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"New" Microminiature Way Of Building Circuits

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1. The Covox Voice Master comes complete with all hardware and software for only 89 95 Add 4 shipping and handling for USA 6 Canada 10 overseas Available for Commodore 64 128 Apple Il il Ic lle Atari 800 800XL 130 XE Specify when ordering Visa MasterCard phone orders accepted WA SZ Cali or write for FREE Voice Master infopak and special combination package offers COVOX INC DEPT me 675 D Conger Street Eugene Oregon 97402 USA Area Code 503 342 1271 Telex 706017 Av Alarm UD CIRCLE 90 ON FREE INFORMATION CARD ANSI VIDEO TERMINAL BOARD FROM LINGER ENTERPRISES A second generation low cost high performance mini sized single board for making your own RS232 Video Terminal This highly versatile board can be used as a stand alone video terminal or without a keyboard as a video console VT100 VT52 Compatible FEATURES MICRO SIZE Uses the new CRT9128 Video Con troller driven by a 6502A CPU On Screen Non Volatile Configuration 10 Terminal Modes ANSi H19 ADM 5 WYSE 50 TVI 920 KT 7 T HAZ 1500 ADDS 60 QUME 101 and 8 Datapoint 8200 Supports IBM PC XT and Parallel ASCII Keyboards a ie Supports standard 15 75 kHz Horiz N Composite or Split Video 50 60 Hz 25 X 80 Format with Non Scrolling User Row Jump or Smooth Scroll RS 232 at 16 Baud Rates from 50 to 19 200 On Board Printer Port Wide and Thin Line Graphics Normai and Reve
2. 96 XT Turbo 4Layers 125 XT Turbo4 77 J70MHZ 125 ATO EMHZ wania ia rahad aiea 450 B AT Turbo 10 MHZ wai eee rete 450 CASES XT Flip Top or Siide 27 MinvAT For XT Prys soe ves Si ree Toate 50 b AT rrene eee eee 72 INTERFACE CARDS Monochrome Adapter 41 Mono Graphic Printer 60 CT6040 Herc Comp 65 Color Graphic Display 44 Color Graphic Printer 55 UA acu dnleswwbe Tine AA 190 gt EXPANSION CARDS XT Disk Controller 1 Pot uy lt n ce ccm om noon 25 XT Disk Controller 2 Ports 27 AT Floppy Disk Controller 60 gt AS 262 POs UU d ere ie Wa 21 AS 232 2 PorSay lt rirun ia poms er neeene eves 29 Parallel Card sss ccs mcpevenccesrareseses 14 Multi lOl cy arom rarer ae a eeew wey IAA 71 YO Plus Gard u tm ams aba rivera ack Mawes 65 ISBAK MTE OK vac stay at eraa tau bon 74 y 6AOK Ram OU AI TAA AI AA om oem 38 Clock Cards 25 y Game Cards UA ITU 15 AT WO Cards pss ss i yarr raaa Masai 65 AT 2MB MTF ste cia ane Sisauna od he TRS 127 FLOPPY DISK DRIVES TeacLook Alike 68 TOAG S60 0 ames UTA TUU Ba Pes ad Ey 86 Teac1 2MB 110 CHIBA GOO raaa Wi aa ded de 78 Chinon asa aaaaa uaaa aaan 110 FUN SY ea
3. Senmonenone BF PICKS UP A WHISPER 50 FEET AWAY The model WAT 50 miniature FM tranmitter uses a 4 stage circuit NOT to be confused with a simple wire less microphone Simply Snap the unit on top of a 9V battery and you can hear every sound in an entire house up to 1 mile away Use with any FM radio Tunes to any frequency from 70mhz 130mhz Easy to assemble kit includes all parts and instructions Only 29 98 tax incl The WIRELESS TELEPHONE TRANSMITTER model WTT 20 Is only about the size of a dime yet transmits both sides of a telephone conversation to any FM radio with crystal clarity Completely automatic Uses power from the telephone line itself never needs a battery Up to mile range Tunes from 7Omhz 130mhz Easy to assemble kit includes all parts and instructions On ly 29 98 tax incl Cali or send MO VISA MC for immedlate delivery Single kit orders include 1 50 S amp H FREE SHIPPING on orders of 2 or more All orders shipped by U S Mall COD add 4 00 Personal checks allow 21 days DECO INDUSTRIES BOx 607 BEDFORD HILLS NY 10507 914 232 3878 CIRCLE 50 ON FREE INFORMATION CARD Classified Commercial Rates 90 per word 15 word minimum 13 50 prepaid Word count includes name and address ZIP code and abbreviation each count as one word P O Box number and telephone number count as two words each Indicate free cate gory heading A special heading is available
4. R6 R7 220 390 18V C2 C4 c6 0 05 yF 0 05 pF R4 5 600 ohms R5 R11 470 ohms R6 220 ohms R7 390 ohms R12 560 ohms R3 5 000 ohm pc type trimmer po tentiometer R8 25 000 ohm pc type trimmer po tentiometer R9 10 000 0hm pc type trimmer po tentiometer Miscellaneous J1 F 61 chassis mount male coaxial connector D C c12 s ye O 1pF 0 05 pF AUDIO OUTPUT R5 cB 5 6K 5 2 470 5 O 22yF 142 8 14 TA 4 la T2 2 9 gt oS RI 1 1 AA IC2 O RF INPUT D 5 330 MC1350 Y o MC 1358 BA OC Ay 15 150pF 6 1 3 7 13 3 gt c9 i c16 C13 0 05 pF taa 0 05pF 0 22 uF o gt a SEE TEXT cs RG A TEXT 0 05yF 25K 10K TONE AUDIO RECEIVER PARTS LIST Semiconductors R2 4 700 ohms J2 Shielded phono jack L1 20 hH choke wound on 10 4H choke see text T1 T2 See text T3 25 2 volt 300 mA power trans former Radio Shack Cat No 273 1386 or equivalent Printed circuit board aluminum chassis box Radio Shack Cat No 270 238 sockets for ICs optional 26 gauge magnet wire ac line cord with plug rubber grommet rubber feet labeling kit clear acrylic spray machine hardware hookup wire solder etc Fig 1 Receiver schematic diagram minus power supply this project This supply is almost identical to that used in the Cable Communications System featured in the September 1985 issue So both re ceivers can be housed inside the same enclosure and can share a common
5. 18 Printer Switch Box oe male KID 20 BulkDiskettes 39 EpromWriter 160 eae ee E ee oe CE ee E Call Cables amp cep 24 gay ET TESTE TYE Call LIMITED OFFER 1 XT System 640K w 2 Floppy Disk Drives Keyboard amp Amber Monitor for 2 We will assemble Systems to your Configura tions for ONLY 5 00 for Components purchas ed from us CIRCLE NO 180 ON FREE INFORMATION CARD A 4 5 MHz FM Receiving System eee this box half with steel wool dry tho roughly and spray three light coats of clear acrylic as you did for the bot tom half Temporarily set the receiv er aside and proceed to the pickup unit if you re using it Otherwise proceed to checkout below Before wiring any components to the board of the pickup unit drill two mounting holes spacing them in from the long sides and centered between the short sides Place the board centered all around on the metal lid of the box that s to house the pickup unit s circuitry and mark the locations of the mounting holes just drilled Drill 4 holes at the marked locations Then drill ap propriately sized holes for the ground lug coaxial connector and twinlead entry and for access to the trimmer capacitor Deburr the holes install small rubber grommets in the two twinlead entry holes and mount the coaxial connector Trim 4 of insulation from both ends of a 2 lightweight zip co
6. Add short lengths of heavy solid wire to serve as leads for the primary windings of the transformers Wrap the 100 microhenry choke with plastic tape and wind the pri mary turns over this Scrape 4 of enamel from the ends of the magnet wire tin with solder and solder them to the added leads Strip the existing windings off the 10 microhenry chokes and rewind them with the number of turns calculated above Solder the ends to the existing leads and spray each reworked choke with clear acrylic Wrap a layer of plastic tape over the windings of one of the reworked chokes Over the tape wind the number of turns of magnet wire cal culated for the primary of 72 Keep in mind that each half of this center tapped winding consists of half as many turns as there are in the secon dary winding Scrape 1 4 of enamel from the ends and center tap of this R2 2 200 ohm 2 watt 5 tolerance resistor R3 82 ohm 2 watt 5 tolerance resistor Misc Printed circuit board suitable metal enclosure Radio Shack Cat No 270 230 or similar 300 ohm twinlead cable small rubber grom mets 2 4 spacers 2 machine hardware hookup wire solder etc Say You Saw It In Modern Electronics winding tin the exposed wires with solder and solder to the carrier leads Spray the windings of the coil and both transformers once again with a light coat of clear acrylic The receiver and optional pickup unit if used is b
7. Fig 6 Conventional through hole and surface mount resistor installation dardization can prove very frus trating when it s necessary to find a replacement part Another area lack ing final standardization is the pin configurations for ICs Figure 5 for example shows three common lead arrangements for SO dual in line ICs Each lead arrangement has its advocates Proponents of gull wing leads point to ease of soldering and simpler component replacement J lead advocates point to higher densi ty boards made possible by the ab sence of protruding pins In the end perhaps both arrangements will be made standard Even though standards are lack ing there can be no doubt that sur face mounting affords a substantial Savings in space Figure 7 shows a cross section of a circuit board con taining a standard Yo watt resistor and a chip resistor The latter device isn t much thicker than the width of the leads of the standard through hole resistor Advantages amp Disadvantages of Surface Mount Technology Though some of the advantages of Say You Saw It In Modern Electronics surface mount technology SMT were cited above to better grasp their significance it is important to review them alongside other SMT advantages Therefore here is a list ing of the major advantages of SMT 1 The small size of SMDs per mits circuit boards to be made con siderably smaller than those de signed for conventional compo ne
8. Hz frequency response with metal tape S N is 62 dB with no noise re duction and 71 dB with Dolby B 76 dB with Dolby C and 86 dB with dbx NR Wow and flutter are 0 06 wrms A multifunction indicator dis plays the operating modes and a LED display indicates the amount of tape remaining The PLL synthesized AM FM tuner section has 15 FM and five AM presets A preset scan feature allows the user to sample the preset stations for 5 seconds 1 300 CIRCLE 8 ON FREE INFORMATION CARD ioe ie ee eT TR SEA ae Personal Computer Scope Analyzer Board A moderately priced digital oscillo scope spectrum analyzer peripheral plug in for selected personal comput ers has been announced by Rapid Systems of Seattle WA Models are available for IBM Apple and Com modore computers The digital scope has four diode protected input channels and fea tures 100 Hz to 2 MHz sampling rate 14 steps gain adjustable from 100 mV to 20 V div 8 steps 500 Hz analog bandwidth 2K data buffer and separate adjustable trigger in put Software features include menu driven operation a help file color graphics keyboard control of mses eel m coe a SA Aa Aa eis mn n mmi ae T P i r i m iii ET trigger gain and timebase assembly routines to speed data collection and display zoom mode to view entire data buffer active scrolling grid dis play store retrieve functions post trigger delay multi cha
9. Potentiometer R3 in the feedback path of JC serves as a sensitivity control for the circuit This control can be set as needed for positive trig gering and to optimize operation Construction There is nothing critical about circuit Say You Saw It In Modern Electronics layout Hence any traditional wiring technique can be used If you wish you can etch and drill your own printed circuit board using the actu al size etching and drilling guide given in Fig 2 Otherwise you can use perforated board and appropri ate Wire Wrap or soldering hard ware or a Solderless breadboarding socket Unless you use the solderless breadboarding socket it is a good idea to use sockets for the ICs Wire the board exactly as shown in Fig 3 taking care to properly orient electrolytic capacitor C5 When in stalling the transistor make sure its basing is correct before soldering its leads to the board Similarly make sure the sockets are properly plugged into the board with the reference pins in the IC pin 1 locations Do not forget to install the three wire jump ers in the locations indicated You can use the cut off resistor leads for these jumpers If you are using a sol derless breadboarding socket you can use the Fig 3 wiring guide as a rough layout for the components and refer back to Fig 1 to wire the circuit Solder the battery snap connector into the circuit Make certain that the red connector lead goes to the point in
10. 1 0 Connector System Catalog Molex is offering an 8 page catalog that fully de scribes its SEMICONN shielded electro magnetic compatible connector system designed to terminate round and flat shielded cable for high speed busing In cluded are drawings photos specifica tions applications and terminating tool ing Fora free copy write to Molex Inc 2222 Wellington Ct Lisle IL 60532 78 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics LETTERS _ Ribbon Blues e On your article on Rejuvenating Printer Ribbons Modern Electronics October 1986 WD 40 does a printhead no good Secondly a procedure taking over 24 hours is not worth the 3 00 to 5 00 replacement cost The proper way to rejuvenate a ribbon is to use aerosol print ribbon ink Ebonize from UP WE GO Computer Supply Inc in Chicago IL at about 8 00 for 3 ozs When a ribbon gets thin printing I open the can and spray the ribbon I then set it aside and use ribbon 2 which I had previously rejuvenated Rejuvenated ribbons are far blacker than any new ribbon and they last longer between treatments Two ribbons Ebonize less than 20 00 Each ribbon can be treated 10 to 20 times with one can saving over 100 00 John Topham Prospect Heights IL e just received my October edition and as always it is filled with useful informa tion with one exception The article on How to Rejuvenate P
11. 1 29 retail XR 2240 programmable timer counter Contained within the XR 2240 is a time base oscillator that uses an ex ternal RC network This oscillator is followed by an 8 bit binary counter that can be programmed for delays ranging from 1RC to 255RC In this article we will discuss the design of ultra long delay timers and options that can meet a diversity of applications Also included is a Timer Beeper that can be used for a special application Other applica 7 3 30 MODERN ELECTRONICS January 1987 tions will be evident as each option is described Inside the XR 2240 Shown in Figs 1 and 2 are the logic diagram and pinout details respec tively of the XR 2240 program mable timer chip The time base sec tion Fig 1 which is quite similar to that in the general purpose 555 timer chip produces negative going clock pulses at pin 14 These pulses have a period of T 1RC A timing cycle is initiated by a pos itive going trigger pulse applied to H Regulator THHHHHHHI El p Totea TB ee 3 gt Control Binary counter ee _ flip flop elements time base binary counter and control flip flop that make up this 16 pin dual in line integrated circuit Say You Saw It In Modern Electronics pin 11 This pulse starts the time base oscillator enables the counter section and sets all counter outputs to their low states Clock pulses at pin 14 are counted by th
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13. NRI has purposely designed your training around equipment that has the same high tech circuitry you ll encoun ter in commercial equipment That means your training is real world train ing And that s unique Inside Your TV This new state of the art Heath Zenith 27 TV included with your training has all the features that allow you to set up today your complete home video center of the future Flat screen square corners and a black matrix to produce dark rich colors Cable compatible tuning built in stereo decoder to give you superb reproduc tion of stereo TV broadcasts even a powerful remote control center that gives you total command of video and audio operating modes Your NRI Training Has Another Special Element Also built into your training is the enor mous experience of NRI development specialists and instructors Their long proven training skills and enthusiasm come to vou on a one to one basis Available for consultation and help whenever you need it your instruc tors ensure your success both during your course and after graduation Step Into the Future Today The richest reward you gain from your NRI video audio training is a firm grip on the future Your knowledge and know how provide you with the soundest possible foundation for keeping up with the rapidly evolving highly inno vative video industry Send For Free Catalog Now is the time to act Send the post paid card to us today You ll
14. The speaker baffle and rear panel are in set within the enclosure walls After cutting all enclosure panels to size strike a pencil line down the center of the speaker baffle board Say You Saw It In Modern Electronics 40 00 300 5K 10K 20K FREQUENCY IN Hz Fig 1 The speaker system s frequency response extends fram about 100 Hz to about 18 kHz for a fairly hefty bass and full range sound Irregularities in the midrange and treble are averaged out so that speaker system actually sounds much better than this curve implies Place the top panel against the end of the baffle as it will be when the two are joined measure 6 down from the top of the top panel and strike a line squarely across the first to locate the center of the speaker cutout Handling it carefully to avoid damaging the cone place the speaker over the crossed lines and position it so that the lines are centered in all four speaker mounting holes Trace the outline of the speaker onto the baffle Turn over the speaker and og typ ere Wa pia me ay i Pathe Fa en Aa measure from the rim to where the basket flares out and mark this mea surement about 4 in from the previously drawn speaker outline With a compass or string and nail draw acircle from the crossed center lines of the cutout area to the last measurement mark If you have a power rcuter cut a channel as wide as the limits between the two drawn circles
15. When wiring the Fig 4 power switching circuit to the basic Ser vant use heavy duty stranded wire for all connections between K and the power relay and the power relay s contact lugs and the chassis mount ac receptacle You can use short lengths of the stranded wires clipped from the ac power cord Before connecting and soldering the ac line cord into the circuit pass the free end of the cord through the grommet into the box Strip 4 of in sulation from the free end of each of the line cord s conductors tightly twist together the fine wires in each conductor and sparingly tin with solder Tie a knot in the line cord about 3 from the free end inside the box and connect and solder its con ductors to the appropriate points in the power relay circuit Note use plastic tubing preferably heat shrink able tubing over all 117 volt ac line level connections Mount the circuit board assembly in the box with the spacers and ma Say You Saw It In Modern Electronics ai CHASSIS MOUNT AC RECEPTACLE K1 CONTACTS 117V ac 10A DPDT RELAY 117V ac Fig 4 High power switching option chine hardware Then mount the battery clip with machine hardware Use one or two strips of double sided foam tape to mount the power relay to the wall of the box Make certain that no part of the 117 volt ac por tion of the circuit can come into con tact with the basic circuit or the met al of the box in which the projec
16. a CS ai PEE Bade Pac bea oe E and high speed LED power meters sight angle 33 Cameo Enterprises Inc 9 Amplifier frequency response is 20 All three lines hot neutral and 171 Cleveland Institute of Elec 22 25 Command Productions 6 Hz to 20 kHz at 55 W and less than ground of the Model EG 40 are pro w CompuCover HA 0 2 THD and 0 05 IM Input tected against emi rfi with a noise re 75 Computer Parts Galore Inc 49 sensitivity is 2 5 150 mV phono aux jection frequency range of 150 kHz 3 kaa Aa _ wenn T and tape S N is 79 100 dB 90 Covon r dive nb nea 9 gt FA 50 Deco Industries BS phono audio and video Equaliza Dick Smith Electronics a tion is 10 dB at 60 250 1k and 16k 95 Digi Key Corp Hz FM usable sensitivity is 11 2 dBf ya PH ED aki Maha mamaa pi WA ees mark Systems ss6005 24V 50 dB quieting sensitivity 1s 179 Floppy Disk Services Inc Cov II 19 2 dBf 54 V mono 39 2 dBf 50 67 Ronikee sowed _ Cov IV s s z rantham College of Engrg ial pV stereo capture ratio is 2 dB D GreentresCoraputer Supple eal alternate channel selectivity is 65 dB 79 Heath Cov essen cone yee rseeee lS spurious response image i f rejec any meets simian ae tion are 85 50 70 dB AM sensitivity 4 Jaw Electrons rs is 500 V meter The receiver mea ii a eevee SAA Wa Hie aR sures 17 W x 94 D x 4 H and McGee Radio 5 5 ete aE weighs 15 lb
17. ce P O Box 63 Accord MA 02018 ES AR CIRCLE 33 ON FREE INFORMATION BE PROMS 270256 250ns 27256 250ns 27128 250ns 27C64 200ns 2764 250ns 2732A 250ns 8000 s Parts in stock EXPRESS Mon Fri 8 5 DER TOLL FREE inside California QUANTITIES LIMITED i MINIMUM ORDER 10 00 u BS USA 300 SHIPPING TOLL FREE ORDERS e 1 800 826 5432 IN CA 1 800 258 6666 m INFO 2173 380 8000 La TWX 5101010163 ALL ELECTRONIC y Calif nts AOO 612 CIRCLE 31 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics 10 for 3 06 MINI PUSH BUTTON S PS T momentary NOCO normally open 7 FOREIGN ORDERS a bushing iiam DISET T AT Oo button 35t each 0 Shipping amp Handiing UPS Ground 5 00 UPS Air 7 00 under 1 1b ALL MERCHANDISE IS 100 GUARANTEED CIRCLE 32 ON FREE INFORMATION CARD January 1987 MODERN ELECTRONICS 91 NEW PRODUCTS eee from page 85 ADVERTISERS INDEX RS Page 4 7 5 AMC Sales Corp 1 BH cator tape inputs and monitor rate master switch all located on the 31 Al Electronics mimi 91 switch subsonic filter MOSFET in front apron of the base unit The 12 gt E WA pig i 7 eckman Industrial 4 put stages differential low noise _ tilt swivel monitor bases can be ad CBS Compact Disc Club 5 phono amplifier loudness switch justed to minimize glare and improve F a ae aa hee eae ales pe
18. ceiver s input directly to the signal source Alternatively you can build and use an optional inductive pickup unit that eliminates hard wiring About the Circuit Shown in Fig 1 is the schematic dia gram of the 4 5 MHz Receiver minus its ac power supply The MC13501 f amplifier C boosts the level of the input signal applied to the circuit through J Thereafter the MC1358 FM receiver C2 provides addition al amplification limiting detection and audio amplification The large amount of amplification provided makes the receiver very sensitive Therefore RF GAIN control R3 is in a Ee ee ee eee eS eee eT cluded to permit operation over a wide range of input signal levels Receiver input impedance is 75 ohms with the 330 ohm value speci fied for R7 to match RG 59 U coax ial cable If you prefer a 50 ohm in put to match RG 58 U coax you must change RI to 220 ohms Transformer 77 supplies a differ ential input to JC The output to the tuned primary of 72 is coupled to the input of JC2 Trimmer R3 permits adjustment of the signal level for proper limiting action by C2 Resonant circuit LJ C7 must be tuned to the carrier frequency The deemphasis needed to compensate for the standard 75 microsecond pre 54 MODERN ELECTRONICS January 1987 emphasis of FM radio and TV sound is provided by C 0 If the output of the receiver at J2 is coupled to a stereo adapter or the receiver is used to detect si
19. cess II s modules are superior to those of other all in one programs there s a strong relational database a slick 3 D graphics function and communications that supports Xmodem and Kermit pro tocols and lets companies set up a small bulletin board or electronic mail system But others are disappointing awkward or both and Open Access II isn t truly integrated in terms of having multiple files open at once As its demo disk says it s a collection of powerful separate programs sharing a windowing inter face but meant to be used one at a time While Open Access comes in a vinyl box big enough to be Barbie s Dream House there s no function key template to help you decipher the constant refer ences lt do gt lt change gt lt line del gt lt macro gt and similar keys you ll need the reference card or the ample on screen help There s no tutorial for the program as a whole but chapters in the mod ule manuals The general layout is appealing F2 al You can t use two applications at once but you can always call Open Access II s desk ways calls a menu of functions executed by typing one or two letters and F8 sum mons built in desk accessories including a calendar calculator alarm clock stop watch and business card file The mod ules have highs the database and lows a dreadful word processor whose over write mode lets you type infinitely long lines the Enter key aligns the
20. dal tad BRIRSESE SSR ESSEE i 2 ESESESEVLEEERREEREE 319 te 4 22 5 250 24 50 za 00 33 75 22 O 47 90 59 50 Re RKER SSASRSBRRELo SSSSsssSSSsssssssesseeess 288 SER FGFS VARESE ERBES SENE SEESE i EH 8 N Fw 8 E 8 E 2925 00 3735 00 Om wine 38 P4209 A821 5 each of the 72 atendard valuas in sanea P4300 13 16 2 0 24 etc througn 910K P4303 WIRE WRAP 1360 total P4305 3 ut DIP SOCKETS JI 1 4 Watt Carbon Film Assortments WI 047 ut each of tha 73 standard values in seres POU aut Standard protie 10 1215 18 22 etc through 10M NPO NPO NPO NPO NPO MPO NPO NPO Universal mounting and 365 tots pce R r amp 28 214 peckeging capabilities gt Contacta sccommodste 5 aach of the 72 standard values in series 09 80 f P4402 15 ot 69 231 015 through 021 rec 11 3 16 2 0 2 eat through 910K P4403 18 pt 3 6 97 5231 or round dual in tine leads 360 tata pcs Paso 22 pt T 637 5 3 Wire wrap potis hetd to true position of 015 pro Peace Hot 1a 8 69 66 7 Fil veding irua positon of JOZI on boards tot stth 1 2 Wert Carton Film Assortments Pato 39 pt 10 889 66 71 chent automatic wira wrapping 5 aach of Ihe slandard values in seres B 4 pt 7 180 88 53 YOUR CHOICE TIN OR GOLD 10 12 16 18 2 2 etc through 1 0M 56 pt T 180 88 53 38 Menai SO microinch yaki ey on poki aoct sts 355 total pcs 6 pt 138 100 35 COPA 7500 TRUM J OP470N gt TEXAS INSTRUMENTS QUALITY 5 each of the mandar
21. power supply If you do this make sure that you upgrade the power transformer secondary s current rat ing to 450 milliamperes to handle the drain of the additional circuitry Also use the Cable Communica tions System s regulator to obtain the 9 and 18 volts required by the 4 5 MHz FM Receiver Input signals to the 4 5 MHz Re ceiver can be supplied through a co axial cable feed wired directly into the source The optional pickup unit shown in Fig 3 can be used to induc tively couple the signal from the source into the receiver obviating the need for direct connection The pickup unit goes between the z aame aa E MOO O OO E s January 1987 MODERN ELECTRONICS 57 Say You Saw It In Modern Electronics V7Vac Fig 2 Ac power supply schematic diagram signal source and receiver where it serves as a high impedance front end for the latter It s simply a broad band voltage follower that reduces the impedance to match the receiv er s input The output can be con nected to the receiver through RG 59 U cable It s best to locate the pickup unit near the signal source The coax both supplies power from the receiver to the pickup unit and carries the signal from the pickup unit to the receiver The relatively high impedance of L2 prevents shunting of the output signal to ground while permitting dc to flow to the collector of Q Plac ing inductive pickup LI near a coil or transformer in t
22. priority control digital display and permanent memory Lunar Antenna Also included in the grand prize is a broadband monitoring reference antenna from Lunar Electronics The GDX 4 covers 25 to 1300 MHz and includes a 6 foot ones ELECTRONICS INC ae egency 7707 Records Street Indianapolis IN 46226 pan ees tare ee a 1 awarded FERESE Z60 Base station scanner l Regency HX1500 Handheld scanner 1 Regency R806 Mobile scanner 1 Lunar GDX 4 Antenna 5 awarded 1 Regency 260 Base station scanner 1 Regency R806 Mobile scanner First Prize SERTER 5 awarded 1 Regency HX1500 scanner Contest rules Just answer the questions on the coupon all answers are in the ad copy fill in your name and address and send the coupon to l Regency Electronics Inc 7707 Records Street Indianapolis IN 46226 Winners will be selected from all correct entries One entry per person No purchase necessary Void where prohibited by law Contest ends June 30 1987 1 The Regency 260 is C a digital alarm clock C an FM radio C a scanner C all of the above 2 The Regency R806 is the world s first controlled crystal scanner 3 The Regency HX1500 features O 55 channels C Bank scanning CO Liquid crystal display C all of the above 4 The Lunar GDX 4 antenna covers to MHz Name Address City State Zipcode I currently own scanners Brands owned pe ee
23. with the exception of a Type In function that is so very use ful to have Clarity How quickly can you find the right new word for you to replace the one you typed This isn t measurable of course but it s easily sensed In this area Word Finder s strength is also a weak ness It pops up a listing of so many words to choose from that the very selec tion of the one you want slows the pro cess down For asynonym list when the cursor was on the word begin for example Word Finder quickly listed 41 words Each word could be explored further by placing the cursor under it and pressing the return key which cuts down on the number of words to choose from and fo cuses more tightly on its meaning Webster s Thesaurus a main competi tor with less than half the synonyms available listed 24 synonyms for the se lected word which is 17 choices less than Word Finder provided But it listed them in two sections numbered and 2 witha maximum line character count of 34 ex cluding the numbers Word Finder lists words in a much wider window that ex tends each line to as much as 68 charac ters It does group words with closest meanings in alphabetical order starting a new grouping without issuing any in dentation number or any other division that would make it easier to read In another instance with the word word 81 synonyms were listed by Word Finder while Webster had only 10 Webster however
24. 00 OD O 2 Years O 1 Year issue 3 Years 36 issues 2 Years 24 issues 1 Year 12 issues O Life O 3 Years Start with ____ Call Zip State Payment Enclosed My account number is O Renewal 76 N Broadway Hicksville NY 11801 VISA C The Radio Amateur s Journal MasterCard D Please send me CQ for O New Name street City Charge My Order To SUKI January 1987 MODERN ELECTRONICS 53 i Project A 4 5 MHz FM Receiving System This simple system picks up sound from TV receivers and other sources that have 4 5 MHz signals and delivers an amplified output suitable for driving an audio amplifier By Duane M Perkins he FM receiver to be de scribed has many possible uses It can pick up sound from your TV set or any other source with a 4 5 MHz sound carrier It also makes a perfect companion for the cable communications receiver de scribed in the September 1985 issue of Modern Electronics The output of that receiver includes the 4 5 MHz audio carrier which will be ampli fied and demodulated by the receiver described here The two units work ing together could be used to extract the video and audio signals from a personal computer to drive a video display monitor Our 4 5 MHz FM Receiver is a complete stand alone system It even includes its own built in ac power supply You can hard wire the Re
25. 14 1 5 All voltages are positive with reference to cir cuit ground January 1987 MODERN ELECTRONICS 59 RF a INPUT i _ r12 j3 iat i i cit i SHIELD GAO Ua RS TI T1 PRI SE SEE TEXT J JUMPER Although it may not be absolutely necessary it s a good idea to enclose TI inside a shield Make the shield from thin sheet aluminum stock that when cut to size and bent to shape forms an oblong box that fits over the entire transformer assem bly Include mounting tabs when cutting the aluminum stock When mounting the shield over 77 use the tabs to hold it in place and ground it via the solder lug attached to the wire coming from the board with machine hardware Drill holes in the board for the tabs as needed The shield se cures to the board simply by bending the tabs Make sure the tabs do not touch any part of the circuit except ground Loosely mount the circuit board assembly in the bottom half of the aluminum box using spacers and machine hardware Carefully mark the locations of the adjustment slots for the trimmer controls on the front panel and the holes for the line cord JI and J2 on the rear panel Re move and set aside the circuit board assembly Drill suitably sized holes in the marked locations Deburr all ey es ce ee S af f E E t ea oe ee p i os ie j RECT1 R T C15 he T
26. 219 95 ya NRI pain SAA 1i CIRCLE 20 ON FREE INFORMATION CARD E r Gh Wee ee P C C t 24 Regency Electronics Inc 5 ower Control Centers to 20 MHz and surge suppression J cecum Engrg anes CPS Electronics Pinellas Park FL exceeds IEEE specifications 587 part 28 Syme gelesen oe ElectraGard multiple outlet power A The Model EG 42 provides multi TA Le sare racemase na be a erwater wee ee eee pea control centers with integral video stage protection on all three lines and Unip Electronics c20s 90 monitor bases feature built in surge protection emi rfi filtering and in dividual power switching for up to five components The Models EG 40 and EG 42 both respond in less than 3 nanoseconds Each has five inde pendent power switches plus a sepa heavy duty emi rfi protection with a noise rejection frequency range of 300 kHz to 100 MHz and surge sup pression exceeds IEEE specifications 587 parts A and B 139 for Model EG 40 159 for Model EG 42 CIRCLE 21 ON FREE INFORMATION CARD K7 i n at a r GSR F ELECTRONICS P in 7 3 a 11176 N Broadway Hicksville NY 11801 be ee wa t pi 3 FREE INFORMATION SERVICE Free Product Information 3 i For further information on products dealers or literature Readers can obtain free information on 7 in this issue circle the appropriate numbers below Be sure products advertised by the above com
27. AA S KAOP Aj 4 78 19 990 f of 15 POPULAR eee 54 gt 4750 e anims end pacea BY cat Dg 6 2 3 24 18 65 3H VALUES E KIT LM7BO5SCT cen sa 92 TAGIN S sin 1 Wert Resistor Assortmasts ANASONIC V SERIES RUMP 15 LM7B12CT 79 n r L 3 i a 00 797 50 S494 Stiched Manzi Filey Q wee BRAARHAAAHS 22 50 gegi Oa fi SSS SBRSS SFR Yi J z RS to Wg aa a ai a Mmt RA LEE SHR SERSSRSLBRB EEE ESBRS GSK RIB 744C643N LMVICLN 4H CBBBN 2 LMZOJAN 74HCADORN LM3O7R 74HC4020N x 74 C4040N TAH C4043 7AHCAO5ON 74 C4060N 74HC4075N 74HCACTAN 74H C4614N 74M C4E38N 74HC4A563N DAL1022LL N 00 MMA36QEST 2 SOf MJER MMSISHA AN 2 50 E MJE722 Interface wna JA z CRRBINSERBCBB as 3B B8 Bg 20 20 13 g 15 63 63 ca 1 08 08 va 08 75 1 20 8 e8 25 amp 63 ba amp 78 83 83 gg 83 0 BE Ornension DO 5 BET BEL BONS 74 500 TTL Pari Price 7AL SOON 45 74LSO1N 50 74L 502R 45 74LS03N 45 74LSO4N 45 74 S05N 48 74LS08N 45 741 509N 48 ZALS10N 45 Signetics 7aLSV1N 45 Pan 4LS12N 46 74LS13N C 4 715141 4 amp M6012F 76LS16N DACOBCN 74LS20N 5 MC1408 7N 74LS21N 74LS22N 74L 26N 74LSZ7N 74LS30N ML SRN aL 53 N 74L538N 74LS40N 741 5426 74L349N TAL SS1N 74LS54N 74LS55N T4LS7IN MPF wz Pert Price f MpS2222A DS 1488N 125 a DStaagan 1 2 f M9523894 DS 1489N 75450N A EEIN RE BESSHSBSRRSRRA KA 17MP LMQ17T LM31BN LM319N KES MUO ee A a a a a N
28. AS a w INN NRO wD att oe 101 taa REGRRESRSLSLRSASERRELLELELLEE SEIZES ARI INBER rer BEESESE 88288 ELELEE T EE EEEE EE TETTEIT FERT 222 w Lal ca wd a a eC a GEA A ND a ame ded KA RO Aa Bo ca ASR B E MERIAME EA NN o 3 A LAFBISCT M222 P ALGAE r 08 825 00 AS101 5 each of valums Q 470 ta SOQ 200 38 01 1 06 742 50 254 total bes 4116 nsec 16 x1 OD R TIP1Z2 9 742 50 AS201 Geach of values 620 107 BRO Price Per Pak Of Piz 5 9 770 00 256 total pcs Part No 128 BIZ 35 J 00 770 00 AS301 Seach of values 8 ZKO to 2 OMO 4116N ND 7 15 64 1397 75 Be 78 j 1255 toral pe 5290N YN 37 RIA 1 x 7B 577 50 2 Wan Resistor Assorimente E 5 aach of values O 178 to 89 MN4164 14 t M150 7 d gt 255 total pc 5 each of values 622 to 7 5KO 255 ioi Ebectrodes Metallized him Dip Kay 5 each ot values B 2KQ to 2 OMO Lead Spacing 200 300 Part No Descaption L A 3 za 90 7 SeH Heating DS GAC 20 Dynamic RAM ee 2 70 W 5 7 i Rec Resistors 5 of 3 25 o x wide 505 PIKI 15 Dynamic AAM 270 gt 5 3 3 O41254C 20 Dynami RAM B15 va 5 m Watt 1E 33 15 V SERIES 16 384 St j 5 787 6555 7 12 DIGI KEY Cap N MOS Ram 0 7 7E rt 7 3 92 9 Part No inf Static RAM 4 13 200 33 14183 Static AAM 24 Di 034 a 154 3 Pa UA 9 0047 Stanc AAM 22 O a5 18 5 3 PaSio a 0056 pel bwen 1D Wets 3 y i 3 338 hw rom Operating Temperatura Ranga 40 C to 65 Capacity Renga 9 0luF to 1 OF Tem
29. Dad was unhappily muttering I should have bought a Hewlett Packard LaserJet Plus The difference comes down to the two tasks of laser printers One is to act as a fast daisy wheel or letter quality device spitting out sharp text in near silence at irresistible speed The Big Kiss 2 995 does that job to a nicety emulating a Di ablo 630 or Qume Sprint while offering 14 built in fonts up to 64 with a plug in cartridge plus downloadable fonts an ample print buffer and the power to glide through a long ASCII text dump 30 000 characters eight single spaced eee ___ ___ E E AA Satay a ee e es SOREN Sos Aa ka anaa SS a ah wano Ses ai pages in a minute and 20 seconds or the 110 page PC File manual in 20 minutes Speaking as someone who produces text files for a living I could live with a QMS But Dad dreams of desktop publishing and fancy graphics where the Big Kiss suffers compared to the industry stan dard Hewlett Packard and all the soft ware available for it While the QMS can emulate an Epson FX 80 well enough to produce Framework II or Clickart Per sonal Publisher graphics they have the fuzzy dot matrix appearance only darker of well FX 80 graphics It refused to right justify text when I tried my word processor NewWord and its FX 80 driver and did so only in draft mode of Microsoft Word 3 0 ignoring the latter s ability to change Epson character size Editors note The NewWord produc
30. Hi Speed 1200 Baud Phone Off Hook Transmit Data Carrier Detect and Auto An swer Included with the modem area plug in power supply data interface cable user manual and CMB Priori ty Response Card The modem mea sures 10 5 D x 5 5 W x 1 3 H and is designed to fit under a desk type telephone 239 CIRCLE 16 ON FREE INFORMATION CARD X K Band Radar Detector The Micro Eye Express from B E L Tronics Ltd Mississauga Ont Ca nada is claimed to be the world s most sensitive automotive radar de tector It is said to be about 20 per cent more sensitive than the com pany s previous XPR Long Range model detector The new model uses atwo stage amplifier that examines a single sideband to reduce noise and increase Sensitivity em moe Be at 2 Say You Saw It In Modern Electronics Micro Eye Express is designed to mount either on the dashboard in an adjustable bracket or on a visor It comes with dash bracket visor clip Velcro strip and cigarette lighter plug 299 95 CIRCLE 17 ON FREE INFORMATION CARD Optical Fiber Stripping Tool Opti Strip from Davle Tech Fairlawn NJ is a unique stripping tool designed specifically for remov ing the secondary coating from opti cal fibers It handles both loose and tight fit fiber optics cables of any length Damage to the optic core during stripping is prevented with supplied front and rear guide bush ings that exactly locate the cable in re
31. Lightning s 50 000 in its spelling check er thesaurus program Word Finder works with most word processor programs such as WordStar Microsoft Word Easy Multimate Word Perfect XyWrite III Framework etc aS well as a host of utilities such as Sidekick Prokey and so on It takes up less than 30K of memory and is ultra sim ple to use The program comes on two disks one of which is a synonym data base that gives you a choice of 220 000 synonyms and a smaller 90 000 one for users with limited disk space Suggested selling price is 79 95 Evaluation Does an electronic thesaurus with the most look up words we know of auto matically make it the very best one in town Yes and no Aside from size key factors to consider are speed ease of use flexibility and clarity In the speed category Word Finder performs like lightning sorry Borland In this respect it s a smidgen faster than Webster s New World On Line Thesau rus in replacing a word in matter you ve typed with a word processor For ease of use we can t think of a less complicated operation than Word Finder s Just place the cursor on the word you want synonyms for press Con trol Function Key 6 together and the list of similarsmeaning words magically ap pears Then move the cursor to the new word you want press enter and it ll im mediately be substituted for the old word But one does give up some flexibil ity for this simplicity We
32. Motorola and Microswitch for pressure transducers and various appli cation notes from Analog Devices and Burr Brown on transducer interfacing GB E Ea January 1987 MODERN ELECTRONICS 73 eT Say You Saw It In Modern Electronics ce er a S Lael ee ee ies HARDWARE HACKER Overflow msb Digital Outputs 05 Q4 RC 03 Q2 01 5V VIN RF CA3306 14 32 Mhz Clock 1 0 volt reference Video input top view Fig 4 A 6 bit 64 level RCA video A D converter There are lots of opportunities out there for new and creative use of sensors particularly strain gauges pressure transducers humidity sensors and such Let us know what hacker projects or ap plications you come up with Show me a video A D converter Analog to digital A D conversion at video speeds has traditionally been a real hassle Yet there is lots of hacker poten tial here particularly for such things as capturing images for personal compu ters in desktop publishing and for doing digital TV signal processing Video rate A D conversion has to be done much faster than can be handled by most traditional circuits Instead a brute force method has to be used in which the input analog video is simultaneously routed to 64 or 256 individual compara tors The result of each comparison is then converted into a 6 bit 64 level or 8 bit 256 level digital code One very popular sampling frequency for video conversion is 14 32 MHz
33. NA N eA N J28 X2SEE SEESE BREE Niom wo E i e FERRE SEGRE CABI IAE SER KATES HALB BRE RNN WE BASRI SEH PSRs 74123N 4125N 74132N SERS BLASE az alae oa A m L OA SE beh rere RRN EPT Dimension L 6 5 B3 8 aonana Oa G P ne a NI Serer D l ad e eee wt FET a PERE STS wu 67 Ni ESESSBRANN ZARES HZNNA S8SSSSCESSS SSSSE RL Eesees D F h h o O AGH 18 155 SSSSSSSSSSESS i KREBS RSSSES EBS Baht Nh a gt BSRSRFBSRRS RSSRR BEILA BSSCS EERE amp Www Wahi ny Ol w wu a BBroeeisBtcsi N aN LM3401N AOCTTIICCN 15 8 f coo 20 1 WO LM3524N ADOIDICCNII 7b ADOJMICCN15 sa BS2PU SLE SRB 330 00 rT Whi ageosiiwi WEI He FEINO 38208 2w Wettape Asi oms Wan Ma Working Voltage zv 30y 500 Astec Ambient Tamp i 7PC 622 50 Onerating Temp Range 55 C 10 W0C 632 50 Dimenpon 130 715 00 412 50 A gt Dimension d og 7325 ft Meta Gude Fim Values in Ohms 047 to 1 OM 25 How To Order Teke ary standard value li 8 1 5K sod Enns mg eda Wt for watt a add a WZ for 2 wan lie gt y IR 3 pa 15KW tor 15KO 1 wan th the Dig K s5 5 99 G 7 10 A a Ed 76451N 173 25 numbe aa a ee eee Tano z e RR te 9 2126 5 RAE 5 Ba 6 ac 2155 am K gt 1 ie Pricing 6 m 500 1 000 A j 2185 TEABAN ae Wan 6 70 900 4000 7250 3 35 tg 1 RA E222 LM7816CK TADIN 2Wat ia 3 50 47 a ky 35 1 Ss 13 1 ASSORTMENT ki f z acct
34. a machine vision system developed by Joseph Wilder of PA Technology and Rajarshi Ray of AT amp T It s called Robotic Acquisition of Objects by Means Including Histogram Techniques In other words it can see and choose specified parts from a jumbled heap in a bin or align thick film ICs while cutting the task from 20 min utes to less than a second Ee eee 6 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics That s about all it costs Subscribers for each page of editorial matter in MODERN ELECTRONICS every month No charge for informative advertisers messages Or for free information requested on our bound in postpaid Free information Service card A bargain You bet MODERN ELECTRONICS is a veritable one stop source of hard information for en thusiasts whose interests spread across the entire spectrum of electronics and computers for work and play The latest technical information and news writ ten by agalaxy of authoritative writers Forrest Mims on Experimenting Don Lancaster on Hardware Hacking Stan Prentiss on Video Len Feldman on Audio Glenn Hauser on Communications and Eric Grevstad on Personal Computers to name a few authors who Share their Specialized experiences with readers every month This neat package keeps everyone abreast of the important developments in electronics and comput ers From new devices and circuits to useful construc tion
35. a registered trademark of Commodore Electronics Ltd Credit card customers can order by phone 24 hours a day Po 7 days a week aoe VISA Mavtecars ASen Toll Free 1 800 328 0609 Sales outside the 48 contiguous states are subject to special conditions Please call or write to inquire SEND TO Item H 1968 C O M B Direct Marketing Corp 1405 Xenium Lane N Minneapolis MN 55441 4494 Send___Modem s Item H 1968 7041 072 at 19 each plus 4 each for ship handling Minnesota residents add 6 sales tax Sorry no C O D orders CI My check or money order is enclosed No delays in processing orders paid by Check Charge O VISA C MasterCard L American Express Acct NO e 2 PLEASE PRINT CLEARLY lame Address KU State lt S Phone i Sign Here M C OM BIC OmMBIC OMB CIRCLE NO 150 ON FREE INFORMATION CARD January 1987 MODERN ELECTRONICS 17 SEIN S Technology Surface Mount Technology FIL This new electronics construction wave will change the way we all build circuits By Forest M Mims III he development of ultramini l ature hearing aids pocket cassette recorders slimline calculators laptop computers tiny radar detectors and many other highly miniaturized electronic de vices has been made possible by the rapidly maturing field of surface mount technology SMT This tech nology is now available to electronics experimenters and it gives us the ca pability
36. about their assembly will help you to better understand the advan tages and disadvantages of surface mount technology What is Surface Mount Technology Conventional circuit boards are as sembled with components bearing electrically conductive leads or pins that are inserted through drilled holes Generally the leads or pins are soldered to copper foil traces on the side of the board opposite the component When double sided boards having plated through holes are used solder may be applied to both sides of the board In contrast surface mount circuit boards are assembled with compo nents that have terminals or small pins that are soldered directly to cop per foil traces on the foil side of a cir cuit board Pins if present are not inserted through drilled holes Sur face mountable devices are generally Say You Saw It In Modern Electronics Fig 2 Assortment of surface mount ICs transistors and chip capacitors EMITTER oll Fig 3 SOT 23 surface mountable transistor package much smaller than conventional components It is important to understand that surface mount technology is not new The miniature flat pack inte grated circuits developed by Texas Instruments in the early 1960s for example were surface mountable Surface mountable ICs LED dis plays capacitors transistors and re sistors were available in the 1970s Many of the principles of surface mount technology were borrowed fro
37. air core form which yielded about 26 microhenries If you wish to use a different size coilform calculate the number of turns needed using the formula N 26 9A 10B A where A is the radius of the coilform and B is winding length in inches After winding the requisite num ber of turns on the coilform secure the turns with a couple of layers of plastic tape Scrape 4 of enamel from both ends of the winding and connect and solder them to the free end of the 300 ohm twinlead cable Use plastic tape to mechanically se cure the connections to the coilform Checkout Before installing the ICs in their sockets plug the receiver s line cord into an ac outlet and use a multime ter to measure the dc voltages refer enced to circuit ground at the cath odes of the zener diodes in the pow er supply section You should get readings of 24 18 12and 9 volts at the cathodes of D1 D3 D2 and D4 respectively the first four entries in the Voltage Checkout Ta ble elsewhere in this article If you obtain these readings power down the receiver and allow the capacitors in the power supply to discharge Then install the ICs in their respec tive sockets making certain you orient them as shown in Fig 5 Plug the receiver s line cord into the ac outlet and perform all voltage Interior view of assembled receiver and pickup unit WW S AAY ui 1 an 7 s i py al Eaa Mi cha AE a gS yA AA E i x Ate
38. all panels including the speaker baffle Don t forget the front and rear edges of the top bottom and side panels Wipe the panels com pletely clean of sawdust Then strip of insulation from the conductors at both ends of a 12 to 15 length of two conductor zip cord Tightly twist together the fine wires and tin them with solder Connect and sol der the conductors at one end to the lugs on the screw type terminal strip Pass the free end of othe zip cord through the hole in the rear panel and mount the terminal strip in place With the screws of the termin al strip screwed fully in fill all around the inside of the terminal strip with caulking or silicone adhe sive taking care to avoid fouling the screws to create an air seal Drive a 2 finishing nail every 3 or so along the lines struck on the ex terior surfaces near the rear and front edges of the top or bottom and aa 9 AA u aa aa SPEAKER CUTOUT 7 TF DIA SPEAKER BAFFLE aa AA 10 RECESS BAFFLE gt i n s m pasi ra ae i B Me i ak i a ta 4 37 BILL OF MATERIALS 8 full range loudspeaker Radio Shack Cat No 40 1286C 4 16 x 84 panels of 1 2 or 3 4 ply wood particle board or solid wood shelving for sides back panel and speaker baffle 1 144 x 8 xX 14 plywood or Masonite panel for grille 2 81A x 8 panels of or 34 plywood particle board or solid wood shelvin
39. all surfaces with a thin layer of DAP When the DAP is completely dry allow 24 hours or more for this lightly sand smooth and wipe away all dust Then either spray or brush on an enamel paint in your choice of color Apply at least two coats of paint to assure a smooth finish al lowing each coat to fully dry before applying the next and rubbing down with fine steel wool between coats Printer Tractor If you are like most laptop computer owners you use your machine heavi ly for writing purposes When you print out your work it s nice to have a letter quality appearance Ra ther than feeding in separate sheets of typing paper one at a time you ll likely want to use a tractor feed with your printer and the newer clean perforated paper The latter when separated does not have the serrated edges that immediately identifies or 52 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics dinary fan fold computer paper However this type of paper has a disadvantage its fine perforations are more fragile than those of ordi nary paper Sometimes the perfora tions partially separate and cause the printer s tractor to jam If you find this happening with your printer there is an easy fix as follows As you are printing out a multiple page document carefully monitor the paper s travel through the tractor to determine just where the binding that causes Jamming occur
40. and about deep to inset the speaker into the baffle If you don t have a router simply mount f ay ad so wa Png lem hn 4 s aleas Sef im TORE a ali Ten ik tal aly s a ka J i e a F a aha A fier i TETE the speaker system s enclosure MENUA PANNE the spea aker baffle flat back loosely fill the interior with fiberglass wool Z E a a a rr L ea e ai aN OEN January 1987 MODERN ELECTRONICS 65 the speaker on the front of the baf fle You can rout the channel either before or after removing with a jig saw or keyhole saw the lumber with in the smaller drawn circle Test fit the speaker in the cutout and trim the baffle if necessary to obtain a perfect fit Centered in the rear panel make the cutout for the 2 lug screw type terminal strip Set the enclosure s top bottom and side panels inside surface up Measure 4 to in from the front edges and strike a line this distance in from and parallel to the edges to use as positioning guides for the speaker baffle when assem bling the enclosure Turn over the panels If you re us ing thick lumber measure in from the rear edge of each panel and 4 or 1 in from the front edge de pending on how far back you plan to set the speaker baffle Strike lines at the marked locations parallel to the indicated edges If you re using Y thick lumber reduce the above measurements by 4 Sand smooth all exterior surfaces of
41. assembly of SMT boards 3 Though it is possible to install SMDs by hand for assembly of pro totype circuits the very small size of SMDs makes the procedure tedious and subject to error 4 Troubleshooting circuits as sembled with SMDs is difficult due to the small size of the components 5 Removing an SMD froma cir cuit board and replacing it with a new device is more difficult and te dious than accomplishing the same task with conventional components 6 Some SMDs particularly those made from ceramic may frac ture if the board to which they are at tached is flexed excessively 7 SMD design has not yet been standardized For example manu facturers make surface mount inte grated circuits having various kinds of lead arrangements each of which requires somewhat different attach ment techniques 8 Currently it is difficult for the average experimenter or proto January 1987 MODERN ELECTRONICS 21 WHEE EL ET i G 1E 1 pi op alala TT AA Se ee kiwa i To be part of it you need the right kind of training the kind you get from Cleveland Institute of Electronics the kind that can take you to a fast growing career in business aerospace medicine science government communica tions and more T oday s world is the world of electronics Specialized training You learn best from a specialist and that s CIE We re the leader in te
42. cost saving benefits the manufacturer accrues from SMT in clude reduced plant size and inventory space smaller products require less storage space a more effective and controlled manufacturing process and reduced freight and handling The customer who buys products in which SMT is utilized benefits too His price if not lower at this time gets him more sophisticated design for his in vestment The product he buys will pro vide better frequency response better electrical noise emi rfi shielding low er cOmponent mass that improves shock and vibration characteristics and improved reliability owing to fewer soldered connections Most equipment using SMT today are hybrids That is both SMD and through hole components are used As more SMDs become available 100 per cent SMT electronic products will be common As a byproduct they will also be smaller more reliable and less costly than the present crop of models Patrick J Chick The kit also includes two compart mentalized boxes containing a gener ous assortment of SMDs The resistor box includes 10 each of 30 thick film resistors having values ranging from 22 ohms to 150K The capacitor box includes 10 each of 27 monolithic ceramic chip capacitors having values ranging from 100 pf to 0 33 F Also included in the capacitor box are 10 2N2222 transistors and 10 1N914 di odes all in SOT 23 packages Vector does not include surface mountable ICs in the
43. devices in SMD form Many of them advertise this fact in the electronics trade pub lications Therefore if all else fails simply ask distributors if any of their client companies make SMDs Another way to obtain SMDs and supplies is to purchase them from a packager There are at least two such companies both of which are de scribed below SMD Technology Service Center The SMD Technology Service Cen ter 5855 North Glen Park Road Mil waukee WI 53209 800 431 4444 a subsidiary of North American Phil ips gives comprehensive in house seminars on SMD technology and sells a wide variety of SMDs and sup plies Here are some representative devices and prices for magazines and tape reels of SMDs Device Qty Price 74LS00 50 33 00 74LS04 50 35 00 4001 50 28 00 40161 25 32 25 LM324D 50 29 00 LM339D 50 22 50 NE555D 100 46 00 uA741CD 100 72 00 non transistor 50 19 00 pnp transistor 50 18 00 1k resistor 100 40 00 10k resistor 100 40 00 01 pF capacitor 100 27 00 1 pF capacitor 100 38 00 The SMD Technology Service Center also sells solder paste 50 grams for 42 00 and other sup January 1987 MODERN ELECTRONICS 27 Conceived to meet the urgent need of manufacturers for extremely minia turized circuitry surface mount tech nology was first commercially used in 1975 to produce digital wristwatches But the growth of SMT has been slow over the years due to the initial high cost of automated assembly equip
44. equipment this book concentrates heavily on theory of operation The text book style text is supported by more than 150 photos and illustrations the great majority of which are schematics Full coverage is provided not only by presenting the theory of telephones and networks but also in informing the read er about specialized telephone test equip ment and tools needed and detailing safe ty procedures that should be practiced Troubleshooting procedures for specific types of telephone equipment are cov ered in related chapters This is an unusu ally complete guide for troubleshooting both wired and cordless telephones NEW LITERATURE Holiday Specials Catalog The Heath Company s Christmas Catalog offers a number of holiday specials on selected items in its more than 350 item line of electronic kits and products running the gamut from audio to video equipment and just about everything electronic in between New in this catalog are PC AT compatible desk top and PC XT compa tible laptop computers a removable hard disk system a computer touch tab let a data line protector a data director a Loran receiver for boaters benchtop portable and shirt pocket DMMs and Fischer technik construction toys among others Full descriptions of each product include technical details price and photo Items on holiday special are clearly indicated For a free copy write to Heath Co Dept 150 815 ME Ben ton Harbor MI 49022
45. few weeks and expect to see two dozen 386 boxes following Com paq s lead becoming commodity items almost before IBM releases its own PC File III Lately when folks urge me to scrap my aging XT clone and join the frenzy I silent ly hand them a clipping from Info World The quote is from a Microsoft market ing manager and concerns DOS 5 0 or Advanced DOS or whatever they ll call the multi tasking colossal memory ad dressing system that s been the center of Version 4 8 C Copyright 1985 by Jim Button Portions C Copyright Microsoft Corp 1983 All rights reserved ButtonWare Inc P O Box 5786 Bellevue WA 98006 attention and anticipation since mid 1984 We ve had 27 people work ing on the new DOS for two and a half years It s a Significant multi tasking system very complex and you can ex pect 25 to 30 substantial bugs when it finally comes out While people gasp and sputter at this confession I go home to play with my XT clone and other less than optimal technologies My favorite product this month is a bunch of software I bought for 6 per disk The Honest Approach Long before big name software publish ers grudgingly removed copy protection enthusiasts responded to the idea of shareware or user supported soft ware programs which you re en couraged to pass along to friends via users groups or bulletin boards Instead of assuming you re a dishonest pi
46. fi z os nect and disconnect of equipment Ji US T if Ri if Wa and elminates the need to run large MONITOR fi z jii unsightly cables between equipment _ adm aaa j ene f Tui ica ow T HER Pra r fa gs aa Sr Abt Si eg It a t WA Sha g ae Pia Tet rs wa ar a Pus a 4 fe ee n Say You Saw It In Modern Electronics January 1987 MODERN ELECTRONICS 13 b ee a e NEW PRODUCTS tors has been introduced by Elenco Electronics The Model LC 1800 has an inductance range of 0 1 H to 200 H capacitance range of 0 1 pF to 200 uF and resistance range of 0 1 ohm to 20 megohms Basic measurement ac curacy is 1 of reading while resolution is 0 1 H 0 1 pF and 0 1 ohm Convenient switches along the left side of the meter s case access seven each inductance and capacitance ranges and six resistance ranges A separate slide switch located under the display is used for selecting the L C and R functions All measurement values are displayed on a liquid crys tal display A 9 volt battery powers the instrument for up to 200 hours The meter measures 6 8 H x 3 5 W x 1 4 D 199 CIRCLE 14 ON FREE INFORMATION CARD Wireless VCR Microphone SoundCatcher is a remote micro phone from SIMA Products Corp Chicago IL that allows the home video photographer to record sounds from subjects up to 200 ft distant It can be hand held or clipp
47. for a 6 surcharge First word only is set boldface caps at no charge Add 20 for additional boldface words Mart Display Rates 1 x 1 col 120 2 x Icol 230 3 x 1 col 330 Prepayment discount 5 for 6 issues 10 for 12 issues prepaid at once All advertisers with PO Box addresses must supply permanent address and telephone number Copy is subject to publisher approval Mailing Information Copy must be received by the publisher by the 20th of the third month preceding the cover date Send Advertising material with check or money order to Modern Electronics Classified Department 76 N Broadway Hicksville NY 11801 en ae SATELLITE Receiver without down conver ters Some have minor scratches all new 35 00 Satellite Visions Rt 1 Box 22 Mar shall OK 73056 CABLE and Satellite Descramblers Major brands Catalog 3 00 Cabletech 3310 10 W Bell Phoenix AZ 85023 DESCRAMBLE the latest video cassette copy protection scheme Our simple LINE ZAP PER circuit takes the jitter out of your picture Complete plans and theory only 9 95 plus 1 50 postage and handling Printed circuit board or complete kit also available Elephant Electronics Inc Box 41865 M Phoenix AZ 85080 602 581 1973 CABLE TV CONVERTERS amp EQUIP MENT Plans and parts Build or buy SEND SASE C amp D ELECTRONICS P O Box 1402 Dept ME Hope AR 71801 FREE VHS Tape Rewinder Forwarder for Details Send S A S E To
48. for transistor amplifiers Schmitt trigger transis tor circuits passive and active filters using Op amps attenuators among others In addition to designing cir cults CompDes serves as an educa tional tool graphic equalizer and video and CD inputs Surround sound is used with stereo sources and requires four speaker systems while synthetic ster eo simulates two channel sound from monaural source material Fea tures include PLL synthesized tun ing with 16 station presets automa tic scan tuning and fine tuning indi Continued on page 92 OMERROLD CORDLESS CABLE BOK TV CONVERTERS 2 MODEL STARCOM 460 1 ww geo ANY QUANTITY miran Instant channel recall E Programmable to go on at a a particular channel and off A automatically e Compatible with descramblers e Volume control 68 channels Mute control Automatic fine tuning JERROLD CORDLESS CABLE TV CONVERTER MODEL DRX3 105 400 58 channels Remote channel changing e Remote on off switch Remote fine tuning JERROLD CORDED THE RABBIT CABLE TV CONVERTER VIDEO MULTIPLYING SYSTEM MODEL JRX3 105 TR 7000 59 95 6 11 a 69 96 1 5 Y 36 channels saa push button gai IT S LIKE HAVING A yy a o0 VCR IN EVERY ROOM lt gt J E MASTER CARD W VISA j CIRCLE 29 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics TV CONVERTER g MODEL DRZ 450 Pill 66 channel
49. learn by doing right from the start you conduct important experiments and tests with your professional dig ital multimeter You assemble the remarkable NRI Discovery Lab and per form a complete range of demonstra tions and experiments in the process MPa ACTION AUDID Terie SETEC Y AB may Geta Ad MLA aa wa uNe y NEH IOCAN PARTON Go ENE Hands On Training As You Build a 27 Stereo TV In just hours you assemble an excep tional state of the art TV receiver using easy to follow step by step instructions During this assembly process you learn to identify and work with components and circuits used in actual commer cial circuitry Then through tests adjust ments and experiments you quickly master professional troubleshooting and bench techniques A ee ee YA j m za ME Hi aa li Ma w ig Wa p sj j d r k L p _ a L a F z1 E T Ta 7 t i p a 5 Pe r aji M E a E ai P G 7 r ku a T g 1 n A v P a g i j fa l 1 I il i zA a i 7 i Ear R ie rae i a a NRI s commitment to you goes beyond providing you with equipment appropri ate to the latest technology Of equal importance is our dedication to training techniques that let you master TV video and audio troubleshooting and repair quickly and easily Best of all we ensure that in the learning process you acquire the very skills that will make you a pro fessional service technician on the job
50. lengthening is called strain and is normally measured in microinches per inch Under normal loading strain values usually range from a few hun dredths to a few tenths of a percent This of course varies widely with the material and the applied load For fairly low stress values the steel will stretch linearly with the applied load It will also return completely back to its original size when the stress is released This is called elasticity By this defini tion steel is much more elastic than rub ber and ceramic materials are even more elastic than steel You could build an electronic scale by measuring the linear elastic strain on a piece of steel as you add weight to it As you increase the stress further you stay elastic but you are no longer linear picking up added strain with added load But you will still return to the original size when the stress is released Eventually you will get to the yield point The stress here is so high that the steel cannot return to its original state Instead a process of plastic deformation occurs Release the stress and the steel ends up longer than it was originally JI STRAIN DIRECTION Fig 2 A resistive strain gauge Many metal forming processes partic ularly deep drawing and bending work by forcing the material into its elastic deformation state The reason that the curve tends down ward past the ultimate strength point is that the cross sectio
51. let you fail The Heathkit Catalog is a simple and FREE first step toward this ex cellent opportunity In our catalog you ll find over 450 interesting and useful items from computer hardware and software to robots and test instruments and from home security systems to color tv s and amateur radio equipment But what makes Heath Company unique is that we offer you the confi aNOW for your FREE Heathkit Catalog AAA SL uu 3 Yes want to see what kitbuilding can do for me IEEE e Please send me the latest Heathkit Catalog Free Ss Ze ig Send to Heath Company Dept 079 492 igi Benton Harbor Michigan 49022 i Nam aw ia AAAAA IIAHI W IAI A aAERBwu3 u 3 Ci mu Heathkit aa i ee Ia i ee Zip Company A subsidiary of Zenith Electronics Corporation P CL 787R14 E L I Ee ee eee ee ees ee ee ee ee ee ee eee Ge YA CIRCLE 79 ON FREE INFORMATION CARD January 1987 MODERN ELECTRONICS 15 PRODUCT EVALUATIONS Iii The Paradise AutoSwitch EGA A video card that automatically changes displays to suit the software A new EGA video card from Paradise Systems Inc is half the size of the IBM version yet gives you more functionality at a lower price The Paradise Auto Switch EGA automatically senses the display needs of application software and changes to the correct operational mode EGA CGA Hercules etc Addition ally th
52. monitor connects to the board viaa DB 9 connector Two RCA jacks on the board are not currently supported by the hardware On theboard itself there are a 6 pin connector for a light pen and a 32 eg rie ete eS WA FGA Card a ee ie a Aaa a T i AutoSwitch pin connector that provides all monitor signals six color bits horizontal and ver tical syncs and blanking and related adapter signals The AutoSwitch can coexist with ei ther a monochrome display adapter or a color graphics display adapter and can be used as either the primary or secondary display When used with another adapt er however the autoswitch feature can not be used The board can work with three differ ent types of monitors enhanced color RGB color and monochrome And the card has downward compatibility with the IBM color graphics adapter and monochrome display adapter the Her cules monochrome graphics card and Plantronics ColorPlus card Installing AutoS witch Installing the AutoSwitch is just like in stalling any other expansion board for the IBM PC series of computers On the PC and XT system board switches must be set and on the AT a Setup program must be run Depending on the type of monitor you have you must set the switches at the back of the AutoSwitch board If you are using an EGA monitor the toggle switch is set to the right and positions 1 through 4 of the DIP switch are set on off off on These switches
53. of a strain gauge is a ratio of how much the resistance changes when length changes A gauge factor of 2 is typical Thus the resistance change will be double the length change Figure 3 shows a typical strain gauge circuit Because of the small changes in resistance involved you normally use a bridge circuit followed by an operational amplifier While you can use a 741 op amp for experiments premium devices with lower offsets and lower temperature coefficients are often better You would normally bond the strain gauge to some material that will change its length under stress using a recom mended adhesive You then use the out put of the op amp to measure the resul tant strain The circuit shown has a gain of 200 since the gauge factor is 2 and op amp gain has been set externally to 100 This means that output voltage will change 200 times more than input strain movement A zero control can be added by placing a small potentiometer in the middle of the left bridge arm The actual materials used and the op amp s gain will depend on your particular application The Omega HBM 6 120 LY 13 is a good choice of strain gauge for hacking Details on this device and many others appear in the company s free Pressure Strain and Force Measuring Handbook along with much more technical details and applications information How are strain gauges related to the pressure transducers we looked at in ear lier columns Well pressure
54. on my desk As you can see components designed for surface mount assembly are generally much smaller than conventional compo nents Capacitors and resistors the small bar shaped objects in Fig 2 are only slightly larger than this letter O and have conductive terminals on either end Transistors the two devices with three small pins in Fig 2 are slightly smaller than resistors and capacitors Figure 2 also shows two 741 operational amplifiers and a 556 dual timer These and other stan dard 4 8 14 and 16 pin inte grated circuits are about inch wide Pin separation is 0 05 inch half that of standard dual in line in tegrated circuits Surface mountable semiconduc tors are often designated by an SO for Small Outline prefix The tran sistors in Fig 2 are encapsulated in SOT 23 TO 236 packages Figure 3 is a sketch that shows the interior of an SOT 23 transistor One or two di aa ee eee SCALE CAPPROXIMATE O O S 1 0 INCH 14 PIN DIP o A MONOLITHIG CHIP So 25 DIopE OR CAPACITOR TRANSISTOR Galaga 774 CA Fig 4 Relative size of several SMD components odes can also be encapsulated in the SOT 23 package A 4 pin version of the SOT 23 package is designated the SOT 143 It can contain either two diodes a 4 diode bridge rectifier or a dual gate MOSFET The SOT 89 is a slightly larger 3 pin package de signed for rectifiers and transistors having a die that is too large to fit the S
55. one end female on other end 10 12 95 20 19 95 8 10 95 All types are fully shieled Don t Pass Up This Bargain AA SIZE NICADS PC amp XT extender board 19 95 Parallel switch box x 2 39 95 Paralle switch box x 4 44 95 Serial switch box x 2 39 95 Serial switch box x 4 44 95 Parallel printer card fully assembled addressable 23 95 20 MEG hard drive Scagae ST225 amp controller Card 3389 95 Uninterrubtable power supply 250 watt i 322995 8 slot case Great housing for our mother boards or you can put your real IBM stuff inside Takes side switch power supply Room far four drives 0 349 95 AT look alike case but designed to house Monitor swivel base 14 sim 12 95 Dust cover covers your monitor and your whole computer Don t take chances with your IVO aema IIS Oscilloscope probes switch seloctable to lx ar 10x In 10x freq response is DC to 2 re ZOIS 150 Watt power supply direct bolt in replacement Has four drive connectors amp PREPAID MAIL ORDERS can be paid by personal check but allow two extra weeks for processing RETURNED ITEMS ARE SUBJECT TO A RESTOCKING FEE OTHER STUFF YOU MIGHT NEED 2 battery pack 1 79 4 battery pack 2 79 MONITOR CHASSIS A complete monitor Requires composite video input and for power it uses 21 VAC On board controls for f
56. plug C 4 s leads into the appropriate holes in the board observe polarity and sol der them into place Repeat for the leads on C75 Be especially careful to install 73 in the proper direction and don t forget to install the insulated wire jumpers Note that the long jumper shown dashed in Fig 5 is needed only if you use the optional pickup unit Also C 6 is needed only if your ap plication requires dc blocking at the input Otherwise replace C76 witha wire jumper If you re using perfor ated board construction keep 77 12 and LI widely separated to avoid feedback that can result in oscillation Trim 1 4 of insulation from both pickup unit shown at left and right respectively Say You Saw It In Modern Electronics i SS aa ka ee ee ee es rE ee ee ee ee ends of a 2 long piece of stranded hookup wire Twist together the con ductors at both ends and tin with sol der Loop one end through the eyelet hole in a No 6 ground lug and sol der Plug the other end of the wire in to the hole labeled SHIELD GROUND in Fig 5 and solder into place Voltage Checkout Table Measurement Point Expected Voltage D1 cathode 24 D3 cathode 18 D2 cathode 12 D4 cathode 9 ICI pins 1 and 8 16 IC2 pin 5 12 IC1 pin 2 12 IC2 pin 7 7 IC2 pins 8 and 13 6 5 IC2 pin 12 6 ICI pin 5 5 5 to 7 as R3 is rotated IC2pins9and10 4 5 IC1 pins 4 and 6 4 IC2 pin 6 3 with R9 wiper at ground IC2 pins 1 and 2 2 IC2 pin
57. projects to evaluations of the latest products Both how to do and how it works information in creases your technical competence every page of the way Two cents a shot And hands on product evalua tions make you a wiser buyer whether it s on a test in strument or a video recorder So whether you re a ser vice technician an engineer abudding one in atechni cal career path or an active electronics enthusiast MODERN ELECTRONICS will serve you well Sub scribe and be sure to get every information packed is 2 CENTS PLAIN sue delivered to you every month It s important read ing you can t afford to miss Just fill out the coupon and mail with your check money order or credit card information Visa or Mas terCard to enter your subscription Do it today to en sure earliest delivery MODERN ELECTRONICS 76 North Broadway Hicksville NY 11801 Please send me Modern Electronics for 3Years 2Years 1 Year Name Z n p r Street B City je aa State Zip Charge My OrderTo PaymentEnclosed Mastercard 3 Years 36 issues wee 45 00 2 Years 24issues 31 00 O VISA 1Year 12issues 16 97 Account Number NN ee ee ee ie SCOPE PRICE BREAKTHROUGH CIRCLE 4 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics Now you can own a profess
58. receive our 100 page catalog free It s filled with all the facts you ll want to know about our training methods with full details on the equipment you ll use and keep as part of your hands on train ing You ll see how our more than 70 years of experience in uniquely suc cessful at home career training makes us the leading technical school today If someone has already used the card write to us at the address below Mirada Schools McGraw Hill Continuing Education Center 3939 Wisconsin Avenue NW wi Washington DC 20016 PHIL BNEW PRODUCTS k For more information on products described please circle the appropri ate number on the Free Information Card bound into this issue or write to the manufacturer Deluxe Car Stereo Kenwood s Model KRC 999 car au dio system offers 44 separate compu terized functions controlled by an outboard 16 bit microprocessor module Access to the preamp tuner and tape functions programmed into memory are via buttons on a motor ized control shelf Two preset vol ume levels a manual volume control and a 20 dB mute button are available A seven band graphic equalizer provides a 12 dB range at 60 120 150 500 1k 3 5k and 10k Hz Four factory preset equalization curves three user programmable curves and manual operation are offered A peak hold spectrum analyzer dis plays relative frequency levels The three motor auto reverse cassette deck has a rated 20 to 22 500
59. see that the XR 2240 has a de lay range from a few microseconds to almost a full month If you were to refer to the litera ture on the XR 2240 you would find a maximum delay of 5 days refer enced This is at variance with the 29 5 day delay calculated using the manufacturer s own maximum com ponent values No attempt was made to verify either delay since waiting even 5 days for the circuit to time out was not enticing In any event a 5 day delay is more than adequate for most applications Also listed on the specification sheet is a typical timing accuracy of 0 5 percent exclusive of errors attri butable to external components The dominant external components that Ry 10K XR 2240 TOP VIEW Output 30 uF Fig 4 External circuitry for using an XR 2240 as a Timer Beeper can contribute to significant errors are the resistor s and capacitor s in the RC timing network in the time base section Employing R and C se lection techniques recommended here errors due to these components can be virtually eliminated leaving the 0 5 timing error of the XR 2240 chip itself as the error deter mining device in the circuit Timer Beeper To make a timer useful in practical real world applications some cir cuitry beyond the XR 2240 is needed to convert the timer s waveform to drive a lamp buzzer or other atten tion getting device or to initiate an event upon which another circuit acts The T
60. temperature of wood stoves so that conditions can be adjusted to maintain an even comfortable tem perature Discrete light emitting di odes display temperature over a 300 CIRCLE 10 ON FREE INFORMATION CARD requirements of videocassette re corders The wrenches are made to match the configuration of the re cesses for adjusting tape feed tape tension and various other functions in VCRs They are available for both Bet d VHS hines F to 550 F in 50 increments Other a E i CIRCLE 13 ON FREE INFORMATION CARD LEDs provide visual indication when flue temperature rises above or falls Digital LCR Meter below safe limits A built in alarm provides an audible alert when flue temperature gets hot enough to cause A handheld digital instrument that measures the values of coils chokes transformers capacitors and resis Era meaa aaa and are connected by telephone type Eazy Connect is a family of adapt ers Each is designed to attach to the most popular computers printers modems and other peripherals to which they permanently attach An Eazy Connect Switch then allows data routing between up to four computers and one peripheral or be tween four peripherals and one com puter to which the Adapters are con nected Additionally the system can be cascaded to provide a low cost network capability ar CIRCLE 12 ON FREE INFORMATION CARD r Hus a7 sina kaika ii HRN RJ 12 cable This enables quick con 7
61. the October 1985 issue of Mod ern Electronics If an audio signal is present at pin 13 of JCJ the complex signal gener ator is eliminated as the source of the problem Hence either the envelope generator or the vca portion of the circuit must be at fault Should this be the case power down the project and remove C2 from its socket Temporarily connect a jumper wire between pins 2 and 14 of the empty socket and power up the project The jumper wire rigs the circuit so that the envelope is turned on continuously If you now obtain an audio output from pin 6 of JC4 the problem lies in NOISE DECAY TRY DIFFERENT VCO SETTINGS meee OOOO B ECHOED SNARE LFO SETS ECHO RATE DECAY SETS NUMBER OF REPEATS of fni C GONG TRY DIFFERENT CONTROL SETTINGS eet OO D BULLET CANNON VARY NOISE amp DECAY FOR WIDE RANGE OF GUN SIZES Fig 7 Switch control settings for generating a range of different sounds 86 MODERNELECTRONICS January 1987 Say You Saw It In Modern Electronics the C2 circuit Remove the jumper wire rectify the problem and then in stall a CD4001B in the socket Re turn the Drum Synthesizer to service When everything is working prop erly try generating some sounds with the Drum Synthesizer Switch and control settings for a good sound for initial testing of the Drum Syn thesizer are shown in Fig 6 Both the noise generator and the Ifo con trolled vco are use
62. the circuit labeled B1 and the black lead goes to B1 Similarly solder the electret microphone s leads to the appropriate points the indicated lead to and the lead to GND inthe circuit You have a choice of either of two microphone elements here both from Radio January 1987 MODERN ELECTRONICS 41 Fig 2 Actual size etching and drilling guide for the pc board Shack If you use the Cat No 270 090 element you can plug it directly into the holes in the board or prepare short wire leads to allow it to be mounted off the board The alternative is to use the Cat No 270 092 which comes with its own color coded leads Also the light duty relay specified for K mounts directly on the board Prepare two 3 lengths of No 22 stranded hookup wire by removing of insulation from both ends Tightly twist together the fine wires at each end and sparingly tin with solder Connect and solder one end of each wire to the points labeled RE SSS eee Eee ee Se R4 PB c57 RE A e LEC Talg _ O M C3 sy R9 C4 JUMPER O Q JUMPER 014 Ge K1 Relay TAI contacts t t Fig 3 Wiring guide for the pc board LAY CONTACTS in Fig 3 The other ends will be connected later House the project in a suitable size plastic or metal enclosure that is large enough to accommodate the circuit a
63. the pads into which the pins of standard DIP ICs plug When Servicing an SMT board even after removing the solder and breaking away device leads from the pads adhe sives may still secure SMDs to the board It is easy to detach the devices at this point though with a little prying To avoid part movement when reinstal ling an SMD a small daub of cynaocry late cement Krazy Glue is an example should be used to secure the part A freon based flux remover should be used if cleaning is necessary Irresistible Attractions Not the least of the attractions of SMT is a considerable reduction in manufacturing cost Here is an analysis A double sided printed circuit board using plated through plug in technology designed to accom modate standard dual inline package DIP integrated circuits with the pins on 0 1 centers and pin rows spaced 0 3 apart and watt passive compo nents might require 60 square inches of board In contrast using the down sized SMD component equivalents this same circuit would require only 12 square inches of board space With good quality pc boards selling for about 20 cents per square inch in the U S the reduction in board space of fered by SMT represents a saving of 9 60 for one board alone Even for equipment manufactured off shore this reduction ratio holds since pro duction is not too labor intensive Cost of course is the most impor tant factor in the manufacturing pro cess Other
64. the plug The choke should be barely warm If it feels very hot do not use this particular choke if you do it will quickly burn up Install the choke in the plastic box with the open end of the E lamina tions pointing toward and flush with the opening of the box Apply a strip 68 MODERN ELECTRONICS January 1987 Fig 1 Modified filter choke ready for installation in plastic box of plastic tape to the exposed metal of the choke A word of caution Don t try to economize by omitting the switch because L will burn out if left energized continuously In use never operate the bulk eraser near audio videocassette or compu ter tapes and disks Do your erasing at least 10 feet away from magnetic media and preferably in another Say You Saw It In Modern Electronics S1 250V 3A 117 Vac Fig 2 Schematic diagram of cas sette diskette mini bulk eraser room Also avoid using the eraser when your computer is running be cause if you do a program running in the computer is likely to crash Press and hold Z as you slowly pass the eraser in a circular motion for five seconds over a cassette to erase it Release S only after moving the eraser about 3 feet away from the cassette As the eraser is operating you may hear a buzz or rattle this is normal and does no damage to mag netic media To erase a floppy diskette place it in the middle of a magazine about the thickness of Modern Electron
65. the wires at both ends of the shield and inner conductor and tin with solder Plug one end of this cable into the holes la beled AUDIO OUTPUT inner conduc tor to the pad that goes to C8 and solder into place Remove 4 of insulation from both ends of two 3 hookup wires Plug one end of these wires into the holes labeled RF INPUT and solder Mount the circuit board assembly in the box with the spacers and ma chine hardware Locate the shielded audio cable and connect and solder the free inner conductor to the tip lug and the shield to the ground lug on J2 Then connect and solder the RF INPUT wire nearest the edge of the board to the tip lug and the other RF INPUT wire to the ground lug on JI Affix rubber feet to the box Determine exactly where on the top half of the aluminum box to drill the access holes for C3 and C7 drill 5 holes in both locations Clean 60 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics ee A ng ge gg a n gt E we Q Nae TAIWAN COMPUTER TRADE CENTER 7220 NW 58th Street Miami FL 33166 305 477 2600 2215 N Broadway Los Angeles CA 90031 213 222 9680 213 224 8610 800 342 2332 MANUFACTURER S REPRESENTATIVE DIRECT IMPORTERS OF IBM PC XT COMPATIBLES FACTORY PRICES TO DISTRIBUTORS DEALERS Prices Are For Quantities of 50 MOTHER BOARDS W O BIOS amp MEMORY Regular 640K eee 87 XT Turbo 4 77 8 MHZ 2 Layers
66. to hand assemble in our own workshops or labs ultraminiature circuits that rival in size expensive hybrid microcircuits For electronics experimenters this may be one of the most important developments in recent years For electronic engineers and lab techni cians SMD construction represents the new manufacturing wave that can be simulated with prototype models And electronic service tech nicians will face more and more equipment built with SMDs present ing them with new challenges Let s face it the plethora of mi crominiature consumer products that has flooded the market has sur passed our do it yourself handmade abilities Thanks to the availability of surface mount technology exper imenters can again design and assem ble circuits as advanced and as com pact as those manufactured by any one That s why I consider this arti cle and the one that will follow to be among the most important I have ever written The tiny LED pulse transmitter circuit in Fig illustrates why I am so enthusiastic about surface mount technology This midget circuit less LED measures only 0 7 x 0 25 and is thin enough to slip between the pins of a standard dual in line IC The circuit includes a 555 timer three thick film resistors and a chip capacitor Despite its diminutive size I assembled this circuit in less than three hours using standard etched circuit techniques and an or dinary 15 watt soldering iron Full de
67. tolerance compo nents considering that their values Time base output at Pin 14 Pin 1 Pin 2 Counter cas ann CSS AA WA AA LO Fig 3 Timing diagram of XR 2240 waveforms Say You Saw It In Modern Electronics ee GF ya ee ES ee eee SS Se SSS January 1987 MODERN ELECTRONICS 31 can vary by as much as 20 percent of rated capacity Tantalum capacitors in the 35 volt rating category are available in 10 ca pacitances ranging between 0 1 and 3 3 microfarads Therefore by con necting as many tantalum capacitors in parallel as are needed taking into account positive and negative toler ances you can put together the value needed Generally it is recommended that the calculated value of R be achieved as described above For the calculat ed value of C you will have to do some tweaking as will be de scribed under Calibration later in this article Listed on the XR 2240 s specifica tions sheet are the recommended ranges of values to use for R at 10 megohms maximum and 1 000 ohms minimum and for C at 1 000 micro farads maximum and 0 007 microfa rad minimum Using these compo nent limits the range of delays can be calculated Maximum delay 255 X 10 megohms x 1 000 micro farads 2 550 000 seconds This translates to 708 33 hours or 29 5 days Minimum delay 1 x 0 001 megohm x 0 007 microfarad 0 000007 second which translates to 7 microseconds From this you can readily
68. transducers are really nothing but strain gauges that have been factory built on a silicon dia phram By measuring the strain on the di aphram you can in turn measure gauge absolute or differential pres sures You normally would use a pressure transducer to measure pressure in a li quid or a gas while you would typically use a Strain gauge to measure deforma tion in a solid Where can I get robotics parts Try Small Parts These people stock all sorts of metals plastics hardware fas teners and whatever all reasonably priced Very small quantities are a spe clalty here They will also custom cut small pieces of steel stainless plastic brass copper or aluminum to size Most importantly they have the parts the average hardware store never heard of timing belts hitch pins plastic balls spring assortments wire clips perforated metal and bunches more Check them out How can I find more out about transducers and sensors First check into the excellent free hand book series available from Omega Engi neering that covers many types of tem perature flow humidity pressure strain force and pH measurement Second look into the many specialized magazines that cover this field Impor tant examples are Measurements and Da ta Control Engineering Instruments and Apparatus News and Pollution Control News Third contact the individual compan ies that specialize in interface electronics such as
69. which is four times the standard NTSC color subcarrier frequency of 3 58 MHz NAMES AND NUMBERS Analog Devices 2 Technology Way Norwood MA 02062 617 329 4700 Burr Brown Box 11400 Tucson AZ 85734 602 746 1111 Motorola Semiconductor Box 20912 Phoenix AZ 85036 602 244 6900 Omega Engineering Box 4047 Stamford CT 06907 203 359 1660 RCA Solid State Route 202 Somerville NJ 08876 201 685 6000 Small Parts 6901 NE Third Avenue Miami FL 33238 305 751 0856 Capturing and storing digital data at this rate is not trivial since you get a new word every 70 nanoseconds or so and since there will be almost a quarter of a million bytes per frame If you are plan ning on processing this image with a per sonal computer some sort of a high speed buffer will be needed between the computer and your A D converter If you are interested only in digitizing to 256 by 256 then a smaller buffer of 64K can be used combined with a lower clock frequency There are some exciting new fast memory chips available called dual port RAMs that are particularly at tractive for this sort of thing Fortunate ly single integrated circuits are now available that will do most of the brute force conversion for you Let s look at two examples Figure 4 is a 6 bit 64 level converter that uses the RCA CA3306 As you can see there is a video input and a reference input The reference input is usually a precise and fa
70. ya i ili f to include your name and address before mailing panies as well as for some editorially 1 2 3 4 5 6 7 8 9 1 11 12 mentioned products Simply circle the 13 14 15 16 17 18 19 20 21 2 23 24 appropriate number printed below an 25 26 27 28 2 32 31 32 3 34 35 37 38 39 40 4 42 43 44 45 4 47T 48 advertisement onto the Modern Bile 49 50 51 52 53 54 55 56 57 58 59 60 tronics Free Information Service 61 62 63 64 65 66 67 68 68 70 71 72 card bound into this issue After filling Se ASS cg fin your name and address just mail the T 85 86 87 68 89 90 9 92 93 94 95 96 y ll be f 5 97 98 99 100 101 102 103 104 105 106 107 108 postpaid card Your request will be for warded directly to the advertiser with a mailing label prepared by our reader service department to ensure speedy re sponse 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 92 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics Floppy Disk Services has been supplying stor age systems to the hobby and professional com puter community for 7 years now You can buy with confidence from a supplier that is in for tne long haul Whether you need advice or technical hele our
71. 3 l i I i i Fig 5 Wiring guides for receiver power supply pc board left and pickup unit board right holes Then thoroughly clean all ex terior surfaces with steel wool When the box is dry use a dry transfer lettering kit to label the J and J2 holes RF INPUT and AUDIO OUTPUT respectively and the holes in the front panel RF GAIN TONE and AUDIO GAIN from left to right You might also want to label the front panel with the identification of the project such as 4 5 MHz FM RECEIV ER Then spray three ight coats of clear acrylic on all exterior surfaces of this half of the box allowing each coat to dry before spraying on the next to protect the lettering If you re using a tape labeler spray the box first when the acrylic has com pletely dried apply the labels Line the ac cord hole with a small rubber grommet and mount J and J2 in their respective holes Pass the line cord through the rubber grom met into the box and tie a knot init 4 from the inside end Twist together the wires in each conductor and lightly tin with solder Plug the con ductors into the board holes labeled AC LINE CORD and solder Remove from both ends of a 4 ir HOLIZNADO Ka did AE bu shielded audio cable 34 of outer plastic jacket peel or separate the ex posed shield back to the jacket and trim of insulation from the inner conductor Twist together
72. 30 8mHz E STATIC RAMS 6264LP 15 150ns CA le KP 18 3 50 Ka 10 for 30 00 MINIATURE TOGGLE SWITCHES S PD T S PD T on on on off on Soider lug Solder lug terminals terminals ae 1 00 each 6 1 00 each 10 for 9 00 100 for 80 00 D PS T LIGHTED ROCKER SWITCH 115 vac lighted rocker snap mounts in S za x15 hole If Orange lens 16ampo coniact 1 50 J v I C 15358 Valley Blvd City of Industry CA 91746 Phone 818 369 2688 O R 800 892 8889 800 882 8181 Outside California CALL FOR CURRENT PRICES amp VOLUME DISCOUNTS Price Shown for Cash MaSterCard VISA add 3 more Prices are Subject to Change Minimum order 10 00 California residents must add 6 5 sales tax FOX MICROFOX Packed with features and perfor mance MicroFox redefines pocket size radar protection This beautifully crafted superheterodyne unit is scarcely larger than a deck of cards compactness made possible by anew analog microchip a Fox design exclu sive Incorporating new ways to boost sensitivity MicroFox can actually ex tract weak radar signals buried in ran dom electronic noise MicroFox em ploys avaractor tuned microwave Cav ity VTC the latest advance in non radar signal reduction When Micro Fox alarms it has to be radar not a false alarm 299 95 Pius 4 00 shipping amp handling 1 800 522 2636 For Orders Only 617 843 1900 For Information Cameo Enterprises Inc
73. 460 Gladstone Avenue Sylmar CA 91342 818 365 9661 is a well known supplier of high quality conventional prototyping printed circuit boards and supplies Recently the company entered the surface mount era witha breakthrough product a self con tained training kit that permits even 28 MODERN ELECTRONICS January 1987 the novice to design and assemble working surface mount circuits The SMT2000 training kit shown in Fig 8 includes six pre etched and plated double sided epoxy glass pro totype boards soldering aids tweez ers 2 solder paste in a convenient syringe and conductive adhesive Say You Saw It In Modern Electronics Manual assembly of SMD circuits while certainly not impossible does re quire special tools and a very steady hand A typical toolkit would contain tweezers or similar component hand ling utensil a low wattage soldering pencil equipped with a microfine tip and an accompanying vacuum type sol der extractor an inspection magnifying lens preferably one with a built in in spection lamp a quick set cement like cyanoacrylate and a good quality 0 015 diameter rosin core solder such as Kester s 44 Hand soldering of miultiple lead SMDs is an exercise in dexterity It re quires a good eye use the magnifying lens a steady hand and a lot of pa tience Because of the very close pin spacing of SMD ICs it is much easier to create solder bridges with these devices than with
74. CIRCLE 24 ON FREE INFORMATION CARD i a ae ee es How To Design Ultra Long Delay Timers eee nee Ti ja edie T Hi Hi a i i eer es hii rei Eo fea LE Tir Fig 7 0 The a inished Timer Beeper assembled on a pc board and housed inside a common plastic enclosure hardware you can use Fig 9 as a rough guide to component layout and refer back to Fig 7 for instruc tions on wiring the components to gether Whichever method of wiring you choose though it is a good idea to use sockets for the ICs Note that the pc board has facili ties on it for the four 1 megohm re sistors that make up R4 and five ca pacitors for timing capacitor C4 The remaining timing resistors R6 R7 and R8 mount directly on time selector switch S If more than five capacitors are needed for C4 you can accommodate them by twisting together the leads of two capacitors at a time and installing both in the same hole pair Note too that the piezo buzzer LED switches and fuse mount off the board House the project in any type of enclosure that will accommodate it Bring the ac line cord through a hole drilled in the rear of the enclosure and tie a knot in it about 4 from the end to serve as a Strain relief Then strip about 1 4 of insulation from both conductors tightly twist to gether the fine wires in each conduc tor and lightly tin with solder Machine the enclosure to permit mounting of time selection
75. COMPUTER ENTHUSIASTS A choice of handsome and durable library cases or binders for your copies of MODERN ELECTRONICS Both sytles bound in green library fabric stamped in gold leaf Cases Each case holds 12 issues Price per case 7 95 three for 21 95 six for 39 95 Binders Each binder holds 12 issues Issues open flat Price per binder 9 95 three for 27 95 six for 52 95 Canadian and foreign requests should also include an additional 2 50 per item for shipping costs Say You Saw It In Modern Electronics MODERN ELECTRONICS Please Print Please allow approximately 4 weeks for delivery P O Box 5120 Dept MOD Philadelphia PA 19141 O Binders To Jesse Jones Industries Since 1843 I enclose my check or money order for Please send me CL Files Name Address City State i l i January 1987 MODERN ELECTRONICS 43 A 20 Drum Synthesizer This easy to build device produces percussion sounds for amateur musicians and experimenters 44 MODERN ELECTRONICS January 1987 By C R Fischer lectronically synthesized per F cussion has been a notable development in modern pop and rock music This electronic equipment can be directly played by a drummer or be triggered by a pro grammable rhythm box or sequenc er Commercial synthesizers that use this technology are costly But if yov r
76. EPC M 1027 South Spruce Bloomington CA 92316 JERROLD gated pulse theory Twelve infor mation packed pages covering DI amp DIC con verter operation Includes introduction to tri mode system 6 95 plus 1 50 postage and handling Elephant Electronics Inc Box 41865 M Phoenix AZ 85080 602 581 1973 CABLE TV Secrets the outlaw publication the Cable Companies tried to Ban HBO Movie Channel Showtime Descramblers Converters etc Suppliers list included 8 95 Cable Facts Box 711 ME Pataskala OH 43062 STRANGE Stuff Plans kits items Build Sa tellite Dish 69 Descramblers bugs adult toys Informational photo package 3 Re fundable Dirijo Corporation Box 212 M Lowell NC 28098 PROJECTION TV Convert your TV to project 7 Foot picture Results comparable to 2 500 projectors Total cost less than 30 00 PLANS AND 8 LENS 21 95 Illustrated information FREE Macrocoma ME Washington Crossing Pennsylvania 18977 Credit card orders 24HRS 215 736 3979 VIDEO Scrambling Techniques the original secret manual covers Sinewave Gated pulse and SSAVI systems 56 pages of solid useful legible information only 14 95 Ele phant Electronics Inc Box 41865 M Phoe nix AZ 85080 602 581 1973 ELECTRONICS TEKTRONIX scopes Free list of recondi tioned 500 series TEK 543 30 MHz scope with dual trace plug in 180 plus 20 U P S Or der now and calibration included fre
77. GNATIONS POSITION FUNCTION yvco NOISE LFO LFO VvCO VCO NOISE LFO NOISE LFO VFO NOISE REPLACE SWITCHES A B C ON 76477 Say You Saw It In Modern Electronics Fig 3 A simple touch sensitive en velope generator using a pressure sensitive resistor R and op amp having to repeat C2 if you do make sure to add another 10 000 ohm series resistor and 5 volt shunt zener diode if needed When build ing only one Drum Synthesizer the inputs of the unused gates in C2 must be tied to either circuit ground as shown or to the positive supply line to assure stable circuit operation Because of the very high input im pedance of C3 the time it takes for the sound effect to fade out is vari able over a wide range The first am plifier in JC3 buffers C8 the second drives operational transconductance amplifier OTA JC4 The CA3080 used for C4 functions as a vca witha high level output that s directly pro portional to the current flowing into pin 5 The audio output is taken from pin 6 for amplification and ad ditional processing if desired Whenever C2is triggered the col lector of Q is briefly brought to ground If S5 is closed this causes the lfo s timing capacitor to be reset If the Ifo is then used to control the pitch of the vco it may produce the familiar synthesized drum sound used in SO many recordings and shows If your Drum Synthesizer is to be played by a drummer a touch sensi tiv
78. HC HIN 7aHCT23N 7AHC 125 F4HC 126N 74HC133N 74HC138N T4HC 139N HE IAIN i4 440151 TSAN s 74145N shaik 74H 154 74 148N 74540N 74RC 157 4150N 3174551N 74K0 158N 4151N 745545 74153N 4 745655 7415AN 245745 74HC162N JA 15AN TASBBN 74HC 1G3N P31 56 745 112N PAHC IGAN 741570 745 113N 74HC145N 74160N 745114N AHC 174N 74161N 745133N 4HC175N 74163N 745 134N 74H 193N 24164 745136N 25 74HC 194N 74165N 745 136N J4HC195N 24166K 145 138N HCN 74170N pp AHC240N 741 73N dd aHCZ41N 74174N 74S 151N 7aHC242N 74175N 7AS ISIN FAHC243N TATION 74S 157N T4HC244N 74177N 74S158N 74HC2ASN 741B0N 74S161N 3 TS 14HC2SIN MBIN 74S 2N zai 74HC2S3N 74182 748 1636 Si 74HC257N 74184N 748 174N 74m0259N 74185N 1451 TEN 2174402665 74190N TAS 18IN J4HCZBON 74191N 745182 74HC2Q9N 74792N 74S 188N T4HC354N 74193N J45189N 74H 356N 74194N 7451946 74HC365N 74195N 745 195N 74HC366N a Men 74197N 74 198N 7420367N LFISIN 74198N 74 197N 74HC368N o EIN 74399N 745240N 74HC373N LFaBON 74261N 74S241N e neem LESSON lay LFSB7N 74365N 745242N 24H C390N SI ee 743966N 74S243N VaHCI93N FAL TCA LM3900n 74367N 7AS244N an C533N F412CN M3905 74368N 745251N tani 53AN ECN LM3309N 8093N 745253N MEAT 80951 SHESEAN k 7a BL M381 1N 74HC574N 39 esen 7 pL M391 4N BOS6N T4HCGAON 3 OFF a OCLIN M39 15N 8097N BON S334N 74354734N 248474AN 74S475AN 45 Nyy 8 SER REAR EBE SAE BSRB IZBIRA UUZE RAZZE R RE BED a a oon
79. HIE DANCING ON THE CEILING Se 348706 Wynton Marsalis J Moods Digttol Columbia 346270 Whom Music From The Edge Of Heaven Columbia 345777 Peter Gabriel So Geffen 344812 Billy Oceon tove Zone 1 album amp hits Includes Love Zone more Jive Arista 308049 Creedence Clearwater Revival Featuring John Fogerty Chronicle Greatest hits Fantasy 340323 Sode Pramise 1 Smash Portrait 318089 Michael Jackson tThriller Billy Jean etc Epic HUEY LEWIS ano THE NEWS 347955 333286 Phil Collins No Jacket Required Album of the Year Atlantic 326629 Bruce Springsteen Born In the U S A Columbio 342097 Barbra Streisand The Broadway Album Somewhere Something s Coming more Columbio 345827 Bob Jomes and David Sonborn Double Vision Warner Bros 288670 Barry Manilow Greatest Hits lfs o Miracle Mondy etc Arista 343095 Philip Glass Songs From Liquid Days CBS 346643 a EF i D a e aS E e ih he re Eg z i j pi ee i F Eg M A incom E ei a i A A ong ne T 314443 Neil Diamond s 12 Greatest Hits Vol 2 Columbio 346809 Dvorak Symphony No 9 New World Carnival Overture The Landon Philharmonic Orchestra Verese Sorabande 346767 Johnny Mathis Most Requested Songs Digitally remastered Columbo 349324 Rodgers amp Hammerstein South Pacific London Symphony Orchestro Dig
80. ICLE PILOT TECH Financiel Ald Piscement Assistance 5 HIGH PAY HIGH TECH EXCITING CAREERS Electronic ee amp Robotic Skills Taught Call or Write for FREE BROCHURE TODAY Ask About Our Correspondence Course 713 690 0405 UNDERWATER VEHICLE TRAINING CENTER 10046 Chickasaw Houston TX 77041 CIRCLE 1 ON FREE INFORMATION CARD Where s my CATALOG Weer You haven t sean the FREE DICE SMITH ELECTRONICS cetalag Or d someon sinal OL copy again Afer afl whe can rasa 146 eolordul paged crammed with 1000 s of electrona goodies ranging from kits amp components t oom puters amp radic conirolled cars The sehection i ime recibhe the valuas are Gen beter Top ri afl off wth our endless 1 S page electronic data tentam and you ll have more than a catalog more shan a raterence is a tobally eter apana bor thie electronic ailhusise and a s 1AT are Bek is our name address and 1 00 for first class postage What are your waiting for Order yours YES Send my copy of the 1986 87 DSE l catalog today Enelosed is 1 00 for postage Nene City State Zipi Q DICK SMITH ELECTRONICS INC PO Box 2249 Redwood City CA 94063 January 1987 MODERN ELECTRONICS 81 OOOO PC PAPERS ot s A e eS e i tt E a E oe aa i P a LN a aoe a a sxy i i i EWE r ai w a a W E es _ sa i ee mi C ia a e he sie Heth ee gr a Fre a aa WA oh 3 i i Se ee a
81. LASTER 15 EM Weapons Plans KW HR METERS 12 Electric Power Meters All Types VORTEX GENERATOR 8 Fantastic Energy Generator Plans THE GOLDFINGER 8 Non Ferro Metal Detector Plans THE SILK WOOD 8 Simple Effective Rad Detector Plans AUTOMATIC TELLER MACHINES 20 Crimes Security MANY MORE 60 Publications ters Electronics Energy W Security Surveillance Sethi Medical TECHNOLOGY SURVIVAL CATALOG 1 FREE With Order Over 10 2011 CRESCENT DR CONSUMERTRONICS ALAMOGORDO NM 88310 90 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics Cer FM TRANSMITTER KIT matchbox size super sound sensitivity adjustable frequency gain Board parts educational instructions 19 95 Pershing Technical P O Box 1951 Fort Worth Texas 76101 LINEAR PARTS TUBES TRANSISTORS MRF454 16 MRF455 12 MRF477 11 MRF492 18 Catalog RFPC Box 700 San Marcos CA 92069 619 744 0728 COCO II UPGRADES PARTS COCO II Upgrade Kits RGB Interface 256K Memory ETC Electronic Parts all types Free catalog Inventive Solutions P O Box 286 Stanfordville NY 12506 SRS ERROM S a i E PROM s 2716 1 25 2516 1 40 2732 1 30 2532 1 60 2764 1 50 2564 1 80 27128 2 70 ASK FOR DRAGAN Memetron Inc 2350 Brickvale Dr Elk Grove Village IL 60007 312 595 2828 EPROM PROGRAMMING FREE catalog Your software data installed in E
82. Limit Cont 3 Separate Supplies 20 nec wlth memory 2 us pulse 1A 3 Amp Power Supply XP 650 511950 DIGITAL LCR METER Model LC 1800 4 48 Measures Inductors Capacitors Resistors ome wapa ar rey Bene se 0 40V 1 5A Inductors 1 uH to 200 H 0 20V 3A Capacitor IPf to 200uf 3 Resistor 012 to 20M Q Fully regulated short circut protected current i ee Ranges 61nd 7cap 7res limit control C amp S SALES 8744 W North Ter Niles IL 60648 7a 15 DAY MONEY 800 292 7711 312 459 9040 Ra u BACK GUARANTEE ASK FOR CATALOG 2 Year Limited Guarantee Add 5 for Postage 10 max IL Res 7 Tax CIRCLE 45 ON READER SERVICE CARD January 1987 MODERN ELECTRONICS 71 W HARDWARE HACKER I Understanding strain gauges video art A D conversion transducer information robotics parts By Don Lancaster If you want to start your own hi tech ven ture check into my Incredible Secret Money Machine book that s chock full of ideas for your own technical or craft ven ture I just happen to have several auto graphed copies on hand here that I ll be happy to lay on you Uh it seems there were some problems with last month s Omnicrom phone num bers Try using 617 881 4100 or 800 447 2326 instead And now onward with this month s goodies What is a strain gauge A strain gauge is a sensor that can mea sure very small changes in physical size Strain gauges are extremely use
83. M Mims III SMT on the Move By Patrick J Chick How to Design Ultra Long Delay Timers Get timing delays from a few microseconds to almost 30 days By John T Bailey Hand Clap Electronic Control Clap your hands to turn on and off electrical appliances By James H Brown A 20 Drum Synthesizer Project produces percussion sounds for amateur musicians and experimenters By C R Fischer Laptop Computer Enhancements Ideas to relieve the special woes of using a laptop computer By Brent Gloege A 4 5 MHz FM Receiving System Picks up sound from TV sets and other 4 5 MHz sources and delivers an amplified output suitable for driving an audio amplifier By Duane M Perkins A Full Range Speaker System A nice sounding low cost speaker system you build in just a few hours By William R Hoffman A Bulk Eraser for Cassettes amp Diskettes By Adolph A Mangieri PRODUCT EVALUATIONS Paradise AutoSwitch EGA By Joseph Desposito COLUMNS Hardware Hacker Author answers readers questions By Don Lancaster Software Focus Word Finder A Giant Synonym Finder By Art Sailsberg PC Papers First impressions Open Access IJ a Big Kiss No Risk Trials By Eric Grevstad DEPARTMENTS Editorial By Art Salsberg Modern Electronics News New Products Books amp Literature Letters Advertisers Index 2 MODERN ELECTRONICS January 1987 EDITORIAL STAFF Art Salsberg Editor in Chief Alexander W Burawa Managi
84. OT 23 package Dual in line integrated circuit packages are also given an SO prefix Thus an SO 16 IC has 16 pins Sur face mountable packages having dozens of pins around the perimeter of a square case are also available These packages are designed for large scale integrated circuits such as microprocessors controllers memory arrays and the like Figure 4 compares a standard 16 pin dual in line package DIP IC with several common SO compo 20 MODERN ELECTRONICS January 1987 nents Note that two SOT 23 transis tor diode packages can be placed end to end on a single pin of a stan dard DIP Almost every category of electron ic component is now available in a surface mountable configuration This includes various kinds of induc tors switches LEDs phototransis tors connectors crystals and trim mer resistors and capacitors Like chip resistors and capacitors many of these devices have been designed especially for surface mount roles Others are miniature versions of standard components with pins or terminals redesigned for surface mounting Because the large scale implemen tation of surface mount technology is a very recent development manu facturers have yet to agree on all standards for the physical size of their components This lack of stan Say You Saw It In Modern Electronics GULL WING STANDARD LOW PROFILE 1 10 WATT RESISTOR CIRCUIT BOARD SOLDER SURFACE MOUNT RESISTOR
85. P BF 352 25009 C9128 28pm wire wrap gola 8 amp 1 69K and add sn X lna 1 BKX thes is tne Digs Key MMS5314 325 9140 40 pin wire wrap gold 27 22 amp Z part number MMS58167AN 15 GO Pricing 5 10 1000 MMSA124AN 13 75 4 War 50 390 30 00 MSM 33 For ange Quantites and prices 3 low as 68 15 M ca NSCB00N 21 2 Digi Key NSCBOON 1 4 Watt Matal Film Assorimenta 923 Beach af ve uss 108 to 97 6O 023 96 la 48 8 86 0 4310 00 1480 1014 pes H 2 00 5 B 7 9 OTE CAT NO F KIT 4 D4 D A 7 z 5 each of values 100C to 9762 79 96 i 2 gt 41 art Price 3 2 20 t Paes sab pod e z oS ASSOATMENT OF 15 POPULAR 5 4 i 76 BP 2NAN24 7 VALUES _ PANASONIC QUALITY ADCOBOSI CN ta 254128 y 5 asch of values 1 J0XO to 9 76K9 29 96 ADCOBOSLENS 63 Jana 3 220 See Md 52 K 9 Metallized Polyester C itors ADOOBOBCCN 12 65 E 5 ian 8 each Of values 10 068 to 97 6K9 172 96 oS 771 etallized Potyes apac ADCOBOSCCNS 88 Ja m aS aa 7 coe pea 5 1326 1105 DIGIKEY warhing Puy Of Paa DI Pas Ot Pap OF ADCUBIOCCN 8 245087 z 5 628 96 i i 163 Pari Mo Yortape F 1a 190 odo pay i e 1 E2103 p 1368 1208 asistors Ja 1 62 E2129 1368 127308 Avasiabie in i a Z Watt gt 77 7 i 116 2153 015 1368 123 06 Wa 13 2273 022 1168 E2273 13 68 E2333 033 agg 2474 23 7N 7450N N an wn A 3 y Fane FON T4HC11N 4HC1ISN 4HC2ON THA IN 74HCION 74HC32N 7aHC42N 74HC73N 74HC AN T4HC SN 74HC76N 74KHC85N 74HCB6N 7HCIOFN 74HCtI2N 74
86. PROM of your choice Fast low cost service Write call Romulus Microcontrol Dept C Box 8669 Rockville Maryland 20856 301 540 8863 Tet CABLE TV Cable TV converters and descramblers Low prices quality merchandise we ship C O D Send 2 00 for catalog Cabletronics Unli mited P O Box 266 M S Weymouth MA 02190 617 871 6500 REGULATED POWER SUPPLY Ay MIU These are Solid state tully regulated 13 8 vac JU power Supplies Both feature 1009 solid state KUZUA construction tuse protection andL E D power SOLID STATE RELAY WA indicator UL CONTROL 3 32vde BPX UT Z 1OAD 140 vac 0 amp ef r Hyran nw fy SIZE 2Qhe x Mx A TE A 9 50 EACH 10 FOR 90 00 RECHARGEABLE NI CAD 269 BATTERIES mes 1 o0ea AAA SIZE 25V KOUMA 4 AA SIZE 25V AR I EOT ut i DE ay 1 35 ca i Cele ares ih CATH PPC 800 BSUB C SIZE erish 3 50 D SIZE 2V 1200mAH 3 50 FLASHERLED 5 volt operation COMMODORE 5 volt operation PRINTER PLOTTER Size 1 00 each Commodore Mode 1520 NEY SEPEN Eve see LAT ft Four color X Y plotter Standard VIC seria intertace XENON FLASH TUBE allows easy connection to gt gt Commodore 64 computers Up to 80 Characters per line upper and lower case In four Sizes PHOTO FLASH 170 m1 330v CAPS 75 ea Three sizes OE CAT PPC 170 gt f 400 mf 330v 2 4 s4 D JE Jf e XPErimentors CAT FLT 1 2 for 1 00 ULTRA MINIATURE 49 95 each
87. SMT2000 kit since they can be purchased from distributors and because including a sufficiently A a AS Sa oa a a aE REN EN SA IS MENS Oe wide variety would have made the kit prohibitively expensive Finally the SMT2000 kit includes an excellent 52 page training manual that describes in detail how to assem ble working circuits using the SMDs included in the kit The manual closes with an SMT Resource Directory that lists dozens of manufacturers and suppliers of surface mount de vices and supplies The SMT2000 training kit is avail able from Vector distributors for 348 A version of the kit that does not include the SMD assortments the SMT1000 is available for 215 If these prices are beyond your means you might wish to consider assem bling your own SMD kit by pur chasing from Vector portions of the SMT2000 kit The 300 piece thick film resistor assortment SMT1206R is 62 00 for example Its 300 piece chip capacitor transistor and diode assortment SMT1206CDT is 71 50 To be Continued For several years I have been assem bling a small collection of SMT ICs Vector s SMT2000 training kit has opened up a new world of circuit possibilities since it has allowed me to use some of these chips to assem ble some tiny circuits that rival in size expensive hybrid microcircuits In a subsequent article I will describe in detail how these circuits can be dupli cated using conventional soldering methods conduc
88. SONIX 80 50 Baxter Ave Suite 120 Elmhurst NY 11373 COMPUTERS TI 99 4A Software Hardware bargains Hard to find items Huge selection Fast Ser vice Free Catalog TYNAMIC Box 690 Hicksville NY 11801 TI 99 4A Discount Software Free Catalog from Microbiz Hawaii P O Box 1108 Pearl City HI 96782 DET E 88 MODERN ELECTRONICS January 1987 r Say You Saw It In Modern Electronics 1 1 800 344 4539 AK Puerto Rico 218 681 6674 Telex 62827914 FAX 218 681 3380 TWX 9103508882 DIG KEY CORP VISA EAC INC 0 J W MILLER AAVID ENGINE IGAR gt YAGEO J W MILLER LUXO L E F JOHNSON ATLANTIC SEMICONOUC Factory Firsts 3C CHEMICALS gt ARIES PLESSEY lt E INTEGRATED C INTEGRATED CIRCUITS g E et e alll DISC CAPACITORS TANTALUM CAPACITORS 7400 TTL LM373K ee fall DAN pica i SOLDER TAIL No Cap Yoh Part Re DIP SOCKETS P200U gt Smgie beam gt Low protiie sa YOUR CHOICE TIN OR GOLD 2 AA PAC 1 Mbinu 50 mcroinch Gow may om poki spensi Wertage Keone LM34CZ apii TIN PLATED SOLDER TAIL min 700 Muccomenes Tin Masia Oise Vonaee LM3SCZ 441 aw SC Rated Ament Temp Port fo Deseripuna 10 00 Memory C905 erie F p IMZ BDmenson D 1 23 320 MM211 N 3L36 x 5 060 060 MM2114N gt CRY2 2 5 Carbon Film Aeusto Values Ohms 10ta4 7M AD Aa a a A MM2I57N tail t 23 2 How To Order Take any pandard resisior value li 6 t 32 and add an E tor 1 8 wa
89. TE ZIP ELENCO PRODUCTS AT DISCOUNT PRICES 20 MHz DUAL TRACE OSCILLOSCOPE 35 MHz DUAL TRACE OSCILLOSCOPE 349 mo 1251 498 mo 1252 Top quality scopes at a very reasonable price Contains ali the desirable features Elenco s 2 year guarantee assures you of continuous service Two 1x 10x probes diagrams and manual inciuded Write for specifications AUTO RANGING MULTI METER with EE TRUE RMS 412 CAPACITANCE and DIGIT MULTIMETER plus transistor tester JF MANUAL RANGING n 7 4 35 Mode kai 3 DIGIT METER e f Wa 65 cw is00 28 FUNCTIONS 05 DC Accuracy j SME Reads Volts Ohms 1 66 Resisiance E M 1180 7 ACY 36 95 h Current Capacitors T with Freq Counter em M1182 25 ACY 39 95 Transistors amp Diodes amp Deluxe Case yg M1181 1 ACY 42 95 nction Generator BREADBOARD GF 8016 Fu ee vith Freq Counter 219 Sine Square Triangle Pulse Ramp 2 to 2 MHz Frequency 1 thru 10 MHz Shown 9434 GF 8015 without Freq Meter 169 190 10 MHz OC or AC Triggered Sweep 9430 1100pins 15 Cailbrated Vert amp Hor 5 3900 9434 2 170 pins 25 Reads volts amp Freq 9436 2 860 pins 35 Triple Power Supply XP 660 50 MHz LOGIC PROBE LOGIC PULSER 1 4950 23 25 0 20V 1A _ 0 20V 1A j 5V 5A esse 3 LP 700 LP 600 Fully Regulated Short Circuit Protected with 2
90. YOUR ONE STOP SOURCE OF ELECTRONICS INFORMATION ICD 08559 JANUARY 1987 1 95 CANADA 2 50 THE MAGAZINE FOR ELECTRONICS amp COMPUTER ENTHUSIASTS 0 SURFACE MOUNT TECHNOLOGY The New Microminiature Way Of Building Circuits 6 CLAP HANDS amp TURN ON OFF APPLIANCES Also 0 Designing Ultra Long Delay Timers A 4 5 MHz FM Receiving System 0 Making Low Cost Speaker Systems 0 Laptop Computer Enhancements A 20 Drum Synthesizer 0 impressions of Open Access Il the Big Kiss and No Risk Trials 6 Don Lancaster s Hardware Hacker e The new Word Finder giant synonym finder Electronic amp Computer News and more 0 74820 JI 1 Plus A review of Paradise s new AutoSwtich EGA system e Eric Grevstad s Simpson Electric Company Introduces FCC The Ultimate in Low Cost Test aaa At last Here is your opportunity to take your pick from a new test eguipment line that Ha ali the features you need and more and at a price that is unbelievably low Here ase six digital and two analog instruments see them at your local distributor to make your choice MODEL 9670 Digital capacitance tester covering 0 1 pF to MODEL 9340 PAOD p Pocket size 312 digit 99 DMM with 20 megohm range and 10 megonm input resistance 44 MODEL 9301 3 2 digit hand held DMM wit
91. a measurement in progress can also drive a digital telephone New from Philips ECG is a set of indicator and calibration adjust dialer that can contact a central eight special purchase wrenches that ments that can be made without hav alarm station to send help in the are designed to meet the adjustment ing to open the case event the alarm goes off when no one Rated resolution is to 1 kHz in isat home 79 95 plus 2 95 P amp H 0 25 second or to 100 Hz in 2 5 sec CIRCLE 11 ON FREE INFORMATION CARD onds over the entire range of fre quencies Accuracy is rated at RS 232 Interconnect 0 0001 1 count LSD achieved Problem Solver with an RTXO timebase Supplied eS with the counter are internally in Eazy Connect from Black Box is stalled rechargeable nickel cadmium designed to solve interconnect prob cells and an adapter for ac operation lems for users of equipment with and battery charging Optional ac RS 232 serial interfaces It offers an cessories include a carrying case Sy to use cabling system for all probe and telescoping antenna 150 types of connectors including those used on IBM PC and compatible and Apple Macintosh computers to con vert the various types of serial con Wood Stove Monitor ___ nectors now being used into a simple A new electronic device called the modular system The adapters termi Just Rite Monitor from Inventex nate with standard modular jacks Inc Lehigh Valley PA gives the flue
92. a personal computer can be broken down into sections for repair pur poses Pinpointing the section you then start isolating the problem until you dis cover a defective part that s causing the problem Therefore if you have a com puter memory problem you ll examine When It Goes Bad RAM boards and devices not your print er disk drive I O section or whatever In this instance I was working with an IBM PC that was converted to a hard disk machine Therefore I pulled out my IBM hardware diagnostic disk and man ual and looked up the code number that appeared on the screen The 201 indi cated a memory problem but 1055 that preceded it wasn t listed After some research however I did find the error code listed in an IBM operating manual It meant that my internal switch settings were incorrect But since the machine was operating fine for about a half year since I made my last switch setting changes upping memory to 640K this was impossible My next step was to run through the di agnostic disk s routines It indicated on screen that the problem was in memory threw up the same code number that wasn t listed in the accompanying Service manual and further displayed a new al phanumeric code 10BE that pinpointed the memory location of the defective module Fantastic I thought so until I discovered that this code too was not listed in the IBM Hardware manual Nor anywhere else Cal
93. about your electronic servicing experiences which can be shared with other Modern Elec tronics readers Thanks bet abbey 4 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics THE CBS COMPACT DISC CLUB HAS THE MUSIC YOU WANT TAKE ANY 2 F 246868 Jim Croce Photographs And Memories His Greatest Hits Time In A Battle etc Saja 349530 The Monkees Then And Now The Best Of The Monkees Includes the new hit That Was Then This ls Now etc Arista 344705 Patti LaBelle Winner In You smash On My Own duet with Michael McDonald etc MCA 334391 Whitney Houston Whitney Houston Greatest Love Of All etc Arista 347492 Glenn Miller Orchestra lIn The Digital Mood In The Mood Tuxedo Junchan more Digito GRP SPYRO GYRA 347245 343582 Yan Halen 5150 Warner Bros 336222 Dire Straits Brothers In Arms Warner Bros 345553 Branford Marsalis Romance for Soxophone Digital CBS Masterworks 343327 Wynton Marsalis Jolivet Tomasi Trumpet Concertos Philharmonia Orchestra Digital CBS Masterworks 336396 396390 Billy Joel s Greatest Hits Valumes 1 amp 2 Counts as 2 Columbia 339226 Gershwin Rhapsody In Blue Second Rhapsody etc Digtol CBS Masterworks i N Sos 344721 a iw ee r T ae j Te z 4 j aF n ee AAA al _ a m tees ua k i a a M LIONEL RIC
94. aching electronics through independent study we teach only electronics and we ve been doing it for over 50 years You can put that experience to work for you just like more than 25 000 CIE students are currently doing all around the world Practical training You learn best with practical training so CIE s Auto Programmed lessons are designed to take you step by step principle by principle You also get valuable hands on experience at every stage with sophisticated electronics tools CIE designed for teaching Our 4K RAM Microprocessor Training Laboratory for example trains you to work with a broad range of computers ina way that working with a single stock computer simply can t Personalized training You learn best with flexible training so we let you choose from a broad range of courses You Start with what you know a little or alot and you go CIRCLE NO 171 ON FREE INFORMATION CARD wherever you want as far as you want With CIE you can even earn your Associate in Applied Science Degree in Electronics Engineering Technology Of course you set your own pace and if you ever have questions or problems our instructors are only a toll free phone call away The first step is yours To find out more mail in the coupon below Or if you prefer call toll free 1 800 321 2155 in Ohio 1 800 523 9109 We ll send a copy of CIE s school catalog and a complete package of enroll ment information For your c
95. ady to run with a 1 year war ranty Call for latest cuotes on your Custom system needs FLOPPY DISK SERVICES NC O SCOPE ceg Audio 4 Siz sae A ranges nt measure me 8 uncon CIRCLE 67 ON FREE INFORMATION CARD ASK FOR FREE CATALOG Money orders checks accepted C 0 D s require 25 deposit is pc Service amp Shipping Charge Schedule Continental U S A FOR ORDERS ADD 25 100 i 4 50 101 3250 6 00 Toll Free 251 500 8 00 b 501 750 _ 10 50 751 1 000 R 12 50 1 001 1500 i 16 50 1 501 2000 A 20 00 In NY State 800 832 1446 ee E
96. ally Grantham College of Engineering is accredited by the Accrediting Commission of the National Home Study Council as a degree granting institution Grantham College of Engineering o 10570 Humbolt Street All lessons and other study materials as well as com S N munications between the college and students are in the Los Alamitos California 90720 English language However we have students in many foreign countries about 80 of our students live in the United States of America This booklet Grantham College of Engineering M 87 FREE 10570 Humbolt Street Los Alamitos CA 90720 Booklet CLIP 5S D g COUPON B S Degree independent study program Fr ae are Please mail me your free catalog which explains your explains the for Na ee ee Grantham B S and mail in Degree Program 1 envelope or offered by inde paste on Address pendent study to postal those who work A City State Zip in electronics card WA Au ee E Say You Saw It In Modern Electronics January 1987 MODERN ELECTRONICS 1 Wl ERs THE MAGAZINE FOR ELECTRONICS amp COMPUTER ENTHUSIASTS JANUARY 1987 18 28 30 d4 50 117v ac TOA DPDT RELAY 54 64 68 16 72 76 MINUTES E 80 fatal a VOLUME 4 NUMBER 1 FEATURES Surface Mount Technology A technological wave that will change the way we build circuits By Forrest
97. also prefaced three of its synonyms with see indicating that there are other alternates to see in anoth AA ee eS Ee EE ee eae 76 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics er window if you select one of these words for further exploration Doing this on the three words which meant moving the highlight bar and using three separate key strokes to get each grouping shown one at a time This brought up 43 more words And these had seven words pref aced by see which enables you to pop up many more words More words can be brought up from Word Finder s 81 word listing too in truth So what we have here is the Word Finder thesaurus with a full listing to view at one time if the listing is too long it continues when pressing a Page Down key that s a bit trying to read and digest and another synonym finder that lists only a fraction of what Word Finder shows in one gulp but can show addi tional alternate words by positioning a highlight bar over the word prefaced by see and pressing a function key Here function Key 2 flips control to the new window if you want to extend words with any synonym shown in the new list that s also prefaced by see Even then you won t gather as many choices in many in stances as Word Finder gives you in one shot In addition contrasting the two fine programs I feel that Webster s highlight bar is easier to work
98. appears at the pin 2 in put of C2 is internally stretched to clock dual D flip flop JC3 Because of the three state counter arrangement of JC3 two sharp at tack pulses are required to generate a positive output at pin 1 that will send 40 MODERN ELECTRONICS January 1987 Q into conduction When Q con ducts it completes the circuit from the positive side of battery B through the relay s coil to ground This causes the relay to energize and pull its contacts closed Any electri cal device connected to the relay s contacts will now turn on Once pin 1 of JC3 goes high it re mains in that condition until another pair of sharp attack hand claps are detected and processed by the previ ous circuitry Therefore it takes two such pulses to turn off the elec trical device connected to the re lay s contacts once the circuit has been triggered Specified in the Parts list is a light duty reed type relay for K1 If you plan on using this project to switch Say You Saw It In Modern Electronics Semiconductors IC1 741 operational amplifier IC2 555 timer IC3 4013 dual D flip flop Q1 2N2222 or similar general purpose npn transistor Capacitors 15 volts or more C1 C2 C3 C4 0 l wF ceramic disc C5 47 nF electrolytic Resistors 4 watt 5 tolerance R1 R2 R4 R5 R10 10 000 ohms R6 150 000 ohms R7 R9 100 000 ohms R8 1 megohm PARTS LIST R11 220 ohms R3 100 000 ohm pc type tr
99. at we reviewed how ever gave us a display of equal quality at a substantially reduced price Moreover it added features not found on the IBM card that allowed us to run Lotus 1 2 3 Say You Saw It In Modern Electronics At A Glance Product AutoSwitch EGA Card Address Paradise Systems Inc 217 East Grand Avenue So San Francisco CA 94080 Phone 800 527 7977 Ext 370 Requirements IBM PC AT AT or 100 compatibles Price 599 and game programs without a problem One could argue however that EGA drivers are now available for 1 2 3 V 1A and that games aren t important on a business computer One might also argue that compatibility problems may exist between the two cards for certain appli cations Although we did not experience these problems we did not do extensive compatibility testing and cannot guaran tee that they do not exist at all Since it is an EGA compatible card the AutoSwitch should also be viewed in relation to other compatible cards In most cases the AutoSwitch outperforms these products just as it does the IBM ver sion In addition its low power con sumption and size which make it ideal for either the IBM PC or XT could also make it a better choice than some of the other compatibles though priced higher than some of them To conclude the Paradise AutoSwitch card offers some unique features in addi tion to EGA compatibility namely auto matic switching If your applicati
100. audio By 1990 our TVs will become inter active computer terminals giving us entertainment information and com munications in one sophisticated video computer audio system Join the Future or Be Left Behind Can you see the opportunity The serv icing and repair market that s there already and the enormous future need created by the millions upon mil lions of electronic devices yet to come If you re looking for a high potential career if you d like to get started in a field that s still ome wide open for the independent businessperson even if you d like to find a way to make extra money part time look into NRI at home train ing now Start Right and There ll Be No Stopping You NRI training in video audio serv icing is the perfect way for you to profit from the new explosive growth in consumer electronics You study at home in your spare time at your own pace No class room pressures no night school grind Even if you ve never had elec tronics training NRI prepares you properly with a thorough ground ing in the fundamentals a foun dation that vou build on to achieve advanced electronics skills With this kind of understanding and practical bench experience built into NRI s exclusive training meth ods you re on your way to take advantage of the new opportuni ties opening up every day Totally Integrated Hands On Training Since NRI training is built around
101. aw It In Modern Electronics you routed it or on the front surface at the edge of the cutout if you didn t Lower the speaker into the cutout and press it into the caulking to assure a good air seal Secure the speaker to the baffle with panhead sheet metal screws While observing the speaker cone momentarily connect a 1 5 volt C or D cell across the speaker via the screw hookups on the rear panel If the cone moves outward the screw to which the cell s positive ter minal is connected is the hot or signal line If cone travel is inward the cell s negative terminal iden tifies the signal line Use a label paint or nail enamel to permanently identify the signal terminal Install the grille connect it to your amplifier and your speaker system s is now ready to use You ll need much costlier multi speaker systems to get extended frequency range wider treble dispersion and deep clean bass reproduction but for nicely balanced clean sound at very low cost this speaker system design will serve many people very well ag L EARN YOUR B S E E B DEGREE THROUGH HOME STUDY Our New and Highly Effective Advanced Place ment Program for experienced Electronic Tech nicians grants credit for previous Schooling and Professional Experience and can greatly re duce the time required to complete Program and reach graduation No residence schooling re quired for qualified Electronic Techn
102. bster for exam ple also has a Type In feature that en ables a user to simply type in the word he wishes to explore with ones that have C BEST rir My snd rca INSERT OH aaia ai aaa a ee Bl all se f f Beer Finder Version 3 2 aol mg Fy Aad nag omg nlp wba gon YA mst other aa Ua a Aa ies and fecerdiog te many industry experts it is the BEST electronic F E adj elegant finest gilt edye r pot e select E KA Boon choice elite favarite ee pick magnificent liest f sencational splendi st finest greater Saini larger largest superior top to de select majestic eatstanding Gps phew superlative RAXINUR mest p ateh Sel ptet uperior top verh a better ca D aut eclipse exceed excel D beyond outdo ou 90 outshine outstrip overs CONGUE defeat taster overcome E 2 age YA 255 SURPASS tr Using Word Finder s Synonym F inder to call up synonyms for the word BEST ina text file similar meanings Webster also uses a function key for Whoops to correct a mistake and get you back to the original Obviously the more operating choices you have the more complex it all be comes though Webster s is certainly easy enough to work with it also has a Help key to list what different function keys will do Nonetheless Word Finder is suffi ciently flexible and so easy to use that it makes up for all this
103. cam On Pig Part No Osscripton 6 Wan Raatstor Assortments Pas DAJ4BHTC a Bn 08 r 5 75 CoR 0302 t09 31 P4527 lu 2 7 DEM BB ht z 053 3 each a vals 930 307 to0 S DB749H gh P MANT g Wp 2 10 160 total pes pan P4529 P4530 P4631 MANO wt te be a How Te Order Take acy pendard value lie 75 and add W5 for 5 watt add W10 for 10 wart lio FESRE SAGES REUSE FARDE amp EI bu A be cD D NEBAN NESHSN NESO4N NESSEAN JLN2003 ILN 2004 TDA2ZBOA TDA 1023 TDA MOZA TDA 019 S8S35 amp SLIG ld 8 KURUSHA Ne WAKE Bg a e K 6 P 4 each of valuas OO to 9 1Q 0 3E ony ct an 196 total pes 74L51S6N TOA 1074 fopracesso A 338 Ja Description z M339 riaden ne 4 aach of values 102 10912 74LS157N 9 t OLOS 88 Ra i yi A IN54 amp D0 34 f gi 7 gt 155 tore pea 74L5 158N gf SG3524N If 08 waka Bi N50 3 Amo 1 Bs T 7ALS1G0N 110 gt Paden 3 hore i 1N540 2 Plastic 37 26 2 iar Ge 150 CAPACITORS 7aLS181N s INADA OPIY Plast 3 297 2640 2310 eee 74LS1626 1 x 15406 3 F y gt 35 Aa y 5 10 Wani Aamator Assortment ASSORTMENT OF 15 243 153N 16 3 ee oe i a S YA POPULAR E R j d 1 700087 k b SD RDO t 3 280 2 each Of af mandec y aLS164N 10 WA 0 0 TNS408 3 Am Sieg leaning i scan pes eer CAPACITORS Sh FB SSSERR2 BEENS Py UG Signin BAS SS WwW en eS The Digi Key volume discount and service charges are simple to appiy Most items said by Digi Key may be combined tor a v
104. can be set from the rear of the computer without removing the cov er For a monochrome or standard RGB monitor the toggle switch is set to the left and the DIP switch is set to off off on off and off off off on respectively For an enhanced RGB monitor the DIP switch would be set to off on on off Whatever monitor is used one can select whether or not automatic mode switch ing is used by setting position 5 of the switch to on for yes or off for no Using AutoSwitch We tested the capabilities of the Auto Switch with Lotus 1 2 3 Version 1A in serting the board into an IBM compat ible AT and connecting it to a Princeton Graphics EGA monitor The toggle switch on the board was set to the right and the DIP switch was set for the EGA mode Normally the 1 2 3 spreadsheet will work in the high resolution mode but will not display graphics EGA drivers are now available for V 1A but we did not use them When we tried to display a graph the AutoSwitch sensed it and immediately changed to RGB mode rather than blank ing out which the IBM version did One minor adjustment had to be made in the l 16 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics vertical hold however Once this was done we switched back and forth from the spreadsheet to graphics without any problems Our next test was done with a mono chrome monitor Since we changed mon itor we had to flip the toggle switch t
105. cing your Apple vol I 15 50 Applewriter Cookbook 19 50 Apple Assembly Cookbook 21 50 Incredible Secret Money Machine 7 50 Postscript Ref Man Adobe 22 50 Postscript Cookbook Adobe 16 50 UNLOCKED SOFTWARE Absolute Reset lle amp Ilc 19 50 Applewriter Laserwriter Utilities 49 50 Postscript Show amp Tell 39 50 Laserwriter Demo Pack FREE Apple Ram Card Disassembly Script 24 50 Appleworks Disassembly Script CALL Enhance vol Companion Disk 19 50 Enhance vol Il Companion Disk 19 50 Assembly CB Companion Disk 19 50 ApplewriterCB ProDOSC Disk 24 50 FREE VOICE HELPLINE VISA MC SYNERGETICS Box 809 ME Thatcher AZ 85552 602 426 4073 CIRCLE 28 ON FREE INFORMATION CARD SAVE MONEY QW CALL 3 gt FREE ZY 1 800 237 3065 7 A M TO 5 P M MON THURS IN CONTINENTAL U S EXCEPT FL FOR ALL YOUR CRYSTAL NEEDS General Communication Industry Marine VHF Amateur Scanners CB Standard amp Special Microprocessor GET YOUR FREE 1986 CATALOG Call or write JAN CRYSTALS P O Box 06017 Fort Myers FL 33906 6017 813 936 2397 Sas Se SINCE F e 1965 za pey CIRCLE 59 ON FREE INFORMATION CARD gener SPEAKER CATALOGHI M a 1001 bargains in electronics Save up to 50 call toll free 1 800 346 2433 for ordering only Order by VISA MC AMX No COD s Missouri Alaska Hawaii call 1 816 842 5092 or write McGee Radio 1901 McGee St K C MO 64108 Postage for catalog 1 00
106. d in the original article Then align the 4 5 MHz FM Receiver as detailed above Tune the matching transformer for maximum signal and adjust the gain on the Cable Communication System receiver for best results NE A Great Gift Idea Send WilE erro ToA Friend LICENSED ELECTRONIC TECHNICIAN Earnupto f 30 an hour and more i a TH No costly school No commuting to class The Original Home Study course pre pares you for the FCC Commercial Radio telephone License This valuable license is your ticket to thousands of exciting jobs in Communications Radio TV Micro wave Computers Radar Avonics and more You don t need a college degree to qualify but you do need an FCC License No Need to Quit Your Job or Go To School This proven course is easy fast and low cost GUARANTEED PASS You get your FCC License or money refunded Send for FREE facts now MAIL COUPON TODAY COMMAND PRODUCTIONS FCC LICENSE TRAINING Dept 220 P O Box 2223 San Francisco CA 94126 Please rush FREE details immediately NAME ADDRESS om eee oe oe oe ol fe eee eee eS CITY a STATE_ _2 P ____ ae SS ee Be aa WA Say You Saw It In Modern Electronics January 1987 MODERN ELECTRONICS 63 Project A Full Range Speaker System Using an 8 dual cone speaker and closed box design it s easy to build nice sounding speaker systems in an afternoon s time while saving two thirds the cost of an equiva
107. d so that you can tell if all three sources are operat ing properly At this point the best way to learn how to play the synthesizer is to experiment with the various switch and control settings Settings for a few of this author s favorites are il lustrated in Fig 7 Of course there are an almost infinite variety of con trol and switch settings you can try Also try using external effects sources plugged into the TRIGGER INPUT to enhance the sound If you ve built more than one Drum Synthesizer circuit into the project box try setting each to a rad ically different sound and trigger all of them from a single source It s amazing to hear how many cheap in struments have been used in recent musical recordings and equally sur prising to hear how a cheesy syn thetic tom can improve the sound of an expensive professional percus sion synthesizer We ve deliberately kept our Drum Synthesizer simple to make it accessi ble to as many people as possible Even so there are a number of re finements you can incorporate to make the instrument much more flexible For example you can exper iment with different values for C3 or and C5 perhaps having a range of values that can be individually se lected with a rotary switch There are a number of other changes you can make to the basic circuit referring to the 76477 s data sheet A very inter esting prospect would be to use an external vco t
108. d valust in seres 1 1 09 90 MI R pt 73 13t 96 COP49BN y TIN PLATED WIRE WRAP m 900 aicroinctnas Tin 13 16 20 24 etc through 910K 1360 For Compete Spaca on Physical Size and Electrica COP49SN gt Pert No Usscrphen 10 100 tole pas Cherecteriatics consult your FREE DIGLKEY Catalog OPEN 75 Bo Ce Bawa 3 360 300 1 Metal Film Fixed Resistors ASSORTMENT OF 18 OPR216N 3 eerie NAA ads 90 8 00 Te ee POPULAR VALUES OPhQ24N CBI 16 ipn wre wrap 3 5h OO t PANASONIC QUALITY mares 3 a ih DPB226N i Js h DPR22AN lag ps te diadh k ses THE if YA 310 DISC 0Psa03N 5000 caz pir wre wrap tr za i i CAPACITORS OPRI045N 3 e in wing wrap 1 r 0 7 k gt iboe D E ha S araa VIN PANASONIC LS SERIES OPB308N Mex Working Vohsge 150V Minciture Ahonen Electralytt Cys rcitare DPR310N GOLD INLAY WIRE WRAP min Mi Mieroinahas Gold Peri ND 0 Retec Ambeent Temp 70c 3 Cescugtion DPB3IIN SB 1 8 pini wia wrap gox 5 80 Operating Temp Range GET to 150PC INSBOSSLN G 7 WA carte 14 pin wire wrap god 7i 7 BO INSSO35N 11 7508 carte 16 mn with wrap gokt as a 40 INS8O33N 6 963 f c9114 18 pin wiin wrap gold g 9 80 Dimenpoan O a3 INS8239N 1t 10 Og cola 20 pin wee wrap gol 19 1 BO 11 Omenson d 6 3 99 S a i 35 127 INSBISAN x yd 22 pin wwe wrap gold 12 80 1 Meal Film Values in Ohma 10 0 to 1 00M ni 124 m wore WIBD gol Ja 1380 1 5 ISBN 9338 128 dl wore wrap pold 1280 How To Order Tere any standard rewstor value l IS
109. duction boards The boards are then etched and rinsed and holes for the component leads are drilled The leads and pins of components are inserted by hand or by machine through their respective holes and the stuffed boards are loaded ona moving conveyor track The bottom foil side of the board is then passed over a spray of rosin and a protrud ing wave of molten solder Other steps may also be involved For example a test circuit may be as sembled to determine if the design of the board subjects the circuit to ad verse noise Also a protective coat ing may be applied to the copper traces of the finished board The surface mount approach on the other hand will provide a board that is considerably smaller and lighter than the conventional board Moreover assembly of the surface mount board is more readily auto mated than that of the conventional board Designing the foil pattern for a single sided surface mount board is usually simpler than designing foil patterns for conventional boards since interconnections are on the top side of the board Therefore compo nents can be placed on both sides of a double sided board 26 MODERN ELECTRONICS January 1987 ed by an automated pick and Should you select the surface mount approach one of your chief decisions will be how to attach the SMDs to the board While conven tional boards are either hand or wave soldered several other options are availabl
110. e and yes decisions have to be made Which road will you take one that doesn t go where you want to be or one that leads to hard work but also to the better life Ah decisions decisions Put Professional KNOWLEDGE Career decisions are so important that you need all the input you can get before locking in on one of them Grantham Col i and a lege of Engineering offers you one source of input which may COLLEGE DEGREE help you in making that decision It s our free catalog i Ji a ay in your Ask for our free catalog and you may be surprised to learn how Elect es C it is easily possible to earn a B S degree in electronics without COT OTIC AREE attending traditional classes Since you are already in electronics Be through you are aren t you you can complete your B S degree work HOME STUDY with Grantham while studying at home or at any convenient place Grantham offers this program complete but with out laboratory to electronics technicians whose objectives are to upgrade their level of technical employment But don t expect to earn that degree without hard work Any degree that s worth your effort can t be had without giving effort to the task And of course it is what you learn in the process as much as the degree itself that makes you stand out above the Recognition and Quality Assurance crowd that places you in an enviable position prestige wise and financi
111. e TE My main musical interest is check one But may always choose from ony category COICLASSICAL interest plus many exciting alternates In O ROCK POP addition up to six times a year you may re Clubs operation with your introductory Mr ceive offers of Special Selections usually at shipment If you are not satisfied for ony Mrs a discount off regular Club prices for a total reason whatsoever just return everything Miss of up to 19 buying opportunities within 10 days and you will have no further ii ia i If you wish to receive the Selection of the obligation So why not choose 2 CDs for Address Apt Month you need do nothing it will be 1 right now shipped automatically If you prefer an alter ADVANCE BONUS OFFER As a special City nate selection or none at all fillin the offer to new members take one additional response card always provided and mail it Compact Disc right now and pay only 695 A ETEO ETE OE PETE ON 141 87 by the date specified You will always have It s a chance to get a third selection at a Do ER ada x dedi a Check pr g ee ONo atleast 10 days in which to make your super low price This offer not available in APO FPO Alaska Hawan Puerto Rica please write for Selections with two numbers contain 2 CDs and count as 2 so write in both numbers Note We reserve the right to request additional information CBS COMPACT DISC CLUB Terre Ha
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113. e binary counter section Figure 3 is the tim ing diagram of the waveforms after a trigger pulse is applied All eight binary counter outputs are open collector stages that can be tied to a common pull up resistor Ri to form a wired OR connec tion With this arrangement as long as one output is low the combined output will be low The combined de lay can be summed simply by adding the outputs connected to the load pull up resistor For instance if only pins 2 and 5 are connected to the load resistor and the other pins are left open total delay time would be To 2 16 T 18T For maxi mum delay all eight pins would be connected to give To 1 2 4 8 16 32 64 128 T 255T where T RC External connections including those for the trigger circuitry for the XR 2240 as used in the Timer Beeper to be discussed are shown in Fig 4 Determining Delay Time Determining the dealy time and the limits that apply to the components being used is the first order of busi TOP VIEW XR 2240 PIN LEGEND 1 1T 9 V 2 2T 10 Reset 3 47 11 Trigger 4 8T 12 Modulation 5 16T 13 Timing R C 6 32T 14 Time base output 7 64T 15 Regulator output 8 128T 16 V 15V max 4V min Fig 2 The pinout diagram of the XR 2240 chip ness The formula for determining delay time is TD NRC where 7D is the delay time in seconds N is an integer equal to the total binary counts selected R i
114. e card contains 256K of video RAM The AutoSwitch EGA card is for the IBM PC XT AT and 100 compat ibles and sells for a suggested retail price of 599 Overview The Paradise AutoSwitch EGA board is about 5 5 long and 4 high which means it can fit into a short expansion slot such as the one found on the IBM PC XT Despite its size it packs all the fea tures of IBM s EGA board foremost of which is the ability to drive a high resolu tion EGA monitor and display 640 x 350 high resolution graphics in 16 colors At the top center of the board isa 1 25 Square custom VLSI chip which makes it possible to have a low chip count low power consumption and small board size This chip not only is designed for EGA compatibility but because it con tains the equivalent of a Motorola 6845 CRT controller it is also designed for IBM CGA and Hercules compatibility Along the left hand side are eight 4 x 64K video RAMs which provide the card with 256K of display memory Compare this to IBM s card which has just 64K of video RAM on board and needs a piggy back board to expand to 256K At the rear of the board are several switches and connectors The main switch is a 5 position DIP switch Four of them are used to set the system configura tion just as with the IBM version and the fifth is used to set the autoswitch fea ture on or off A second switch is a toggle switch which lets you select the type of monitor in use A
115. e for SMDs 1 Hand Soldering The SMDs are cemented or taped to the foil side of the board and carefully soldered in place using a low wattage iron and small diameter solder Having as sembled surface mount boards in this fashion I can assure you that hand soldering is tedious Neverthe less with a magnifying lens and a lit tle patience hand soldering can be mastered It is commonly used to as semble prototype surface mount boards 2 Wave Soldering The SMDs are cemented in place over the re spective foil footprints on the board The board is inverted and run through a wave solder machine To avoid excessive thermal stress the board must be preheated before it passes over the solder wave 3 Solder Paste or Cream Solder paste contains microscopic particles of solder suspended in a flux It s ap plied with a syringe or silk screened on the footprints for each SMD The SMDs are then placed in position manually or by automated pick and place equipment There is usually no need to cement the SMDs to the board since the solder paste holds them in place Next the entire board is baked for 30 to 45 minutes at 50 to 80 degrees C to force out some of the solvents from the solder paste Final ly the entire board is briefly heated to the melting point of the solder When the solder melts its surface tension tends to center the SMDs di rectly over their footprints thereby correcting slight errors in component plac
116. e me e AUTO eo a 20t 200 wh aut a Fw 200m 2000m 7 Pe ci 7 lt TIN S pr ay d p t i k d 17E ee O wadi IN Usa B me a ES A 64 pin surface mount LSI device is used for display drivers in a Keithley Model 175 DMM saving 5 to 6 times the space that would be required for throughhole devices tors and capacitors see main article for more details Editor However due to their tiny sizes the critical nature of the assembly procedure just about eliminates the possibility of hand as sembly in large volume manufacturing Hence semiautomatic and automatic high speed machines are almost always used for component placement Types of equipment used in commer cial manufacturing plants in which SMT is used range from human opera tor loaded semiautomatic machines that can secure and simultaneously sol der all pins of a four sided LSI flatpack IC right on up to fully automated high speed component placement machines The latter remove individual SMDs from pre loaded tapes and accurately position them on the circuit board s conductor pattern Such machines can perform up to 8 000 pick and place op erations per hour hour after hour with out a break plies Minimum order requirement is 150 00 Contact the company for a comprehensive wall chart that lists all the SMDs and supplies as well as their prices Vector Electronic Company Vector Electronic Company 12
117. e pad for dynamic control of the sounds becomes almost mandatory The pressure sensitive resistors dis cussed in Forrest M Mims Novem ber 1985 Electronics Notebook in Modern Electronics are ideal for this Say You Saw It In Modern Electronics purpose A circuit arrangment to produce this type of dynamic enve lope is shown in Fig 3 This circuit is built around a general purpose oper ational amplifier with R being the pressure sensor and R a fixed resis tor whose value is the same as R when it is not touched The R R arrangement keeps unwanted offset voltages out of the main circuit s vca The diode at the output of the op amp in the Fig 3 circuit vca The diode at the output of the op amp in the Fig 3 circuit allows both the orig inal trigger input and the touch sen sitive function to be used indepen dently and simultaneously The Drum Synthesizer requires a bipolar power supply that can deliver between 6 and 12 volts dc A typical ac line operated power sup ply is shown in Fig 4 Since current drain is relatively low the circuit can also be powered by a pair of 9 volt transistor batteries for portable op eration as shown in Fig 5 Keep in mind though that the positive side of the supply operating at a drain of 18 milliamperes will run down at a much faster rate than will the nega tive side which normally has a drain of only 3 5 milliamperes The solu tion of course is to swap the bat t
118. e willing to forego a bit of sound quality and control sophisti cation you can get a useful taste of electronically produced percussive sounds by building our low budget about 20 Drum Synthesizer With this Drum Synthesizer you can emulate the sound of a snare drum tom tom and gong for exam ple while setting repeats and echoes Quality is high enough for use in re cording and other professional ap plications though some people might find the sound quality to be a bit tacky when compared with a 2 000 synthesizer But at a hun dredth of the price of the commercial unit one can easily adjust to a sound that s a bit off color and even use it to advantage On the plus side our Drum Synthesizer offers some very interesting and useful sounds differ ent methods of triggering and expan sion possibilities About the Circuit Shown in Fig 1 is the complete sche matic diagram of the Low Budget Drum Synthesizer minus its power supply At the heart of the circuit is the C1 76477 complex sound genera tor CSG chip made by Texas In struments The 76477 was originally developed for generating video game sounds and similar mischief which accounts for the slight tacki ness of its sound that some people find appealing With a few additions as we shall soon see this chip can perform as a musical instrument Contained within the 76477 CSG Say You Saw It In Modern Electronics P
119. ear taper resistor and two 1N914 diodes see tantalum potentiometer text lettering kit clear spray acrylic C3 C5 C7 0 1 pF polystyrene preferred R18 1 megohm linear taper poten spacers machine hardware hookup or disc tiometer wire solder etc a a aaaeeeaa Fig 1 Schematic diagram of Drum Synthesizer minus power supply p al ii aaaaa Say You Saw It In Modern Electronics January 1987 MODERN ELECTRONICS 45 Sound Selection Code Table Switch Sound Selected vco noise Ifo vco noise lfo noise lfo vco lfo vco noise inhibit no sound A 0 0 0 0 l l 1 l OF OroKHolA O O e O OD are two oscillators one voltage con trolled a noise generator for sound sources an envelope generator and an amplitude modulator The last two are not useable in this applica tion However by using other ICs to generate an envelope and process the output you re rewarded with a wider range of envelope times wider dynamic range and lower level of leakage when the sound is supposed to be off Also contained on chip is a precision regulator that outputs a stable 5 volts The various sounds are generated by JC NOISE COLOR control R3 is used to set the bandwidth of the noise source to create sound effects ranging from wind to cannon fire Initial frequencies of the LFO low frequency oscillator and vco vari able frequency oscillator are set with R10 and R12 respectively A few
120. echnology behind sat ellite TV it begins with a brief history of satellite communications in general Then the remaining seven chapters quickly bring the focus to satellite TV with each chapter devoted to a specific topic Chapters 2 through 5 for exam ple deal with the uplink the satelites themselves earth stations and the kind of programming available on the satellite channels Chapter 6 discusses the current legality of private receive only TVRO stations that more and more people are installing to expand their viewing hori zons The two closing chapters look into the future and discuss career opportuni ties in the satellite T V field Supporting the text are drawings pho tos some of current satellite receiving equipment for the home and tables The text itself is informative and well written handling the topicin a relatively nontech nical manner Complete Guide to Telephone Equip ment Troubleshooting and Repair by John D Lenk Prentice Hall Hard cov er 237 pages 29 95 This book concentrates on a basic troubleshooting approach that can be ap plied to both current and future tele phone equipment By avoiding equip ment specific troubleshooting proce dures the material presented will remain current as new technology is incorporat ed into future telephone equipment Since the secret to effective troubleshoot ing and repair of anything relies heavily upon the technician s knowledge of the faulty
121. ecutive page numbers July and August issues is somewhat annoying Perhaps there is a yearly special issue that contains all the missing pages and parts of articles and projects Keep up the good work Hans Kneip Victoria Canada Pages appear to be skipped due to pos tal regulations when there are insert cards which have to carry assumed page numbers though they re not printed as such So you ll see two apparently skip ped ones in a few spots in each issue THE AMAZING THE NEW 65 9028 VT VOICE MASTER ENTER THE FINAL FRONTIER OF MAN TO MACHINE COMMUNICATIONS There is nothing else like it Voice Master gives both speech output and voice recognition with this single hardware product Your voice controls programs or home appliances robots and more with spoken commands Verbal response back gives status verifies or requests your reply Speech output and recognition patterns are recorded in with your voice Or use the voice of your friend boss teacher mother even the family pet Programming is simple with new commands added to BASIC A music bonus program lets you write and compose musical scores simply by humming the tune Unlimited applications for fun education and commercial use Design your own programs for profit Soeech and recognition qualify unsurpassed by even the most sophisticated machines Only Covox provides this high tech marvel at a price less than most common peripherals
122. ed to a belt as desired The receiver is compatible with any video camera A Velcro at tachment gives the user a choice of Stand Alone Modem New from Practical Peripherals Westlake Village CA is the Model 1200 SA fully Hayes compatible stand alone modem This 300 1200 baud modem features auto dial auto answer capabilities supports all communications software and in cludes an upgrade path for a pro grammable enhancement card Auto matic adaptive equalization is built in for consistent and error free oper ation over the telephone line Other features include semipermanent stor age of up to 10 telephone numbers menu driven configuration no switches to be set pulse or tone dial ing volume controlled speaker and two modular jacks to accommodate voice and data calls Operating modes include auto where to place the receiver on the camera Plugging into the camera s input the receiver also has an earphone that allows the user to audit the sound while shooting a scene A dual LED panel signals when the unit is operating and sound is being re ceived Supplied with the Sound Catcher is a soft carrying case 134 95 CIRCLE 15 ON FREE INFORMATION CARD aE ha a A 14 MODERN ELECTRONICS January 1987 matic answer and originate selection computer controlled dialing and answering autodial from memory and automatic speed mode detec tion Indicators come on for Modem Ready Receive Data
123. ee ee res Ties i i a 8 E a a a a EE C a 4 2 oe M te E fh ee eS ee i a uu amp i t f amp Se i a iki E amp koe no ee ft COVER YOUR INVESTMENT Macintosh Monitor amp Kiwanda 12 95 Macintosh Plus Keyboard add 1 00 with Mac Bottom add 3 00 Image Writer 12 95 Image Writer I 174 95 External Drive EA See IBM PC or XT or AT vps wane ne 22095 IBM Pro Printer Heb dihean hea 16535 C itoh Okidata Over 3000 covers to choose from You name it We got it Anti Static ditferent colors ORDER LINE 1 800 874 6391 800 342 9008 VIA Dealer inquiries Invited Customer CompuCover Service P 0 Box 310 Dept D 904 243 5793 Mary Esther FL 32569 82 CIRCLE 26 ON INFORMATION CARD Telex 469783 L E k amp kh a W N af iiss E QReis amp 7 a R t a E a 1 kE se A let you switch among files on a desktop the SPI program creates one whopping 1 1 MB hard disk file but makes you close and save your spreadsheet before work on a word processing file Lasers in the Annex Besides setting up a consulting business to occupy his semiretirement my dad has bought so much hardware and software since outgrowing his Apple Ile that my parents house has become the PC Pa pers Annex I was there last weekend to check out his latest purchase a QMS Big Kill laser printer I was envious but
124. een looking for all along Take advantage of substantial savings over the newsstand price by E 7 MILLION TUBES subscribing now Don t miss out on even one single issue of a Includes all current ob ji POPULAR COMMUNICATIONS order your subscription now ame annue handia al trial radio TV types LOWEST PRICES Major brands in stock Unity Electronics Dept M P O Box 213 Elizabeth N J 07206 PAY TV and Satellite Descrambling 100 pages of theory and schematics for major cable systems and Satellite systems By passes how illegal decoders are detected Or ian and VC pirate chips etc 14 95 Cable TV how systems work two way cable 9 95 Exper iments with Videocipher 9 95 MDS MMDS Handbook 9 95 Satellite Systems under 600 11 95 Any 3 for 26 New catalog 1 POPU LAR SHOJIKI ELECTRONICS CORP 1327P Niagara Street COMMUNICATIONS 76N Broadway Hicksville NY 11801 Niagara Falis NY 14903 COO s 716 284 2163 Yes The NEW POPULAR COMMUNICATIONS is just the magazine I ve been looking for Start sending it to me now understand that may cancel at any time for any reason and receive a full refund on my unused subscription r Use re Paid by OCheck O Money Order MasterCard Visa LJ 1 year 12 issues 16 00 banter free My account number is O 2years 24 issues 31 00 N i info card Name Canada and Mexico one year 20 00 US two years 39 00 US three years 58 00 US Foreign one year 22 00 US tw
125. els with the appro priate legends Figure 6 shows a typical panel arrangment for one Drum Synthesizer circuit If you use a dry transfer lettering kit label the panels as soon as the box is dry and then spray three light coats of clear acrylic over all exterior surfaces waiting until each coat is dry before spraying on the next to protect the lettering If you re using a tape label er spray on the acrylic first and ap ply the labels after the acrylic has completely dried Mount the switches controls and jacks in their respective locations line the ac power cord hole with a rubber grommet and mount the cir cuit boards with 4 spacers and ma chine hardware Referring to Fig 1 wire the controls switches and J and J2 into the circuit If you ve in corporated the touch pad into your Continued on page 86 Wu ee AA UU 48 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics Computer Parts Galore 1 800 431 9008 DISC DRIVES 360K CAPACITY DSDD al 1 2 HEIGHT 48 TPI PANASONIC JU455 5 109 00ea 2 for 199 00 QUMETRACK 142 5 79 95ea IBM COMPATIBLE KEYBOARDS Model SISI Pictured 74 95 Seperaiz keypad and cursor pad PC and XT compatible Model 5060 sssssmssmwssesose 64 95 LED status panei large return key automatically switches between AT and XT MALIA Rene reer ee 54 95 oe XT compatible Laid o
126. ement There are several ways to heat a board bearing solder pasted SMDs The simplest is to place the board ina convection oven and increase the temperature until the solder melts Say You Saw It In Modern Electronics Another is to place the board on a hotplate until the solder melts The vapor phase reflow method is more complicated but is faster and applies less thermal stress to the board and its components Here the board is placed over a pool of boiling liquid fluorocarbon in a closed chamber Some of the vaporized fluorocarbon condenses on the board and the SMDs and the heat given off by the condensing vapor heats the solder paste to the melting point Still other heating methods employ lasers or heating coils 4 Conductive Adhesive This procedure uses an electrically con ductive adhesive In one method both the foil footprints on the board and the terminals of the SMDs are coated with a thin film of activator material The adhesive material is then applied to the footprints and the SMDs are placed in position The adhesive cures in a minute or so As you can see mounting compo nents on surface mount boards in volves many more options than ac complishing the same task with a conventional circuit board And we ve not even discussed the various ae a m i i ire i a Py Se A a he B i A Say You Saw It In Modern Electronics Fig 8 Vector Electronic Company s SMT2000 surface mount traini
127. eries every few hours of playing the Drum Synthesizer to equalize power consumption and extend battery life Construction There s nothing critical about laying out and assembling the Drum Syn thesizer circuitry Hence just about any traditional wiring approach can be used If you feel ambitious you can design and fabricate a printed circuit board Otherwise use perfor ated board and Wire Wrap or solder ing hardware Whichever method you choose a 4 4 x 3 board should suffice for the main circuitry of asingle Drum Synthesizer system and a smaller board can be used to accommodate the power supply cir cuitry If you re planning on build ing more than one Drum Synthesizer into a single box you can increase the size of the main board to accom modate the additional circuitry or use individual boards for each syn thesizer module It s a good idea to use sockets for all ICs Examining the prototype of the project shown in the lead photo you will note that controls R3 R10 R12 and R 3 are pc type trimmers and switches S7 through S6 are all con tained in a single 6 position DIP switch module If you re planning on housing the project in an enclosure it s much more convenient to use mi niature or full size panel type poten tiometers and toggle or slide switches for easy accessibility and convenient operation especially if you re plan ning to build more than one synthe sizer module into the b
128. ertiser with a mailing label prepared by our reader service department to ensure speedy response ELECTRONICS Catalog 13 7 High Voltage It s a simple fact All catalogs are NOT created equal Some are more powerful than others One catalog stands alone in the highest category of them all High Voltage and it s available only from MCM Electronics Our catalog gives you the POWER to save money with affordable prices the POWER to find the parts you need with our wide selection plus the POWER of quick delivery Discover for yourself the High Voltage POWER of MCM s Catalog 13 Cali TODAY for your FREE copy Call TODAY for our newest Catalog TOLL FREE 1 800 543 4330 In Ohio call 1 800 762 4315 In Hawaii or Alaska 1 800 858 1849 858 E Congress Park Drive eCenterville Oh 45459 MCM ELECTRONICS A PREMIER Company Source No ME 19 CIRCLE 20N FREE INFORMATION CARD January 1987 MODERN ELECTRONICS 77 D O o NE E The Sams Hookup Book Do it Yourself Connections for Your VCR Howard W Sams Soft cover 92 pages 4 95 Hookup arrangements shown in the manuals that accompany videocassette recorders rarely address the needs of the owner who wants to use two or more pro gram sources with his VCR If he has an outside antenna and a cable feed or any of the many program sources popularly used with VCRs this book can help him put together a properly integrated sys tem More tha
129. est assembled on a printed circuit board but you can use perforated board and suitable soldering hardware if you prefer In either case it s a good idea to use sockets for the ICs If you decide on pc wiring use the actual size etching and drilling guides given in Fig 4 to fabricate one or both boards After drilling the etched receiver board plug 73 into it and mark on the board its tab hole locations Drill a 4 hole at both marked locations and a third hole midway between the two long edges and about in from the short edge at the opposite end of the board Set the board centered all around on the floor of the bottom half of the aluminum chassis box that is to house the receiver Mark on the box the locations of the three board mounting holes Remove and set aside the board Drill 4 holes at all three locations Wire the receiver pc board as Fig 4 Actual size etching and drilling guides for receiver power supply and shown at the left in Fig 5 except do not plug the ICs into their sockets if you are using them If you use per forated board instead of a pc board use Fig 5 as a rough guide to compo nent layout Pay careful attention to the orientations of the electrolytic capacitors bridge rectifier diodes and ICs or their sockets before sol dering them into place Place C74 and C75 side by side with the lead of one near the lead of the other and tape them to gether With C75 on top
130. f for the profes sional reader because what the author covers and just as importantly how he covers it in this thick volume has the mark of a professional who knows his job well Geared toward the needs of the TV service technician it starts with a chapter on common sense servicing tips Then chapter by chapter it details trou bleshooting various Circuits common to all solid state color TV receivers includ ing a chapter on remote controllers con cluding with servicing the black and white chassis Troubleshooting tips for particular problems and actual case histories of five different chassis problems are given in each chapter Each case history details how to localize the problem to the partic ular faculty component Though not every possible problem that can occur in a given circuit can be covered in any book of this nature this book makes a credit able effort to present the broadest possi ble picture including tough dog problems that can frustrate even the most dedicated technician We would not hesi tate to recommend this book to any TV repair technician who wishes to sharpen his servicing skills Satellites Today 2nd Edition by Frank Baylin Universal Electronics Inc 4555 Groves Rd Suite 3 Columbus OH 43232 Soft Cover 167 pages 12 95 This nontechnical book is a primer on the current situation for people who have an interest in satellite television Basical ly the story of the t
131. ful for electronic weighing and scales load cells materials testing accelerometers elec tronic music keyboards pressure and force measurement stress analysis ro botics traffic sensors unique game input devices and much more Despite costs starting at 4 and their simple use strain gauges remain virtually unknown as hacker components Yet the opportunities here are mind boggling Let s start at the beginning Say you had a piece of steel and started pulling on it If you try this you will generate the classic stress strain curve shown in Fig 1 If you pull on the steel only moderately it will spring back to its original shape If you pull harder it will stretch like taffy Pull too hard and the steel will fail by snaping in two The stress you apply to the steel will be determined by the force you use and the cross sectional area over which that force is applied Stress is often measured in psi or pounds per square inch If you are pulling on the steel you place it in ten sion much the same as the cables of a suspension bridge If you are pushing on the steel instead you put it in compres sion similar to the loading on the con crete pylons of a highway bridge As the steel is stressed it will get YIELD POINT Stress in PSI elastic region plastic region ULTIMATE STRENGTH failure Strain in micro inches per inch Fig 1 Stress versus strain curve plot for mild steel longer This
132. g for enclosure top and bottom panels Miscellaneous 2 lug screw type ter minal strip 0 5 cu ft fiberlgass wool wood glue caulking or sili cone sealer zip cord sheetmetal screws grille cloth flat black paint finishing materials 2 finishing nails solder etc E AEE a a Fig 2 Dimension and assembly details of the speaker system You havea choice of materials and thicknesses for the enclosure walls one side of the enclosure Drive the nails only 4 in Liberally coat the edge of the smaller panel with wood glue and nail it to the rear panel making the latter flush with the rear edge of the former Do the same for the selected wall squaring the panels as you work Run a bead of wood glue along the mating edges of the speaker baffle align the baffle with the setback lines on the interior sur faces of the panels and nail the two panels together Drive finishing nails partially into the remaining panels of the enclosure along the guide lines Coat with glue 66 MODERN ELECTRONICS January 1987 the remaining edges of the speaker baffle rear panel and the mating panel edges Nail the panels to the enclosure s rear panel and speaker baffle Then tightly clamp or weight the enclosure for 24 hours When the glue has set run a thick bead of caulking or silicone adhesive along all interior joints including those for the speaker baffle to air seal the enclosure Then mask off the front edges of the encl
133. gnals that have no preem phasis the value of C10 must be changed to 0 001 microfarad Audio output from the receiver can be taken from pin 8 rather than from pin 12 of JC2 if additional amplification isn t needed AUDIO GAIN trimmer R9 controls an elec tronic attenuator that increases out put signal level as its resistance is reduced TONE control R8 C13 doesn t affect the output from pin 8 and can be omitted if it s not needed Output signal level from pin 12 of Say You Saw It In Modern Electronics R3 RF GAIN 4 7K IVO C1 0 05pF R4 D1 D2 12 volt zener diode D3 D4 9 volt zener diode IC1 MC1350i f amplifier Motorola IC2 MC1358 FM receiver Motorola RECT 1 VM6O8 bridge rectifier Capacitors C1 C2 C4 C5 C6 C9 C11 C16 0 05 uF disc 3 C7 15 to 150 pF trimmer C8 C13 0 22 nF disc or Mylar C10 0 01 yF disc C12 0 1 nF disc C14 2 200 nF 35 volt electrolytic C15 220 pF 35 volt electrolytic Resistors 14 watt 5 tolerance R1 R10 330 ohms IC2 is sufficient to drive a low power audio output stage It can be con nected directly to the base of the power transistor to provide both bias current and signal current use an emitter resistor to limit the current Dc blocking for those applications that require it is provided by C8 Figure 2 is the schematic diagram of the ac power supply for the receiv er Shunt regulation using zener di odes DI through D4 is adequate for
134. gs photos and diagrams But if there is ever anything in your lessons you don t under Stand you can write of phone your instructor and you can count on getting an authoritative answer Send for free facts and color brochure No cost No obligation No salesman will visit vou MAIL COUPON TODAY Ics SCHOOL OF TV VCR REPAIR Dept DLO16 Scranton Pennsylvania 18515 Please send me free facts on how can learn TV VCR Repair at home in my spare time No salesman will visit Aa Name Age Address City State Zip Phone WA eee January 1987 MODERN ELECTRONICS 67 Project l A Bulk Eraser For Cassettes amp Diskettes Erasing an audio or computer cas sette by running it through a tape deck is time consuming And delet ing all files on a floppy disk doesn t wipe the slate clean it just changes the first bit A bulk eraser like the miniature one described here will improve these operations by wiping out anything recorded on tape or diskette in just a few seconds There fore you gain erasing speed for tape and data security for disks You can build the ac line operated bulk eraser for nothing if you have a well stocked spare parts box or for just a few dollars if you don t Commercial line operated bulk eras ers consist of an electromagnet that delivers a powerful ac field that wipes out anything recorded on mag netic media Our mini eraser uses the same principle using a laminated iron core fil
135. h 0 25 basic accuracy and 2 000 hour battery life 69 MODEL 9370 3 Ya didit autorangin DMM with a memory Lote ae basic DC acetiracy 559 MODEL 3401 4 2 digit full function hand held DMM with 4 05 accuracy and data hold 129 MODEL 9101 Compact VOM with 27 ranges MOCEL 9701 digi clamp compact AC clamp on volt ohm including a 100 ammeter with data hold megohm range 69 Son 5290 Mercer Electronics products reflect the design and quality standards established ky simpson Electric Company an industry leader for over 50 E L E A T R O N C S years and Soan worldwide for its ue and PINGU EXENENES amp NI In Stock Available Now Stop in at your nearest distributor and see Division of Simpson Electric Company this new compete line of Mercer test instruments For the name of the 859 Dundee Avenue Elgin IL 60120 3090 MERCER dis ritutor in your area call 312 697 2265 or send for our 312 697 2265 Telex 72 2416 new line catalog CIRCLE 32 ON FREE INFORMATION CARD Which Way To YOUR Future Are you at a crossroads in your career Have you really thought about it Are you planning for your future or perhaps refusing to face the subject Which way will you go down the same old road Or are you ready for something else In electronics you can t stand still If you are not moving ahead then you re falling behind At the crossroads of your career various choices are availabl
136. he signal source cou ples the signal through C into the base of Q1 Construction The coil and transformers in the re ceiver are nonstandard components that are easily home fabricated using readily available standard r f coils as cores on which you wind additional turns of 26 gauge magnet wire For TI you use the existing turns of a 100 microhenry choke as the secon dary while for 72 and LI you use 10 microhenry chokes Starting with T7 count the num ber of turns in the existing 100 mi crohenry choke To obtain the num ber of turns you must wind divide by 2 the number of turns counted To ee AA ee calculate the number of turns needed for the windings of 72 and LI first count the number of turns on the ex isting 10 microhenry chokes and multiply by 1 4 Round off the result to the nearest even number of turns For 72 divide the result by 2 to de termine where to make the center tap Use strips of perforated board as supports for TI and 72 Make the strips long enough for the existing C1 470 pF disc capacitor C2 0 01 nF disc capacitor C3 0 05 yF disc capacitor J1 F 61 chassis mount male coaxial connector L1 Pickup coil see text L2 100 4H choke Q1 2N3904 or equivalent transistor R1 22 000 ohm 4 watt 5 toler ance resistor 58 MODERN ELECTRONICS January 1987 PICKUP UNIT PARTS LIST Fig 3 Schematic diagram of optional pickup unit leads to fit through the end holes
137. hese two circuits to gether note that these are strictly ad vanced hacker components A decent os cilloscope is almost essential as is a very carefully done printed circuit board lay out It is extremely important to use low noise power supplies possibly even to the point of using a separate regulator for the converter itself The supply lines must be thoroughly bypassed directly at the converter pins using very high quality capacitors Tan talum capacitors are almost essential since many electrolytics have uselessly high impedances at video frequencies The input video must come from a low impedance source preferably from an on bolard input buffer The RCA CA3450 is a good choice for this There are really two reference voltages needed one for the top and one for the bottom of a resistor chain that forms the reference for each of the 64 or 256 com parators While I ve shown the bottom end grounded you can move this up Say You Saw It In Modern Electronics 0 CE1 CE2 CLK 450 GND 5A VIN 5V MC10319 top view Digital Outputs Plan To Move Let Us Know O 1uF 10uF O 5V Isb or down a volt or so as needed One use would be for automatically strip ping sync It is very important that your reference voltages be low noise and low imped ance In a real circuit you will probably want to drive these from the output of an op amp setup as a unity gain voltage buf fer driven from a suitable stable so
138. i rie a aa 78 HARD DRIVES amp CONTROLLERS 20 MB Seagate 68 MS 295 30 MB Seagate 40 MS 598 20 MB Seagate ST238 w Adaptec Controller 480 Western Digital Controller 101 AT Floppy amp Hard Disk Controller w Cable 200 POWER SUPPLIES TOS ea uss nde kee ate IAA Ors 50 SOW ow ark II Feng B 55 ZOOVY wina msye mea Beth oP SESS tae N 90 KEYBOARDS KIS 5150 acca saa anin werd chem peek WE 40 BTGo15l aa rI DHATRI Pade ae 55 5060 XT AT o 50 BIGOT IAT n scenaron ssnst eanta ia e 50 KG O E E E YA TT 50 Ko 8 wet Be awe Dies areo kaa Nin 55 BaSZ ii den Digg ete FU IIIA 65 MONITORS Samsung Amber 00000005 68 SAMSUNCLONCON ae WA Hes Seen eee 65 Belton Tilt amp Swivel 85 Mitsubishi RGB ua weet iinacs ees Baa 230 TVM RGB Green Amber 275 EGA Mitsubishi 395 OTHERS Speakon g a sea paws Ses kag Belews Me da san 1 Disk Storage 100 7 Keyboard Drawer 30 Modum Internal 121 LogiMouse UWA ana 77 JOY StiC TIE eB wigs bales Ra a A alll 16 Printer Stand Big cxvecwesestarace csvosenrnen 8 Printer Stand Small 7 Power Strip 6 Outlets 5 Power Strip w Surge Protector 6 Power Pad w Surge Protector
139. icians Through this Special Program you can pull all of the loose ends of your electronics background together and earn your B S E E Degree Up grade your Status and pay to the Engineering Level Advance Rapidly Many finish in 12 months or less Students and graduates in all 50 States and throughout the World Established Over 40 Years Write for free Descriptive Lit erature COOK S INSTITUTE OF ELECTRONICS ENGINEERING E 147 RAYMOND ROAD GIE ro 80x 20345 JACKSON MISSISSIPPI 39209 CIRCLE 31N FREE INFORMATION CARD LEARN TV VCR REPAIR No Previous Experience Necessary N ow you can train at home in spare time for a mon ey making career as a TV VCR Repair Specialist No need to quit your job or school We show vou how to troubleshoot and repair videocassette recorders and TV sets how to handle house calls and shop repairs for almost any make of television or VCR You Jearn about TV receivers tuners and antennas x ray emission the characteristics of sound how electrical impulses are con verted into a TV picture and much much more Tools are included with our course so 4 ou can get hands on practice as you follow the lessons step by step Send for free facts about opportunities in TV VCR Repair and find out how you can start making money in this great career Experts show you what to do how to do it guide you every step of the way Everything is explained in easy to understand language with plenty of drawin
140. ics and move the eraser in a widening spiral over the diskette Flip over the magazine and erase the other side of the diskette in the same manner Again move the eraser at least 3 feet away from the diskette before releas ing SJ The whole operation should take no more than 10 seconds If you have more than one diskette to erase do each about 5 minutes apart to avold overheating the eraser I tried erasing cassettes at various ac voltages powering the eraser through a powerstat For my particu lar choke erasures were satisfactory R down to about 65 volts This means that it s possible to install a suitable power resistor in series with LI to re duce coil voltage and current I did not attempt to use the project to erase videocassettes I suspect though that these may require a larger electromagnet and a more powerful magnetic field to assure complete erasure Adolph A Mangieri Say You Saw It In Modern Electronics SUBSCRIBER SERVICE CHANGE OF ADDRESS Planning to move Please let us know six weeks in advance so ATTACH LABEL HERE you won t miss a single issue of MODERN ELECTRONICS Attach old label and print new NEW ADDRESS HERE PLEASE PRINT address in space provided Also include your mailing label NAME whenever you write concerning your subscription to insure ADDRESS prompt service on your inquiry Modern Electronics CITY o STATE 76 N Broadway Hicksville NY 11801 DA
141. imer Beeper mentioned earlier contains all the circuitry need ed to sound an audible alert when the count down cycle has timed out The audible alerter in this circuit is a pie zoelectric buzzer that is driven in a manner that produces an attention getting chirp at the end of the tim ing cycle Shown in Fig 5 is the oscillator circuit used in the Timer Beeper to generate the system s characteristic chirping sound This portion of the circuitry uses a dual 555 timer housed in the usual 556 dual timer chip and just a few external com 32 MODERN ELECTRONICS January 1987 ponents The values of the external components have been selected so that the circuit generates brief groups of current pulses that when sent to a piezo buzzer creates the chirping sound With the component values shown there will be two or three chirps per second With the first timer in the 555 con nected in the astable mode the wave gt a Oo m Fig 5 This circuit produces a steady chirping Disconnecting link be tween pins 2 and 6 of LM556 silences buzzer Link between pins 2 and 6 starts buzzer which is basis of Timer Beeper s operation Say You Saw It In Modern Electronics Fig 6 Waveform at pin 5 of LM556 form at pin 5 will be a continuous stream of pulses like that shown in Fig 6 High time t 0 693 Ra Rp Cl 0 693 100 000 10 000 x 4 7 10 0 358 second Low time t 0 693 R
142. immer potentiometer Miscellaneous B1 9 volt transistor battery K1 Spst reed relay with 5 volt dc coil Radio Shack Cat No 275 232 or similar MIC Electret microphone element Radio Shack Cat No 270 090 or 270 092 see text Printed circuit board perforated board and soldering or Wire Wrap hardware or solderless breadboarding socket see Project Bi 9V T C5 47 uF text sockets for ICs 2 lug screw type terminal strip see text snap connector and mounting clip for 9 volt battery quick set epoxy cement or silicone ad hesive 4 spacers machine hardware hookup wire solder etc Note The following items for moderate to heavy power switching are optional as ex plained in the text Power relay chassis mount ac receptacle eliminate the 2 lug screw type terminal strip if this option is used ac line cord with plug rubber grom met plastic or heat shrinkable preferable tubing double sided foam tape Fig 1 Overall schematic diagram of the Sultan s Servant on and off moderate to heavy duty appliances you must use a second re lay whose contacts are rated to han dle the amount of power drawn by the load you plan to switch There are a number of relays on the market suitable for this purpose some of which will switch loads of 10 am peres and more Should you decide to use a power relay use the project s relay K contacts to switch coil power to the power relay
143. ional quality 20MHz dual trace scope for under 450 Best of all it s a full featured instrument from B amp K PRECISION famous for quality dependable products Compare these outstanding features then compare price e Dual or single trace operation 2mV div sensitivity 20MHz response at a true 3dB e AUTO NORM triggered sweep operation with AC TVH TVV and Line coupling e Calibrated 18 step timebase with x10 magnifier X Y oper ation Bright sharp rectangular CRT with P31 phosphor e Front panel trace rotation control e Tilt stand and soft handle Selectable slope e Built in calibration source e Compact low profile design For immediate delivery contact your local B amp K PRECISION distributor or call B amp EK PRECISION today r3 DYNASCAN NUU CORPORATION 6460 West Cortland Street Chicago Illinois 60635 312 889 9087 InternatlonalSales 6460W Cartland St Chicago IIlinofs60635 CanadianSales AtiasElectronics Ontaria South and Central Americcn Sales Empire Exporters Plainview NY 11803 January 1987 MODERN ELECTRONICS 7 Become one of America s most sought after technicians put your talents and spare time to work for you in the explosive growth world of home entertainment electronics Train in state of the art video audio servicing and become a fully qualified service professional the uniquely suc cessful NRI way It s hands on train ing at home designed ar
144. irly high current source of 1 0 volt This reference sets the full scale value of the input video You also have to input on pin 7 a refer ence clock equal to the sampling rate you want It is extremely important that the highest video frequency you are sampling is less than one half this value Thus some sort of input low pass filtering or other bandwidth limiting must be done before doing the actual A D conversion Sometimes you may want to vary the clock rate In many applications there is no point in sampling the sync and blank ing times Finally you have six data outputs one for each bit of the 6 bit digitized video and a seventh overflow line While we have shown the chip select on pin 6 grounded here for most uses you will want to use this to tri state control the digital outputs A newer Motorola 8 bit video A D converter circuit is shown in Fig 5 Un fortunately this chip is larger and needs a negative 5 volt supply besides the usual positive 5 volt supply It is also faster which means that it may be noisier for most hacker uses Cost of these chips is M a 74 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics Video input 14 32 Mhz Clock 1 0 volt reference RF RF GND msb Overflow Fig 5 An 8 bit 256 level Motorola video A D converter currently in the 20 to 35 range but lower priced plastic versions should shortly be available Before you throw t
145. is a glorious idea a combination of a 1Dir or Le Menu style file manager and a switcher that lets you keep multiple programs in memory though it prefers PC DOS 2 10 to my hard disk s MS DOS 3 1 eats memory fast and lacks the cut and paste ability of my favorite switcher Awesome Technology s Multiple Choice Finally though I m far from the first to do so I must salute the shareware king Jim Button His PC Calc spread sheet 64 95 is limited to 64 columns by 256 rows and lacks Lotus fancy financial functions though it can calculate loan interest and payments but it s a first class worksheet for moderate jobs PC File II 64 95 among the most popu lar user supported programs is a sensa tional if not relational database with fast flexible searches macros calcula tions password encryption and import export formats galore Try a shareware copy and I ll bet you ll want to register if only because the disk based manual reads rather like Hamlet with all of Hamlet s speeches replaced by This section has been deleted from your evaluation copy Not Quite Integrated It s unfortunate that while I was testing Software Products International s Open Ee 80 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics Access II 595 Ashton Tate aban doned copy protection so I could stop boycotting my favorite integrated pack age Framework II Three of Open Ac
146. ital CBS 348649 The Pachelbel Canan And Other Digital Delights The Toronta Chamber Orchestro Fanfare 342667 Beethoven Piano Concertos Nos 3 amp 4 Concertgebouw Orchestra Digitol CBS Masterworks 328307 Tina Turner Private Dancer Capitol 321570 Beethoven Symphony No 5 Op 67 Schubert Symphony No 8 Unfinished Vienno Phil Orch Lorn Moazel Cond Digttal CBS Master works 263293 Bolling Suite For Flute amp Jazz Piano Rampal Bolling CBS Masterworks 339200 Stevie Wonder lIn Square Circle 1 album Tamia 347054 David Lee Roth Eat Em and Smile Warner Bros 219477 Simon amp Garfunkel s Greatest Hits Columbia 316604 Tchaikovsky 1812 Overture Marche Slave Beethoven Wellington s Victory Lorin Maazel Vienna Phil Digitol CBS Masterworks 343251 Bach Goldberg Variations Glenn Gould Digital CBS Masterworks 287003 Eagles Their Greatest Hits 1971 1975 Asylum 328740 Mozart Piano Concerto No 26 Coronation Rondos Murray Perahia and English Chamber Orchestro Digital _CBS Masterworks MisE DIGITAL AUDIO The age of CD sound is here and you have a practical new way to find the CDs you want As your introduction to the CBS Compact Disc Club you can choose any 2 CDs listed in this ad for just 1 00 Fill in and mail the application we ll send your CDs and bill you for 1 You simply agree to b
147. kan 5 VDC RELAY CAT t Fujitsu C i FBR211NED005M20 Tt COM 1520 y High sensitivity COIL 120 ohms 1 25 each CONTACTS lamp 10 tor 10 00 Mounts in 14 pin DIP socket EXTRA pen sets 1 50 per set 2 amp constant 4 amp surge 20 00 each 3 amp constant 5amp Surge 27 50 each LASERS gt HE NE Complete 129 95 Modulated sys tems available LES Electronics P O Box 800276 Dallas TX 75380 HARD Disks 10 20 30 MEG HT Starting at 149 ea LES Electronics P O Box 800276 Dallas TX 75380 INVENTORS INVENTORS Can you profit from your idea Call AMERICAN INVENTORS COR PORATION for free information Over a de cade of service 1 800 338 5656 In Massachu setts or Canada call 413 568 3753 INVENTORS INVENTORS Have idea for product or in vention don t know what to do Call AIM we present idea s to manufacturers Toll Free 1 800 225 5800 MISCELLANEOUS ASIAN women seek friendship marriage Correspondence Club Photos Details GRE Box 555 Elmont NY 11003 EARN 100 per hour conducting countermea sure Sweeps using our low cost de bugging equipment SSE P O Box 15104 Cleveland OH 44115 ASIAN LADIES want correspondence for fnendship marriage SUNSHINE INTERNA TIONAL Dept TW Box 260 North Holly wood CA 91603 ted 48 KEY ASSEMBLY FOR COMPUTER OR HOBBYIST NEWT I KCYBOANDS O PROCESSORS 8087 2 8mHz 8087 3 5mHz 80287 3 6mHz 80287 8 8mhHz V 20 8mHz v
148. lation to the stripping blades and eliminate sagging during stripping Depth of cut is infinitely variable between 0 and 0 118 0 to 3 mm The tool is light in weight and easy to use It comes with its own storage case a set of different size guide bushings and full instructions CIRCLE 18 ON FREE INFORMATION CARD Circuit Design Program CompDes from Esoft Software Co lumbus OH is a low cost electronic circuit design program that runs in IBM PC and compatible computers Designed for students technicians and engineers this menu driven software too has menu selections that start with Basic Electricity and work up to Circuit Designs The soft Continued on page 85 Say You Saw It In Modern Electronics ree Famous hi tech ai atalog A very special computer amp electronics guide that shows you what the exciting world of kitbuilding can do for you Challenge Knowledge Achievement Enjoy ment All of these things are yours when you build a Heathkit high quality product Our colorful in formative catalog reflects the years of experience and technological expertise that make these things happen for you Amateur Radio Terminal Node Controller HERO 2000 Educational Robot and Courseware IBM PC Compatible Expandable Computers dence and pride that you can only get by building a state of the art product yourself And you re backed by our promise We won t
149. lent commercial product By William R Hoffman orking with electronic cir Ws can be a stimulating experience Yet many of these circuits require electromechani cal or electrical adjuncts In the case of an audio amplifier for example you often need a speaker system or two if it s stereo It s not uncommon for someone to build a fairly capable audio ampli fier for a modest sum only to discov er that a speaker system to match its performance costs many times more than the electronic parts did In other instances you may want to add ex tension speakers to a fine stereo sys tem but the cheap ones sound pretty bad acoustically In either case here s an opportunity to build a pair of nice sounding speaker systems for 40 or less in materials that s equivalent in performance to sys tems selling for as much as three times the cost Our home made system uses a high quality dual cone 8 loud speaker that can be driven well by a 10 watt power amplifier while 30 watts the driver s maximum contin uous handling power will fill any moderate size room with good qual ity very high levels of acoustic out put that will do justice to any rock or orchestral music The loudspeak er is available at most Radio Shack stores SS enim r zF a H a ni s a W AA kl Sa n i E A ai a sa ie i im amp Pl Cs oa 2 t UA AA The speaker system s midrange and treble are detailed and clear while ba
150. lifornia Penal Code 593 D forbids us SUBTOTAL from shipping any cable descrambling unit Shipping Add to anyone residing in the State of California 3 00 per unit COD amp Credit Prices subject to change without notice Cards Add Sa PLEASE PRINT TOTAL Name Address City State Zip Phone Number Cashier s Check Money Order COD Mastercard Acct Exp Date Signature NAA ZCc PAZA ia ie WA EE FOR OUR RECORDS DECLARATION OF AUTHORIZED USE the undersigned do hereby declare under penalty of perjury that all products purchased now and in the future will only be used on cable TV systems with proper authorization from local officials or cable company officials in accordance with all applicabile federal and state laws LOW EST Dated Signed __ PRICES Pacific Cable Company Inc WHERE 7325 2 RESEDA BLVD DEPT 20 RESEDA CA 91335 818 716 5914 gt No Collect Calls 818 716 5140 S C E N i F C A T L P N A U N S Repairing and maintaining electronic equipment and computers ranks high among the interests of Modern Electron ics readers We know this because 76 1 said so when we made an intensive read ership study last year This figure was corroborated by other responses For ex ample 65 4 of respondents noted that they were professionally involved in elec tronics or a related industry while 10 4 reported that they plan to make electron ics a career So the t
151. ling IBM itself resulted in them di recting me to the dealer from whom I purchased the machine Unfortunately the dealer isn t around anymore So it was Suggested that I contact any other IBM dealer and tell em my story Con tacting some IBM dealers however didn t reveal what the codes meant either But I did manage to get the dealer IBM technical assistance hotline phone number which I quickly called They didn t know what the codes meant either and redirected me to their dealers Tired of this round robin I proceeded on my own learning from the diagnostic disk that the computer s motherboard 64K was fine That left 576K of memory in add on boards to check out I changed the board switch settings to set the machine for various memory banks hoping that I d see some change from one to another The 128K switch set ting brought up a new error code Parity Check 2 Buying a single 64K bit chip from a local Radio Shack store I substi tuted it for the present chips in the parity M EDITORIAL locations No changes Then I checked out connections again especially the wire strappings for IDCs insulation displace ment connector These are the pin open ings with a slit that cuts into the wire s in sulation Connection points on an ohm meter checked out fine again I knew that the problem was on this single board so I wrote a little note in preparation for shipping it back to its maker for repair Before
152. loose ends were left when the 76477 was put together For ex ample although three pins are pro vided for selecting the various sounds there isn t a separate specific pin one can use to enable a given source Instead a somewhat irra tional code must be used requiring that you perform some mental acro batics whenever you want to change the sounds These are summarized in Sound Selection Code Table Switches S 2 and S3 are used to select the desired sounds 4 applies the lfo to the vco for a variety of fre quency modulation effects S5 is used to synchronize the Ifo to the trigger pulse and S6 places the Ifo in either the audio or the subaudio range to increase the sound possibili ties Figure 2 shows one practical way to simplify selecting the sound sources The nonshorting rotary switch and diode array make the dif ferent sound sources available at the twist of a knob Note though that the inhibit function listed in the Table isn t available at any switch position setting To activate a sound a 5 volt TTL level pulse is applied to the trigger in put Since the 76477 contains a 5 volt regulator for internal use this can be accomplished with a momentary ac tion spst switch located between pin 5 of IC and the TRIGGER INPUT Of course anything that puts out a pulse of the proper level can be used as a triggering source including a rhythm box a synthesizer and even a computer After JC gene
153. m the well established field of hy brid integrated circuits Indeed some of the capacitors and other components developed originally for hybrid microcircuits are now being used in surface mount roles Though surface mount technol ogy has a long history only in the last few years have engineers and manufacturers fully realized its po tential One of the key factors in the high level of interest in surface mount technology is its compatibili January 1987 MODERN ELECTRONICS 19 PC board real estate is used more efficiently ty with automated manufacturing The uniform shape of surface mount devices or SMDs SMD is a service mark of North American Philips Corporation and their small size makes them ideally suited for auto mated manufacturing Resistors ca pacitors trimmers diodes transis tors and integrated circuits can be loaded in plastic magazines or pack aged in sprocketed tape wound on reels Depending on the equipment automated pick and place equip ment can select and place from 1 500 to 500 000 SMD components per hour Equally important manufac turers need no longer go through a hole drilling procedure An attrac tive byproduct is that pc board real estate is used more efficiently al lowing a full complement of compo nents to be easily mounted on both sides of a pc board Surface Mount Devices Figure 2 shows several surface mount components placed near a pa per clip
154. margins but won t start a new paragraph The spreadsheet is a good middle exam ple adequate size 3 000 rows by 216 col umns twice the speed of Framework II though half that of 1 2 3 a helpful goal seeking or reverse what if function that lets you enter a result to find a variable and financial functions for not only dollar format but mark franc pound yen pe seta lira krona guilder drachma and shilling format as well With such sophis tication you wonder why it requires man ual recalculation and sets format attri butes through a bizarre syntax of chang ing say the value represented by the fifth in a row of eight question marks Open Access II has some strong abili ties but it s something of a renegade among integrated packages Others are composed of various disk overlays but accessories August 3466 BA 1789 04 4803 28 Current Time 82 51 47 PM imi pek hini j Rie Bw o 0 a ee ee Lal Se a ce m u O Pk k a eS Model C a Calculator T ime NUM R er weet el ee ee E eS SS ee a Say You Saw It In Modern Electronics 3188 BA 1132 54 6189 18 Alarm Stop Watch Appointments Third Quarter Sales Division E September Total 3674 38 1752 26 5287 23 18258 38 4673 74 16199 53 away 198 un Mon Tue Hed The Fri Sat LOADOW 14 51 47 PM Value_Converter Cards deek Address Put Your Electronic Skills to Work in ROBOTICS NOW ROBOT VEH
155. ment lack of industry standards and a limited variety of surface mount components Industry s failure to fully capitalize on the benefits of SMT is about to come to an abrupt end Organizations like the Surface Mount Technology Associa tion based in Los Gatos CA the Elec tronics Industries Association EIA in Washington DC and others are work ing with manufacturers and component suppliers to establish standards Mean while the electronics manufacturing in dustry is revving up for SMT production Forecasts indicate that surface mounted circuitry will be used in nearly 30 percent of electronic equipment be ing manufactured by the end of 1988 This represents a 300 percent increase over the 1985 figure and this technology is likely to become the primary means by which electronic products are pro duced in 10 years or so On the Manufacturing Floor Surface mount devices are physically only a fraction of the size and weight of their standard size counterparts An SMD integrated circuit for example re quires only 30 percent of the surface area and has only 10 percent of the mass of the same IC in a traditional DIP de vice A typical SMD that replaces a standard DIP IC with 0 10 pin spacing would utilize a standard SMD pattern with lead spacing of only 0 05 Size differences and space savings are even more dramatic with discrete resis DATA LOGGEA STO CLA ACL ON atm ro Wila SMT on the Move a 1 r
156. ming capacitor see text C5 4 7 pF tantalum electrolytic C7 1 000 pF 16 volt axial lead elec trolytic C8 470 pF 16 volt electrolytic Fig 8 Actual size etching and drilling guide Resistors 4 watt 5 tolerance R1 R2 R13 R14 R15 10 000 ohms R3 330 000 ohms R4 20 000 ohms R9 47 000 ohms R10 5 100 ohms R11 6 800 ohms R12 100 000 ohms R16 330 ohms R17 1 000 ohms R18 390 ohms R5 thru R8 1 megohm 1 tolerance timing resistors see text Miscellaneous F1 ampere slow blow fuse S1 4 position switch see text 34 MODERN ELECTRONICS January 1987 52 Spst slide or toggle switch T1 6 3 volt 300 mA transformer Piezoelectric buzzer Radio Shack Cat No 273 065 or similar print ed circuit board or perforated board and Wire Wrap or soldering hard ware suitable enclosure sockets for ICs optional fuse holder LED panel clip or small rubber grommet ac line cord with plug lettering kit insulating tubing machine hard ware hookup wire solder etc Note If you cannot obtain the XR 2240 programmable timer IC locally it is avail able from Circuit Specialists Box 3047 Scottsdale AZ 85257 for 2 49 _ AYVWidd Fig 9 Wiring guide for pc board Say You Saw It In Modern Electronics Regency Scanner Answer Ye a ee a a araa ne ve pe ee oe ae er m it Here s your chance to win a complete monitoring package from Regency Elec
157. n half of the book is devot ed to perspective drawings and text that detail each step in the connection proced ures and the various ways to operate each of the 17 configurations covered The by the numbers text gives the reader a checklist of every step and can be fol lowed even by someone who has no tech nical background in video Hookups covered are basically simple arrangements that use only couplers splitters A B switches and cables They range from the simplest antenna VCR TV receiver setup to an arrangement that integrates a cable TV line cable TV de coder and satellite TV block converter in which all remote controllers are opera tional Though fairly comprehensive the detailed arrangements do not take into account switching multiple program sources directly to the TV receiver or monitor nor do they cover integration of more than three sources into a system All hookup arrangements are based on a single VCR in the system However the arrangements provided should suit the vast Majority of current needs and a technically knowledgeable reader can easily tailor them to his needs Troubleshooting and Repairing Solid State TVs by Homer L Davidson Tab Books Soft cover 450 pages 24 95 Good troubleshooting books for solid state TV receivers are ararity This book is one of them written by an author who brings to its pages almost 40 years of ex perience on a wide variety of TV chassis His experience pays of
158. nal area is getting progressively reduced through a process called necking down Other materials have different stress strain curves Ceramics are almost entire em a En ES a a ee 72 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics as ry V 1200 1200 10K Strain 1200 gauge 1 Meg 5b o STRAIN OUTPUT 10K Fig 3 A typical strain gauge bridge and amplifier ly linear with no plastic deformation at all Such materials are said to be brittle A brittle material is elastic up to its ulti mate strength and then fails without much in the way of deformation More details on all of this appear in most any college level text on strength of materials What we are interested in here is how to measure strain While there are many types of strain gauges the typical resis tive type is shown in Fig 2 What you have here is a foil pattern on an insulating carrier As you slightly stretch the pat tern the resistance of the foil changes In use the strain gauge is carefully ce mented to the material to be stressed The strain gauge the material and the adhe sive to be used must be carefully matched to each other particularly if temperature effects are to be compensated As you stress the material the strain gauge will slightly change its resistance Nominal resistance values range from 120 ohms upwards Such low values are used to minimize noise pickup The gauge factor
159. ndling capacity is 350 watts music power Speaker design is becoming less of an art today and more of a science Techron Elkhart IN for example recently introduced its V Box Res software program to make designing and comparing low frequency speaker systems more accurate as well as faster and easier The program also provides information on required enclosure parameters to attain performance goals From collected data its Polar program generates a polar display for up to 400 different frequencies and Output Sound Pressure Level dB SPL can be plotted at various angles on and off axis and measured at a Single frequency or band of frequencies APPLE SWELLS EARNINGS Apple Computer reports it doubled earnings and net income in fiscal 1986 ending September 26 Though sales dollars were essentially the same 1 9 billion net income rose 151 percent to 154 million MACHINE VISION Use of machine vision in the electronics industry will outpace auto makers by 1990 according to a University of Michigan study The market for automated vision overall is projected to grow from 58 million to 457 million over a five year forecast period Al most half of the specific machine vision applications for electronics will be in inspection related tasks Color will be especially impor tant The one millionth patent since the U S Commerce Department began using an automated patent printing system in 1970 was issued to Object Recognition Systems for
160. ng Editor Dorothy Kehrwieder Production Manager Elizabeth Ryan Art Director Barbara Scully Artist Pat Le Bianc Florence Martin Phototypographers Hal Keith Illustrator Bruce Morgan Photographer Joseph Desposito Leonard Feldman Eric Grevstad Glenn Hauser Don Lancaster Forrest Mims III Stan Prentiss Contributing Editors BUSINESS STAFF Richard A Ross Publisher Art Salsberg Associate Publisher Dorothy Kehrwieder General Manager Frank V Fuzia Controller Arlene Caggiano Accounting Cheryl Chomicki Subscriber Services SALES OFFICES Modern Electronics 76 North Broadway Hicksville NY 11801 516 681 2922 Eastern Advertising Representative Herb Pressman 76 North Broadway Hicksville NY 11801 516 681 2922 Midwest amp West Advertising Representative Market Media Associates 1150 Wilmette Ave Wilmette IL 60091 312 251 2541 Ted Rickard Kevin Sullivan Offices 76 North Broadway Hicksville NY 11801 Tele phone 516 681 2922 Modern Electronics ISSN 0748 9889 is published monthly by Modern Electronics Inc Application to mail at second class rates pending at Hicksville NY and other points Subscription prices payable in US Dollars only Domestic one year 16 97 two years 31 00 three years 45 00 Canada Mexico one year 19 00 two years 35 00 three years 51 00 Foreign one year 21 00 two years 39 00 three years 57 00 Foreign Air Mail one year 74 00 two
161. ng kit kinds of pick and place systems ro botic arms if you will that are now available for automated assembly of surface mount boards Figure 6 is a photograph of the business end of one such system that s placing SO devices on a circuit board Where To Buy SMDs and Supplies Small quantity buyers have been able to purchase surface mountable semiconductors from manufacturers like Signetics for several years Until recently however it was difficult to purchase small quantities of such passive SMDs as chip capacitors and resistors Hopefully electronics parts suppliers will eventually stock SMDs and supplies Until then the small quantity purchaser has other options The first 1s to contact electronic parts distributors that represent makers of SMDs and supplies to see if they will sell these items in small quantities Several companies have published lists of SMD manufac turers complete with addresses and telephone numbers One is Surface ef ia a ee rs ee r ee a a a A a W F a b a Mount Technology Equipment Supplies and Services a brochure published by Texas Instruments P O Box 225012 MS 54 Dallas TX 75265 Another listing of SMD manufacturers and suppliers is given in Guide to SMT a manual sup plied with the SMT2000 surface mount training kit from Vector Elec tronic Company described in de tail below Most electronic parts manufac turers now supply their
162. nnel display print screen and user definable in terface routines The spectrum analyzer features FFT sizes from 16 to 1024 2 s 16 point to less than 10 s 1024 point execution time 100 Hz to 500 k Hz sample frequency 1 6 to 320 V p p inout range rectangular or Hanning windows baseband or vernier opera tion power spectrum computation and averaging better than 1 Hzreso lution disk save recover spectrums hardware software keyboard trig gering and transfer of digital scope 12 MODERN ELECTRONICS January 1987 4 Hn time series data to spectrum analyzer for frequency analysis 798 for Apple and IBM comput ers 649 for Commodore computers CIRCLE 9 ON FREE INFORMATION CARD 1 3 GHz Frequency Counter Though it is small enough to fit into a shirt pocket OPTOelectronics Ft Lauderdale FL Model 1300H fre quency counter is not short on band width The 4 H x 3 5 W x 1 D counter has a specified bandwidth of from MHz to beyond 1 3 GHz Measured frequencies appear in an eight digit red 0 28 high LED dis play Input to the instrument is via a BNC connector Switches are provided for ac bat tery operation fast slow gate time high normal sensitivity and 1 to Say You Saw It In Modern Electronics 500 MHz and 500 to 1 300 MHz a chimney fire or it gets cooi enough VCR Adjustment Wrenches range selection Additional features for the fire to go out The Monitor Z AHE il Lae include
163. nts Indeed circuits made from SMDs can rival in size circuits made using hybrid microcircuits 2 SMDs are well suited for rapid turn around fully automated assembly 3 Surface mount circuits are potentially less costly than those made using conventional compo nents Recently the cost of SMDs has dropped significantly Simpler smaller circuit boards and more compact production facilities con tribute even more to the economy of surface mount technology 4 Circuits assembled from SMDs exhibit improved electrical performance The absence of com ponent leads and small size of SMDs enhances switching speeds and re duces stray inductance and capaci tance Noise pickup is also reduced S SMDs can be easily installed on both sides of a circuit board thereby further increasing their size advantage over conventional com ponents 6 Boards assembled with SMDs have higher resistance to shock and vibration due to their small mass and size The advantages of SMT are tem pered by several drawbacks Some of these disadvantages will fade away when SMT becomes more widely ac cepted In the meantime it s impor tant to understand that 1 SMT requires new approaches to component installation solder ing Storage and purchasing Per sons experienced in designing and as sembling conventional circuits will have to learn new procedures and techniques 2 Special costly equipment is re quired for automated
164. o the left and reset the DIP switch for monochrome Normally with IBM s monochrome card 1 2 3 graphics cannot be displayed We used the Lotus Utility disk to enable the monochrome drivers for 1 2 3 We could not display graphics naturally since the AutoSwitch was emulating the IBM monochrome card We then used the Utilities disk to switch to install the Hercules drivers on the 1 2 3 program Now we could display graph ics since the AutoSwitch sensed the new drivers and automatically changed to Hercules emulation We further tested the AutoSwitch by trying to run a game program called Digger that would not run under the IBM EGA The program came up in CGA mode and ran perfectly AutoSwitch Software Utilities A utilities disk is included with the Auto Switch hardware One program on the disk checks the BIOS ROMs in an IBM PC If you have a PC manufactured in 1981 or 1982 you must upgrade the ROMs the older ROMs do not support EGA The other program lets you take control of AutoSwitch through software This program overrides the default set ting of the switch that controls the auto switch feature It also allows you to boot game disks with exotic copy protection schemes Comments amp Conclusions IBM s EGA card which lets you display 640 x 350 pixel graphics in 16 colors is certainly an attractive though expensive option for IBM PC XT AT and com patible computers The Paradise Auto Switch EGA card th
165. o years 43 00 US three years 64 00 US Street City State Zip A Great Gift Idea Send the following gift subscription to my friend at my expense Please indicate your name above A gift card will be sent Paid by OCheck O Money Order O MasterCard Visa L 1 year 12 issues 16 00 Maana m beni D 2 years 24 issues 31 00 Name Canada and Mexico one year 20 00 US two years 39 00 Seel US three years 58 00 US Foreign one year 22 00 US two o years 43 00 US three years 64 00 US City State ______ Zip MPUTER ELECTRONICS MANUAL DISK SERVICE MANUAL 420 Align Adjust Pepai Fluoptes Without Special Equipment Software All Types 100 Figures COMPUTER PHREAKING 515 Crimes Tempest Van Eck BBS CRYPTANALYSIS TECHNIQUES 15 6 Programs IC MR N Gram Kasiski Analyses MSDOS Disk 25 ABSOLUTE COMPUTER SECURITY 20 Dozens Methods Software 1 000 Ciphertext Contest MSDOS Disk 30 STOCKPRO 10 Stock Investments MSDOS Disk 15 PRINTER PLOTTER MANUAL 15 Selections Repairs Tips f SUPER RE INKING METHOD 8 Cloth Ribbon Re inker Plans GO HIGH VOLTAGE DEVICES 15 Dozens Types and Plans PHONE COLOR BOXES 15 16 Types and Plans Software STEALTH TECHNOLOGY 515 Radar Invisibility Much More HEAL THYSELF 8 EM Healing Plans FDA Approved Devices ELECTROMAGNETIC BRAINB
166. o drive the noise gener ator to obtain dramatic flanged noise Say You Saw It In Modern Electronics Se Ee ee SS ESSE ee eee ee eee ee effects that would otherwise tie up a lot of hardware One of the most interesting possi bilities is the use of a microprocessor to memorize and control the sounds for a fully programmable project The potentiometer controls could then be replaced with MOSFETs or optical isolators With the proper software the microprocessor could play back the sounds on command as well as vary the timbre for some real ly unusual effects I haven t at tempted to do this myself but the subject has been covered in books like Hal Chamberlain s excellent Musical Applications of Micropro cessors Hayden Press Our Drum Synthesizer is hardly the last word in percussion synthesiz ing circuitry However it does show that it is possible to obtain a musical ly useful instrument without spend ing a fortune NE SS eee SL How To Design Ultra Long Delay Timers from page 36 used for C4 until the timer s accur acy approaches the rated 0 5 percent basic tolerance of the XR 2240 timer chip itself The three remaining ranges of 15 minutes each included in the Timer Beeper are obtained by switching 1 megohm resistors R6 R7 and R8 in to the RC timing network in series with the 4 megohm composite value of R5 All resistors must have 1 per cent tolerances For other applica tions requiring other delay
167. ocus vertical hold brigthness contrast vertical size hori zontal hold AMERICAN MADE A SUPER DEAL 19 95 If you want your Project Ideas to relieve the special woes often faced when using a laptop computer Laptop Computer Enhancements agd ae Ld F a f S Pa 2 adio Shack NEC and Epson R led the way with portable laptop computers Now a bevy of other manufacturers offer such machines Laptops however often pose several special problems If you are one of the increasing num ber of people who owns One here are a few project fixes that will make life with your portable computer more enjoyable Battery Powered Fluorescent Lamp Most laptop computers have liquid crystal display LCD screens which are not backlit they require good lighting to read what s on the screen Since you have gone to the By Brent Gloege trouble of buying a computer that frees you from a cord it would be a shame to tie yourself down with a lampcord whenever the lighting is in adequate However you can over come such a problem by building a battery powered fluorescent light to provide smooth even illumination for your LCD screen It s built from a widely available style of fluores cent lantern A few simple altera tions will convert this battery oper ated light into a gooseneck lamp that you can take with you whenever you need portable light for your computer The par
168. older in series with it With this modifica tion you can use eight D size Ni Cd cells which now gives you8 X 1 2 9 6 volts which is almost perfect to drive the fluorescent lamp A Versatile Printer Work Stand Most desktop computers are left connected to their printers with the latter usually on its own stand With the laptop computer however your lap is your desk and has no room for a printer Hence there is no need for a special stand for your laptop computer except when you want a printout of your work Our second project is a printer stand designed just for the laptop computer owner It s relatively inexpensive to build Because it is designed for use with your laptop computer the printer stand shown in Fig 3 has several fea tures not found in other printer stands For example it has a special pull out shelf for your laptop com puter With the shelf pushed in your laptop computer is stowed safely out of the way Pull out the shelf flip up your computer s case top display screen and you are ready to print If you make the printer stand so that gp a Le a January 1987 MODERN ELECTRONICS 51 Fig 4 Rear view of printer stand Paper is guided back under supply paper by way of a chute the shelf is at the proper height you can even use it as a work desk for your computer if you wish to com pute at home or in your office where the printer stand is located For this a
169. olume discount items that are not discountabie ara identi i 5 tified by the sutfix p ND following the part number After writing your Order total all of the discountable items and apply the appropriate discount To this subtotat add the non discountable items Then add the service SERVICE CHA RG ES VOLUM E DISCOU NT charge We pay all shipping and insurance to addresses in the U S A Canada and Mexico when check or money order accompanies order Digi Key only ships orders within the continental U S Alaska 0 00 9 99 Add 2 00 0 00 99 99 NET Hawaii Canada and Mexico coe Add 0 75 100 00 249 99 Less 10 WHEN ORDERING BY PHONE CALL 1 800 344 4539 AK call 218 681 6674 BY MAIL SEND YDUR DRDER TO DIGI KEY P O Box 677 Thief River Falla MN 56701 s e Add 0 50 250 00 499 99 Less 15 You may pay by check money order Master Charge VISA or C O D DIGI KEY GUARANTEE Any parts or products purchased from Digi Key that prove to be defective will be replaced of refund Add 0 25 500 00 999 99 Less 20 ed if returned within 90 days trom receipt with copy of your invoice PRICES SUBJECT TO CHANGE WITHOUT NOTICE No Charge 1000 amp Up less 25 CIRCLE 95 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics January 1987 MODERN ELECTRONICS 89 mr a ee p Op U LAR CLONE Kits Modems Hard Drive Kits Disk Drives Diskettes Printers Memory ICs
170. on has a need for these kinds of features then the AutoSwitch is an excellent choice How ever if you are interested only in viewing an EGA display have software that sup ports EGA e g Lotus 1 2 3 V 2 0 and are shopping for price there are some less expensive cards on the market And of course if your application demands absolute IBM compatibility in every con ceivable instance which may be the case with Paradise s AutoSwitch but obvi ously we did not check out every piece of software extant you may have to go with the original board Chances are that you ll choose to bypass the original though Joseph Desposito phone An affordable introduction to COMMODORE VICMODEM Use with the Commodore C64 the SX 64 or the VIC 20 Computer Bell 103 Compatible Full Duplex 300 Baud Manual Dial Direct Connecting eo FCC Registered This Modem is LOW liquidation priced because it was closed out by Commo dore Add it to your computer for access to timely financial information news and reference libraries as near as your phone computer services and you can communicate with computer users who also own modems Use with data cassette included or with terminal program software available at computer stores 90 Day Limited Factory Warranty Mfr List Price 59 00 Liquidation Priced At Only H 1968 7041 072 Shipping handling 4 00 each Commodore is
171. on the rear of the stand guides the return paper to the lowest shelf allowing it to fan fold in the normal manner without requiring 6 or more space to be left between the stand and the wall behind it as would normally be the case Fabrication of the printer stand is quite easy and lets you use a choice of materials You can use either 4 or See Se Fig 5 Epoxy putty adds paper guides to printer tractor feed for smoother paper handling plywood or furniture grade particle board for the sides shelves and upper rear panel The lower chute panel can be 4 plywood or Masonite or even heavy Bainbridge board if you desire All panels for the stand can be cut from a single sheet of plywood or particle board Lay out on the board all panels and carefully cut to size If you have a power router you can make fitted joints that allow you to assemble the entire stand with wood glue and just a few finishing nails Otherwise you may have to butt join the panels and use woodscrews and perhaps even bracing hardware Devise some means for preventing the computer shelf from pulling completely out of the stand If you do not fit the chute to the rear of the stand in a routed slot use thin lum ber and nails or L brackets and short screws to anchor it at an angle that will assure smooth paper feed Finish the printer stand by sanding all surfaces smooth If you use open grain plywood or particle board cover
172. ons on the flashlight switch can be used as safety positions to prevent the light from being turned on acciden tally Just be sure to disconnect from the switch any unused wires since some of the flasher circuitry if pow ered can slowly drain the battery even with the incandescent lamp re moved if it is left in the flashlight If you plan to use rechargeable nickel cadmium cells to power your portable lamp you may discover that they provide too low a voltage for proper operation This 1s because the Ni Cd battery outputs only 1 2 volts per cell as opposed to the 1 5 i T am i PE Ba k P a jm i ree T WAA nt a as BLF ai A ea aa a ft Fig 3 Front view of the laptop printer stand volts obtainable from ordinary car bon zinc and high energy alkaline cells With six Ni Cd cells in the lamp only 7 2 volts 6 x 1 2 volts is available to power a system designed to operate from a 9 volt dc source To compensate for the lower volt age you can replace the end cap that held the incandescent lamp with a two cell D type battery holder These battery holders are almost the same size as the end caps and thus are easy to install Bring the wires from the battery holder through the rear of the assem bly and cement the holder battery Opening side out to the end of the flashlight housing Break the con nection leading from the original battery compartment to the lamp cir cuitry and wire the two cell h
173. onvenience we l try to have a representative contact you to answer your questions Cleveland Institute of Electronics 1776 East 17th St Cleveland Ohio 4114 Ci YES I want to get started Send me my CIE school catalog including details about the Associate Degree Program I am most interested in computer repair television high fidelity service telecommunications medical electronics robotics automation broadcast engineering other Print Name Address A pt City _ State Zp Age Area Code Phone No o lt E E Check box for G I Bulletin on Educational Benefits Veteran Active Duty MAIL TODAY MO 72 Surface Mount Technology eee Fig 7 Surface mount componen ts being position place machine Courtesy Universal Instruments Inc type shop to locate and purchase small quantities of SMDs Assembly Techniques Let s say that a company has devel oped a digital data logger and that it now wishes to manufacture several hundred of the devices each month Assume you have been hired to de sign the circuit board for the new product Also assuming that the company has complete facilities for producing both types of boards con ventional and surface mounted which production approach should you choose First let s review the steps in the design and assembly of traditional circuit boards The board is designed and the traces are photographically transferred to copper foil coated pro
174. or of Q in the pickup unit With L connected to the pickup unit you should hear the extraneous signals as before If you aren t using L1 simply touch your finger to C and note the excellent sensitivity of the receiver Using the Receiver To use the 4 5 MHz FM Receiver to pick up sound from a TV receiver you must locate the 4 5 MHz sound i f section in the latter If you find an exposed coil or transformer in the i f section slip LZ over it and carefully adjust the RF GAIN control until you hear some of the picked up sound Adjust C7 and then C3 for best re sults Readjust r f gain after each tuning adjustment With a strong enough signal you will obtain good audio without noise You may have to adjust the TV receiver s fine tun ing to maximize results If your TV receiver doesn t have coils or transformers in the sound i f section try inserting a 100 micro henry choke in the core of the pickup coil and connect the choke to the out put of the 4 5 MHz i f amplifier in the TV receiver through a dc block ing capacitor If the above doesn t work connect the twinlead directly to the signal source ground to ground and signal to C1 If your TV receiver has a hot chassis use two 0 001 micro farad capacitors rated at at least 200 volts One capacitor goes between the grounds of the FM Receiver and the signal source the other in place of C1 in the pickup unit For added safety connect the FM Receiver
175. osure and paint the speaker baffle and interior surfaces of the walls in front of it with flat black paint You can finish the enclosure as Say You Saw It In Modern Electronics 7 a m aes i i oh ie Soe SSN a The grille Ver the Speaker system PAT of mE open weave T Mai Is stretched on a thick frame and is held in place by friction you wish paint it cover it with self stick sheet plastic veneer or fora really professional appearance ap ply a colorful plastic laminate or a wood veneer stained and finished as desired If you re painting or apply ing self stick plastic to the enclosure prefinish the exterior walls with a good sanding and athin coat of DAP to fill the grain and any gouges When the Dap has completely dried sand it to a smooth even finish and apply a coat of sealer Cut to size an open weave grille cloth and mount it on a thick ply wood or Masonite frame Paint the frame flat black before stretching the grille cloth over it and use spots of glue to hold the cloth in place Make the frame large enough to hold the grille in place without hardware Pull the free end of the zip cord through the speaker cutout and loosely fill the enclosure with 0 5 cu ft of fiberglass wool Connect and solder the free end of the zip cord to the speaker s lugs Run a bead of caulking around the perimeter of the speaker cutout in the recessed area if Say You S
176. otal here of serious readers those who read Modern Elec tronics for both professional and avoca tional reasons virtually matches the number who expressed a strong interest in electronic servicing From the foregoing I assume that if one s own equipment a TV receiver personal computer videocassette record er breaks down this group will attack repairing of it themselves If your exper iences in this area are similar to mine and why shouldn t they be many of your per sonal equipment problems fall into a tough dog category that defies and stymies all your efforts This might be an intermittent problem that only occurs once a week or so ata very late hour The next day when you re bushy tailed and ready to rip the equipment apart it works just fine for hours at a time Or it might be a breakdown that defies the standard troubleshooting procedures that should illuminate the problem with dispatch I ll share one of my recent repair chal lenges with you to show you what I mean My desktop computer which goes through a self check before the user can reach a screen prompt startled me with a beep sound and ascreen display that indicated there s an error along with a numeric code number Well servicing microcomputers is akin to servicing a home entertainment sys tem Actually it should be easier I feel though I have much more experience with the latter repairs Like an audio video system
177. ound the latest electronic equipment you build and keep as part of your training You Start from scratch and discover by doing You conduct key experiments perform vital tests build your own systems and do it all at the pace that suits you best There s no stopping the incredible boom in consumer electronics Soaring sales new and improved video prod ucts entirely new technologies have opened up new opportunities for the trained technician as never before Now at 26 billion in annual sales the consumer electronics industry is creating a whole new servicing instal lation and repair market This year TV sales alone are expected to hit 16 2 million units Every day sales of home Only NRI gives you a 27 high resolution stereo color TV you build to prepare you for today s video servicing careers VCRs a product barely conceived of 10 years ago reach 20 000 units Every day And the revolution has spread to the business sector as tens of thousands of companies are purchasing expen sive high tech video equipment used for employee training data storage even video conferencing The Video Revolution Is Just Starting Already disc players can handle audio CDs and laser video discs And now there are machines that will accom modate laser computer disks as well Camcorders are becoming smaller lighter and more versatile 8 mm video equipment produces high resolution pictures and digital
178. ox Wire the Fig 1 circuitry as shown leaving installation of the ICs until after you ve powered up the project D gt Fig 4 A typical ac power supply for the Drum Synthesizer 7812 12V TRANSFORMER SECONDARY 24v C T 450mA January 1987 MODERN ELECTRONICS 47 A 20 Drum Synthesizer eee Fig 5 Battery operation makes pos sible portable synthesizer operation and checked for the correct voltages at the various power and ground pins of the IC sockets Make sure that when you install them the polarized capacitors and diodes are properly oriented and that the transistor s basing is correct before soldering Also when wiring the ac version of the power supply make certain that you insulate all leads of the power transformer from all other points in the circuit and double check bridge rectifier voltage regulator and elec trolytic capacitor orientations be fore soldering If you re planning on incorporat ing the touch sensitive option in your Drum Synthesizer install its circuit ry on the Synthesizer s board and wire it into the main circuitry The cathode of the Fig 3 circuit goes di rectly to pin 3 of JC3 and the free end of R goes to the negative power sup ply line Touch switch R connects to the op amp s noninverting input via a panel jack whose other contact goes to the positive supply line Use and insulated jack for this circuit When the circuitry is completely wi
179. p CIl 0 693 10 000 x 4 7 10 0 0326 NOTE TANTALUM See text D1 IN4001 second Therefore T t t 0 386 0 0326 0 3906 second and F 1 T 1 0 3906 2 56 chirps per second Connected in its monostable mode the second timer in the 556 is triggered by a negative going pulse from the first timer This pulse is ap plied to the second timer at the pin 5 trigger input From the second timer is generated a 110 microsecond pulse that is fed to the piezo buzzer Pulse width 1 1R1C2 1 1 x 10 000 x 0 01 10 110 microseconds The first timer in the 556 in its astable mode determines the repeti 630pF 30 pF 1000uF Fig 7 Schematic diagram of Timer Beeper and its power supply Say You Saw It In Modern Electronics tion rate of the chirps With the ex ternal component values shown the repetition rate was calculated above to be 2 56 chirps per second The sec ond timer in its monostable mode determines the duration of the chirps which was calculated to be 110 microseconds Shown in Fig 7 is the complete schematic diagram of the full Timer Beeper circuit including its ac line operated power supply This di agram shows how the long delay waveform generated by the XR 2240 is coupled to JC3 through 4066B ana log switch C2 Pins 1 and 2 of the normally open 4066B switch are con nected to pins 6 and 2 of JC3 When the connection between pins 2 and 6 of C3 is opened this chi
180. p is disabled and the piezo buzzer is silent When ICI times out and goes high the 4066B s control pins pins 13 and 14 are activated the switch closes pins 2 and 6 of JC3 are shorted together and the buzzer starts chirping In the power supply section a half wave rectifier supplies the two voltages required by the Timer Beep er circuit These are 9 volts for the 556 and CD4066B and 6 5 volts for the XR 2240 and light emitting diode LED which serves as a pow er on Indicator Construction There is nothing critical about com ponent layout or construction The relatively simple Timer Beeper cir cuit shown in Fig 7 lends itself to just about any traditional type of wiring including printed circuit Wire Wrap and point to point You can fabricate a printed circuit board using the actual size etching and drilling guide shown in Fig 8 If you decide to use a pc board wire it exactly as shown in Fig 9 tak ing care that ICs electrolytic capaci tors LED and piezoelectric beeper are oriented or connected as shown If you choose to use perforated board and Wire Wrap or solder type January 1987 MODERN ELECTRONICS 33 Semiconductors D1 1N4001 rectifier diode LED1 Light emitting diode IC1 XR 2240 programmable timer IC2 CD4066B analog switch IC3 LMS556 dual timer Capacitors C1 C6 0 01 pF ceramic disc C2 630 pF ceramic disc C3 30 pF 10 volt electrolytic C4 4 4 pF tantalum ti
181. petature Coefficient Ac 2 5 Stnierd Capectty Tolerance 5 OClamipetton Factor man 0 Inayviettion Reeliance 75 C O00MO F Voltage Coefficient DC Nagipbir Aging Aate Negugive SiS cs ee R dad Ga bad HANG Va Paws eee NESSION NESES NESS12N NESSI 4N NE5532N NESOH4N NE5539N NESd2N TDAIS1S TDA TOAIDISU TO41620u TDA 19104 NE 5B7A NESBA PCE2100N PCE2110N NESDOON NESSON NES IN Ld S DESER SEBSES SSSSSEsse h rey TETELA IE ESVaHIRBARR ISERE S wm WI WA NINI JALS74N 74LS75N WAL S76N 74 5788 74 SB3AN 74LS85N 7al SB6N a8 74513 Pagi4s Pa515 P8516 P4517 Dascnption Php Operating Temp Range S amp C to 250 C 19 4t Do 4t BD 7 00 580 0 Tamp Coefficient 300 PPM Di Ommengon 220 480 DO 4 DO 41 7400 54 Wrewoung Aeciangular Aassta a 5 Watt Values DO 41 0 9302 toZOKM 10 Wart Vaues 08 to 3 OKO DO 11 00 ma AA Ai amp BRZSe p amp B VIO Gwe wih 74 S112N 74 51 74415114A 615122 4L5123N 74L5125N 74151276N 74LS1IN FAL G136N 74L5738N 74L5139N 74S 153N 74LS 183N 7aLS154N 74aLS155N a P4518 P4619 JA 5 P4520 BWS for 7 528 watt this s the Digi Key pact number i 3900 Wa Sa pans X P4521 3 AMP SILICON RECTIFIERS Pricing 19 100 6 1 000 P4522 m Swen F 2400 00 NEC Microprocessor C 1 000 375 1 000 Swe 32 299 2400 9000 18000 Paar 4 10 Wan 35 3 20 o0 100 00 130 00 P4524 Dig Koy qam nes prce va 4 OO
182. pplication you would want the shelf to be positioned so that the computer s keyboard is between 27 and 30 from the floor This height leaves room below the computer shelf for separate shelves for a carton of printer paper and the paper return In keeping with the streamlined di mensions of the laptop computer our printer stand has a slimmer pro file than most similar stands on the market In fact it need be no more than 3 wider and only about 6 deeper than your laptop computer This takes into account the thickness of the stand s walls maneuvering room on both sides and the rear of the computer and the 11 depth of a carton of printer paper With the typical laptop computer measuring only about 12 to 13 wide by 9 or so deep your printer stand need be only 16 maximum in width and 16 deep The extra depth allows the shelf to be pulled out far enough for the computer s display panel to be flipped to the operating position while still retaining a good 5 of the shelf inside the slot for ri gidity Of course if your printer is wider and or deeper than this mini mum stand width and depth will be limited more by the footprint of your printer than by the dimensions of your computer A slimmer profile is achieved mainly by guiding the return paper back under the supply paper see Fig 4 rather than having it drop directly behind the stand as most printer stands do A thin chute
183. r reflector as sembly will become the top of your portable lamp Disassemble the gooseneck lamp However do not remove the wiring that routes through the gooseneck to the lamp socket Prepare about 24 of light duty lamp cord by stripping away of insulation from both conductors at both ends Tightly twist together the fine wires in each conductor and sparingly tin with sol der Securely tape one end of this lamp cord to the lamp socket end of the wire in the gooseneck and care fully pull on the other end of the ori ginal lamp cord until the new lamp cord protrudes from both ends of the gooseneck Remove the tape and set aside the original lamp cord Drill a hole in the center of the fluorescent tube s reflector Make this hole large enough to accommo date the threaded part of the goose neck Secure the gooseneck in place with the nut that originally held it in place on the lamp Now drill the same size hole in the clear plastic lens that covers the flu Say You Saw It In Modern Electronics orescent tube and fasten to it the other end of the gooseneck with the other nut you removed during disas sembly Solder the other ends of the new lamp cord to the points in the flashlight circuit from which you clipped the wires coming from the fluorescent fixture Snap the lens cover back in place and replace the end caps The finished battery pow ered fluorescent light is shown in Fig 2 If you wish the extra positi
184. rate user supported software relies on your honesty if you try a program and find yourself liking and using it you re asked to become a registered owner entitled to support upgrades and usually a real man ual to replace the skimpy hints on disk It s a fine concept which I just en dorsed by paying 20 for a year s mem bership in one of a half dozen leading shareware houses PC SIG of Sunny vale California Actually I got the 39 USA Which drive for the Database A Z gt C4 The best 65 database around a shining example of shareware special of membership plus five disks normally 6 each with 4 shipping my bill came to 43 Having tried my first selections and scanned the PC SIG cata log I m pleased If I used Turbo Pas cal I never realized there are so many Turbo hackers utilities out there I d probably be ecstatic Many user supported programs are great choices for someone who doesn t already have say a communications package or checkbook balancer if rarely enough to make you abandom the com mercial packages you ve used for years PC Write from Quicksoft s Bob Wallace registered price 89 has the heart of a primitive word processor separate edit ing and printing programs but so many tweaks tailfins bells and whistles it can keep up with almost any medium range program ProComm 25 offers a spectacular variety of communications options and protocols DOSamatic 39
185. rates it the signal is ready for envelope shaping by the vca voltage controlled amplifier portion of the circuit Applying a pulse to the TRIGGER INPUT at Jl causes the monostable multivibrator circuit made up of gates in JC2 to output a pulse of constant amplitude and duration to simplify interfacing requirements This pulse is coupled through D and charges C8 with a positive voltage As soon as this pulse ends the capacitor discharges at a rate set by R17 and DECAY con trol R78 Note that a 10 000 ohm resistor and two 1N914 diodes in the pin 1 circuit protect C2 from damage due to excessive high positive pulses and negative trigger input voltages Any input pulse greater than 5 volts causes the upper 1N914 to limit the input to 5 volts Conversely any input more negative than about 0 7 volt causes the lower diode to con duct the negative voltage away from IC2 You must install these compo nents inthe circuit unless you are cer tain that the trigger source outputs a safe pulse for the Drum Synthesizer Note also that only half the gates in C2 are used in a single Drum Syn thesizer circuit If you wish you can add a second such circuit without Fig 2 Use this circuit to select the various sounds without having to remember selection codes listed in the Table The lines labeled A B and C go directly to pins 27 26 and 25 of IC1 eliminating S1 S2 and S3 46 MODERN ELECTRONICS January 1987 SWITCH DESI
186. rd Separate the cord s conductors about 1 at one end and 4 at the other end Tightly twist together the wires in each conductor and tin with solder Connect and solder a No 6 solder lug to one conductor at the 1 separated end Connect the other conductor at this end to the tip lug of the coaxial connector Secure the sol der lug to the front panel with 6 32 x machine hardware Now remove 2 of the bridging plastic at both ends of a 36 length of 300 ohm twinlead cable and trim of insula tion from all conductors Twist to gether the wires in each conductor and tin with solder Wire the pickup unit as shown at the right in Fig 5 observing proper basing for Q Then identify the con ductor of the zip cord that goes tothe ground lug near the coaxial connec tor and plug this into the ground hole for this connector on the board Sol der into place Plug the other zip cord conductor into the signal hole for the coaxial connector on the board and solder into place Plug one end of the 300 ohm twin lead into the rubber grommets in the front panel Plug the conductors into the TWINLEAD holes and solder them into place Mount the board to the front panel using 4 spacers and 4 40 machine hardware The inductance of the pickup coil for the pickup unit isn t critical but it should be about 25 microhenries The prototype coil consisted of 50 turns of 26 gauge enameled magnet wire wound on a diameter
187. rd or write to AMERICAN RADIO RELAY LEAGUE Dept CQ 225 Main Street Newington Conn 06111 This space donated by this publication in cooperation with the American Radio Relay League Hand Clap Electronic Control Clap your hands and this electronic servant turns on and off lights and other electrically operated devices By James H Brown egend has it that wealthy sul tans simply clapped their hands to have servants do their bidding You can do the same with our Sultan s Servant This electronic servant will turn on and off virtually any type of electrical or electronic device with the clap of your hands Clap twice to turn on a device clap twice again to turn it off About the Circuit Sharp attack sound triggers the Ser vant Such sounds can be generated by the clap of hands snap of fingers and a variety of different conditions The Servant requires at least two sharp attack pulses to activate This greatly reduces the possibility of un desired random noises causing the cir cuit to trigger A single sharp attack hand clap in the vicinity of the Servant is picked up by the input electret microphone MIC in Fig 1 and is coupled through C into operational amplifi er ICs inverting input at pin 2 The negative peak of the signal at the pin 6 output of JC then triggers 555 timer C2 which is configured as a monostable multivibrator The trig ger pulse that
188. red ICs still not installed in their sockets connect the Drum Synthe sizer and power supply modules to gether as detailed in Fig 1 Turn on the power and connect the negative or common lead of a multimeter to circuit ground Set the meter to dc volts and measure the voltage at pin 14 of ICI pin 8 of JC2 and pin 7 of IC3 You should obtain about 12 volts or approximately the positive BLACK INDICATES POSITION SELECTED SCL O 0 vco TUNE LN 4 NOISE COLOR DECAY Fig 6 Switch control arrangement for initial testing of Drum Synthesizer that can be used to determine if all three sources are operating voltage of whatever other power sup ply you re using at all three points Without moving the common lead of the meter from ground measure the voltage at pin 4 of JC3 This should be about 12 volts or whatever neg ative voltage your power supply is putting out If you obtain the appropriate readings power down the Drum Synthesizer and allow the charges to bleed off the capacitors Then install the ICs in their respective sockets making sure each is properly or iented before pushing it home Prac tice safe handling procedures when installing the ICs to prevent damag ing them with static electricity Select an enclosure large enough to accommodate the Drum Synthe sizer and power supply modules with plenty of room left over for the controls switches jacks and ac line cord if you re
189. rinter Rib bons You ve got to be kidding Is there really anyone so poor that he can not afford to buy a new ribbon for his printer I for one have a few thousand dollars invested in my computer system and there s no way I would even consider rejuvenating the ribbon to save a few bucks The last time I bought a ribbon for my Epson MX 80 it was 6 00 That was about a year ago Yes it is starting to get a little dim but I ll somehow find the 6 00 and buy another I know that rib bons for some printers cost more but I really feel that no matter what the cost this is a false economy Keep up the overall great publi cation Bob Hill Burbank CA Lots of people feel differently about this than you do There are computer rib bons that cost as much as 40 you know One fora NEC Pinwriter P 5 series costs more than 20 Further there are many ribbon types that are not readily avail able even for popular printers And many times a ribbon is bought that has dead spots This combination has generated a ready market for ribbon re juvenation that is filled by commercial products Computer Friends 6415 SW Canyon Ct Portland OR 97221 which specializes in re inkers for example claims 50 000 MAC INKERS are in the field Ed Skipping Around e As a new subscriber to your magazine first issue July 1986 I would like to say you have some fine articles and useful projects But not having cons
190. roject F A 12 C4 c3 3 3pF oF st A s2 s3 A s4 an a AO B cO DO 5 21 271 26 25 22 Ic4 6 J2 CA3080 AUDIO JCci OUTPUT a 76477 16 R4 100K ci 0 001 pF R18 1M A DECAY D1 R17 1N914 T 6 01 15K 2 14 8 252222 R14 22k 100K Ic2 6 3 IC3 CD40018 FLOB2 a a ca c7 pF 3 O 1pF 5 a ATI aad SEE TEXT 42V PARTS LIST Semiconductors C4 3 3 pF 20 volt tantalum Miscellaneous D1 D2 D3 1N914 diode C6 C8 1 pzF 20 volt tantalum J1 Phono jack IC1 SN76477 complex sound generator J2 Phone jack Texas Instruments Resistors 4 watt 5 tolerance S1 thru S6 Spst slide or toggle switch IC2 CD4001B CMOS quad NOR gate R1 39 000 ohms or 6 position DIP switch see text IC3 TLO82 or LF353 dual JFET input R2 R6 R7 R8 R9 R11 10 000 ohms Printed circuit board or perforated operational amplifier R4 R14 R16 100 000 ohms board and suitable Wire Wrap or sol IC4 CA3080 operational transconduc R5 R15 220 000 ohms dering hardware suitable enclosure tance amplifier R13 1 megohm sockets for ICs 5 to 12 volt Q1 2N2222 or similar general purpose R17 15 000 ohms power supply see text control knobs npn transistor R19 22 000 ohms normally open momentary action Capacitors R3 200 000 ohm linear taper poten spst pushbutton switch see text C1 0 001 pF disc tiometer 10 000 ohm watt 5 tolerance C2 10 pF 15 volt electrolytic or R10 R12 500 000 ohm lin
191. rse Screen Attributes m ki 3 9 9 P KIT w 100 Page Manual Cumulative Character Attributes De inten ADD 40 FOR A amp T t H Reverse Underline and Blank 10 Programmable Function Keys and Answerback message 5 X 8 Character Matrix or 7 X 9 for IBM Monitors Mini Size 6 5 X 5 inches Low Power 5VDC 7A 12VDC 20mA Digital Research Computers OF TEXAS P O BOX 381450 gt DUNCANVILLE TX 75138 214 225 2309 OPTIONAL EPROM FOR PC XT STYLE SERIAL KEYBOARD 15 SOURCE DISKETTE PC XT FORMAT 5 IN 15 Call or write for a free catalog on Z 80 or 6809 Single Board Computers S 50 Boards and other S 100 products TERMS Add 3 00 postage We pay balance Orders under 15 add 75 handling No C O D We accept Visa and MasterCard Texas Res add 5 1 8 Tax Foreign orders except Canada add 20 P amp H Orders over 50 add 85 for insurance CIRCLE 38 ON FREE INFORMATION CARD 79 ALL SALES SUBJECT TO THE TERMS OF OUR 90 DAY LIMITED WARRANTY FREE COPY UPON REQUEST WPC PAPERS _ kk First Impressions Open Access II a Big Kiss No Risk Trials By Eric Grevstad oe A tm Every so often people tell me I m behind HI J L J the times sticking with low cost software and affordable 8088 systems instead of E lining up for the new 80386 supermi cros I m going to the Comdex Fall trade show in a
192. s You will probably discover that the paper is not being properly routed into the tractor pins By using epoxy putty to mold paper guides as shown here you can fix things so that the tractor handles so called clean perf pa per without a hitch Over 75 000 active amateurs in over 125 countries As you observe the paper s travel be especially careful to look for and fill in any snags that occur in the pa per s path Once you apply the epoxy putty allow it to set for at least 24 hours At the end of this period run the paper through the tractor again while ob serving how it behaves It will prob ably take you two or three tries to catch and rectify all the snags The effort is worth it though because when you are done you will have a printer that can be left unattended as it flawlessly churns out page after page of copy WE Order Back Issues BACK ISSUE ORDER FORM Please send me the following issues of Modern Electronics 2 50 each Month s amp Year s Number ordered 2 50 each Total Payment Enclosed Check or M O only NAME STREET ADDRESS CITY Your order may be tax deductible STATE ___ ZIP throughout the world read and enjoy a different kind of ham magazine every month They read CQ It s more than just a magazine It s an institution SUBSCRIBE TODAY lili Say You Saw It In Modern Electronics 52 00 O 35 00 O 18
193. s a linear potentiometer with a dial preferably a multi turn pot with a vernier dial could be substituted for R5 through R8 Bear in mind that if you use a pot no matter how precise its dial settings are claimed to be the accur acy of the delays selected will be less than you would obtain if you used precision resistors instead WE January 1987 MODERN ELECTRONICS 87 We stock the exact parts PC Board and A C Adaptor for an article published in Radio Elec tronics Magazine Feb 1984 on building your own CABLE TV DESCRAMBLER 701 PARTS PACKAGE 29 95 Includes ail the original resistors capacitors diodes transistors integrated circuits coils and IF transformers 702 PC BOARD 12 95 Original etched amp drilled sifk screened PC Board used in the article 704 AC ADAPTOR 12 95 14 volts DC 285MA Both 701 amp 702 39 00 701 702 amp 704 49 00 FREE Reprint of Radio Electronics Article on Building Your Own Cable TV Descrambler with any purchase Add 2 50 Shipping amp Handling 4 50 for Canadian Orders ORDER TOLL FREE 1 800 227 8529 Visa MasterCard or C O D JeW ELECTROMICS INC SZ manstieid MA 02048 E23 CIRCLE 7 ON FREE INFORMATION CARD NEW FROM DON LANCASTER HANDS ON BOOKS CMOS Cookbook 14 50 TTL Cookbook 12 50 TV Typewriter Cookbook 12 50 Active Filter Cookbook 14 50 Micro Cookbook vol 15 50 Micro Cookbook vol Il 15 50 Enhancing your Apple vol 15 50 Enhan
194. s circuit ground to an earth ground If you aren t using the pickup unit connect a jumper wire in place of C16 and don t use the dashed jumper wire in Fig 5 The extra pad at the top left of the board is provided for a blocking capacitor if your applica tion requires one Otherwise con nect the input lead to the pad im mediately to the left of this and ig nore the extra pad Connection of the 4 5 MHz FM Receiver to the Cable Communica tion System s receiver mentioned earlier requires another matching transformer and a blocking capaci tor A series tuned primary will pass the 4 5 MHz signal and present a high impedance at other frequencies This minimizes loading that would otherwise attenuate the video signal in your TV receiver Fabricate the required transform er on the core of a 10 microhenry choke by winding the primary as you did for LI in the 4 5 MHz FM Re ceiver Then wind the secondary over this and use only half as many turns as in the primary Usea 15 to 150 pF trimmer capacitor in series with the primary winding to block dc and to provide for tuning The signal source for the Cable Communication System s receiver can be any transmitter that is similar to the UM1285 vhf modulator Per sonal computers and VCRs usually have such a transmitter with an r f output that is switchable between TV channels 3 and 4 Align the Cable Communication System s receiver first according to the instructions provide
195. s 3 e Automatic fine tuning A B switch option i am m 10 lot January 1987 MODERN ELECTRONICS 85 9 gt Pans ATPPSTAR Advanced Surge Protector Filter 1 SURGE PROTECTION Do you want the best protection available at the best price with a lifetime warranty The U S NAVY AT amp T U S AR MY NASA and the Colorado state school system did so THEY CALLED US ZAPSTAR S 6 SURGE PROTECTOR FILTER 59 95 Six Grounded Outlets Light to Indicate Protection is in Effect Dual Stage EMI RFI Filtering On Off Power Control Rocker Switch 15 Amp Circuit Breaker Full Three Mode Surge Protection ZAPSTAR S 6 SPECIFICATIONS Under 1 Nanosecond 151 Volts 100 Joules 1 000 000 Watt 100 Microsecond FILTER ATTENUATION 55 DB 1 1000 MHZ So It s no wonder that the people with the most to protect call us for protection Call Toll Free 1 800 624 8189 In Florida call 305 722 7770 sazo Why settle for less VISA Manufactured by SEVERTS ZORMAN ENGINEERING INC Ft Lauderdale FL RESPONSE TIME CLAMPING VOLTAGE DISSIPATION CAPABILITY CIRCLE 6 ON FREE INFORMATION CARD S yond RAG A 20 Drum Synthesizer from page 48 project use an ohmmeter to check for short circuiting between either contact of its jack and circuit ground and the chassis box Repeat for the other contact If you note any read ing other than infinity correct
196. s a fairly good bass re sponse down to about 100 Hz at 6 dB for such a simple speaker system design The midrange is solid and ex hibits little brightness coloration There is also plenty of treble to do justice to most music played through this speaker system Building It No special tools or skills are needed to build this simple speaker system All you really need are a hand saw and a hammer to assemble the enclo sure with simple glued and nailed butt joints If you have a power table saw and or router you can get as fancy as you like with mitered joints that are held together with wooden splines You can use solid lumber ply wood or particle board for the enclo sure This can be either 4 or 4 thick with no changes in exterior di mensions of the enclosure Though there will be a slight difference in in ternal volume the fiberglass wool filling dominates the loading effect Construction details for the speak er system are given in Fig 2 Notice that the enclosure 1s a sealed acous tic suspension design and requires no internal bracing The dimen sioned drawing shows simple butt joints which is reflected in the di mensions for the enclosure panels in the Bill of Materials If you re as sembling the enclosure with mitered joints make the necessary adjust ments in panel sizes Whichever method of joinery you use only glu ing and nailing are required to hold together the cabinet panels
197. s resistance in megohms and C is capacitance in microfarads For a Tp of 1 hour for example an N of 204 4 8 64 128 anR of 4 megohms and a C of 4 4 micro farads would give a delay of 204 x 4 x 4 4 3590 seconds This is just 10 seconds shy of 1 hour though for Technology Project critical timing it would be inade quate Another combination that gets closer to the mark might be N 255 R 3 megohms and C 4 7 microfarads This combination works out to 3596 seconds which is now only 4 seconds short of 1 hour Neither of these value combinations should be regarded as practical es pecially if a highly accurate delay pe riod is desired Though you can obtain 1 percent tolerance resistors values of 3 meg ohms and 4 megohms are not stan dard Fortunately both can be had simply by connecting in series three or four 1 megohm 1 percent toler ance resistors which are common values Going this route you can ob tain a series tolerance that is much less than 1 percent simply by select ing l megohm resistors that have negative and positive tolerances that cancel out to give a tolerance ap proaching zero percent Resistors are not the problem when it comes to selecting compo nents for the timing networks The problem is with the capacitors For stable timing applications the capa citor should always be tantalum types regardless of the value re quired But even tantalums are not exactly tight
198. ss is natural and clean with no apparent hangover or boom In addition owing to its simple design the system is readily constructed with only simple tools allowing it to be built in a single afternoon Technical Details The speaker system s dual cone 8 loudspeaker has a rated resonant fre quency of 57 Hz anda Q of 0 45 It s designed to be mounted in a 0 8 cubic foot enclosure In this proj ect you install it in a 0 43 cubic foot enclosure using 0 5 cu ft of fiberglass wool to effectively raise 64 MODERN ELECTRONICS January 1987 the loading on the speaker to 0 8 cu ft System resonance is then 95 Hz The speaker system s frequency response is shown in Fig 1 This curve was obtained with a calibrated condenser microphone positioned on axis in front of the speaker sys tem at a distance of 1 meter Though the system has the typical rising re sponse on axis at high frequencies this is offset by a falling response off axis Hence the system s aver age response is quite smooth While the response curve appears to be very irregular at the higher fre quencies it represents good perfor mance for the simple and inexpen sive speaker system described here Say You Saw It In Modern Electronics Actually our speaker system has a much better sound than would nor mally be obtained from low end speaker systems costing twice what ours does to build Figure 1 shows that the speaker system ha
199. ssembly and power relay if you include it Drill a hole for mount ing the battery clip and holes and slot for a 2 lug screw type terminal strip Drill four more holes for mounting the circuit board and a hole in the front panel just a bit larger than the microphone element s diameter Test fit the microphone element If the fit is too tight enlarge the hole If you are using a power relay mount it on one of the walls of the 42 MODERN ELECTRONICS January 1987 box A good choice is Radio Shack s Cat No 275 220 dpdt 120 volt ac re lay which has contacts rated at 10 amperes for switching relatively high power loads via their ac lines Wire the power relay into the circuit as shown in Fig 4 using the free ends of the stranded wires previously installed on the board to connect it to KI s contacts Otherwise connect the wires to the screw type terminal strip after mounting the circuit board in place When adding the power relay you must also add to the circuit an ac line cord with a plug and a chassis mount ac receptacle This allows you to plug in the device to be controlled and drive it from the ac line via the proj ect s ac line cord obviating the need to make changes to the device itself If you are adding the power relay to the basic project machine the box for the chassis mount ac receptacle and drill a hole for entry of the line cord Deburr all holes Then line the line cord hole with a rubber grommet
200. staff Is here to serve you Complete line of drive enclosures The Service in Floppy Disk Services stands for the confidence youll have in dealing with us We do not make you wait when a problem comes up We will be there to heip and more import antiy support and guide you In the unlikely event we cannot answer your Questions a staff member will return a call to you in a timely and profes sional manner with the answer 800 223 0306 CALL FOR FREE CATALOG Deaier Inquiries invited VISA Warranty is a term that sometimes is taken for granted At Floppy Disk Services we support one of the strongest war ranty policies in the bus iness Our policy is to replace any equipment found to be defective in any way during the war ranty period Its as simple as that No waiting for the merchandise to be sent back to the factory If we find a problem other than abuse we simply ship a new unit back fo you on 39 Everett Dr Bldg D Lawrenceville NJ 08648 609 799 4440 CIRCLE NO 179 ON FREE INFORMATION CARD The XT clone system pic tured above is our Super System Vil XT clone It contains a turbo pro cessor a 20mb hard disk formatted RLL to 34mb 640K RAM two 360K flop pies 1 AT 1 2 mb drive mono amber Monitor par port ser port clock and AT type keyboard You might expect to pay thousands for this system but Floppy Disk Services inc will supply if re
201. switch S1 power switch 2 light emitting diode LEDI the fuse holder for F and the circuit board Solder short lengths of wire to the holes labeled S1 LED1 and BUZZER using color coded wires if possible to keep track of the anode and cathode con nections for the LED and positive and negative connections for the buzzer Mount the fuse holder and then the circuit board with 6 32 x 34 machine hardware and 1 4 spac ers via 7 s tab holes and the hole at the other end of the board Mount the switches and LED in their respective locations using a panel mount clip or small rubber grommet Slip over one of the wires coming from the circuit board holes labeled LED1 a 1 length of insulating tubing Carefully solder the LED wires to the LED s leads taking care to connect the cathode K wire to the cathode and anode wire to the anode When the connections have cooled slip the tubing up over the se lected lead to insulate the two from each other Referring to Fig 7 wire the fuse holder and power switch in the pow er transformer s primary circuit as shown Mount the piezoelectric buzzer on the front panel of the enclosure and wire it into the circuit see Fig 9 making sure to observe proper polarity Then wire the time selection switch into the circuit Shown in Fig 10 is the finished Timer Beeper wired on a pc board Note that this prototype has a push button switch assembly for the time selector If
202. t is housed Set the microphone element in its hole and arrange its front surface flush with the outer surface of the box Run a thin bead of quick set epoxy cement or silicone adhesive around the element inside the box to anchor it in place Calibration and Use Connect a 9 volt transistor battery into the circuit via the battery snaps Now connect a multimeter set to the lowest resistance range across K1 s contacts Set R3 to about mid rota tion and step back about 10 feet Clap your hands sharply twice pause and then clap twice again If the cir cuit is operating properly and R3 is set correctly the meter should indi cate infinite resistance after two claps and then zero resistance after two more claps as the relay s con tacts open and close Repeat the clap test several times to make sure If you do not obtain these results ad just R3 for higher sensitivity more gain from JCI It may take several claps to syn chronize into the on off cycle Bear in mind too that the circuit can be accidentally triggered by any other sharp attack sound So make sure when performing the test that you do so in a quiet environment When using the Servant position it so that there is an unobstructed view from the sound source to the project s microphone pickup ele ment Then just sit back and you can be a modern day sultan NE To preserve your copies of 7 THE MAGAZINE FOR ELECTRONICS amp
203. t line which is functionally similar to WordStar has been acquired by Micro pro WordStar s parent The local dealer supplied a memory resident utility called PopSet designed to save QMS owners the complex chore of programming font and emulation modes from the printer s keypad it clashed with Word and QMS tech support line con fessed that it was meant for the slower 1 995 Kiss not its big brother Mean while Dad tells everyone he meets If all you need is text printing there are lots of good lasers to choose from But if you re lured by pictures of gorgeous re ports and page layouts get the Laser Jet Such conversation attracts atten tion on the streets of Sunapee N H ME Names and Addresses PC SH 1030 D East Duane Ave Sunnyvale CA Siete Rim 245 67 17 Software Products Int l 10240 Sorrento Valley Road San Diego CA 92121 519 450 1526 OMS Inc P O Box 31450 Mo bile Al 36689 NEW PRODUCTS 000 from page 15 CompDes runs under MS DOS 2 0 or up in any IBM PC XT AT jr or compatible computer with either a color or a monochrome monitor 49 95 CIRCLE 19 ON FREE INFORMATION CARD Digital AM FM Receiver Sherwood s new 55 watt channel Model S 2750CP digital stereo re ceiver offers surround sound and synthetic stereo circuitry a 5 band ware performs resistance decibels VSWR ratio resonance and other calculations It also has menu selec tions for circuit designs
204. tails about this and other micro miniature circuits will be given in a subsequent piece Even if you are not now interested in assembling ultraminiature cir cuits you should become well in formed about surface mount tech nology That s because this technol Fig 1 An example of a subminiature LED transmitter assembled by the author from an assortment of surface mounted components 18 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics ogy offers several important advan tages over conventional circuit board assembly techniques Already some major manufacturers of electronic circuit boards have switched from conventional circuit board assembly techniques to surface mount tech nology and many others are consid ering the change These changes will eventually affect virtually every area of electronics Therefore it is essen tial that electronics professionals and experimenters become familiar with this technology Here I will explain in some detail why surface mount technology is so appealing and then discuss various surface mount components and as sembly methods Finally I will dis cuss suppliers of surface mount components and supplies and a new SMT training kit available from Vec tor Electronic Company In the fu ture I ll provide construction details for some tiny surface mount circuits you may wish to duplicate Even if you don t assemble these circuits the details
205. ter choke salvaged from an old vacuum type TV receiver A 1 Henry 350 milliampere filter choke is the main component The choke I used measured 2 by 1 square You can use any similar unit Any choke that has 0 5 to 4 Henrys of inductance 30 to 100 ohms of dc resistance and a current rating of 400 to 250 milliamperes is suitable for the mini bulk eraser The choke is typi cally made up of E and I laminations with the former holding the coil and a fish paper separator To make the bulk eraser remove the frame that holds together the E and I laminations Discard the frame and I laminations Figure 1 shows the choke as it appears stripped of its mounting frame and ready for instal lation in a plastic container The coil is usually firmly stuck to the E lami nations However if it s loose insert LI i a ett he i LI w i hh ar gi i h ee SA eet cardboard shims and fill the voids with epoxy cement to make a solid structure Then wire the bulk eraser as shown in Fig 2 The choke I used fitted snugly in side the cap of a spray paint can Since this left no room for the switch and fuse I used an Amphenol fused plug and installed S in the line cord A better approach might have been to house the entire circuit inside a suitably sized oblong plastic box Once you ve prepared the choke as described temporarily connect to it a line cord Plug the line cord into an ac outlet and after 10 seconds pull
206. the problem before proceeding When the voltages check out okay wire the jack to the touch pad circuit Then wire the power supply into the system For the touch pad I ve tried using the conductive foam carriers that protect CMOS ICs as the pressure sensor R in Fig 3 with disappoint ing results Their linearity and re sponse leave much to be desired Therefore the better approach would be to use commercially made touch sensors Setup and Use It s time to check out the Drum Syn thesizer Before you do this tempo rarily or permanently if you wish connect a normally open momen tary action spst pushbutton switch between pin 15 of JC and J s tip lug Then connect the AUDIO OUT PUT from the Drum Synthesizer to your audio amplifier and power up the system Make sure your ampli BLACK INDICATES SELECTED POSITION A B e D E OFF A SYNTHESIZED TOM LFO fier is off and its volume control is turned ali the way down before mak ing the connection If when you press and release the pushbutton switch you don t hear anything from the Drum Synthesizer do the follow ing Check at pin 13 of JC for the presence of an audio signal For this you can use any audio amplifier but be sure to place a 0 1 to 10 micro farad capacitor in series with the sig nal line to keep unwanted offset volt ages out of the amplifier An in expensive amplifier designed for audio troubleshooting was presented in
207. ticular flashlight you need for this project is a three way type that has a 9 long fluorescent tube A typical example of such a light is the Sears Stock No 4823 but any 50 MODERN ELECTRONICS January 1987 Br J Fig 1 The three way lamp before conversion similar model from another source will do as well You will also need an old high intensity gooseneck desk lamp The gooseneck on this lamp should be about 14 long and 2 in diameter Whether or not the goose neck lamp works does not matter since all you want from it is the gooseneck portion If you do not have such a lamp lying around you can probably pick one up inexpensive ly at alocal thrift shop or flea market Begin modifying the flashlight by removing the two end caps and all the circuitry not related to the fluo rescent part See Fig 1 for the three way lamp before conversion What you will be removing are the incan descent circuitry the flasher for the incandescent lamp and the built in a a E ES Say You Saw It In Modern Electronics if fe a kar F a a ay faa E sa ja oa E E Fig 2 The finished gooseneck fluo rescent lamp buzzer and its circuitry if it has the last Remove the fluorescent tube its holder and its reflector assembly Cut the wires that connect this sec tion to the circuitry inside the flash light taking careful note of which wires were cut from each point The fluorescent tube holde
208. tive adhesive and solder paste In the meantime en courage you to begin preparing for the surface mount era by collecting additional information on surface mount technology from the sources given as well as above articles and ads in electronics trade magazines A new era of miniature electronic con struction techniques and opportuni ties awaits KE Editor s Note This article was prepared in place of the author s Electronics Notebook column January 1987 MODERN ELECTRONICS 29 Say You Saw It In Modern Electronics By John T Bailey irtually all electronics en thusiasts are familiar with the ubiquitous general pur pose 555 timer integrated circuit chip This device has deservedly gained an excellent reputation as the timer of choice in a wide variety of applications and ranks among the most widely used ICs of all time The 555 has its limitations though For example when accurate time delays ranging from microseconds to up to a month are required the 555 cannot nt EXTERNAL iEXTERMALI T sie Time base Fig 1 This block diagram shows the internal details of the XR 2240 programmable timer chip Note the three basic How To Design Ultra Long Delay Timers Timing delays of from a few microseconds to almost 30 days can be obtained with an inexpensive programmable timer chip from Exar plus a Timer Beeper you can build match the performance of Exar s twice the price
209. tronics and Lunar Antennas 18 scanners in all will be awarded including a grand prize of the set up you see above the Regency HX1500 handheld the Z60 base station scanner the R806 mobile unit and a Lunar GDX 4 Broadband monitoring reference antenna 55 Channels to go When you re on the go and you need to stay tuned into the action take along the Regency HX1500 It s got 55 channels 4 independent scan banks a top mounted auxiliary scan control liquid crystal display rugged die cast aluminum chassis covers ten public service bands including aircraft and it s keyboard programmable Compact Mobile With today s smaller cars and limited installation space in mind Regency has developed a new compact mobile scanner the R806 It s the world s first microprocessor controlled crystal scanner In addition the R806 features 8 channels programmable priority dual scan speed and bright LED channel indicators Base Station Plus Besides covering all the standard public service bands the Regency Z60 scanner receives FM broadcast aircraft transmissions and has a built in digital quartz clock with an alarm Other Z60 features include 60 fe Send in a photo like WA this one of Mike Nikolich and his Regency monitoring station and receive a free gift from le Regency Be sure to include your phone number Name address and Giveaway 1 Lunar GDX 4 channels keyboard programming
210. tt or a Q lori 2 watt n solder tad ti 4 aren WH for 1 2 watt ie 3 20 tor 20 1 4 watt this the Dig K rtn GOLD INLAY SOLDER TAIL nan sa Micron a Dig Key part numbe ree Ge Pricing 6 20 000 Pact Bo Descreption 1 8wat 640 2500 caa p jod s 1 swan 25 340 13 0 C9815 18 pi de t gold a70 45 0G 1 2 Wa 2 3 50 16 00 CSE 1 a Joli n 745 1854 pinged i 3 d DA guarana MA Os as ow an bo M J JAS BON c 20 2 god 3 5 1 8 Wan Carbon Film Assortments a gi cz 4 R8112 5 each of the 73 nka JASZA7N 10 1 2 15 18 ZZ me though 1 0M 74S288N I6 tore pcs 745289N 145387N JASA PAN SE MAGN MG IN TER aS T oi 256K 262 144 x 1 DRAM 150NS 5 70 1 39 95 9 2ODES DIAMOND TOOL UNGAR Por 7400N 7401N 7402 740 7404N 2001 72003 P2004 P20 7E P200 P2069 PA P2012 2201 2 7405N 7406N 7407N JADAN 7409N 7410N 74 74134 7414N 7416A 7A 7N 74200 22234 FAN 7525N 7427N 7430N 7432N 7437N 7438N 7440N TAS AN LM 3352 LM3362 25 LM3362 5 0 L Maas LM3a7M LM3377 LM238K L339 LM340K C 5 LM340K 32 LM340KC 15 LM3A40T 5 M340T 12 LM340T 15 Opsraung Temp Range Dimension L BO 650 9550 190N 74 5 199N 74LS221N MLS240N 74LS241N 74L9242N 7ALS24IN 744 S244N 74L 243N 74LS251N 74L S263N 74LS207N 741 5298N 74LS266N 74LS 279N 74 52598 74LS290N 74 S29GN 7442N 4 S296N 7445N 74L S352N 7446N 76 9 74LS383N 74 5365N FALSIGAN tALS3I67N ninyi PARE RSSSRS K Cee EBRES ROEE SA
211. ty is ya Ep a E WA rll ee ie Fae a d el ea oe pr 62 MODERN ELECTRONICS January 1987 Seo east ESS ahs en a te a a oe Wea i en ak 1 jet ay ha SRR an Re oa a Te EAN ea A k E i Soca aah a ie Sethe aA ee WA WERI 7 SNe a Wk a L i sarah x Say You Saw It In Modern Electronics la a ia i uana ia uu ai Wu SS EE EE SS measurements given in the Voltage Checkout Table If everything ap pears to be okay the receiver should be working as designed Temporarily connect the FM Re ceiver s output to the input of an au dio power amplifier and set R3 and R9to mid rotation You should hear the hissing sound that is typical of an FM receiver with no input signal Adjust RF GAIN control R3 until the hiss is at maximum Then connect a short piece of hookup wire to the pri mary of 77 at the point on the circuit board labeled RF INPUT see Fig 5 You should hear a mixture of extran eous signals being picked up by the short wire antenna Increasing r f gain should increase the strength of the noise Now test the pickup unit if you ve decided to incorporate it into your project When using this option make sure C76 and the optional jumper wire are installed on the re ceiver board Connect the pickup unit to the receiver with a length of coaxial cable terminated at both ends with suitable connectors and check for 12 volts with reference to circuit ground at the collect
212. urce Careful control of grounds is also im portant The input analog ground return must be direct and must not share any common mode digital ground noise If you digitize a 1 volt video waveform to 255 levels that is something like 4 mil livolts per level It is trivially easy to get digital ground noise that is hundreds of times higher NE z E 7 z ATTACH LABEL HERE NEW ADDRESS HERE ADDRESS NEED HELP Phone or write your Hardware Hacker questions directly to Don Lancaster Synergetics Box 809 Thatcher AZ 85552 602 428 4073 SUBSCRIBER SERVICE CHANGE OF ADDRESS Planning to move Please let us MODERN ELECTRONICS you won t miss a single issue of Anach old label and print mew address in space provided Also include your mailing label prompt service on your inquiry Modern Electronics Whenever you while conceming 76 N Broadway know six weeks in advance s your subscription to insure Hicksville NY 11801 January 1987 MODERN ELECTRONICS 75 W SOFTWARE FOCUS II I Word Finder A Giant Synonym Finder By Art Salsberg Microlytics 300 Main St East Roches ter NY 14445 newest Word Finder the saurus Version 3 22 has become a giant with 220 000 synonyms for IBM PC XT AT and compatible computers The previous version had only 90 000 syn onyms which itself was very competitive with other on line thesaurus s such as Webster s over 100 000 and Turbo
213. using an ac power sup ply or a pair of battery holders if you re using an ac power supply ora pair of battery holders if you re using a battery supply Machine the box s front panel so that the switches and controls for a single synthesizer cir cuit all mount in a single line across the panel see Fig 6 for a typical pan el layout Then drill holes through the rear panel for JI and J2 and for either the ac power cord or the bat tery holders and in the floor of the enclosure for mounting the synthe sizer and power supply boards If you re building more than one syn thesizer module into the box make accommodations for the additional holes needed for their controls switches and jacks If you ve decided to use the touch switch option drill a suitably sized hole for its jack through the rear panel Caution One side of this jack goes directly to the 12 volt power supply line Therefore it is essential that this jack be fully insulated from every portion of the circuit includ ing case and circuit ground and that there is no possibility that it can be confused with the TRIGGER INPUT and or AUDIO OUTPUT jacks There fore it s best to use a plug jack ar rangement other than the phono type for the TRIGGER INPUT and phone type for the AUDIO OUTPUT After machining the enclosure de burr all holes If you re using a raw aluminum box thoroughly clean it with soapy steel wool and label the front and rear pan
214. ut just like the genuine article Lighted Num Lock and Caps Lock keys Model 516l meamea 88 95 The biggen the best Similar to 5151 but switches automatically between XT md AT compatibility Has a large retum key 640K Motherboards in your choice of flavors Flavor One Totally Bare no pars at all Comes with a parts list Parts placement is clearly silk screened on the board Not a turbo Mane ee 29 95 Flavor two Assembled amp tested with OK installed 2 layer construction BIOS included lt lt sse sws 129 95 Flavor three Same as two but 4 layer ccs 149 95 ELAVORS TWO amp THREE ARE TURBO 8MHz BOARDS Terms our minimum order is 10 00 There is a shipping and handling fee of 5 for UPS ground delivery Minimum shipping amp handling is 2 00 there is an additional 2 50 charge FOR COD ORDERS we only accept CASH CERTIFIED CHECK OR MONEY ORDERS unless you are a big corporation or have previously established credit with us we also accept VISA MASTER CARD amp Computer Parts Galore Inc 56 Harvester Avenue Batavia NY 14020 NY RESIDENTS CALL 1 716 343 6133 On phone orders AMEX CIRCLE 75 ON FREE INFORMATION CARD order sent COD Inc kik CABLES PARALLEL The standard cable used to hook up an IBM or compatible to a printer 10 9 95 Serial Cables DB2S to DB25 all pins connected WI Extension Cables 36pin centronics connectors Male on
215. ute IN 47811 L reeserveetconen _ zyvmz zywme_j detork of olternatve offer Bl MODERN ELECTRONICS NEWS ll CONSUMER PROTECTION PROPOSALS A California bill that requires con sumer electronics manufacturers to retain functional replacement parts for seven years passed State Assembly and cleared a Senate committee This is for merchandise that has a wholesale value of more than 100 with goods in the 50 to 100 range proposed to have only a three year parts retention requirement The full Senate must pass the bil AB 3835 in order for it to be a go Legislation is being considered in California Connecticut Florida Iowa New Jersey New York City and San Francisco requiring retailers to label gray market merchandise COMPUTER AIDED DESIGN VIDEO A new videotape CAD to Reality is available from CalComp in VHS or Beta format for 5 The eight min ute recording outlines CAD applications in engineering architecture and facilities management Write CalComp Videotape P O Box 3250 M S 60 Anaheim CA 92803 AUDIO SPEAKER DEVELOPMENTS Matsushita Electric parent of Panasonic Technics and Quasar has developed an ultra flat panel speaker for wall mounting It s only abut 2 1 3 deep and features twin cabinet construction to house two woofers and a mid low speaker separately Overall dimensions of the system are 3 ft sq plus the afore mentioned depth of not much more than 2 inches Impedance is 8 ohms while power ha
216. uy decision If you ever receive any Selection without having 10 days to decide you may return it at our expense The CDs you order during your member ship will be billed at regular Club prices which currently are 14 98 to 1598 plus shipping and handling Multiple unit sets PO Box 1129 Terre Haute Indiano 47811 1129 Please accept my membership application under the terms outlined in this advertisement Send me the 2 Compact Discs listed here and bill me only 1 00 for both agree to buy two more selections at regular Club prices in the coming year and may cancel my membership at any time after doing so 2 more CDs at regular Club prices in the may be somewhat higher After completing Sendme f T next year and you may then cancel your your enrollment agreement you may cance these 2 CDs es eee ey membership anytime after doing so How the Club works About every four weeks 13 times a year youll receive the Clubs music magazine which describes the Selection of the Month for your musical membership at any time if you decide to continue as a member youll be eligible for our money saving bonus plan It lets you buy one CD at half price for each CD you buy at regular Club prices ADVANCE BONUS OFFER Also send me 10 Day Free Trial We ll send details of the a third CD right now at the super low price of just 695 which will be billed to m
217. with than Word Finder s speedy cursor Furthermore Webster requires a second confirmation function key press when automatically substituting a word in your text which may be preferred by some people who ha bitually make such initial mistakes In conclusion I m very impressed by the new version of Word Finder Lots more synonyms are very welcome If the makers would revise its synonym display so that each group of closest meanings was easier to sight perhaps prefacing them with numbers I d make it my num ber one choice even giving up the type in facility I love As it stands I think Web ster wins by a nose for me Others who want the most synonyms available by far however might choose Word Finder That s horse racing for you P S For computer owners with CP M operating systems there s a Word Finder version available for you too with 120 000 synonyms up from 90 000 ME Say You Saw It In Modern Electronics Free Product Information Use the free into card How do I get more data Readers can obtain free information on products advertised by certain companies as well as for some editorially mentioned products Simply circle the appropriate number printed below an advertisement onto the Modern Electronics Free Infor mation Service card bound into this is sue After filling in your name and ad dress just mail the postpaid card Your re quest will be forwarded directly to the ad v
218. wrapping it up in a package I decided to check the con nector points one last time The very first check I made the 128K connection points did not show any continuity I couldn t believe it Pulling out the wires with long nose pliers and using an Xacto knife to scrape out residual insulation I checked the one inch long piece Againit did not have continuity Replacing it with a new length in the IDCs each end shoved into the appropriate hollow pin hole double checking it for continuity which was there I replaced the board in its computer slot started it up and bingo there was my display prompt Fixed and ready to go Looking back it was a simple intermit tent wire break that didn t reveal itself by looking at the insulation or by resistance measurements If there are any blessings it was in the sockets that the RAM mounted in which obviated any solder ing work and in a screen display that gives some indication of where the prob lem lies If there are any curses it s for a manual that does not cover all the error codes that its accompanying diagnostic disk spews out and the difficulty in get ting service information from a manu facturer or dealer Additionally it was interesting to observe that the IBM man ual requires fighting through the written matter to overcome unclear presenta tions A similar manual by Zenith is a joy to behold probably thanks to a Heath hand in it I d be interested to know
219. y enough to hit a good combination of capacitors early on If you work carefully and use a highly accurate standard to monitor the timing cycle you can tweak the composite value of the capacitors Continued on page 87 kia au uli ete T S iii 36 MODERN ELECTRONICS January 1987 Say You Saw It In Modern Electronics at ae on ald Andy is a Ham Radio operator and he s having the time of his life talking to new and old friends in this country and around the world You can do it too Join Andy as he communi cates with the world Enjoy the many unique and exclusive amateur bands the millions of fre quencies that Hams are allowed to use Choose the frequency and time of day that are just right to talk to anywhere you wish Only Amateur Ra dio cperators get this kind of freedom of choice And if it s friends you re looking to meet and talk nd you can too Ya m n with Amateur Radio is the hobby for you The world is waiting for you If you d like to be part of the fun if you d like to feel the excitement we can help you We ve got all the information you ll need to get your Ham license Let us help you join more than a million other Hams around the world and here at home Who are we We re the American Radio Relay League anon profit representative organ ization of Amateur Radio operators For information on becoming a Ham operator circle number 110 on the reader service ca
220. years 145 00 three years 216 00 Entire contents copyright 1987 by Modern Electronics Inc Modern Electronics or Modern Electronics Inc as sumes no responsibility for unsolicited manuscripts Al low six weeks for delivery of first issue and for change of address Printed in the United States of America Postmaster Please send change of address notice to Modern Electronics Inc 76 North Broadway Hicks ville NY 11801 Say You Saw It In Modern Electronics oF 1 8 A LOWEST PRICES ANYWHERE SINGLE DEALER UNIT 10 UNIT PRICE PRICE RCA 36 CHANNEL CONVERTER CH 3 OUTPUT ONLY 2995 18 00 ea PIONEER WIRELESS CONVERTER OUR BEST BUY 08895 72 00 ea LCC 58 WIRELESS CONVERTER 92 95 76 00 ea JERROLD 450 WIRELESS CONVERTER CH 3 OUTPUT ONLY 105 95 90 00 ea SB ADD ON UNIT 10995 5800 ea BRAND NEW UNITS FOR SCIENTIFIC ATLANTA Cali for specifics MINICODE N 12 109 95 58 00 ea MINICODE N 12 VARISYNC 11995 62 00 ea MINICODE VARISYNC W AUTO ON OFF 179 95 11500 ea M 35 B CH 3 OUTPUT ONLY 13995 70 00 ea M 35 B W AUTO ON OFF CALL FOR AVAILABILITY 199 95 125 00 ea MLD 1200 3 CALL IF CH 2 OUTPUT 109 95 58 00 ea INTERFERENCE FILTERS CH 3 2495 14 00 ea JERROLD 400 OR 450 REMOTE CONTROLLER 2995 18 00 ea ZENITH SSAVI CABLE READY DEALER PRICE BASED ON 5 UNITS 225 00 185 00 ea SPECIFY CHANNEL 2 or 3 OUTPUT Other products available Please Call Output Quantity Channel Ca
221. you wish to use this type of switch arrangement you can do so However for purposes of ma chining the enclosure it might be more prudent to use an ordinary ro tary switch This type of switch is more readily available and affords a simple means for mounting the tim ing resistors directly on its lugs After assembling the project use a dry transfer lettering kit or tape la beler to label the front panel see lead photo If you use dry transfer letter ing spray on three or four ight coats of clear acrylic to protect it Wait for each successive coat to completely dry before spraying on the next If after final assembly your Timer Beeper does not work check out the beeper section first To do this tem porarily connect a jumper wire be tween pins 2 and 6 of ZC3 If the beeper section and power supply are operating properly the buzzer will chirp The problem then lies in JC or C2 or both Calibration Only one component in the timer cir cuit must be adjusted to achieve the desired time delay This is C4 C in Fig 4 In the case of the Timer Beeper the 60 minute delay requires a 4 4 microfarad capacitor To ob tain this value start with 3 3 micro farads and parallel it with lesser values This trial and error proce dure will require you to monitor the circuit until it times out and the buzz er sounds It may be quite time con suming if you wish to obtain a high degree of timing precision unless you are luck

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