counts as 2 Troubleshooting amp Repairing a VCRS 2 SECOND EDITION Gordor McComb PPP b gt DP 3777 32 95 Counts as 2 A gt s a MM ca se ELECTRON B VOLT PROJECTE E f IO T Oe La A Frec nag q ELECTRONIC DROITS 24 95 Counts as 2 1367P 3275 22 95 Suli State ELECTRONICS THEORY v h Y vperiivittida How to Read Electronic Cireult pa e ml ns i 2 2925 2880P 14 95 25 95 BLD AR OWN TEST EQUIPMENT 16 i The TAB gt Service Manual for VAT on i CCTV and MAY gt x S 3343 29 95 3475 427 95 Counts as 2 Counts as 2 1991 ELECTRONICS BOOK CLUB Blue Ridge Summit PA 17294 0816 GETTING STARTED WITH ELECTRONIC PROJECTS Once you ve decided to put together the parts that make up a circuit there are several things that you should do before starting actual work The first isto understand exactly how the circuit works what each part doesinthe circuit Don t just putit together hoping it will work You can be sure you have put it toget
150. re numerous since they have to handle more electrons It s sort of like adding freeways to eliminate traffic congestion Gallium arsenide cells are specially suited for concentrator setups They ll operate at 200 degrees centigrade with no heatsink and little loss of efficiency An equivalent silicon unit drops appre ciably above 50 degrees centigrade By water cooling the A1GaAs cell and concentrating the light to 1000 suns a single cell 1 3 inch in diameter is capable of producing 10 watts of power Of course this system must be able to track the sun as it journeys across the heavens but considering the gains it s well worth it Tracking capability in any solar collector will increase its performance by 40 i ll TE t ie a a E pe pa ie E fr yi E n T al fi Ti L E k ni F e Solar power can eliminate the need for constant battery recharging in remote installations such as this railroad signal A trickle charge can be maintained thereby allowing the signal to function with minimum attention Bargain Cells Some researchers are taking the opposite road reducing manufacturing cost and settling for less efficiency The cost of growing and Cutting crystal igots is astronomical in comparison to subsequent steps since over half is lost to dust Let s look at one manufacturer s solution First a ceramic substrate is coated with carbon This enables the molten silicon to adhere The Substrate is dipped and the resulti
151. resistance which we abbreviate as Rez Rin Basically what we have here is a voltage divider Rai C and Re2 Rin across Vi The noise voltage caused by V will be increased by the folowing factors 1 an increase in the magnitude of V1 2 an increase in the frequency of V since C s impedance drops at higher frequencies 3 a decrease in source to receiver distance because this increases C and 4 an increase in the equivalent parallel resistance Re2 Rin Voltage and Frequency It is apparent that high voltage high frequency Circuits are the most trouble some noise sources as far as the electric field is concerned Digital logic is one of the most common examples of this type of circuitry Signal swings are large between five and fifteen volts usually Furthermore even though the repetition rate of the pulses or Square waves involved 48 ELECTRONICS HANDBOOK may be low these signals still have a high harmonic content For example pulses with a 5 nano second rise time have significant harmonic energy right up to 30 MHz even if the repetition rate is much less than that At the receiving end the most noise susceptible circuits will have high impedances and operate at low levels that is with small V2 This latter factor low levels is very often accompanied by high gain Common examples of such noise sensitive circuits are high gain FET preamps low level analog comparators and op amps with large feedba
152. rself selecting them over more complex oscillators 1OQKHz 100KHzZ 10KHz 10Hz 5 VOLTS 16 nl 11 10f 9 4017 14 2 3 4 St 6 7 8 NEON 5 VOLTS Mer 1ahian2h1 10 918 PRETT 5 VOLTS TEER 5 VOLTS TOE 5 VOLTS kailio 918 7419390 TEETE 5 VOLTS FIGURE E The author has used circuit A a CMOS Schmitt trigger to calibrate equipment as a clock in a frequency counter and even as a source of clock pulses for a digital clock By using a 7490 decade counter or a 4017 counter divider you can divide the output frequency to obtain highly accurate frequen cies below the oscillator frequency Schematics of two professional quality frequency generators are shown in Figure E and F FREQUENCY GENERATOR KHI 100Hz 5 VOLTS 16 J 11416 9 th 121111 104 9 4017 4017 11 2 31 4 5 6 7 8 1 2 3 4 si 6 7 8 so 1HZ LO 5 VOLTS 16 1 127 11 10 9 4017 11 2 3 4j 5 6 7 8 FIGURE F A a VOLUME X 27 0 01pF 0 01 nF 2k 1 10MHz CRYSTAL 0 068yF FIGURE 25pF C 20MHz 100k TUNING VOLTAGE 2200F T My 1405 0 10Y 20 0000MH2 20 0070MHz 1000 FIGURE H VOLTAGE CONTROLLED CRYSTAL OSCILLATOR VCXO 10 25MHz AT CUT FIGURE K CRYSTAL STABILIZED RELAXATION OSCILLATOR For those of you who like working with transistor circuits G and H should be of interest Circuit H is an e
153. s The junction is formed at the same time It s within these seven angstroms the elite society will set up housekeeping the remaining wafer thickness is largely for physical support An angstrom is equal to 10 4 microns A micron is one millionth of a meter Two discs are placed back to back during the procedure This avoids forming a junction on both sides of one cell Our silicon slab is now a bona fide photovoltaic cell All that s necessary is to remove the free electrons and put them to work The front surface the one Sporting the junction is printed with a network of thin lines all interconnecting with one another Here the manufacturer must make a compromise The grid can be silk screened a simple process Producing thick heavy lines or extremely thin lines can be made by vacuum deposing metal through a mask Obviously the wider grid lines block photons from reaching the junction while the thinner vacuum VOLUME X_ 69 formed lines require a larger equipment investment and higher manufacturing cost to produce This is a tough decision because the grid lines must be of sufficient quantity giving the electrons a short path to travel or else they get chummy and combine with an atom This means the more numerous the lines the more photons that are blocked The exception is space destined cells Here efficiency is paramount and cost secondary There s another variation in aerospace solar cells wafer thickness
154. s ats pet ge F og Esae AN y m aJe ft ta ae L En e a 4 era FE A o A a a l J j a al E a COMPASS By Steve Sokolowski Throughout the centuries man has been fascinated by magnetic fields When discovered some thousand or so years ago that the earth was encapsulated by this same phenomenon scientists of that day unearthed a startling fact By having a small piece of magnetized steel suspended in the air by twine the needle always pointed to the north The uncovering of such a strange occurrence eventually led to the highly accurate navigational equipment used today Not until four years ago the ancient compass was catapulted into twenty first century technology By combining the miniaturization of mechanical as well as integrated circuitry techniques not available until recently the Dinsmore Instrument Company of Flint MI was able to perfect the electronic compass With this article we will introduce you to the Dinsmore Digital Compass And hopefully spark some interest in the development of some other high tech compass projects of your own The Compass Sensor would see something similar to the illustration in Figure 1 Here a small magnet is allowed to pivot freely around for Hall Effect switches When pointed north the miniature magnet turns slowly to align itself in parallel with the earth s magnetic field or field of flux When aligned the attraction supplied by the bar magnet closes the 1 Hal
155. s examples We learn the painstaking process by which an idea is transformed into a working prototype Once a prototype has been built and tested the inventor must decide how his device is to be marketed The first alternative is to seli the invention to a company and collect royalties For someone with no business experience this will probably be the best choice But how do you find a Suitable company Not through one of those classified ads that say Inventions Wanted Most of these people make their money on the gullibility of the inventor not on the merits of his invention As Dr Knapp says run like hell as soon as anyone asks you for a fee to promote your invention You ll find the best sales leads for your invention in the business section of most public libraries and the book explains how to make use of this information The author also discusses how to negotiate with a company thats interested in your invention To protect yourself don t show them the prototype until after the contract is signed Too many inventors have been cheated out of their just rewards by unscrupulous wheeler dealers The alternative to selling your invention to a company is to form your own company and manufac ture the invention yourself For most inventors without business experience this could be the road to ruin but for those who prefer to do it this way the author furnishes complete information on formu lating a business plan
156. s the load demands from the battery Of course in practice system losses and other variables require that the solar panel and battery Capabilities be greater than the actual load demand The blocking diode is an important part of the charging system In darkness and low illumination the battery voltage could exceed the solar panel voltage Without the diode in the circuit the battery would then discharge into the solar source Under the condition of high battery voltage and low charge voltage the diode is reverse biased Consequently the anode becomes more negative than the cathode and the discharge path into the panel from the battery is opened BLOCKING DIODE SOLAR PANEL BATTERY Figure 6 Blocking diode prevents the battery from discharging into the solar panel when light is absent or at a very low level The solar panel must supply the total power required by the load This it must do when sunlight is available The battery function is to smooth out the power delivered to the load as the sunlight varies and to supply power when the light level is low An additional factor that must be known is the number of peak sun hours per day for a mounting site This information is available from appropriate charts and tables Peak sun hours in the southwest for example would be greater than along the east coast Consequently the ampere nour Capability would require more solar panels at a mounting site in the east as Compar
157. schematics and use them for troubleshooting Part I A Covers monitors how to find monitor problems with wiring P O BOX 813 EH diagrams gives symptoms where to look covers both raster SELMER TENNESSEE 38379 scan and X Y monitors 56 min 00 39 95 cor Te 80 Tune Computer is a project which is not only easy to build but also fun to use Its uses are many and are limited only by the imagination of the builder This is an excellent beginner s project because of its simplicity A masked microprocessor special Integrated Circuit or IC does all the work Any of the 80 songs can be selected by the telephone style keypad A push of the Play button makes the selection The Stop button resets the microprocessor The selected tune will start each time the Play button is pushed as long as power is on andno Reset or Stop occurs Complete plans to build the 80 Tune Computer 2 95 Ul Custom Microprocessor 9 00 PCB Printed Circuit Board 4 95 Add 2 00 for postage amp handling For each combination of the above items send check or money order U S funds to C amp E Hobby Handbooks Inc P O Box 5148 North Branch N J 08876 16 ELECTRONICS HANDBOOK APU TELEPHONE 601 287 1594 99 TUNE COMPUTER BONG LIST 0 AMERICA 1 ANCHOAS AWEIGH 2 BATTLE HYMN REPUBLIC 3 CAISSONS GO ROLLING 4 CALL TO COLORS E CAVALRY CHAAGE 6 DIXIE T HAIL BRITTANIA Y YANKEE DOODL
158. selects the range with the greatest accuracy and resolution The function and measurement range are even shown on the LCD display Touching the RANGE button on Models 3220 and 3230 prevents the instrument from changing ranges which saves time for repetitive go no go checks Both models also have an audible continuity feature which causes the meter to beep when the circuit under test is closed After pressing the DATA H button on Model 3230 the meter captures the measurement beeps and locks it on the display so you can focus your attention on the probes and circuit With this data hold feature the DMM automatically updates for each new measure ment All 3200 Series multimeters come with safety test leads operator s manual batteries spare fuse and 3 year warranty And each meter is priced under 100 For further details write or call HMC Co P O Box 526 Canton MA 02021 617 821 1870 DESOLDER STATION OK INDUSTRIES addresses the problem of desoldering PCB s with high thermal demands by intro ducing a new high power desoldering station The SA 600 design incorporates a unique high capacity nozzle high power heating element and quick rise vacuum pump 21 Hg to optimize efficiency The SA 600 offers a safe 20V handpiece with a 65W heating element for excellent heat recovery and temperature stability The high mass desoldering nozzles provide superior heat capacity allowing efficient solder flow
159. sent job until you re ready to make your move And all throughout your training you have the full support of your personal NRI instructor and the NRI technical staff always ready to answer your questions and give you help whenever you need it FREE catalog telis more Send today Send today for NRI s big free catalog that describes every aspect of NRI s innovative computer training as well as hands on training in TV video audio servicing telecommunications industrial electronics and other high growth high tech career fields If the coupon is missing write to NRI School of Electronics McGraw Hill Continuing Education Center 4401 Connecticut Avenue NW Washington DC 20008 IBM is a registered trademark of International Business Machines Corp QuickTech and R A C E R are registered trademarks of Ultra X Inc SEND TODAY FOR FREE CATALOG For Career courses approved under Gi Bill LJ check for details VFB Schools t i McGraw Hill Continuing Education Center 4401 Connecticut Avenue NW Washington DC 20008 Check one FREE catalog only CO MICROCOMPUTER SERVICING LJ Computer Programming C TV Video Audio Servicing U Security Electronics C Industrial Electronics amp Robotics C Electronic Music Technology LJ Desktop Publishing O PC Software Engineering Using C C Telecomm unications i U Basic Electronics please print Age City State Zip Accredited Member National Home Study Council 22
160. ses maintenance that is how to clean and lubricate the machines so that they stay in good working order He also addresses the problem of battery care and charging Videotape cassettes can some times cause problems too so there is one chapter devoted to cassette maintenance and repair The bulk of the book however concerns itself with what to do when the unthinkable happens when your expensive camera or VCR grinds to a halt despite your 12 ELECTRONICS HANDBOOK NL dmiitiet a o y DO O OS OO I E lIl I II H A A mm Trt BOOK REVIEWS best efforts at maintaining it in good condition Excellent mecha nical drawings show how to dismantle equipment without damaging it Key anatomical features are illustrated in nume rous photographs The author targets common sources of trouble such as motors and switches and shows how to test and repair them using a DDM and some simple tools Every owner of video equipment should realize that sooner or later a malfunction will occur When it does Camcorder Maintenance and Repair will help you set things right and perhaps avoid an expensive trip to the repair shop The book costs 16 95 and is available from TAB Books Inc Blue Ridge Summit PA 17214 9988 Or ask for it at your local bookstore THE HOMEBUILT DYNAMO By Alfred T Forbes Like ostriches with their heads in the sand Americans by and large ignored the dangers of their dependence on foreign oil durin
161. should make these modifica tions on a cheap expendable cassette deck More expensive cassette players will sometimes have a built in speed adjustment For example the Sony Walkman WM D6 allows the tape speed to be varied by 15 which might be enough for your purposes The big disadvantage of trying to control the tempo of music by varying the tape speed is that the pitch of individual notes is also affected Cutting the tape speed in half for example cuts the tempo in half and lowers all the notes one octave making your fiddle sound like a cello How Long Do CDs Play i bought a CD of my favorite chart toppers and it had only 13 cuts totaling 36 minutes and 44 seconds of music on it Is there some reason we can t get a full hour or so when we pay 15 or more for a CD And what s the most they can put on a CD anyhow Melvin Danzig Perth Amboy New Jersey You re right some record producers do put surprisingly small amounts of music on CDs It seems to be the decision of the company to put out just what the artist and the A amp R supervisor want to release on a new disc They could easily put more music out at little increase in cost to them at least 60 minutes Up to 70 or more minutes can be fitted on todays CDs For example Arista has 25 tracks for a total of 72 minutes 30 seconds on the recently released Monkees Then and Now CD ee AE VOLUME X 7 NEW Thera der cores orton the welll Beal h
162. so note that the PC Board requires three jumper wires that must be installed With all the LEDs and resistors installed on the board the last components to be soldered are the compass sensor 1C1 and IC if you wish IC1 can be installed on a 16 pin DIP socket By using a socket destructive heat generated by the solderihg iron can be eliminated altogether without worrying about blowing the device While soldering the compass sensor and voltage regulator a heatsinking material should be clipped on their leads before applying heat A simple alligator clip can be used as such a device But be careful when removing it since it will be hot to the touch If care is not taken severe skin burns can Occur 8 LEDs INDICATING COMPASS HEADINGS NOTE REVERSAL OF NORTH LED FIGURE 8 The final wiring of the compass takes the form of the 9V battery clip and the push button These parts can be wired in any number of ways but for clarity 38 ELECTRONICS HANDBOOK we ve included copper traces on the PC Board where they can be soldered These locations will provide a strong connection point for the series circuit as well as enhancing the appearance of the overall project FIGURE 1A When properly assembled the Electronic Compass draws about 100mA of current for its operation Standard carbon 9v batteries can deliver this amount current but for only a brief period To overcome this problem it is recommended that the Electronic Co
163. specially interesting circuit since it is a voltage controlled crystal oscillator VCXO This circuit could easily be converted to a low power narrow bandwidth FM transmitter by applying a 0 10 volt audio signal to it Circuits 1 J and K round out our discussion of 28 ELECTRONICS HANDBOOK crystal oscillators These circuits use comparators to make crystal oscillators While the integrated circuits used in these oscillators may not be standard hobbyist IC s you can obtain them by writing to Linear Technology and finding out where in your city the nearest distributor of Linear Technology parts is located From that point you are on your own Have fun E CIRCUIT FRAGMENTS Reading about electronics can be fun and instructive but the only way to become a knowledgeable technician is to get hands on experience by actually connecting resistors and capacitors together in circuits that do something These circuits can be as simple as turning a light on or off or making some kind of alarm sound As long as we have a power source and a load connected together by wires we have a functioning circuit Another way to think about circuits is to consider one part the input and another part the output This is notably true of amplifiers The circuits in the following Circuit Fragments section are like this they all Do something These projects are comparatively simple and each uses fewer parts than t
164. stable squelch excellent sensitivity and lots of speaker volume It runs on a 9V battery and is ideal for air shows or just hanging around the airport 30 page manual not only provides step by step instructions but provides details on pilot talk also Detailed instruction manuals make these kits easy and fun to assemble For more information contact Ramsey Electronics Inc 793 Canning Parkway Victor N Y 14564 716 924 4560 FAX 716 924 4555 DIGITAL DECADE SUBSTITUTERS Substitution boxes are eco nomical indispensable tools used in a variety of engineering design troubleshooting and service applications With convenient side by side thumbwheel switch es you can easily dial in the desired resistance Capacitance or inductance value These sustitution boxes are used to set resistance Capaci tance and inductance values for engineering design trouble shooting and service applications Just dial in the desired value using convenient side by side thumb wheel switches no fumbling with multiple slide or rotary switches Different colored switches separate the various impedance ranges Since the impedance values are set and read directly no mistakes can be made as with rotary or slide switch decade boxes There s no need to examine groups of switches simply read one number Made of high impact plastic these substituters are very portable and reduce clutter on a busy lab bench Four s
165. system the most common way of delivering power to the various stages of a piece of equipment Two power leads run from the supply to one stage and then from there to the next stage and so on Such a scheme is simple and generally practical except when you have the situation shown in Figure 5 Here we have a low level source Vs driving a high gain amp stage with resistor R and inductor L representing the resistance and inductance of the interconnecting ground lead Current from the high current stage and current from the swtiching stage both flow through the power bus in particular through R and L Since the amp responds to the potential difference between its input and ground leads any voltage developed across R and L due to 11 and 12 appears in series with Vs and Hi noise voltage VN gets amplified right along with KIGH CURRENT SWITCHING LOW CIRCUITRY CIRCUITRY AET ar Figure 6 When different types of circuits are sharing a single power source in a parallel distribution system ground noise is often totally eliminated The arrangement isolates the various circuit components from their neighbor s power source The power source should have low impedance and be connected to points A and B by very short wires Now let s suppose R and L represent a piece of 22 wire One foot of 22 has a resistance of 16 14 milli ohms and if 11 is a direct current of about 61 milliamps then VN equals 1 millivolt This is small but
166. t RFC 2 5 UH choke coil 6302 SW1 SPDT switch SW2 6 position rotary switch 10YXD62 SW3 On Off switch on rear of R10 J1 Closed circuit earphone jack SPKR 3 or 4 inch 8 PM speaker MISC 8 pin IC socket antenna and ground terminals coil wire 24 or 26 hookup wire PC board chassis board and front panel etc VD1 C1 SW2 and RFC may be purchased at Circuit Specialist Inc P O Box 3047 Scottsdale AZ 85271 3047 46 ELECTRONICS HANDBOOK THE EXPERT S PROJECT BUILDING VA UIDE TO By Walt Sikonowiz By Watching Out For Noise You Can Build a Project That Works Right The First Time Project Building is supposed to be and generally is a challenging and entertaining adventure Yet there are times when it can turn out to be a miserable disappointment all because of a pesky little gremlin known as electronic noise To the electronic engineer noise is a catch all term that refers to any signal appearing someplace where it does not belong Even if you have constructed just a few projects chances are that you have been introduced to noise whether you realized it or not While noise cannot be eradicated completely it can be effectively minimized once you understand its origins In most instances the key to a noise free project lies in good construction practice so let s examine some of the techniques used by skilled project builders When dealing with electrical interference it
167. t of his predicament drop us a line and we ll put you in touch with Mr Campbell A More Thoughts About Tools l am writing this letter to call your attention to an article on Essential Tools for Electronic Construction by Walter Sikonowiz Vol VII of Electronics Handbook The question Walter brings up about Straight line cuts in PCBs is always something of a problem priced the Kepro Model MS 6 shear and found it to be rather expensive The alternative using a nibbler gets to be rather tiresome A friend at work suggested that try the following Company which specializes in small tools Micro Mark 340 Snyder Ave Berkeley Heights NJ 07922 have xeroxed three pages of their catalog containing alternative devices to deal with this problem What is your opinion of these tools Joe Toms Forest Hills NY First of all thanks for the tip about Micro Mark Joe Their catalog looks like a good one The devices in question small benchtop mounted table saws and jig saws are intended for use by model builders but see no reason why they should not also do a good job of cutting PCB laminates Just be sure to use a very fine saw blade When sawing glass epoxy commercial fabrica tors of PCBs use carbide tipped blades because glass epoxy is a very abrasive and rapidly dulls a conventional steel blade For home use however a conventio nal carbon steel blade will be satisfactory Paper base phe
168. tection devices cabinets workbenches PC board shears heat guns adhesive guns and cleaning supplies from all the top manufacturers If you want tool kits Contact East offers 27 different kits all reasonably priced To get your catalog write to Contact East 335 Willow St South North Andover MA 01845 mo A e aeta o Md J Pra EIER TRANSCAT INSTRUMENTS All of the major electronics retailers have a section of their catalogs devoted to test instruments since these items are always in demand But how many instruments can you fit into 25 pages or so Not many at all and that s why we were delighted to receive the new catalog from Transcat Instruments This 480 page behemoth is just chock full of interesting test gear Of course they ve got the standard items like oscilloscopes multimeters logic probes function generators power supplies digital capacitance meters and frequency counters from such manufac turers as Fluke Beckman Simpson B amp K Soar Ballantine Labs Hitachi Leader OK industries VIZ Kenwood Non Linear Systems Tegam and Valhalla But they ve also got exotic offbeat test gear like digital thickness gauges vibration meters leak detectors electronic stethoscopes gas monitors dew point indicators open stream velocity meters and noise dosiometers Whew Write to Transcat P O Box D 1 Rochester NY 14606 C amp H SALES CO Drop into C amp H Sales in Pasadena any day of the week
169. th RC time constants of 4 7 or 5 uF and 220 000 ohms the warning indicator LED will remain on for about two seconds 56 ELECTRONICS HANDBOOK AS 3 LED INDICATOR PARTS LIST FOR THE ROBOT EAR TTL PARTS LIST FOR THE ROBOT EVE TTL C1 C2 0 1 uF ceramic capacitors 15 VDC C3 2 2 uF electrolytic capacitor 15 VDC D1 small LED IC 1 555 timer Q1 FPT100 phototransistor or equivalent R1 250 000 ohm linear taper potentiometer R2 47 000 ohm 2 watt resistor R3 470 ohm Y watt resistor R4 220 000 ohm Y watt resistor CJ 4 o OUTPUT C1 0 1 uF ceramic capacitor 15 VDC C2 5 uF electrolytic capacitor 15 VDC D1 small LED iC1 555 timer Q1 Motorola MPS A13 Darlington transistor R1 47 000 to 100 000 ohm watt resistor R2 470 ohm Y watt resistor R3 220 000 ohm watt resistor LED ADDS LUSTER Through the addition of a transistor driver a small LED indicator can give the visual state of an Op amp such as might be used to detect noise impulses as in an alarm system The 2N4401 NPN transistor provides plenty of power and gain for such an application The method can be used both with and without an audio indicator like a small loudspeaker as well You will have to experiment with the value of R1 to obtain triggering depending upon the impedance of the mike used PARTS LIST FOR LED ADDS LUSTER C1 0 1 uF ceramic capacitor 15 VDC C2 10 uF
170. th a solar panel of a given dimension Typical efficiencies of modern silicon solar cells fall between ten and twelve percent Series and Parallel Connections Higher voltages and higher current capability can be obtained with appropriate series and parallel connections of solar cells The voltage is increased when cells are connected in series just as there is a voltage increase when batteries are connected in series Also there is a higher current capability when solar cells are connected in parallel just as the current capability is increased when batteries are connected in parallel Four 0 4 volt solar cells Connected in series will provide an output voltage of 1 6 volts 4 x 0 4 Four 1 2 ampere cells connected in parallel will result in a current capability of 4 8 amperes 4 x 1 2 If 16 of these 0 4 volt and 1 2 ampere cells are connected in series parallel as shown in Figure 3 the output will be 1 6 volts with a current capability of 4 8 amperes 1 6 VOLTS 4 8 AMPS Figure 3 Connecting solar cells in series increases voltage and in parallel increases current Series parallel steps both up a a E muni a XP aaa i A ja a When a higher voltage is desired panels can be connected in series just as individual solar cells For example two such panels in series would provide an output of 28 volts Two of them connected in parallel would provide a current capability of 4 2 amperes mg ra i Eyr p mnt i
171. the units we are expressing The common prefixes which correspond to exponents of ten are given in Figure 1 Referring back to our examples for the first one we can take the prefix Mega from the table as it corresponds to 1 0 and we get 2 54 Mega volts or 2 5 Mv 2 76 milliamps 8 99 kilo ohms 750 kilowatts Figure 2 Table of electrical quantities with scientific notation and engineering units 60 ELECTRONICS HANDBOOK BAND 1 DIGIT 1 BAND 2 DIGIT 2 BAND 3 BAND 4 i wor rout dh Oo Figure 3 The Resistor color code In the second example we have an exponent of ten of 8 From the table we can see that there is no prefix for 10 4 so we must move the decimal right one place so that we have 10 which has the prefix nano This gives us 15 79 nano Amps or 15 79 nA When converting to engineering notation the rule is that the first part of the number should be between 0 and 999 By choosing to place the decimal point so that the number falls in that range you can always find an exponent of ten for which there is a common prefix Probably most of you have encountered these systems of notation before but maybe you have not used them for a while In Figure 2 a table of electrical quantities with their scientific and engineering notations has been set up If you want practice in converting just cover the middle and right columns with a piece of paper and do the conversions yourself Then uncover
172. to put a project together and it doesn t work the first time Connect the outside antenna and ground to the all wave receiver Turn the volume control on full Start with the tickler coil L3 straight up and down which is perpendicular to L2 and L1 Turn SW2 to the broadcast band or last tap Rotate the regeneration coil to almost wide open You should now hear a sgueal in the headphones Rotate the large tuning control and notice all the various squeals and whistle noises as it is rotated Each squeal is a station If you get no squeal or whistle noise reverse the coil connections of L2 Stop the tuning control at the loudest squealing noise Back down the regeneration control until you hear a plop or the station comes in Slowly rotate the vario coupler coil to improve the signal This coil can be fairly touchy on shortwave stations but will help the feedback action and separation of stations Rotate the bandspread control to separate the various stations Now go to the high end of the shortwave band Adjust each control as with the broadcast band Rotate the vario coupler and regeneration control until feedback occurs Turn C2 until you hear some loud whistling noises Back off the regeneration control If the high band will not oscillate move the coil wire closer together between the top coil connection and tap 1 VOLUME X 45 R4 3 4 SW2 O 4 O VOL CONT 0 FRONT PANEL REAR CHASSIS FIGURE 9 Figure 9 Dimensions of t
173. tom Microprocessor 9 00 PCB Printed Circuit Board 4 95 Add 2 00 for postage amp handling For each combination of the above items send check or money order U S funds to C amp E Hobby Handbooks Inc P O Box 5148 North Branch N J 08876 THE 80 TUNE COMPUTER he 80 Tune Computer is a project which is not only easy to build but also fun to use Its uses are many and are limited only by the imagination of the builder This is an excellent beginner s project because of its simplicity A masked microprocessor special Integrated Circuit or IC does all the work Any of the 80 songs can be selected by the Play button Stop button resets the microprocessor The selected tune will start each time the Play button is pushed as long as power is onandno Ken SI BUCKLE DOWN WINSOCKI 4 CHARGE SS DEAR OLD NEBRASKA U BO TUNE COUPUTTA SONG LIST 0 AMERICA 1 ANCHORS AWEIGH 2 BATTLE HYMN REPUBLIC 3 CAISSONS GO ROLLING 4 CALL TO COLORS CAVALRY CHARGE 6 DIXIE 7 HAIL BRITTANIA 9 YANKEE DOODLE DANDY 9 LA MARSEILLAISE 10 MARINE HYMN 11 REVEILLE 12 STARS A STRIPES 13 TAPS 14 WILD BLUE YONDER 15 ALOUETTE 27 IH HEAVEN IS NO DEER 28 JIMMY CRACK COAN 29 JINGLE BELLS 30 KING OF AOAO 31 LA CUCARACHA N LONE RANGER 33 MODEL T 34 THE OLD GAEY MARE 35 POPEYE M AAINDROPS 37 SAILORS HORNPIPE 59 GO NORTHWESTERN 60 HAIL PURDUE 1 HEY LOOK ME OVEA 62 HOLD THAT TIGER 83 ILLINOIS LOYALTY
174. ty of electronic gear some of it high tech some of it off the wall all of it intriguing Plans parts kits and assembled units are available Looking for a laser They ve got them in all shapes and sizes How about a Tesla coil a plasma discharge globe or a magnetic cannon They have them too Private eye types will love the wireless microphones tracking devices bug detectors and voice scramblers devices so small that they ll hardly make a bulge in your trenchcoat pocket Finally if hostile aliens ever set up shop in your attic you can blast em back to their own foul planet with one of Info Unlimited s stun guns Get all the facts by sending 1 00 to Information Unlimited P O Box 716 Amherst NH 03031 84 ELECTRONICS HANDBOOK CONTACT EAST Contact East s new 147 page full color catalog contains all the test gear and tools necessary for the assembly maintenance and repair of electronic equipment Test gear includes DMMs from Fluke B amp K Soar Beckman Mercer Tektronix Triplett and Extech scopes from Hameg Tektronix Hitachi Beckman and B amp K AC power analyzers from Amprobe and BMI datacom testers from Datatran and IQ Technologies and PROM programmers from Data I O and Logical Devices Their tool lineup includes screwdrivers nutdrivers wrenches tweezers pliers cutters strippers Crimpers power tools knives files saws wire wrap guns soldering stations solder pots static pro
175. ure i and receive a E 9 Signature and build or repair more on your own have fun ee a Signature and a and save more money Supplements are sent ME ali orders 4 5 times a year No risk guarantee you pay a Name upon approval Wi nddres e oma ga v E City State Z 97 Indian Field Rd E Greenwich CT 06830 lt Sorry orders from foreign countries can only be accepted if they are prepaid in US currency Shipping and handling cost 15 00 per internationa shipment 10 00 to Canada e ain ee CALL 1 800 222 WEKA FOR FASTER SERVICE ee es
176. voltage resistance and transistor tests should locate a defective component or improper wiring Check the schematic for voltage measurements Push together and widen shortwave coils to bring in the different bands The allwave vario coupler receiver can bring back many memories to the old timers out there who constructed shortwave receivers from scratch This receiver can take you back into time when building receivers was the way of life Constructing operating and owning one of these relics can be a lot of fun even if they are produced with solid state devices Happy listening E PARTS LIST FOR THE ALL WAVE VARIO COUPLER RECEIVER Q1 MPF 102 FET transistor 1C1 LM 386 audio IC C1 10 to 80 PF trimmer capacitor C2 Modified 365 PF variable capacitor see text C3 amp C6 100 PF disc capacitors 50 V C4 01 UF disc capacitor 50V C5 amp C8 1 UF disc capacitors 50V C7 C10 8 C13 10 UF 35 volt electrolytic capacitors C9 002 disc capacitor 2 001 capacitor in parallel C11 220 UF electrolytic capacitor 35 V C12 047 UF disc capacitor C14 100 UF 35 V electrolytic capacitor R1 22K Y watt resistor R2 100K watt resistor R3 100K variable linear control R4 2 2 K watt resistor R5 50 K variable linear control R6 4 7K watt resistor R7 10K audio taper control R8 10 ohm watt resistor VD1 Varactor diode 35 PF MV 2109 L1 L2 4 L3 See tex
177. wering specific electronic project guestioris that you send to him Personal replies cannot be made Sorry Spies Like Us Do you have any information about obtaining kits or schematics for the following electronic dissolution of memory devices using infrasonic sound waves ultrasonic sound devices for crowd control laser or microwave transmitters Also do you have information on detecting dentally implanted transmitters used by such agencies as the FBI CIA etc Thank you for your prompt attention R G Hellstrom Lexington KY PII answer your questions in the order you ve presented them Devices capable of obliterating memory are beyond the editorial scope of this magazine Electro nics Handbook is supposed to be the fun way to learn electronics and to be honest R G scrambling someones brains with infrasonic acoustic energy doesn t sound like much fun not for the victim anyway Ultrasound devices designed to intimidate dogs and other attackers are available from a variety of sources Information Unlimited P O Box 716 Amherst NH 03031 offers several plans and kits Note that ultrasound devices by themselves may not be sufticient to control a large hostile crowd of people particularly if they all stick their fingers in their ears assume that your interest in laser and microwave transmitters stems from a desire to eavesdrop on a building with restricted access where it would be impossib
178. wledge of this budding science they were able to produce the first silicon solar cell the forerunner of today s photovoltaic cells Well the success of solar generators in space is apparent As bigger more efficient cells become available and oil supplies dwindle terrestrial solar technology will branch off by itself conjuring up its own special magic Solar Cell Theory The solar cell or photovoltaic cell makes a direct conversion from sunlight solar energy to electricity No fossil fuel is required Moreover photovoltaics are safe and nonpolluting and are manufactured from materials in relatively abundant supply Manufactu ring costs are high but declining steadily while other methods of generating electricity involve energy costs that are rising sharply Additionally photo voltaics require no moving parts and minimal maintenance Associated components have a long life and no waste products are generated Solar Radio Photovoltaic supplies are used extensively in the radio communication services such as for repeater relay and rebroadcast stations that must be mountain top located or located at a remote site where there is no source of power The two way radio services in particular can now make use of repeater sites at high locations where there is no convenient power Weak signals from mobiles can be picked up by the receiver and then retransmitted to obtain a rant AS MATT Ue e ry ge OO DU He on US SBS Agu
179. y CIE rewards you for fast study CIE offers an Associate Degree degree the less your overall tuition program based on actual study time used The faster you complete your State of the art laboratory equipment is yours to keep and it comes assembled ready for hands on experiments Approved for educational benefits under the G I Bil for veterans and other eligible persons Upon graduation CIE offers free preparation to pass the Certified Electronics Technician Exams core lessons applicable to all areas cf electronics And every CIE course you take earns you credit towards comple tion of your Associate in Applied Science Degree So you can work toward your degree in stages or as fast as you wish In fact CIE is the only school that actually rewards you for fast study which can save you thousands of dollars SEND TODAY FOR YOUR CIE COURSE CATALOG AND WE LL SEND YOU A FREE 24 PAGE CIE ELECTRONICS SYMBOL HANDBOOK FINANCIAL AID AVAILABLE TO QUALIFIED INDIVIDUALS i _ YES I want to get started Send me my CIE school catalog includ ing details about the Associate Degree Program For your convenience CIE will have a representative contact you there is no obligation Name a Address __ AE City a State Zip E Phone No Check box for G I Bulletin Benefits Veteran Active Duty C TED ag an 0 CLEVELAND E INSTITUTE OF Foug gtt ELECTRONICS 17

Vol 10 - American Radio History

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