TAB BOOKS No. 470 34.95 By Byron Wels Transistor Circuit Guidebook Byron Wels TAB BOOKSBLUE RIDGE SUMMIT, PA. 17214 Preface Ibeforeme supposea (alongpioneer the my transistor in first was with many other World War the field. We were using experiencewith solid-state known. Unlike today's experimen- II GIs) as somewhatsolid-state of receivers devices marks FIRST EDITION devicester,own with semiconductors! with a whichFirst, to youexperiment, swiped a pair choice of sealed, encapsulated,or tank. Here's how we did it: Then you carefully took one of earphones from the we had to construct our and very exotic nearest of the THIRDSECONDFIRST PRINTING-SEPTEMBER PRINTING-AUGUST PRINTING-JANUARY 1972 1970 1968 plane,wasyouAnphonesantenna. emptywound strung apart toilet Afterout as paperclipping high jeep, full of wire, closely spaced. and unwound the wire from rolland served asthe far catchasas theit would off coil a safety form, -pin, you The remainingthe magnet wire inside. reach-for the whichstuck Copyright © 1968 by TAB BOOKS coatedNext,it intomind youneededa you,hunk not of woodlacquera razor so blued. , ribbons -of -steel, but a blade. Oh, none of thethe pointfancy projected plasticA bayonet at right stuck hilt -deep It was placedblued so bladethe point -quench -blued , angles. in the of - isoutReproduction assumed express permissionwith or respectpublication of to the the ofpublisher, usethe ofcontent the is prohibited.information in any manner, No contained liability with- Printed in the United States of America thefoundphoneground pinhear could theTokyowas served right wiredcontact Rose! spotas toa on ground it.blade, the blade's bluing, you couldconnector, actuallypin, and antenna coil. and the other ear- If you herein. Hardbound Edition: International Standard Book No: 0-8306-8470-X upcollectionterest your inalley. of circuit transistorRegardless function and of your It was compiled for those niche in the world of electronics, andsolid-state application. circuits should be right with an intenseIt is in- not a primer this Paperbound Edition: International Standard Book No: 0-8306-7470-5 Library of Congress Card Number: 68-56093 treatises;onofcircuitsign the circuit circuitssolid-state is rather, accompaniedhighlights, covering itart-you is a by a and in most cases,the several many fields ofcollection electronics. of won'tbasic haveand tobrief wade "non through -technical" lengthy description advanced de-applications Each arequireservemind suggested, asa familiarity youtypical readwithFor examples. and designersthe with ashope occasionsthese thatand circuits techniciansmany and moreneeds it arise. is hoped many circuits and future equipment. For experimenters Certainly, technicians who ac- will be better able to will come to will CONTENTS etc.partsandcopeignored,get construction-to withit lists, enableoperating. present either. you -minded You'llAmateur to actually findreaders and manybuild hobbyist there ormade-to-order ismodify enough the information, circuit component specifications, interests haven't been charts, circuits forcoil data, and PAGE operationthe home, of office, manyThe hampreparation companies, shack, of auto,who a book readilyetc. such made as this necessitated the co- The author gratefully acknowledges the their re- TUNER AND RECEIVER CIRCUITS 11 assistancesources available. offered by: Motorola,Microwave Inc. Associates RFAC/DC3 -VoltBooster Receiver Portable Receiver 1215 TexasRadioRCA ShackInstruments AM/FMFMFM IF TunerReceiver Amplifier 202218 hopelessforinto the what encouragement and must uselessThe have author vocation. appeared,given also him To wishes duringthank to him hisexpress earlyin some appreciation ventures to his father at that time anyway, small as a MOSFMIntegrated IF FET Strip FMCircuit Tuner IF Amplifier 252427 measure, I respectfully Joseph Wels and lovingly dedicate this book to: Byron G. Wels DualICFET FM-Gate FM Tuner FrontMOS FMEnd Tuner 353032 1968New York, N.Y. Varactor FM Tuner AMPLIFIER CIRCUITS 37 Amplifier/OscillatorTelephone Pickup/Amplifier 4341 89 1050 -Watt HighPA Amplifier Fidelity Amplifier 444846 SimpleGridSignal Dip TracerVoltmeter Oscillator 9391 One7035 -Watt -Watt Class AmplifierHigh AB Amplifier Fidelity Amplifier 505452 ACSquare Voltmeter -Wave Generator 9495 6 HighPreamp-Transistor and Stereo Control Amplifier Fidelity Preamp Circuit 605856 POWER CONTROLLING CIRCUITS IC25Stereo -Watt Amplifier: PA Amplifier Audio Driver 3 Watts per Channel 6264 VariableSpeedSCR Current ACControl Control Control System 1019899 545-Milliwatt60IC -Watt PA IC Amplifier Transformerless Amplifier Amplifier 686765 ElectronicSCRIntegral Heat HeatControl Controller Cycle Ratio Power Control 105103107 ICComplimentary2 Phono -Watt Stereo Amplifier -TransistorAmplifier Amplifier 727570 SCRThyristorIC Motor Speed PhotocellControl/Servo Control Timer Amplifier 109110112 Low4 -Watt -Noise Stereo Preamp Amplifiers for Low -Impedance TEST EQUIPMENT Mikes 7977 SCR Overload Protector LIGHT CONTROLLING CIRCUITS 113 BatteryNo -Contact Eliminator Switch 8483 CarSCRLight Light Light Minder Switch Flasher 119116318 ElectronicSensistor Temperature TimerTime Delay Indicator 868587 SiliconLightSCR -Activated Lamp Dimmer Switch Photovoltaic Light Sensor 324122120 VariableThyristor Lamp Dimmer Rate Flasher 126127 TRANSMITTER CIRCUITS AudioSCRIntercom MixerVoice Control 166165168 SonobuoyBroadcastRemote Control TransmitterBand TransistorMini -Transistor -Receiver 134133129 SPECIAL RECEIVER CIRCUITS 40MarineWireless -Watt Band BroadcasterCW Transmitter 135139137 S Beat-Meter Frequency Oscillator 170172171 500300/600v100 -MHz -Watt One PowerLinear -Watt AmplifierSupply Oscillator 145143141 ShortNoise Wave Converter Limiter 174 Varactor50Mobile -Watt Power TransmitterFrequency Amplifier Multiplier 149151147 Transistorized AUTOMOTIVE ACCESSORIES Ignition System 176 ZenerFETZener VFOSpeech Clipper Protection for Power Amplifiers 156154153 Battery Charger DIFFERENTIAL,AND INTEGRATED, COUNTER CIRCUITS 177 Electronic Metronome SPECIAL AUDIO CIRCUITS 158 LinearLow -Noise Integrated Differential Remote Control Amplifier Counter System 182180184 StereoLineMultiplex -Operated Balancer Demodulator Phono Amplifier 163159161 ShiftBistableDecimal Register Counter or Ring Multivibrator 188186 TUNER AND RECEIVER CIRCUITS Photographic Slave EXPERIMENTAL CIRCUITS Flash 192 RF Booster AutomaticElectronic Keyer Theremin 196193 Initcapable spite can ofserve of its boosting at any very obvious simplicity this frequency within weak signals to a usable the toleranceRF of amplifierQl, circuit level.receiver RF While this is Low -Voltage CONVERTER -INVERTER CIRCUITS 198 componentsbooster.circuit's widest C3 -L1 application,The greatest advantage To adapt the circuit to a for attaching anmust tune to the desired of this circuit is that perhaps, is as a externalspecific antenna use, tank to equip- frequency. it provides an circuit VoltageFrequency Regulator Stable 20 -Watt Inverter200 -Watt 60 -Hz Power Inverter High Current Converter 204200 expedienttheonout,ment antenna resulting though, not means originallydesigned efficiency. signal-to-noiseChances are that you that the effectiveness will want toWith use a smallunit or inefficient for such use.ratio will be quite low. of the amplifier depends It must be pointed like this with a antenna, TELEVISION CIRCUITS broadcasttransistorbyantennaIf all the means receiverterminals.bandradio. usereceiver, antenna If your it.For that matter, it can If it hasn't,is thena ferrite try type, receiverwhether does have or not an it is equipped obtain one just likethis besimple used trick:with any antenna jack, with ColorIC Sound TV ReceiverAmplifier/Detector 206207 aligned.it andferritereceiveras close attach antennaYou antenna. as its can possible terminals with use If allyour the samethe method coil winding with a loop atto onethe littleend,receiver's transistorbetween antenna, C2 receiver and ground. -typehasThen BCBa long tapetry wind-similarly ingitself.to aAdjust thefew booster,turns C3 for thusTo use the unit, tune to a maximumof wire around volume, the turning inducing more signal station near the middle other end and connect down the receiver's in the ferrite rod of the band. these volumememberhavestick to Llcontrol adjust tofor turn additional as Lithe needed. for booster any gain. Then otheroff whenFrom adjuststation you then the onturn on,core off you the the band, just re- of the loop - shouldreceiver! not CONVERTER LlA IF AMPLIFIERS T3 Q3 T4 R1 R1 R7 R8 C14 C2 ANTENNATO RECEIVER 81 0 TO EXTERNAL ANTENNACl "1---1 $ L1 TERMINAL R6 DETECTORSECOND Dl 51 QI S1 41....1( C3 AUDIO 14 POWER = RECEIVER CHASSIS GROUNDOR GROUND TO LUG DRIVER AMPLI FIER PARTS LISTCourtesy: Radio Shack R4 SP TRANSISTOR:CA PACI TORS:Q1C3-365Cl, -2N166 2-.01 pfd mfd COIL:BATTERY:RESISTOR:R1B1-1. -36KLl-broadcast 5v band loopstick 3 -Volt Portable Receiver versionactually of formingCourtesy: the oldThe aBCB part antenna receiverof is formed loops. Frequencyon a ferrite bar, RCA the antenna. Really, an withupdated the input coil selection WhiletableOperatingan extraRFbroadcast its performance on amplifier, a -bandmere 3receivermight orvolts, an beadditional this is improved a fullyclassic byin circuitthe design. IF stage, these would-transistorized por- addition of is tank.inofC6.accomplished the2N1526) emitter and bycircuit. themeans local of oscillatordual -gang signal tuning The input signal Heterodyningis applied to takes place in C6 and L18 function as the the converterthe stage converter, (base with the is injected via C5 capacitor C2 - oscillator bemation.12 of no benefit in our search for basic operating infor- intermediate frequency signal appearing at the converter col - 13 TRANSISTORS:PARTS LISTQ1 -2N1526 BATTERY: B1R17-47R16-100 -3v ohms ohms DIODE: DIQ5,Q4Q2, -1N295-2N2614 3-2N15246-2N408 COILS: Ll-oscillator19suitable#3/44 coil; turns; woundLitz for L1B, awire #10-32 from 155 on turns,slug;coil formL1A, tap- AC/DC Receiver CAPACI TORS:C3,C2,Cl-trimmer, 6-ganged4-0.02 mfd, 3 tuning toC2-9.5to 109 ceramic15 pfdpfdcapacitor, to 141 pfd; C6-7.2 TRANSFORMERS:Ti-antenna wiremary,tunespedattransformer; wound with8 110 turns 100 turns on from pfd pri-a 3/4" #10/41 atground 990 x 1/8"kHz Litzend, x In this transistorized version of the old "5-toober," as the antenna. coil LlIt also C5-0.005C10-2C9-128C8,C7-trimmer, 12, mfd, mfd,pfd14, (part electrolytic,17, ceramic3ceramic to 18-0.05of 20 T2) pfd 3vmfd, per4" chassis;withstart#10/41ferrite inch); transformerof Litzrod secondary,the (pitch, wireprimary; woundmounted 50 6 turnsQ-100 at theon transformer should functionsis woundwithapplied capacitor on as ato the base of thethe inductiveferrite formportion and servesCl. The signalthis schematic mixer transistor. selectedshows by the a separatetankof the tank circuit, Unlike the pre- local oscil- circuit is formed C16-0.005C15-125C13,C11-10 20-100 mfd, pfd, mfd, mfd,electrolytic,(part3v ceramic electrolytic,of T3) 3v T3-2ndIFT2 -1st IF transformer;tune13550,son with - Ramo 135or Thomp- equiv. pfd - Wooldridge at 535 kHz E0- cedingformerlatornal.in the stagecircuit, T3 input circuit, whose resonantand capacitor tuning C10. the local oscillator Since C10circuit is gangedis formed by tracksthrough the couplinginput sig- ca- with Cltrans- RESISTORS: R4R3,R2-3.R1,C19-125 -5K 9-10K15-1.5K 9K pot, pfd, audio (part taperof T4) T4-3rdIFT5-driver transformer; transformer;13552,son13551, --Ramo Ramo or Thomp- equiv. -- WooldridgeWooldridge E0-E0- pri- pacitortofeeds bythe theC13 thebase diode455 to ofThe -kHzthe local output oscillator the audiothe basesignal of the mixer, IF amplifier signal is applied to input IF transistor.is After applied to the transformer andT1 and the mixer driverrectification stage collector then R11-270R8-330R7R6-6.R5-470R10 -39K 8K -2.7K ohms,ohms ohms T6- output transformer;centermarytappedary impedance,-tapped; impedance, secondary 2K,10K; second- im- 100 ohms, center - pri- throughboard,is the volume andpossibility oneThis of receiver works very control R8.suggestion that camemodularization. The show up when servicing well, mounted on through loud and advantages of an etched is needed. circuitmodu- clear If lector. R14-240R13-2.R12 -10K ohms2K Interstage transformer T2 couples the IF signals to pedance,15voice ohms) -coil impedance of 12 to 15 ohms (to match larnewneedyouhave constructionas one.the do groundato separate replace really or common a faulty If the receiver is circuit boardhot. for circuit, caution builtstage on a metalis remove each stage, then must be observed. chassisit servingand plug in a all you formertrolbythe the base R4 second coupling toof thethe detectorAfter basefirst is employed (ortwoof diode theinput) stages 1N295audio betweenIF of stage. anddriver.IF amplification, fed the throughNotice driver volume thatand the outputtrans- signal con- is rectified Theeasilyoperate importantchassis be from addedmay point:One be additionacross we'd like AC sources is a You'll littlefind that more adding convenient, an to make on allthe AC line. small pilot lamp. transistorThat circuits brings up on -offtoo. switch Place it in the This can another makes that the14stage. bias on the base of the first IF amplifier. AVC voltage, developed across R6 and C11, varies hotusing side this of unit the circuita between the line cord and R20. 5 TRANSISTORS:PARTS LISTQ2-40489Q1-40487 COIL: Ll-antenna coil;43mary,ial, turnscoreFerramic 120 permater- turns inch;Q or equiv; pri- #32 wire wound secondary, DIODES: Q4-40490Q3-40488D1Q5-40491 -1N295 primarypedance,5 turns600at 790 kHz of inductance,kHz;260 #34 and ohms unloadedwire; 130 at output 1400 Q, at1500 kHz; 0.413 uh kHz125 at im- CAPACITORS:D2-40495Cl, 2, 10, C2),capacitor;section 10 to (C10 antenna228 +pfd; C11), 9 to 11- ganged section (C1+ oscillator 118pfdtuning TRANSFORMERST1-first IF (455formerondarycitors kHz) (includes across windings); primary 110 -pfd capa- turns ratio Ni/N2and sec-= trans- C4,C3-0.005C5-10 6, 7, 12,mfd, mfd, armicelectrolytic, ceramic disc 17-0. 05mfd, cer- disc 3v of edQunloadedondary,3.16;tapped = turns 75.68; N3/N4primary, Q ratio= secondary 80, = 33.4; primary of tapped sec- loadedQ = primaryunload- load- C8-6.C9-0.02C14-200C13-0.001 8 pfd, mfd, NPO pfd, mfd,ceramic ceramicceramic ceramic disc disc disc ed coefficient64;Q Thompson-Ramo-Wooldridge= input 80; secondary impedance of coupling = = 14. 55K 0. 85; # C16-10C15-100C20-10C19-0.047C18-100 mfd, mfd, mfd, mfd, electrolytic, mfd,electrolytic, electrolytic, electrolytic, ceramic disc 10v12v25v10v T2-secondEO-22646, IFpacitorformer15267, (455 kHz)(includes oracross equiv. primary 110 -pfd Automatic # EX - trans- wind- ca- C21,C22-100 23-0.01 mfd, mfd,disc electrolytic, 300v 150v ceramic ratiomary,ing); ofturns Ni/N2 lower ratio =section of tapped pri-2. 57; of pri- turns = RESISTORS: R2R1 -270K-1K Q3.36;mary unloadedto secondary, Q = 80; 35.2; input impedance N2/N3 loaded = R4-2.R3R7-680R6R5 -820K -18K-82K2K ohms T3-oscillator#ridge18K; EX coil: Thompson-Ramo-Woold--15267,# EO-22645, turns or equiv. Automatic ratio of R9,R8-2.R14-560R13-4.R10, 11-6.8K 5K 12-22K 7Kpot, ohms audio taper primaryof maryary,ratiofull N1/N2primary ofbelowtunes full primarytap, to section to with 100 -pfd- capa- 9.6; N1/N2 - 26;Automatic full pri-second- R16-180R15-1.R19R18-5.R17-270 -10K5K ohms6K ohms T4-audio outputondaryprimary#citance ETriad -6181A65-51, transformer; impedance, atimpedance,# S990 -12X, kHz; or equiv. 3.22. 5K; ohms; sec- 16 R20-250 ohms 17 AM/FM Receiver producehimdesignerdesign. by the hasthe very avery number industry bestThis ofcircuit circuit unavoidable in which he is included he It should be pointed out as a classic example of commercial can, but it must be producedthat the commercialrestrictions radio placedparticipates. He must upon additionaltrulyaudiousesWith aunique. aamplifier. singleminimumnumber amplifier N-channel/NPN, stages. of components, dual-FET/bipolar this receiver unit circuitas the It can provide up to 2 watts of outputIt is thiswith device no which makes the circuit While the schematic indicates tion.designminimumat a low any cost. but parameters.Some the One best, engineersway making to do takethis, quality aof high their -horse While such high ethics are to be praised, they aren't attitude,course, is and to designrefuse to only considera- transformerandband,cuitAM -FMcapacitorto using virtually design, appropriatespecifications values any frequency are tunedshown must incircuits, onbe the thechosen VHF schematic. of course. communicationsaccording CoilResistor to and re- it wouldn't be too difficult to adapt this cir- soawfulconsumercuitalways even design, thelot rewarded. of ultimatewho low consider has -price, So user to before shellthe lowappreciates situation out you the praise low-costfrom -quality receivers are being money to buy the set. An or condemn such cir-the viewpoint of the engineering in sold, quirements. 11XMIs 1S1 what he buys! 01 Am, 7N0 AM-.MIr &MP 0. 540 3110 FM 11 AIM 111.17 07 MO 0 M ISO 17 M I loco n 466 .,14 X 710 2, col 15 601:0 1/0 0300 4 170 4 MO 0 0177 0010 1( .047 K. co 0 won IWO MC 0 +M 4 0015 AC X 033 470 0 320 L XI" om 17oorX ,.., NI X .01 X .001 "OD 0 ISO KF.O MO 0

.1.1,0 1030 0 1./ 44 143" X 1 40 0 MI /0 .017 X ICOO 0 o 1.0 .047 10.1. 1010 AM 115, 0141 Am. AM C 0,4 /11311 o. .047 X * IOW r_-_1 I.00 K77 4700 Fm AFC Pm AK - 470 ho .047 /700 0 107-0 C }.0770 11100 0 .047 1100 0 t-- I .031 v0344.1 74-6-1 501.3 OVAL .47C0 0 110 15 1 6.1 0 61 1.0 1.1630 341 230 6v =I I 1447* i ED( 11.007 2200 18 Courtesy: Texas Instruments 19 AMPLIFIERFIRST IF TS AMPLIFIERSECOND IF T2 FM IF Amplifier R -8V Since the function of the IF strip is to amplify the heterodyned 0 TRIGGERCIRCUITTO MULTIPLEX youthere'ssignal, want alaw a lotof diminishing returns here. the more amplification you get, of amplification, but it's got to be faithful It may be true that the better. But AMPL.THIRD IF IC13 R16 downgradingandpromiseamplification adequate must of qualitybeto the doworked signal.you to avoidany out goodbetween the possibility at all. of distortion sufficient amplification Obviously, a com- and C15 PARTS LIST R11 OUTPUTAUDIO DIODES:TRANSISTORS:Ql, 2, 3-40245 or 40246 R3,R12-470R13-68 4, 7, ohms ohms 8, 11-220 ohms -8V CAPACITORS:C2,Cl,D3Dl, -1N2952-1N5424-4.7 5, 8-0.01 pfd, (matched) ceramic disc mfd, ceramic 1218,RI1216-1K1115-3.9K1214-22K 7-1. 19-6.8K 5K 0 Crurtesy: RCA C10,C9-1.0C7-5C3, 6-1000 11,pfd, pfd, 12-330 ceramic discpfd,ceramic1000v pfd, disc discceramic ceramic disc TRANSFORMERS:T2-thirdT1-second IF IF (10.7Wooldridgeformer, (10.7equiv. MHz) MHz) N trans-trans- Thompson - Ramo - E019310 -R2 or tionThisand and performance circuit a ratio also detectorThis iscriteria, circuit,equipped consisting provides which for doesthe of three additiontwo an stages excellentmatched of of a amplifica- jobmultiplexdiodes. of satisfying quality RESISTORS:C13-0.05C15-5C14-0.02 mfd, mfd, mfd, electrolytic, ceramic ceramic disc disc10v T3-ratio detectorequiv.Wooldridgeformer,Thompson- transformer, Ramo - Wooldridge Thompson - Ramoft - E019311 -R1 or andaudioofadapter. Q3. a pairoutput With of aforloudspeakers. multiplex application unit Theto attached, a stereophonictuner in you the willfollowing amplifier obtain circuita dual The multiplex trigger is tapped off at the collector 20 112,121, 5, 9-12K 6, 10-2.7K * E019312 -R3 or equiv. forand excellent the multiplex stereo FMunit reception. presented later is a good combination 21 T RF AMPLIFIER T2 MIXER T3 diC2 C3 Q1 C9 Q2 R7 I -1_ - C4 R2 C10 R5 C12 'II1C1T FM Tuner R3C6 R4 R6 JJ OFTO FIRSTBASEIF AMPL. C5 LOCAL - C11 -C18 0 -8V C15 OSCILLATOR Q3 -1 T4 T C17 C20 _C21 issimplicity. the beginningThis of a worthwhiletypical FM addition superhet to circuit is offered for Requiring only an 8 -volt power supply, this unit its basic R8 R9 C16 R10 MHztem, usingoutput the may multiplex be applied adapter to described later. any suitable IF amplifier. a home stereo sys- Its 10.7 - C- 19 valuelatorC17, andof is oscillator appliedalso appliedThe throughcoupler oscillator to the C18the base tank output,determines of circuit the taken mixer formedthe from transistor. the emitter of the oscil- injection volt- by T4 and The RESISTORS:Courtesy:R1, 4-3.3K RCA RF SECT I ON T2-RF interstage coil; 4 turns componentage and is dependentplacement. upon such factors as circuit layout and R3,R2, 6-3305-18K ohms woundof spacing#18 barewith between -tinnedapproximately copperturns on wire 1/8" 5/16' ' TRANSFORMERS:R10-1.R9-4R8-8.R7-100 . 2K7K 5K ohms oftanceresonatesisdiameter removedfull at winding, 100 coilwith after MHz; form 27 6.1K;coil -pfd impedance (coilis input wound);capaci- form tap TRANSISTORS:PARTS LISTQ2-40243Q1-40242 C4-27 pfd, ceramic disc Ti-FM antennacopperary,Type0.181"slug 4-tuned;transformer; 1RN9turns wire in diameter, woundof orslug, #22 equiv.; 0.250" withbare second-1-tinned wirelong, - Arnold putcatedtaplocated =tap so is that 540so impedancethat ohms impedance with at the in- at 590 ohms; output tap lo- CAPACITORS:Cl,Q3-40244 7, 17-ganged tuning 7 ca- C10-2000C5, 6, 11,14, pfd, 19-feed-throughcapacitor,1000v 1000 pfd ceramic disc, jacentdiameterdiameter turns spacing coil or 7/32"form, between outerresonates ad- - T3-first IF (10.7Wooldridgeformer,transformer -MHz) #properlytrans- E019309 loaded -R4 or Thompson - Ramo - C2, 8-trimmermaximumsembly),ofpfd:pacitors, capacitor ganged C17 approximately- tuning (part capacitor 17 pfd as- (iCl, to 21 pfd 7.25 to 19 C18-0.22C15-3.C13,C12-0.01 16-1000 3pfd pfd, mfd, todisc, NPO3.3 pfd, ceramic 1000v pfd ceramic disc ceramic withendwiremary,MHz, 27 of close-pfd impedance2secondary turns capacitance wound of #30and =below 6.1K; Gripezeatin 100same cold pri- T4-oscillatortweenwoundofequiv. coil;#18 turnsbare with3 1/2 -tinned on3/22" turns 7/32" spacingcopper diameter wire be- 22 C3, 9-5.6 pfd,ramic minature ce- C21-12tor,C20-tubular 1.5 topfd, 10 ceramicpfdtrimmer disc capaci- biasingshuntingdirection, network) effect impedance of = RF 460 (includesamplifier ohms tapped.coilafter form coil (coil is form wound), is removed center 23 Integrated Circuit IF Amplifier Vce +9V IF strip. The resultIntegrated is miniaturization, circuits can be excellent used to goodsensitivity advantage in an of 1500 FM (8isentialmicrovolts or determined IHFM), -mode andisvoltage asrequired an follows: all-around gain ofat the goodCA3028A interstage set up. into filter.An a input3000 -ohm load The differ- 140 um 44.5 my 15.8 my 2 vms Courtesy: RCA This degree of Vgvoltage = gain requires an input of approximately Yo + -Yr YL = 0.3835 x 10-3x 10-3 = 92.5 = 39.3 db channellossfier.15receiver microvolts of 28 attenuation withdb isat a usedthe5 -microvolt is base permisin a of low the sableIHFM -gain CA3028A , IHFMsensitivity. front receiverdifferentialend, you'll sensitivity haveampli- a Even if a triple -tuned filter having a voltage insertion If 26 db second - FM IF Amplifier ±is 753 microvolts. kHz input 3 db below the transferPARTS characteristic LIST knee. Audio output is 155 my RMS for 140 v, CAPACITORS:ICs: C2C1-680Gl, to2-CA3028A C7-.01 pfd mfd R9R8-4.R7-150R4, -10K 5-2K 7K ohms byherecollectorIf C6 you'reyou and go! R9.lookingof The the The multiplex3rd discriminatorfor IF an amplifier, IF trigger strip output designedisrectified taken is fed(via byfor toD1, C7)FM a multiplex,and frommultiplex, shaped the RESISTORS:C14-.001C12,C8C15-5 to 13-330C11-56 mfd mfd pfd pfd TRANSFORMERS:R15-1.R13R11,R10-68 -68K 12-6.8K 5K ohms demodulator.oneamplifier thing sectionit is theIn performs IF an section FM tuneranumber that orlargely receiver,of useful determines functions. the Forre- the intermediate frequency 24 R2-82R3,R1-47 6,ohms ohms14-1K Tl-InterstageT2-Ratio detector transformerTRW TRW #22486 #22516 or equiv. formeranyceiver tuner selectivityT2 is couples applied characteristic. the to signalthe input to theterminals. second stageInterstage of amplifi- trans- The 10.7 -MHz output of 25 cation, and then through T2(b) to and D3, which are a matched pair, the output stage. function as a follower.ratiodetectoranaudio whichDiodes D2 amplifier through a are 50v ceramicAll resistors discs,can be applied are 1/4 either watt; to .01-to an demodulate the composite signal cathode or (in this case) an emitter - and 330 -pfd capacitors are audio amplifier, or to and .05-mfd ca- and provide pacitorsfrequencysquarecoupling,1KV discs. -wave which responseAdditional selectivity is often designed transformers through the use of a Tschebychev is overcoupled. with a depressed notch in the top, an This results in roughly a into intermediate area in which TRANSISTORS:PARTS LISTQl, 2, 3-40481 critical tuning can occur. R2, 6-3.3K DIODES:CAPACITORS:D2,D1Cl, -1N295 3-1N542 3, 4, 8-.01 mfd R3,R14R12-1.R10,R9R4, 7, -22K 8-22013-470-68K 11-8.2K 8K ohms ohms aa. . C9-.C7-5C6-.05C2, 5-3.368 pfd mfdpfd pfd R16-1.R15R17, -1K 5K18-6.8K --1(-111 RESISTORS:C10,R1,C13-5mfd, 11, 5-18K 12-330 10v pfd TRANSFORMERS:T3-T2-TRW-E0-21125-R1Tl-TRW-E0-21124-RA TRW-EO-23023 The performance of this circuit, with respect to sensitivity, MOS FET FM Tuner tors.thatlimiting,ous ofReceiver -response other IF rejection,tuners performance, rejection using and figures,high-performance image particularly dependsrejection, in to regard bipolar comparesa great transis- extentto spuri- on with and 26 caresuch usedthings in as construction. physical layout, power supply decoupling, Using a negative supply voltage 27 supplysimplifies decoupling. the Thismatter unit of aims tuned for circuit the elimination grounding of and spurious power response as a primarypeatedly,selected.is ahard direct goal. to Whentuner reproduce.function Usually, performance the ofRF In athe amplifiersome operating remained systems, transistor points consistently was changed re- circuit having low spurious response circuit performance of the transistors the same. TRANSISTORS:PARTS LISTQ2-40479Q1-40468 COILS: Ll length,turns,Tunes 1/4" Q with at ID, 100 34 7/16" -pfdMHz capacitancewinding = #18 bare copper wire, 130. 4 CAPACITORS:Cl,Q3-40244C4,,C3,C2, 8, 16-166-0.0027-2-125, 18-5.5-22.5 pfd pfd, mfd trimmer pfd, gang- L2-#18 bareend.proximatelyat 100copperturns,1 1/2 MHz. turns 1/4" wire, 1Antenna fromturnID, 4 from7/16" ground link ground winding end. Gate tap approximately ap- C13-1000C12,C11-0.01C10-2.7C9-5000 14, pfd15-1000 mfdpfded feedthrough tuning pfd capacitor type L3- #18 bareturns,imatelyatTuneslength, 100copper 7/32"withMHz. Q3/4 at wire,34 turnID, 100Base -pfd 7/16" MHz4 tapcapacitance windingapprox- = 120. RESISTORS: R1C17-2-10R5-4.R3,R2 -100K -220K 4-47K 7K pfd, trimmer groundproximatelyat 100imatelyTuneslength, MHz. end. with Q 2 atBaseturns 134 1/2100 -pfd tapfrom turnsMHz capacitance approx- groundfrom = 120. Emitter tap ap- theThe transistor best correlation in the wascircuit. found Forthe withR8R7R6-8. normalthe -120K-22K 2Koperating spread current of oper- of TRANSFORMER:Tl-IF transformerend. oflowintorejectionating the -capacitance,this currentMOS FMis about transistor tuner; inThe this +140468 all circuitdb. provides other MOS (3.5stages field significant to effectuse7 ma), high-performance, transistor improvements the variation has been in incorporated bipolar types. The wider dynamic range 28 viouslythe rejection with bipolar of spurious RF amplifiers. response over that achieved pre- 29 C2 L 1 C3 ------""- 300 OHM C12 Dual -Gate MOS FM Tuner ANTENNA R10 0 15V "IF Dual -gate MOS FETs are coming into their own, as this sche- C15 zcC17 maticcircuit,it'sIF schematic a good indicates. and ideathis shown canto shield easilyin this the bebook. accomplishedtuner Should from you the by decide balance using to build, This front end will operate with any FM Etch the top of double - of the Courtesy: RCA foiltheboardthensided boardside. simply copperwhere Grounding to accommodate etchcomponent-clad away thelaminate unsoldered spot lead all forland necessarywires your areasside pass layout. of on components,thethrough the board reverse to permits the ofand used the TRANSISTORS:PARTS LISTQ1-40468 COILS. Ll (AntennaR10-220R9-4. Coil)-#18 7K ohms bare cop- 4 turns, 9/32" ID, passedHowever,it awayto act through so as youthat an musteffective nothe short ground be sure RF cladding that shield sufficient forto the the cladding critical circuits. circuits occur. As the components are foil -soldered side, is etched CAPACITORS:C2-150CIA,Q3-40244Q2-TA7151 B, pfd C-6-19.5 NFOtuning pfd capacitor ganged (TRW #57-3A) tappedinductanceperlinkturns3/8" wire, approximatelywinding from = 0.86ground length, uh, end, Q1 turn=.120, antenna from approximately nominal 1 1/4 formersolderingyou will cans findto and the anIf groundcoil youwantextra shields foil. to windcan be the grounded, coils, tie an simply end of bythe wire to a con- bonus in the ease with which trans- C3,C9-270C8-5000C6,C4, 7, 14-155,16-2-14 15, pfd pfd pfd17-2000 pfd NFO pfd L2 barenominal9/32"ground copper ID, end. inductance 3/8" wire, winding = length,(RF Interstage Coil)-#18 0.864 turns,uh, farvenientcoil,stretching ends tie doorknobto two your will lengths coiltakeout and form. of then any wire Wind pullkinks to thethem or doorknob,wirebends. tight taut. and close, walk- To wind a spaced and attach the This slight RESISTORS: C11,C10-3C13-3. 12-1000 pfd 3 NFO pfd pfd L3 (OscillatorID,copper1Q 1/2= Coil)-#18 5/16"120, turns wire, tapped windinglength, from 3 bare1/4 approximatelylow turns, end. 9/32"nom- nessandWhening towardyou of the willthe coil the wire.be isleftdoorknob completed, with a tightlyas you simply -formed go unwind coil spaced the second the thick- coil Coat the completed coil with polystyrene to keep the wires tight. R6-100R4R3R2-220R1, -180K-12K 5-100K ohms TRANSFORMER:IA -1 uh RF turninalchoke= inductance120,from tappedlow end. = approximately 0.062 uh, 1 Q soldercoil30 dope, the tapsand intowhen place. it has dried, scrape the dope away to R8R7 -56K -22K T1 (Input transformeriifier)-TRW to IF amp- #21124-R2 31 FET FM Front End FETsmon-sourcetypical provide one. RFThe some stage systemdescribed interestingusing germanium applications, is a frontFET. end with a corn- Add anand FM this IF is a formance,problemsAddstripOf anasparticular wellamplifier, encountered and as a AGCTheinterest detector, and FM characteristics.you in arefront manyandhave power you'veend an RF FMis gain, amplifiers representativegot radio. asignal-to-noise dandy and FM mixers.of tuner. many per- of the design Also important are effecttransistoriousconversion response gain, rejection. in large this -signalcircuit, Consider handlingwith the the performance unitcapabilities, tuned of to theand field spur- - 75 98 MHz: 2.7 ImageSpuriousSensitivityTuner rejection 6 responsedb for bandwidth 30 db rejection S + N/N at ± (119.4 MHz) (103.35 MHz) kHz deviation 28.8 425 7457 usualSince tothe turn junction the device FET isoff operated toOscillator gainTuner inAGC thepower injection depletionaction. gain EMF (less mode, 16 it db is loss/IF secondary) This can be 490 possiblebiggestAGCadmittance.Considercalled voltage but"reverse advantages that is oftenOnce gaindo AGC." not better reductionthe of continue reversedevice However,in many is iscausedAGCto respectscut reduce forward isoff, only that thanthefurther by littleAGC gain. reversereducing AGCincreases isOne not AGC. powertransof only the in - enceisnotis 32needed. veryaffected little since change the asantenna AGC varies.and RF tank circuits experi- Another advantage is that the overall selectivity 33 lessoperation. positive so Forwardas to drive AGC the isFET accomplished into by making Since the gate -source diode becomes enhancement -mode the AGC voltage forward - circuit.biased,causingtheresistor. source Thea lowthe -biasinggate drain impedance current gate resistor and is is limited presentand the to a Also, as the drain increases, drain source voltages to decrease, drain resistor increases,across the antenna tank safe valuethe by IR a 20Kdrop across IC FM Tuner providingselectivityAGC,thesponse AGCwith additional rejection. respectcausesis delayed AGC ato degradation reverse untilaction. fairly AGC, strong signals This is not very significant, however, if The disadvantageof of image forward and spuriousis that re- the reduced tuner are being re- Integrated circuits are used here to efficiently miniaturize an hasorceived. monreverse been -source Only used AGC. asslight devices. the Even AGCdetuning though example, is observed the common -gate configuration the same applies for com- with either forward adjustedforisFM converter.used a front-end. power and for the gain anFor Theinsertionbase ofbest CA3028A15 of noise db. the loss constant performance of is 2 used db -current to as keep anthe RF sourcethedifferential amplifier noise is biasedfigure modeand The RF amplifier input circuit is TRANSISTORS:PARTS LISTQ3Ql, -2N38262-FED TIXM12 COILS: L1-3 turns,length, tapped at 0.7 turns #18 bus, 5/16" and noiselow.withrectly Because figure a noiseto the for thefigure integrated Thoughthe input front of abouttransformer'sa singleend circuit 6alone db-tuned noisefor is insertioncommercial circuit7.5 figure db, is as lossofshown compared tuners.5.5 adds db,between di- the the collector CAPACITORS: C7-33C4,C2,C1-6-21 5,3, pfd pfd 6,10, 11-10 pfd 9, 13, 14-.001 mfd L2-2.5 turns,formlength,(Arnold1.51.0 withturns, turns A1 powdered wound -13J). wound on ironon 1/4" 1/4" core paper paper tapped at 0.3 turns #18 bus, 1/4" and forthetunedof converter.the the same circuitRF amplifier 3 dbis preferredbandwidth and the to asbase reduce the of single the spurious converter, -tuned circuit, a double in- - If the double -tuned circuit is critically coupled response from RESISTORS: R2R1-120C12-4.7C8-.01R3-5. -20K mfd ohms 6Kpfd L3-2.5 turns,(Arnoldformwoundlength, with A 1-13J)on powdered 1/4" . paper iron form core with tapped #18 bus,at 0.3 turns, 1/2" follows:verterstagesertion stage coil loss at at willapproximately1500The 150 remaincollector ohms. the RF of same. voltagethe ohms RF stage andgain the isis tappedbasecomputed of down the con-as on the inter - R6R5-2.R4 -10K-1K 7K L4-RF choke13J).powdered iron core (Arnold Al - If an IF converterBaseAntenna transformer to collector to base having an impedance of 10,000 22 db 0 db Ohms is employed,VGc _ the calculated -Yt YL = 112 = 41.3 dbvoltage gain is as follows: 34 Yo 35 r T2 CV1 CV2 CV3 RFC1STRIPTO IF I - OHM L2 Varactor FM Tuner 1 . C11 -.3- 1(k / C9 /C5 C6 R5 R ceptionceptanceElectronic of in FM tuning industrial automatic with and varactor frequency military diodes controls, electronics. has high gained Withcost wide has the kept ex- ac- Vcc = +9V 0 Thethe varactorprinciple out of usingof the diodes consumer to replace or entertainment the main market. tuning gang -Odb +22db - 13d +50db +41db RCA low-costtheis now TIV300-303 madevaractor possible series.diodes byRemote by the Texas recent tuning Instruments, introduction using an extended designated of uniform, cable ICs:PARTS LISTGl, 2-CA3028A COILS: L1-3 3/4 turns,per #18 wire; tinned winding cop- length Courtesy: 5/16" on vibrationquiredis easily to isaccomplished vary eliminated Frequencythe capacitance bysince theshifting only substitution of a thecaused variable reverse by of DC movement -biased diodes. and capacitor plate stable,voltage solid- is re- CAPACITORS:C3,C2-470Cl, 7-104, 5, pfd 6,pfd 9,mfd 10, 11, 16-.001 L2-3 3/4 turns,9/32"perprimary #18 wire; form; tinnedform; -2winding turnstapped coptapped #30length- at at1SE 3/4turns; 6 2 1/4 5/16" on tremelycapacitorbystate vibration diodes fine also andtuning, andresults shock. apotentiometer toin a savingdegree of neverwhich size beforeandis relatively weight. possible, unaffectedAnd canex- Removing the bulky parallel -plate C15-1C13,C12-82C8-15 14-27 pfd pfd pfd L3-3 1/2 turns,9/32"perturns, wire;#18 form.A tinnedwinding3/4 turns. cop- length 15 pfd 5/16" on to coilsthebeimprove attaineddiodes can RFbe simply mountedstability. by where using theya multi are -turnisolated from each other may be located in any convenient place, the tuned Using the new layouts available, new potentiometer. As RESISTORS: R4-100R3-1.R2,R1, 8-2K6-1K 2K ohms TRANSFORMERS:RFC1,Cv1_3-variableCv1_2-variableT1-Mixer 2-1 uh choke A 4 C C szl 15 pfd transformer TRW biasedcapacitanceand differentcontrol areVaractor cabinetconcerned, designs diodes are given arecharacteristics, as a function as of far reverse as the - PN voltage by: possible. junction MeasuredR5-47R9-50R7-150 gain ohms ohmsinto ohms the converter collector is 42 db. T2-Input #22485#22484 or equiv. transformer TRW The Where k is a constant determined by the semiconductor ma- C t - (Vr + Or k ameasured 10,00036 ohm voltage load gain is 52 of db. the RF amplifier and converter Calculated gain is 50 db. into tor.terial, Vr junction is the reverse -biasedarea, and control impurity voltage; levels 0 inis the diodesemiconduc- 37 'R 08.4 0-111 courtesy= Texas Instrument; 4j r- II (NI 0 U4,O AFCDETECTORFROM VOLTAGE FM o, so, lc( Ill ,re-cre,r'eni_ ---1( 11 Oscillator Modification for AFC TRANSISTORS:PARTS LISTQ2Q1, -2N4255 3-2N4254 R5,R4, 12-2.7K 10, 14-330 ohms CAPACITORS:DIODES: Cl,D1, 6-ARCO 403pfd or equiv., 3.35 2, 3-TIV301 R15R9,R8-270R7-820R6, 17-10K-100K11-9.1K ohms pot linear Cr C3-3.C2, 3pfd4, mfd 5, 8, 12, 15, 18-0.001 R18,R16 (Thermistor2.7K T1 - TM 1/4)- 19, 20-330K II C10,C7-12C14-10C13-2.2C9-240 11-0.01 pfd pfd pfd Duramfd Mica COILS: L2-5L1-5 turns, #185/16"9/16" bus, length, turns ratio 6.7:13.3:1 #18 bus, 1/4" ID, Cs1 RESISTORS: C17-ARCOC16-1.2 pfd pfd400 or equiv., 0.9-7 RFC1-ferriteL4-4L3-1 turns,cl bead,1/2" length RF choke #18 bus, 1/4" ID, 38 R2,R1-4. 3, 7K 13-1K TRANSFORMER:T1-TRW #21157-R1 or equiv. 39 contact (or internal) potential, which is typically 0.7 volts for n factorsiliconcurve. diodessince The itexponentat controls 25° C; n has a value of 0.50and for the an exponentthe shape of the capacitance -voltage is called the slope ideal abrupt - comparedjunctionareent validof diodefrequency. to in wavelength, designing andAtfrequencies where the 0.33 for a guardedCapacitance -junction values100 -MHz circuits. The figurethe total capacitancesize of C the t is diode independ- package is small, measured at one kHz diode. of merit (Q) isWhere defined rs byis the equivalent the equation: Q = 2 a f Ctrsseries resistor at the frequency1 AMPLIFIER CIRCUITS of highwhatasmeasurement. shown end. better on AFCtheIf youdesire action at better AFC, modification diagram. This provides the lowoscillator end of tank the bandmay thanbe alteredsome-at the Telephone Pickup/Amplifier Thisvolumeups,Ll, the isand input, acontrol straightforwardit is is R1one and of thecoupling 3 many-transistor capacitor amplifier connected to the base of transistor Q1 through ferrite core telephone pick- Cl. Two additional circuit. Coil phoneuseForcollectortostages it example,amplification, as of a audio means base. you are of This can provided, buttracing mountcircuit'sit can down be the primary inductively coil on application a plastic generated Or substitute a jack for the coil and both capacitively coupled from used in a number of ways. wand and is tele- noise pectbothin mouthpieceanyautomobile sides audio of input a engines.or telephoneUnits transmitter.can be such used. conversation. as this have However, been used successfullyit to amplify your own voice going into The author has a device of this the telephone to amplifydon't ex- 40 sort on his office desk, and while it is fine for letting a group 41 listen to what is being said, the person doing the talking has partytionto rel"speaker,speak amplifier/pickup/speaker, atecho up,the and that andother the Therealis slightenddisturbing. allclose can-in delay to -one usually the creates unit,phone,has hearonewhere a in"bottom bad himselforder the feature. phone to-of over -the sits the-bar- on the combina- Also, be very, very careful. be heard. The Amplifier/ Oscillator languageamplifyingMake sure that thatthe will conversation-theyyou make tell people you jump at themight in other just end come that out you with are embarassment. thefier-thataThis collectorsignal circuit is,is ofapplied is Q2 a simple,to tothe the base straightforward base of Ql.of transistor two Ql. -stage The ampli-output if you eliminate the circuitry connected from In the amplifier mode, Lacc T1fromof to Q2, thethe andfirstloudspeaker. fromstage Q2's collector collector is directly through coupled output to transformer the base As you know, when you couple the Cs, thefronthenceintroducedoutput input of the a of throughear-splittingPA an inloudspeaker amplifier this capacitor unit howl backby system. coupling whenCl. to itsThe a input,Feedback microphone thekey output feedbackserves is signaldeliberately isonly placedwill toback occur, re- in to withfirstaHowever,move humidity thoughta heat the coupling,sensor,if that detectortheThis keywill the and(whichcircuit occurinstead, unit therefore thenishas theandin numerous becomesa actuating theyoucode feedback. have practice a device)applications. firea rain alarm. oscillator. isalarm replaced Use Obviously,that the TRANSISTORS:PARTS LISTQ3-2N255AQl, 2-2N46 BATTERY:R5R3-6.R2, -56K 4-1 2K meg ponentsofwill Q2. tell (key you and when Tocapacitor) useto close this from circuitthe windows.the asbase an ofamplifier, Q1 to the simply collector remove the com- RESISTORS:CAPACITORS:R1C3-100C1, -5K 2-. pot1mfd mfd TRANSFORMER:COIL: T1-MatchB1L1-see -9v Q3text output to speaker hastencrystallevelWithout source, toor them, point ceramic suchthe out unit asphonothat, functionsa crystal while cartridge, anasor anamplifierceramic amplifier or a tuner. microphone, such for Weanyas this musthigh- isa These parts of the circuit provide a feedback loop. friend,quality.itmore adoes two than notinghave We-transistor adequate make limitations. the thissimplicity foramplifier, point the A purposes only two of the because-transistor circuit,to which an immediatelyoveramplifier it was -enthusiastic designed, is stillpro- so do not expect high fidelity 42 amplifier.ceeded tobuild a pair of them and wire them as a hi-fi stereo If you connect a ceramic or crystal cartridge to 43 the inputs and a pair of speakers to the outputs, sure you're z Z Z 0, goinga code to hearpractice stereo. oscillator, Stereo? Yes! High fidelity? the forced feedback works realone. No! As 4.-.r-> .-i0sO2 02 CO 02 02CO well, for the tone is a pleasant PARTS LIST RESISTORS: cs, 0 0 0 Q CAPACITOR:TRANSISTORS:Q1Q2 -2N104 -2N408 TRANSFORMER:BATTERY:R2R1-500 -10KB1 ohms-6v pot a aktujoja! 0 C1-.01 mfd T1-output to match Q2 to speakerKEY 0 O -4 0ct w TY11 cc Q1 Q2 R1 5 T1 SPEAKER J1 (e) R2 CO CO Curtesy: Radio Shack ---AA/Nisi T > T -I cn> -4 o cq1-1 m>> CO U) g gC4 50 -Watt PA Amplifier ) 4. 1:5 ]in .20 CnNI ,,,,, 7 . 1 ..,ate 0 ,,, , I .v'... <.0 I 7 4Ln, g `,T 7r4 f, 0,1 This unit makes an ideal bull -horn for use in a boat or an air- E-, _ en rr 0 -4. T0 7. 7z t. 0 00 0° ra, 7-4 ci7 cn 7'.° 7 ri. !AEA o co -4 cq cn 7, 7 7 7 i 7 q:, c- co C) -I - °° . i a; c, -.4 plane. Power output is in the order of 50 watts, more than Or a(Y(YCY,A.g .. A

6 -Transistor Stereo Amplifier R7 R1 R3 ACIDC117 V Capable of 2 watts output per channel, this 6 -transistor stereo with 0 C7urt.r.ry: RCA amplifiercontrols.linematicany crystalahead doesn't circuit of or R25 showmagnetic operates and it, attached cartridge directly to input.either from thethe loudnesspower line or tone Since each amplifier circuit requires a separate a switch can be inserted in the power Although the sche- PARTSTRANSISTORS: LISTQI, 5-40359 C10-0.047C11, 14-100 mfd, mfd,15v400v ceramic (dual electrolyticdisc, capacitor electrolytic, numberloudness of and operating toneTwo control, controls. additional they may resistors be ganged in the tohot reduce side ofthe R4 and R5 will D2D,CAPACITORS: E4: QID1-40265Q3, 6-404240 4-40399 RESISTORS: R1-82C12, 13-0. ohms, 005may mfd, be ceramic used) disc 5% helperror.by keepyoungsters. volume down, in case the amplifier is being used While not exactly in the hi fi category, this circuit Values can best be determined by trial and C3,C2,C1-100 4-0.00225-0.01 mfd, mfd, mfd,electrolytic, ceramic ceramic discI5v disc mfd, electrolytic, 3v R3R2 -68K-1K, (This pacitor)placedresistor by may 0.047-mfd, be re- 5% 400v ca- providesapplications54 quite . acceptable quality for many low-cost phono C8,C6,12 007v-59-0.1 mfd, ceramic disc, R4, 5-5 meg pot,meg, tapped linear taperat 1.5 55 R6, 7, R12,R8, 9-47K 13, 10, 11-8.2K TRANSFORMERS:R26-200R25-6.8 ohms, ohms, 4w 2w Fp./AM R2R1 ti R17 -15V R41 R15,R14 -6.8K, 16-50K 2w pot, audio taper 18, 19-1K Ti, 2 -audio outputprimary transformer; impedance, 2.5K; sec- RHONO C C3 R11 R27 R29 R33 C27 3.2 C20 CONTROL R39 R17,R22,R21, 20-18K 23-1124-82 ohms,ohms ± 5% orondary Freedequiv. impedance, #R6A-8, Triad #S - 12X, ohms; R3 R9 R12 C9II C11_)1, R21 C C21 L11:L-4 R34 OUTPUT si 1C4 R7 R13 C14 C17 R25 LOUDNESS 830 CONTREBLE TRO R35 Q3 R19R20 2 LOUDNESSCONTROL I, R14 CONTROL R36 Preamp and Control Circuit S2 C5 Q R24 TC15_ R26 C22 R31 CONTROLTREBLE This preamplifier and tone control circuit works with any R4 R10 R15 C10 If _ I.C12 C16 C23 '1C26 OUTPUT mountedstereo amplifier. on the same chassis (or board). But why a preamp? Each function can be wired separately or PHONO FM R6R5 C2_ C6 C8I* R16 R18 R28ONTROLBASS R32 R38 C28R40 R42 taloutput.quiringMost or ceramic basic aboutYou amplifiers can cartridge.three get to this five are sort voltsdesigned of drivedrive for in from orderhigh-level a tunerto deliver orinput, a ratedcrys- re- But, if you want to apply a low- AM PARTS LIST PREAMPLIFIER C24 -15V plifier'sneticfirst.level Suchsignalcartridges functions low-level to a orbasic is from tosignals amplifier, provide tape are heads. the theyou've convenience type got you to get preamplify offrom multiple mag- it Another of the pream- CAPACITORS:TRANSISTORS:Q3,Q1, 4-402632-40395 R3,R2, 4-120K 5-56K tone,unplugginginput connections input leadso you wires. needn't be constantly plugging and level, and balance controls needed for high fidelity A preamplifier also provides C7,C4,C3,Cl, 2-56006-6800 pfd 8,5, 25,19, 26-2 24-0.047 mfd, 12v mfd R12,R13,R9,R7, 15-100K 8-114, meg-220K 10, 11, 17, 16, 18, 35, 34, 37,36, 39,41, 42 40 authortoYouamplification. improve can, frequently with the alittle Thisversatility likes thought, four to tape-transistor of modify recordthe unit. thecircuit directly circuit performs off in somethe air.all ways of these functions. For example, the If C20,C14,C13,C11,C9, 15,23-10 10-3300 12-10 mfd, mfd, pfd 6v 15v 16, 17,21, 18-0.2222-0.01 mfd R25,R21,R19, 20,26-150K24-3.3Kped at 5 andpot,-10K 10K 22, 23-1.5K linear; tap - fier!andbeayou connected youadd cananother record to jacka tape anything. to01 recordereach beingchannel, input played and (use throughconnect the LINE theit through -mfd ampli-input) capacitorS1 and to S2 each can outputbe a 2 -deckterminal, 3 -position the new switch, jack can with one RESISTORS:RI,C27, 6-47K 28-0.15 mfd R30,R29,R27, 31-25K 28,32-50K pot pot, 33, 38--5. 6K linear deck for56 each channel. It isn't very likely that you will 57 .g. want one channel playing one source, the other playing a dif- And by combining the switches in this man.. c.,Y 2,C1,2 Y. ferent source. 1 1 1 -m-, 1 withner, youa cleaner will simplify control panel. the switching function and come up Finally, you can add more po- 00AI.- 0 -I = W WI-CC0 VOWt.. positionhi-fi/stereositionscomponentsand jackfor to system,thisa markedtape youswitch. input. add might "extra" a Youtape add canor inputin "auxiliary"the also jack future. add and a switchanotherfor any position switchadditional If you like to play tapes through your ====NNNN

I X e 0, 7777moXX 0 to High Fidelity Preamp L'Ll - QMx gOJ Here's an excellent preamplifier and control center for use 0 0 > ,..,_!- CD % Q) withamplifierthis any a flexible amplifier is monophonic, addition circuit. to A anywide stereo assortment system. of Sinceinputs this makes a pair is needed for stereo, of pre- > 0 > - N > 6 >0 > 00/-100>"d 0 e0 .g v0 .boE course. The unit requires a supply voltage of -22 volts, and k 4ii ,tc.c% 1-S,i6I tti, t'..7,4 201110 t`. CO al ,-I input.its output connects to any power amplifier with a 3300 -ohm titeitta711 'EE, 4;975.14-17.1) ?) .11!..2 cu C4ZP4== RCA -type phono plugs are recommended at the input - E w -Si Ifterminals. you go the The stereo outer mode, shields you should can obtain be grounded dual -input to the jacks chassis. (one Eg oa6i -Pc"csio m '! LIE., ":1! '"' Ts E w Z -5 t 4 ) for each channel)Three on a singlepotentiometers, phenolic insulator. R1, R3, and R4, are marked "level." mE-,cn NO 2-4;2_,.`g"d14m 1 n912:212 4 'oc1466,-,0; 0 (DoX 0 a Cl.°1) Further along in the schematic, you will find R17, marked mounted a¢ . rNM(.14UTM11111 .g7716ao.o -1111W7177 0.sououou ouououou waaamaNMr000C-COM,662&12 .... OrniNc1.0 a on"volume." the58 rear apron R1, R3, of theand chassis,R4 level and potentiometers in our experience are the NI! 59 whichbest controls have a short,for this fluted application shaft. Each are control the finger is set -adjust to achieve type whenvolumecloser changing balance control sources betweenR17. without the several constantly inputs tobe prevent fiddling blasting with -15V

Stereo Amplifier: 3 Watts per Channel Courtesy: -15V RCA POWER AMPLIFIER 60 Hz directlytionsaThis 15 -voltis indicated from 5 -stage, line a stereo -operated by3 -watt arrow tuner -perpower heads.or -channel from supply a tape stereo with deck amplifier unit which incorporates connec- has a This circuit may be driven PARTSTRANSISTORS: LISTQ4,Q3,Q1, 2-2N26146-402535-40457 RESISTORS:R5,R2,R7,R6,RI, 10-2.2K3-8.2K 4-56K9,8-27 ohms 11, 14-220 ohms first.cartridge,low-levelplayback preamplifiersource,you will have built to go in. through a preamplifier stage such as a tape head or a magnetic phono To operate the unit from a CAPACITORS:DIODES: D3,DI,Q7, 2-1N37544-402668-40398 TRANSFORMER:R23-330R19,R12,R15, 13-3.3K20, ohms 21, 22-1 ohm, lw 16, 17, 18-180 ohms cantransistors.for anbe input paralleled, impedanceThe although loudspeakers matching a single the are -to impedance direct -double -coupled, -endedof the andoutput driver should be selected For monophonic work the two input terminals C9,C7,C4,C3,Cl, 2-108-0.0566-10010-505-500 mfd, mfd, mfd 15v 15v6v3v T 1-power transformer;#EX4744Better22vcenter at -tapped;Coil 95P, full ma, and -wave DC 20vTransformer output at 285 voltage ma; Co. C -P Electronics atedapplications,threetowardstage at watts full muchshould output.of anddrivemore be infact,Whileused. isin more the nothe thanhum unit adequateproblems will rarely forshould ifmost ever be consumer be oper- While many audiophiles tend wayto lean of power, you will find that encoun- C14-2000C13-500C11, 12-500 mfd, mfd, 15v mfd,25v 25v MISCELLANEOUSFl-fuse, 0.5#8970, amp, orsloblo equiv. wheretered60 with in this this book unit, would the full provide -wave rectifiera smoother design shown else- power source. 61 25 -Watt PA Amplifier achannels.fierat suitableThis25 circuit watts complementary Here ispreamplifieraudio doubled, again, power, usingsymmetrysince isand required. thethis for single audiostereois a basic poweramplifier operation power supply circuit theamplifier, for ampli- is both rated The balanced bridge equipmentleftputnoisepower isturned -freeobtained supply on,reproduction.continues alsoOnwith across many helpsthe to droppinglevel sit occasions eliminateIn there thisdown resistor amplifierand so ripple,electronic ascook, toR15. aresultingbe anddual inaudible. equipment the voltage problem,in better, out-is inadvertently The droppingthatlamparoundnonthelesswhile the across not this, lamp resistoras not thesevere is exactly primaryplainly in inseries thebenefical visible.of case withT1, and ofthe to solid-state mountthelamp-about unit it itself. in circuitry, such 220K, a way 1/2 it seems expedient to add a simple neon pilot Make sure that you use a To get is NEavailablewattand -2H should an bulb. attractivewith do a thedropping red job. jewel resistor that provides built into ample the lamp light holder with an There also are neon pilot lamps Courtesy: RCA canapplicationsvided be there used iswouldin suitableanThis electronic include amplifier drive highfidelity, organ,from can bea as preamplifier.used a of playback course,in a number butamplifier it of also applications, pro- Typical TRANSISTORS:PARTS LISTQl, 2-40398 C4-1000C3-250C2-500 pfdmfd, pfd 50v themusicalforsufficient switcha tape instrument deck,and protection the transformer, amplifier. in this unit: Threeshould The fusesbe primary a chassis offer fuse, more -mounted between than and the 25 watts is sufficient for use as a DIODES: Q5Q4-40466Q3-40544D2,D1 -2N2147 -1N3754 3, 4, 5-40266 RESISTORS: R1-2.C8-1000C7-3500C6-1000C 5-250 2K mfd, mfd, 15v 25v50v istype, constructed accessible62 on from etched the -circuit back of boards, the chassis. the other two fuses If the circuit CAPACITORS:C1-5 mfd, 15v 1R2 -t3 -12K -100K C or t . 63 R6R5-68R4-390 -1.2K, ohms ohms lw TRANSFORMER:R15-mono:R14-560 ohms 680330 ohms, ohms, 1w; 2w stereo: vCC (6V) R10-100R9-82R8R7-33 -75K ohmsohms, ohms, 2w 2w MISCELLANEOUS:T1-transformer:Type CP X-10307 Electronics or equiv. +5V VIN can be mounted far more conveniently R13-130R11,right 12-0.39 on ohms the ohms,board, lw F3-fuse,Fl, 2-fuse, 5 amp 2 amp, sloblo type O VOLTAGESQUELCH malboardtorsorYou forresistance withQ4can more and eithera small convenienceQ5 ofuse should nut1.5°C fuses and be withper bolt.attach mounted watt pigtail clip or onleads-type less. heat forfuse sinks board holders with a to ther- the The two output transis- Temperature - mounting, themumcompensating heat forwardsink with -voltage diodeQ4. Dl of is0. selected8 volt and on should the basis be mounted of a maxi- on VEE (-6V) Courtesy: RCA TRANSISTORS:IC:PARTS LISTQ1,Gl-CA3007 2-2N2102 TRANSFORMER:RESISTORS: T1-StancorR4-16R2,R1 -6K 3-18 ohmsto 12Kohms TA -10 IC Audio Driver 545-Milliwatt IC Amplifier corporatedis TerminalIfa 300you needmw in 2 deviceanultra-compactearliershould stages,usingbe grounded, an it mustlowintegrated -power orbe ifconnected a circuitsquelchaudio amplifier, asto circuit +5a driver. volts. is here in- detailfierforthanInput full regardingadequate voltage as anrequirement a additional forand thisimportant circuitoperating application is 45directly millivolts forfrom the cartridge. Beforepower we gooutput. into tape playback amplifier or a phono ampli- This is a high fidelity circuit, more 2N2102RCABoth CA300764 driver transistors. integratedand amplifier circuit, are shown here. The driver, an is used to feed a pair of experiement.this amplifier, let's consider a small but very enlightening 65 it so the loudspeakerTake faces an ordinaryupward (if radio it's receiver from its cabinet and p1 p1 so let's say radios and you'd like a better sound quality. that you bought one of today's small FM tran- Build this tinnysocalit on youandshock). a non-conductivetotallyget clear lacking reception. in surfacedepth. Youwill to avoid notice the that the Now turn the unit on and tune to a local Without changing the an AC/DC type danger of elect sound is stati controltectorerintegratedsistor in output.a You caninput usually terminal.good pick cabinet, up the audiocircuit at the amplifier, volume use a good-sized 3.2 -ohm speak- and connect the input to the ratio de- verticallyameterformingor the equal volumea columnover to thesetting, the at speaker leastloudspeaker roll two upcone, feet a tube size.inalmost lengthof heavy in and contact an inside Hold the paper wrapping with it.staticpaper, tube di. Suddenly,You"big will speaker" be startled performance. to hear the difference in sound there are rich bass sounds, +9V and you're quality,getting DETECTORRADIO RI Ti IC Transformerless Amplifier OUTPUT CI SP sufficientformeraThis receiver. circuit is needed.for A is comfortable45 ideal my Outputpower for drive converting listening. is required, is 310 an AM milliwatts,and orno FM output tunermore trans- intothan C2 C curtesy : RCA variousthat vast electronic groupIf anybodyof publications. people greeted who make integrated money circuitsby writing with for delight, the Here was a brand new de- it was CAPACITORS:IC:PARTS LISTGI-CA3020 RESISTORS: R3R2-0.6R 1-510K -5K potohms triode,gotviceas to tothe go anjump transistor back old on, radio a bit.a "component"did! tube To with understand a chunky that would howblack changethis base worked, from things which you've just The story really begins with the type 73 thiselectrical quite well,energyWhy? and into did A audio so loudspeaker when it operated is a transducer designed to convert C4-.01Cl, mfd 2, 3-1 mfd energy or soundTRANSFORMER: waves.TI-Argonne 174 or equiv. exposed and with- It does aonly"plastic."the semi connecting two -flexible "plastic" WeSo calledpins youone materials-a usedemerged.called it bakelite. the "beetleware." 73 rigidtriode one to designcalled andbakelite build and a one -tube re- Today, we'd call that base a In those days there were soundabaffles,coupleout small thepaper in the radioand favor generated largertube. we of compactness, oftenBut speaker sound a haveloudspeaker conesinto to and thesacrifice work ifadjoining must a transistortoward thedo qualityair. that has end. of the more. Cabinets, anIt out-, must In bigfacturerssoldvariableceiver, black thethe came bases),based storyticklerarticle out all on coil.to overwith aa regenerativeYouradio again.miniature wrote magazine. an 7 Hartleyarticle-pin When all on -glassoscillator howthe tubetubesto do withmanu- it(no and a you redesigned your little one -tuber and By this time things had some- cost,puta smallimpedance size,66 loudspeaker and weightof 130 with ohmsof a amatching a130 smart -ohm designer transformer. impedance is going and to use save the waswhat still improved, a bit of confusion and in the resistor field, however. The you could even get prewound coils . There 67 IC:PARTS LISTG 1-CA3020 +9V C OU1' teSy.' SP RESISTORS:CAPACITORS:C3-.01C2-.Cl, 4-1 I mfd mfd mfd old "body -endR2R 1-510K -dot"-5K pot colors were giving way to today's banded ORRCA 130-OHMEQUIV. -111113 SPEAKER gettypes. it into operationGotAlongAndNow an asguess cameAMwe a receiver.have orwhat.the FM integratedtransistor. tuner? Quite Herefrankly,circuits. is a you'll quick find and easy way to plifiertransistorsoundamplifieringthis andamplifier circuits, starts you radioinput knowblaring atoo. handyhasacross the a out defectivedevice batterythe the receiver amplifier'sfor is amplifier. testinggood, volume simply transistorloudspeaker, control. connect radio your am-the If your receiver suddenly stops work- If the

60 -Watt PA Amplifier 0Cq ,-I y CO 0> 142 0 '3)cS,' 0 0 ,T ° ° CIV -ico."' FDE'O . c, C0 . , oz E ,-. c, ...c, pGqcn rn " CO I I -.4 , 1 I 41 ,..; ''''' (lcHL) 0 0 ,-. I I RatedThe outputspecifications is 60 watts of music this amplifier power to speakan 8 -ohm for themselves:load. Sen- < ,-I 0.00V< ' 0.? Of I--1 Acs .- C4 a) c.)'''0 0,1 c.)Cq thansitivity 0.15%68 is intermodulation1.0 volt rms into distortion 10K for at full full rated rated output. output. Less At a 69 1 kHz, at full power, less than 0.1% THD. Bandwidth is -3d topermitsprovide atbelow 10 Hz fulla 10 directand -ratedHz. 100 The-coupledAt outputkHz. the circuit same at output all design time, frequencies to low theapproach -frequencyspeaker in the uses load.audio a split power supply to response range This biasedspeaker.can be throughlimitedInput aas base desired, circuit -to -ground Q1 and resistor.Q2 form a differential amplifier. Q1 is and DC can be kept out of the Q2, biased by a 0 emitterthanandgroundsimilar 10 Q2 drivermy becauseare are supplied stage. realized of the as bi-symmetryaat dual the output.unit and of typicalthe local offsets circuit. of less resistor, causes the output to be at equivalentSince the output is an emitter -follow- Q3 is a common - Q1 e® terer,mfdcircuitlosses -follower. capacitor andis a outputfull directly complimentary transistor across transconductance. the symmetry bases of Q6 Darlington andQ3 Q7. must emit- swing the full load voltage, If parasitic oscillations occur, plus saturation add a The output . 001- The glamour queen these days is the integrated circuit mod- IC Phono Amplifier becausefrommonoandule, behold!a a littlephonograph. supplythat's device whatwhich whichit Inuses is. this a islowcircuit, simply -voltage power wired tap for oninto the place, ICphono is anddrawn motor lo It performs like a multitude of devices, simply A typical IC application is this inthewinding. such ICentire or consumer you IC mightcircuitLinear product damage right integrated in areasit. the as tonecircuits TV arm! receivers, have established high fidelity a firm foothold Check your 9 -volt power supply before hooking The cute idea here is to mount up n.alg I productsFM70 receivers, canbe traced to many factors, not the least of which and phonographs. IC advances in consumer 71 PASTS LIST C14, 18-100 mfd, 30v ponentfactTheis economics.that IC until manufacturersmay it beis at more least expensive asare inexpensive loathe than to introduce a as transistor the one a newitthat replaces doescorn t The reason for this rests primarily on th TRANSISTORS:Q1,Q4,Q3, 6-2N3'7085--2N37042-T1S58 RESISTORS: R1,C20-1000C19-500 7, 8-3.5 mfd, mfd, meg 50v 50v pot ofequivalent the IC, job, but consider the cost fairly. not just against the transistor, but againstCheck t the co DC109I; Dl,Q7, 2-1N2069 ES: 8-TIS90M R5,R4,R3,R2, 11-220K10-412-22K9-180K meg pot findengineertransistor that there who and are selects Therelated several point and components types issearches that to whendo until a that given you he are findswork job. replaced. one with to ICs,do the you will often The hasty CAPACITORS:OO15ccc 321:6. 8-560 pfd T011Sm9f1Md mfd R14,R13-2.5R6-2.5 25-100 meg meg pot ohmsfrom tapped bottom at 1.4 meg hethejob finds familiarand then one 8 stopsto -ball. do isthe effectively job, but will putting look himself for all of well those behind that The careful engineer will not stop when C12,C11,C5,C4, 10-.00569-220 16-5015-5 pfdmid, mfd, pfd 30v 30v R19,R18,R17,R15, 28-30032-24K33-1.3K16, 26, ohms27-2K Cont. designeditcan best. do aroundhisThis task, circuit, those and ICsthenlike that theselect doothers the jobonein thisbest. of thosebook, that can do has been C13, 17-20 mfd, 20v BASS C1 TREBLE R20, 34-10 ohms LOUDNESS RI t I C2 R4 .-X R3 -t 1 R5 R2* I C3 eiN I 2 -Watt Stereo Amplifier I -05 thebeforehigherThis controls. is -priced thean inputeconomical commercial stages, rig,ganged units. but itpotentiometers has all of the arefeatures used forof They are not ganged in the sense that a single Notice that in the section -C=3 CR2 CR1 BALANCE. I ±-4 R7 thebeCertainly,shaftsults used, printed controls in of a thiscourse.cleanercircuit both isThe more board.units;panel output a appearance,instead,matter transistors of coaxial taste, areseparate heat-sinked shaftingand whilecontrols is used.toit re-themay copper foil of To assure good heat sinking, a layercircuitapplied. of silicone boards The diagram greaseare used also designed for indicates the for separate thatthis twopurpose amplifier separate should printed stages. be - R8 c C6 _L R11 R13 bematterThis sure is point-to-point to72also heat a sinkmatter the wiring of output taste, would transistors. not notan essential.be out of order-just For that R9 R10CST C1OTR12 R29-1.R23,R22,R21,R37-220 24,31-36030-200 2K ohms ohms 35, 36-3.9 ohms MISCELLANEOUS:TRANSFORMER:T1-SuitableCR1, 2-SonotoneCT power secondary transformer,24T cartridge f R27 5o 30v Complimentary -Transistor Amplifier f R26 C16,1, R32 f R25 wattfidelityHere'sa one and an -watt characteristics.1 economical kHz reference is 0. 8%. monophonic isFrequency 3 responseamplifier Totaldb harmonic down at 40 distortion Hz to 18 atkHz. one Sen- at 1 kHz withagainst some high L______..-I PC PC BOARD #1 tosupplysitivity Thetwo -wattcomplimentary currentfor oneaudioThe iswatt amplifier13 circuit outputma. output configuration needs is circuit of the provides used here 680 my. The total zero -signal fulfills many ofentertainment the one - industry. considerable cir- R21 endedcuit simplicity. driving isNo required. transformers are needed, The TS9OM and TS91M compli- especially suitable for low- and only single - R 16 f 7---7C13 leadSilectcost,mentarycopper on high-performance package these foilsilicon onunits provides the transistors allows printed economy,amplifiers a high are dissipation while the coppercapability. -circuit board can be used for heat - of this type. The Plastic collector The R15 C12 K R18 sinking,sinks. thus eliminatingThe biasing the method results in a simple, highly need and extra cost of separate Diode selection is reproducible R/4 Q2 R19 f Q3 OFF Ti D1 resistorseliminated,alternativeat the input are toand required. hasthe only severaluse a of single, seriesadvantages. low-cost diodes. The use of a field-effect transistor Circuit simplicity and transistor and two Courtesy: TexasPC Instruments BOARD #2 -...- 5)R20 117V 60 r -0111I -1 OWD2 impedances in excess of one megohm are easily obtained. 75 0 Low -Noise Preamp for Low -Impedance Mikes producedday,"WhatdoyouWhen with transistors modernthat do like techniques,away better,first with hit tube thatthelow scene,humcharacteristic-noise or transistors transistor noise. have hiss"? How- been To- the current joke was IXif) Mr' boxever, and use shieldedThis circuit cable is for designed all external for use connections. with a dynamic mikeif oryou other build this unit, you'd better put it in a shielded pedanceprovidesputlowProper impedance -impedance toshieldingthe the necessary inoptimum source. the of 50-both matching Theimpedanceto the 250 amplifier transformer -ohm from for range. theis low designedand source Thetransistor amplifier transformer output for noise.an chassis im-in- CC \r--"-411it 1H I I putvoltageis noisenecessary EMFvs ambient for with low the temperature-noise input operation. short-circuited. is found Equivalent by measuring input noise out- (Av=1000 at 25°C). Divide this cc istics?putfigure-55°C noise by to voltagethe +125°C voltage at operation, 25°C gain. is 4 and µV. a 54 mw Up to 6 my input voltage, 1% maximum distortion, Other circuit character- power supply drain. Typical in- TRANSISTORS:PARTS LIST R4R3-51. -750K 1K > R5-61. 9K 65= '0 0,cs1 .6 m m a 0 a::..§a CAPACITORS:DIODE: D1-1N753AQ1, 2, 3-2N780 R9-16.R7,R6 -200K 8-20K 2K 4El Eii--,O NR NR N R E-4 2 8 :11 ., E.4 C.)°Ez. - ""' n--i o c' o. '72 clE °'-' E' 7ci:1" 11 1 1 ol co 0 °0 o o c,, 00 i C2-10C1-33 mfd, 35v6v R11-475R10-3. 01K ohms g4E-' 0 TRANSFORMER:

13. 5V R22

R9 T1 'Ws. R15 -C 12 SP 1 R ill R4

)1 C9

LEFT C2 CHANNEL -7--- C8 -±1(--

--VV\,-----4,R20

Courtesy: RCA

RIGHT CHANNEL

R8 R12< R SP 2 TCu R19 D1

7 -, --- . C5 120V AC/BC C10 C13AT

00 parallelofments load resonant provided circuit conditions,circuit, by associated with series resistances. and shunt Fordamping a given ele, set the peak value of the transient clippingplished,current.transistorcanvoltage be limited isandand bydirectly thewithout limiting to desired a proportionalvalue compromising the power within maximum output theto the costmaximum can value collector factors. be obtainedof ratingthe Thiscurrent collector withoutisfor done andthe In most cases, this type of limiting can be accorn_ TEST EQUIPMENT withoutbyvoltage.outputshown judiciously the providestransistor Because use ofchoosingCollector protection transient driverthis ratio circuit supply current -suppressionagainst is 3:1, constants.voltage limitingexcessive approximately, devices. to is thecollector provided emitter the voltages by -basemost the ratio of the The amplifier Battery Eliminator volt- ply.rangecurrent This within typeeventhat canof if the currentthe flow desired transistor in limiting this power transistoris doesshorted range not is toeffect three the 13.5thetimes dynamic -volt the sup-bias of the amplifier. It them.If soonagesyou Thisexperiment payin a circuitforrange provides itself in battery costs. R1 permitsthat eatsyou up batteries aswith fast solid as you andstate, you you can need read operating the supply voltage a variety of DC voltages and willcan buyto vary level formance.primaryconstants.limits the provides peak The voltagetreble additional control developed damping placed for thewithacross given no the sacrifice collector transformer in load per- thenbytheholdsput multiplying voltage rectified of the output, fullvoltage byTransformer -wavesilicon level reasonably T steps down the meter reading by 10. rectifier is filtered diodeby Cl, rectifiers D1 and D2. the AC line to 12 volts. constant. While the out- which also The out-This is TRANSISTORS:PARTS LISTQ2,QI, 4-40359 3-40399 R4R3-5 -47K meg dual control1.5 meg tapped at isput suitable ripple percentagefor many applications. may PARTS LIST leave something to be desired, RESISTORS: it CAPACITORS:DIODE: Cl,DIQ5, -40265 2-56-40424 mfd, 3v R15,R12,R6,R5R8, -50K 7-11 13,21-18K pot ohms, 5% 9, 10, 11-8.2K 14, 23-1K CAPACITOR:DIODES: D1, 2-silicon Ratingpower should equal Ti. rectifiers. MISCELLANEOUS:TRANSFORMER:R2R1T1-110-12. -100-10K -ohm pot,6vct 2w C6,C5-100C3,C10-.047C7, 9-.014-.1 8-.0022 mfd, mfd, mfd mfd, 15v 200vmfd 400v R16,R20R19-68R18-200 17-82 -68K ohms ohms,ohms (may 4wbe.047-mfd 400v capacitor) replaced by C1-1000 mfd, electrolytic, 25v Si M1-0-1 ma RESISTORS: R2R1-82C13A,CII, -1K, 12-.005 ohms,B-dual 5% 5% mfd100 mfd, 150v TRANSFORMERS: Ti,R22 2-output, -6.8K, 2w equiv.Freed2.5K R6A-8,to speaker. Triad S -62X or 110V AC 82 Courtesy: Radio Shack 83 Sensistors are silicon resistors used as temperature compen No -Contact Switch Sensistor Temperature Indicator employing a sen- satorsturesensistoravailable change or in indicatorsin the causespower bias the ratings circuitin triggervarious ofof aoutput1/8 Schmitttypes to 1/4to of changetrigger, circuits.watt. states.a tempera- By using a They're The heated,equallysistor.HereH2/11 across circuit increases, is another Atits room resistance temperature increases heatR1 -sensing and sensistor circuit, R2. also and when it reaches the firing point the 100 -volt source is dropped and the voltage across the As the sensistor is perlydevicewheresufficientsensistor selecting is the high inchangetemperature enoughthis values, diagramis irreversible.to the causechange circuit is the occurs, triggercansensing the to element. switch.resistance By ofpro- the be operated to a point When a terminedof setting.the lamp, by theThere are many applications I1 lights. The lamp firing choice of sensistor and indicator for machines that must for this circuit. temperature is de-the potentiometer For example, be TRANSISTORS:PARTS LIST R3,R2-5.R4-1. 5-680 6K 5K sensistor ohms circumstanceslimiteditcanbeHowever, usedin temperature according as where a safety temperature rise; to the local fire nabobs in fact, rise is a tellsignificant us that while factor. fire does it can serve in many this circuit is RESISTORS:R1Ql, -50K2-2N2537 pot +10V DC R7,R6-330 8-10K ohms fireindeedinefficient but cause from as damaging asmoke. fire alarm. By heat, the They PARTS LIST timethe biggest the heat danger from isa notfire fromdoes RESISTORS: R1R2 -10K -10K sensistor MISCELLANEOUS:PSI1-NE2 -100v neon power lampCr.u=ts.r supply Texas Instruments R2 84 85 tollits damage, and the alarm chancesIf you will feelare sound thethat onsmoke the deaf light will is firstinsufficient have ears. as an indicator, tak an bell,photovoltaicNE -2H neon lampcell tocan indicate be substituted the lamp for ignitionthe NE by or you can fully automate the system by -2, and use having the ringing a P1 fan.ambientcases,itsphotocell temperature the temperature closedevice a reachesrelay,can be rises, turning used a predetermined such to off turn as a pieceonan equipmentair of conditionerlevel. when equipment when In other or a the NOCURRENT CURRENT LOAD 0.8 Electronic Timer TRANSISTORS:PARTS LIST Q2-KD2102QI-KD2101 R5-150R4R3R2 -10K-47K-3K, ohms 5w viceyouAn arezooms. electronic at all Connectedinterested timer is in quiteto photography, an usefulenlarger on itthe value of this de- many occasions, but if DIODES:CAPACITORS:D5,D1 to 6-KD2100 D4-1032103 SCR 15v MISCELLANEOUS:R7-33R6-470R8-15F1-3 ohms ohms ohms amp placetunerplaynoticecontrol gamesiscan to that the getbe with lightusedthispretty this-that systemduration.in sloshy a photographic uses third withLooking a allwire3 -wirekinds at ground the of wetness is vital! around. darkroom, you know the grounded plug.schematic,helps you will to accurately Don'tIf the RESISTORS:C1-50RIC2-50 -1 mfd, meg mfd, electrolytic, pot, electrolytic, 2w linear 150v P1,I1--G. J1 E.-3 NE83 -wiretacle plug (see text) and recep- plugtimer.ultraof potentiometerit intosimple Take the an (and timer electricThe Rl. ultra loadmost clockfast) socket. important with Arbitrarily a aspect of set this timer Don't let this throw way to calibrate this type of sweep -second hand and is the calibrationyou. Here is an potentio- aThis predetermined circuit is used period to delay after powerthe control application switch isto a Electronic Time Delay turned on. load for R1theseconds.Whenmeter faceand repeatyouR1of the toinitiate aclockuntil given the theuntil point start, timer the inthe timer stopsits second rotation shuts the hand clock off. and will start the in exactlyNowmove readjust ten around timer. watts.chassisIt fromcan be The fiveground used delay seconds with and time anyhave to canaboutAC/DC a total be two adjusted devicepower minutes. ratingthat by doespotentiometerThe in excess delaynot employ a is deter- of 240 R1C2 byten plugging seconds.86 in the electric clock. Repeat the procedure, marking the dial forCalibration every can be checked at any time simply thetomined the 2 -transistorvalue by the needed length electronic to causeof time neonswitch. required lamp Ii to to charge fire. capacitor This triggers 87 When switch S1 is turned on, the full -wave rectified lessfromresistor than the KD2103 seven R2. The volts bridge charge by circuitvoltage on Cl charges isdivider held capacitor to circuit a peak C1R2 potential oi throughand R7,curr KD2102thearesistorsSimultaneously, potential two become -transistorR1 of and about saturated, R3 timing in switch.80 series. volts, capacitor When neon C2 thelamp starts charge Il firesto oncharge andC2 When transistors KD21O1 achievestriggers and Signal Tracer to asresistortrip a repeatablea camera R8 and shutter,Coupled delaytrigger before thewith silicon actuation.an auditory controlled device rectifier. such as a bell, this it will allow you time to get into thethey complete the gate through Used with a solenoid serves notThe serve signal as tracera signalis actually generator a passive or signal device injector. in that it doesThe probe is yourpicture. garage lights.PARTS LIST Used with a slave relay, R3R2 -47K-3K, 5w it can be used to contr heardcuit,resemblingis simply through diode thea typical loudspeaker, receiver touched D1to the serves circuit as ina rectifierquestion or and detector. the signal Then, through volume control R2,if ita signalisdetector is present. -audio amplifier cir- Closely after DIODES:TRANSISTORS:DIQ2-KD2102Q1-KD2101 to D4-KD2103 R8-100R7-180R6-470R5-150R4 -10K ohms ohms ceiveramplifiedthestep-by-step detected turned by The signaltransistorson, troubleshoot best place passes way the Q1 to probe describea typical on the function and Q2. circuit. Withthe areceiver's radioof the re-unit first is toam- actually CAPACITORS:C2-50C1-50D5-KD2100 mfd, SCRelectrolytic, 150v15v MISCELLANEOUS:P1,Il-NE-83R9-33F1-3 J1 ohms-3 amp -wireneon plug and rec plifierplateMoveThis,loudspeaker, ofto course,the terminal. grid you isof can done Ifthe you assume next with hear stage, which will the switch inthat the RFthe position.stagethe is RF operating. signal in the tracer be the mixer. R1-1 meg pot, 2w linear ON 0 LOAD tacle --. INCREASE DELAY CW tor.dicatesAgain, hearingthat the thesignal signal has atcome the through the coupling capaci- control grid of the mixer in- P1 Fl traceraudio speaker. position. AfterContinue you frompass gridthe detectorto grid in stage, the audio change stages the .switch Now you should hear the audio signal in to the the 60 120VHz tested.iscouplingorIf notheits needassociatedsignal However, is toused failsfear between remember circuitrytheto be presence presentthe are probethat suspect.of atyou DCany are on point, Becauseindeed the terminalsthat working capacitivestage being and/ and the input signal, there with CURRENT LOAD VOLTS -DC canBya live usingbe circuit, reduced miniature and considerably. exercise components, proper the preacutions overall size at of all this times. unit It is designed to be grounded NO 88CURRENT 13.5 6.4 C"urte3yt RC theto avoidthe ground unit accidental under lead wiretest grounding byand the the clip clipto -leadassociated itself grotmd. are circuits.fully Make insulated sure that to 89 am 0 an sa Grid Dip Oscillator 1111mT instrument-atperformThe grid two dip frequencies from 3.4 to 97 basicoscillator functions-an shown activein this anddiagram a passive is designed test to MHz. With the frequencynearbyInitswitch tank is thisa anresonant circuit closed,modeactive of the Ll/C5. a gridcircuit signalL1/C5 -dipper When whoseiscircuit, generated the and frequencygrid aa portion -dip at a frequency ofcorresponds and battery voltage applied to the circuit low -power signal generator. oscillator is brought the current gen- determined to the down,eachtheonerated thefrequency plug-in henceinmeter thatIn thecoil. itsMl.circuit directly. othername By iscalibrating mode, griddrawn Use dip. athat off,different the ofcausing acapacitor, passive calibration a reading device, you can scaleto theoccur forgrid dipper The meter reading at resonance will go read quencynance,reading.circuitcan be and usedandof The an in tunewith meter externalthis capacitor theway will switch circuit. you tell willyouC5 open. The forbewhen meter ableBringan youincrease to reading it determinehave close reached inwill to the an meteractive reso- indicatethe fre- ?\/\/\/ 1-4 anafterover active -couplingthe ultimate circuit, in thealldip. cases,meter providingwill dip slightly a slight before rise before and after and Similarly, when used passively with tofield toreachingthe the maximumInthe passive peak. mode, the oscillatorstrength can be indicator. used astransmitter's Useda relative with anyfrequency, transmitter, you can tune the transmitter and tuned 90 41_ it also optimum output with no difficulty at all.becomes a valuable counter -bugging tool. With power In this same way, 91 frequentlyremoved, used you by simply electronic tune surveillance the unit through equipment, the ranges namely most forjusttransmittershowthe a sensitivity peak.citizens a peak is frequencies indeedcontrolwhen its puttingR1 frequency and themoveout FM isa around signal,neared. frequencies. the You room In this fashion, you will know when the meter youcan are then get_ If a lookhidden vviuad_ Simple Voltmeter ting closer to the hidden unit. Cl C3 Youmeter,The maytransistorized has have a voltmeter, decided advantage overnoticed the nonelectronic on your nonelectronic types. voltmeter the like the vacuum -tube volt- Li byvoltlegendsistor quite the "20,000 aorunit vacuum measures, ohms tube) per you does volt." will not load load your the circuit bit of resistance. The electronic voltmeter (tran- whereThis adding means an thatadditional for every at all. under test This PARTS LIST C4 Courtesy: -111t-eo--1131 Si RCA 46 loadcan will be important make for ininaccurate some circuits readings. CAPACITORS:DIODE:TRANSISTOR:C1-33D1-1N34AQ1 pfd, -2N1178 mica, 50v BATTERY: B1R5R4-3. -13.5v,R3R2-220 -39K -3K9K RCA ohms VS304 C5-variableC4-0.C3-5C2-0.01 01 pfd, mfd, mfd, capacitor,mica,equiv.)(Hammarlund paper, paper, 50v 50v 50v type HF-50 50 pfd or MISCECOILS: L LANE°Ml-microammeter, US:L1-plug-in coil(Simpson (see table) model 1227 or equiv.) 0 to 50 na Courtesy: Radio Shack RESISTORS: R1 -250K pot COIL -WINDING DATA J1-phoneX1-jumper, jack, normallyomitments for below -closedmeasure- 45 MHz TRANSISTORS:PARTS LISTQ1 -2N357 R6,R5R4-100 -1K 7-470 ohms ohms Coil1 Freq. Range 3. 4-6. 9 MHz #28Wire enamel Size 48 1/4, close wound No. of Turns RESISTORS: R2R1-1Q2 -100K-2N270 meg MISCELLANEOUS:BATTERY: B1-1.R8 -5K 5v pot 65432 25-4713-276.7-13.5 MHz MHz 46-78 MHz #24#24 enamel enamel 422, 1/8,19 1/2,1/8, close close wound wound close wound Withthe electronic meter, you just don't have this problem. R3 -10K M1-0-1 ma 92 typeCoil 24-5Hforms areor equivalent.Amphenol 74-97 MHz #16 tinned pins,incheshairpin and 1.4 longformed, inch including wide 1 7/8 orwhetherAs a a television result, you are circuit. testing a hi-fi amplifier, a ham transmitter, you get more accuracy in You'll also find that this unit is not critical readings, 93 uumjustsistorsquicklyreasonfor highly tubes in as do; accurate,thethis they therefore, criticalis age.that transistors circuits. components do notwon't heat change up the value way asvac. it Forretains even its more accuracy. accuracy, use 1% re, Part of the C2 R10 AC Voltmeter PUSH-TO-READ SWITCH TRANSISTORS:PARTS LIST Courtesy: RCA R3-100R2-10 meg ohms whichequipment.voltages,andThis ismeter feedsdesigned which circuit its outputmakes primarily operates toit ana meterfromforideal reading ainstrumentwith 22-1/2 a alternatingbalanced volt for battery testing bridge -current source audio rec- The unit is basically an AC voltage amplifier DIODES:CAPACITORS:C1-0.01D1Q1 to D3Q4-40461 mfd,-1N34 paper, 600v R10R7,R6,R5R4, -47K 11-33K9,-5K 14-390K 8, 12-10K R19tablishingtifier. is a zeroing maximumLike control readings any for electronic the on meter.the scale,meter, and this potentiometer unit will not load down thePotentiometer R13 serves as a level control for es- RESISTORS: C8-50C4,C3,C2-25 6-100 mfd, mfd, electrolytic,ceramic electrolytic, disc, 25v 25v 6v 5, 7-0.33 mfd MISCELLANEOUS:R19R16,R15R13 -2K-1K 17, pot, pot,18-5.1K linear linear taper fullycircuitmetermeteringsufficient remove under of known circuitsgain test.the meterforFour accuracy. must reading stagesmovement be Here'scalibrated, ofeven amplification from thea helpful lowest its obviously, case hint, alsovoltages. and too.provides theagainst two a Care- The R1 -1K M1-DC milliammeter andarymounting pencilareplace quill screwspen.eraser, themThe withthat carefullypush holdAC -to voltage the-read remove scale switch markings, inthe place. inmilliampere no usingWithway effects Indiaan ordin- ink the battery volt- values Square -Wave Generator age,ever,andTheincorporated which themeter for switch remainsmost circuit with will applications onwill aprovide piece constantly. be on ofreadings onlyweequipment, would when when thelike it isequipment to pressed. see a How- is on If this voltmeter is to be all well and good second ancircuitry.positiveSince electronic the and Triggered equallyswitch byasnegative, well.an external Also, because pulse, of its associated square -wave generator provides a pulse equally it serves well in computer it can be used as batterystantswitch94 drain.is addedused to in power series the with circuit, the supply it will voltage,not be under so that con- if a' anyistransients circuit and designed sharp riseto pass andVery or fall process times,useful any a in ACanalyzing signal. amplifier circuits and, in fact, square -wave signal Apply 95 a square -wave signal to a given circuit. Check the square fidelity equipment you try to depend on audio signals from youwavecircuitshape a atnumber theat performance: the input ofoutput indications with of an the oscilloscope, circuit.which can thenbe analyzed examine for the overall Close observation will wave, give properprogramhighright!stereo settingBi-levelsound for the is balance bouncingchannelmaterial. control volumeoutmaterial. ofIt's on the hard,is loudspeakersequally Many for example, ofhard us from haveto set to attempted determine to get stereo channels when aroundleft to with the circuit.calibratedamplifier stage,scope)Rate you the of willamount gain be in ableof amplifier actual to see gain circuits:and achieved measure (on If you are checking by the an a thisprogramstateyoumighthavemakerecord by frequencytheir manufacturers, purchasing stereo test records.records more versatile, provide moreimmediate tests needtests for. areAs atoo result, short the for steady- more than a moment in an effort (misguided, perhaps) to Unfortunately, the than n 1 S1A 4 adjust.properlyor steady-statetwo or improperly-not tone permitting you of sound, allowingWith you this to unit determine you plug only into the input jack enough to allowto makeyou to adjustments truly to your if you're set and have a J1 EXT S2 R3 4 heart's content. INT PARTS LIST Courtesy: Radio Shack Distortion: As the input is a square RESISTORS:TRANSISTORS:R1,Ql, 2-2N1042-510 ohms TRANSFORMER:T1R4R3 -50K-100K-6v filament pot transformer wave, any distorti ofinterferenceingwill vertical ofbe the immediately spikes corners, toNoise onthe the slopingsignal, apparentimpingement: display. thisof on the will the rise Should be or apparent fall. your circuit in the addfo noise or othe scope. Look for round provides96 either a sineThis or unit a square is handy wave. for checkingOften, in outcheck hi-fi equipment, 97 Pi POWER CONTROLLING CIRCUITS PARTS LIST RESISTORS: R1 -33K, lw Courtesy: Radio Shack CAPACITOR:DIODES: C1-1D5-SCR,D1 to D4mfd -1N34 6 amp, 200 PIV MISCELLANEOUS:R2P1,F1-5 -100K Jl-standard amp pot ceptacle AC plug and re- zeroThis tofull 100% -wave over circuit an AC provides load. AC Voltage It can serve as a dimmersymmetrical forControl control from DuringincandescentSCR.agesamples of theWhen the the positive motorsupplylamps the primary halforvoltageand load -cycle,to voltage control andthrough the rises thearm the ofabovegate the terminal that of the of the compares it with the back volt- speeds of AC motors. potentiometer rec- Whenbetrolledremaindertifier, created you level. limitwhen of thatthe this applications half circuit -cycle is voltageusedof this in unit to the to load at the the SCR is triggered by diode D2 which DI suppresses the inductive spikes that would controlling a motor. controlling in- applies the con- Here is a flasher circuit capable of switching 240 watts worth SCR Current Control else withtotrolcandescent be forprojecting thisplunged unit lamps youabruptlySome canslides only, additional graduallyinto orDl darknesshome isn't applications scale required.movies. from down a thefor this unit include lightedPeople room, do and not like room lighting light con- isClosed,comesthatof appliedadvertising needs a pulsating fine "on variable and DC off." voltage speed Used frommetronome. with the an KD2103 auditory When bridge device, switch rectifier it Si be- is across the load and the parallel SCR and resistancesigns, Christmas tree lights, or anything Since the SCR is in a - plunges98chanceas the intofilm to seedarkness! gets that started. film loops are properly formed before he This also gives the projectionist a PulsesPassivecapacitance charge state, C2 thecircuit to load the C2, neoncurrent RI, lamp and is firing low.R8. potential. When the As a result, input 99 throughlamp fires R7 at provides approximatelyQ1 and an Q2 input operate 80signal volts, asto aaboutthe two base 2-stage milsof amplifier the ICD2109 of current conductionistransistor regenerativenot conducting. will and remainswitch. full The current in R6amplifier the in cutoffthe base mode of Q2 appears across the load. output triggers the SCR whenguarantees the neon that rather than ; la into the p Speed Control System Cot.t. y RCA J1 R1 FLASHINGINCREASE RATF Inlow-levelWhig the voltages advantage of solid-state to control a relatively high -power devices is their abilityelectric to use motor you needed a circuit. P1 camewithlarge theequipped required control.past, to control a large Steppedwith attenuators control handles or almostcapacities as large were huge variable transformersand expensive. They as the LOAD !VOLTS -PC troltechnology,steering the speed wheel a of small hugeon your knob, industrial equipment. The circuit car! twisted with two fingers, can con- Today, thanks to solid-state motorshown NO CURRENTCURRENTi PARTS LIST 15 1 plete(thewithcurrentpeakshere automaticwas control designed despite drive to control)100varying amp. Notice control a 20 amp, 24v DC series loadis incorporated conditions. to provide com- that a feedback system DIODES:TRANSISTORS:Q2-KD2102QI-KD2101 RR5-680R3, 6-47KR2 4-2.2K -3K, ohms 5w fullvibratoroperate saturation (Q10 at lowThe and or power switchingcompletelyQ11) dissipationwhich action off,holds allowing of the this circuit levels. The circuit compon- is provided by drivera multi stage - either in the driver stage to CAPACITORS:C1-50D5-KD2100DI to D4-KD2103 mfd, SCRelectrolytic, 15v MISCELLANEOUS:I1-NE-83R9-150R8R7-4. -22K 7K ohms willisent settingthe controlling cause 50K of variablethe the switchingthe resistor ratioresistor toof action oneonin the-off end tomultivibrator. time come for to a halt, of its rotation or the other the power switch An extreme and the RESISTORS: R1C2-50 -10K pot,mfd, 2w electrolytic, linear 150v P1,F1-3 J1 -3 amp -wireceptacle AC plug and re-' tablishingwillthanpowererates controlextremes switch at anabout the effectivewill will percentage100 either establish Hz. speed be full ratio control.the on pulseof or off full width, time off. to and on thereforetime, es- The multivibrator op- Settings other abilitiescationscircuitcurrent could closerequiring of the This beto flexiblecircuit100 highercircuit amperes. areenough orwas lowerlimited designedWith to voltages.work onlysmall atto by modifications, a functionThe numberthe number at 24 volts current cap- of andappli- at a andthe 100 Powercurrent stage. carrying capacity of the parallel transistors in the 101 PARTS LIST 0X if TRANSISTORS:Q8Q6,Q5Q1 -2N1302-2N511to 7, Q4 9-2N1372 -2N514 R7-100R6,R5-10R10-100R8-200 ohms ohms, ohms ohms 2w 9, 12, 13, 14, 15-1K cn DIODE: Q11Q10 -2N1373-2N1038 R17-30R16-20R11-40 ohmsohms, 20w5w Cg CAPACITORS:D2-dependsD1 -1N2069 on motor R21-191R20R19-500R18-270 -50K ohms pot 0 CCCC C1-16C3-10C2-.5 mfd, mfd electrolytic, 100v MISCE LLANEOUS:R22-50R23-478 ohms, ohms 5w Wv cc RESISTORS: R1, 2, 3, 4-.05 ohms M1-20 amp `>' J cc OSCILLATOR 8 0 0 ct ccco CONTROL SPEED DRIVER SWITCHPOWER LOAD 0 \A"--11cr AUTOMATIC DRIVE CONTROL CY ccG=1 0C1 4 0 V 1 Integral Cycle Ratio Power Control CY forcontrollingtrolThis of transistorized the an electric integral hotplate, cycle ratiofor example, power control where is con- good average power level is desired. This unit needs 102 fexas instrum, notothe thermostatic load socket control, andmaintain. set either. R6 for It'sSimply the also desired pluggreat heat the for hotplatelevel keeping you into anwish electric coffee pot 103 hot. Wherever you want a relative ratio control for of Q3 through diodes D7 and D8 to the diode net- Thiscurrenttypicalnating circuit currentexample electric could loads, of motors-in bewhere you'lleasily this findbuiltsome might this right hand becircuit intoused tools, thehandy. is intoolfor alternating instancehousing.Another alter, opposedworktoconduct emitter which provides oppositealternately,silicon controlled providing regulatedis based power on a time-sharing rectifiers D5 and D6. These -going pulses to principal in which a the directlyto the load. then time.withwouldand R6the result couldspeed in beadirect infinitely coupled function variable to a ofspring trigger speed -return position control trigger. atfor the any given This tool loadtiometer,portionOperationwatts is when 2N3669 SCRsof 800the are outputwatts when voltage, type is applied to the load 2N3228 SCRsdetermined are used,used. orby 2000the level poten- at a given time. Maximum This is not a "blinker" PARTSoutputsitition LISTrate are controlledappliedQ2 and from Q3by the formbalancing collector a free potentiometer -runningof Q2 through multivibrator, R6. Ql, and with the rep.. The ID typegiven device inperiods. which the output It's truly a regulator. is triggered on and off for DIODES:TRANSISTORS:Q2,Q1D1, -2N2614 3-2N3241 3, 7-1N3754 R5R4,R3-180R2, -2K, 8-1K7-6.8K ohms 5w CAPACITORS:D5,D4,D2-1N1199A 8-1N37566-2N3228text) or 2N3669 (see TRANSFORMERS:T1-transformerR6 -100K pot,autotransformer used); (primarylinear tapped taper tosecondary provide 1 used -to - as not This circuit application further SCR Heat Control demonstrates the amazing RESISTORS: R1C3-500Cl, -3K, 2-15 5w mfd, mfd, electrolytic, electrolytic, 15v 50v T2-transformerused);64655 step-up(secondary or Stancor equiv. in voltage; #P-6465not Stancor or equiv. #P- withofjunctionversatilitystarting this the circuit, SCRwith at of one itself:other the end silicon devices. and working let us depart from the controlled rectifierSince used the in SCRcon- itself is the across. andInstead, usualyou can procedure let's see beginthat of heart circuittifiesdiodewithsensor. the abridge smallconsisting SCR TheThe rectifier.portion fullyamount SCR ofopen of theofTheis the thedirectlyregulation transistors bridge currentload will acrossactually the samples line, these componentsand apply feeds tothe monitoringconductand through the temperature the 4 - - and rec- potentiometertheT SCR gate,In Rl. however,this circuit,according is youpredetermined to must the temperaturefirst select by heat range -sensing in which you are inter- the setting of element 117VAC Again,R1controlested so (shieldedthat we circuits). can cut microphone corners by usingcable ais well used you can set Then you have to calibrate potentiometer its dial as you would a -calibrated thermo-to couple it to the thermostat. 1014 zneter as a guide. Just make sure that the thermometer has 105 ponentstemperatureon"settled" and Cl off, and andto at R5an markwhich exactare thelatching thereading, triggering adjustment components then point adjust occurs. on thatR1 will, your dial with so the load Circuit an on ifcool, in, goes the untileluded you in reset. the circuit, serve to keep the load in 240M MAX LOAD R2 I NCREASE Courtesy: RCA mode S1F1 D1D2It R3 TEMPERATURETURN -ON P2 69 120VHz D3D11 TH1 Electronic Heat Controller J1 P1 ployedsortinallCertainly thisyouplan of experimentation.book,as athis todesigner, you dois anis will experimentelaborate or find are circuitstruly device in interestedsimple more for circuits.controlling appropriate in a high heat,-quality to If, on the other hand, you are em- Elsewhere this if TRANSISTORS:PARTS LISTQl-KD2101 MISCELLANEOUS:R5-33R4-470R3-180 ohms ohms (see text) straightforwardBisunit for-B, that you.C, willand The operateD interlockingon -D -and are repeatedly -offto give action. circuits you and the indicatedwith option good by ofaccuracy, letters latching A this -A, or CAPACITOR:DIODES: D5-KD2100D1Q2-KD2102 to D4-1CD2103 SCR TH1-thermistor,1500temperaturevariationperature ohms negativecoefficient, over range desired tem- from operating 150 to resistance planperature to use range; forIn selecting yourbut more application. yourimportant, thermistor, For select example, you the typehave you that thecan you choiceob- of tem- RESISTORS: R2R1-250C1-50 -3K, ohm 5w mfd, pot, (seeelectrolytic, 2w text) linear 15v, J2,J1,F1-3 P2P1- amp -3 Fem -wireceptaclenectors, ale AC and plugAmphenol male and con- re- 80-2 or equiv. tainwilltoliquids. awaterproof thermistorintroduce it ain yourselfdelay a waterproof in eitherthe reading, byhousing potting and for oralso immersionsealing introduce in glass in in- If you choose a type that is not so equipped, planning it makes an idealSince control this circuit for an turnsattic fan.on with When an theincrease in temperature, temper- littleaccuraciestoquentlyin the schematic. used that in you damp canAs atmospheres, heatincorporatejust ascontrollers easily this design typeof this aroundofcare. typeline Observe cordwithare fre- ina thatyour a circuit.3 -wire groundedBe sure line it would be a wise move cord is shown 106aturematicallyature is insidereduced, goes the onagain attic and by risesremains a given to a in presetamount. operation until the temper- amount, the fan auto- hazardto of electric shock.ground the third leg to the chassis and cabinet to avoid 107the REGENERATIVEFIRST SECOND SWI TCH SWITCHREGENERATIVE IC Motor Control/Servo Amplifier SiFl 03 Just as the transistor opened new avenues for research and P1120V 60 Hz havedevelopment,weightway always to are sought of so prime has make things. for a better, cheaper,importance-aircraftthe Inor integrated certainmore compact areas circuit. of instrumentation, endeavor, Experimenters size and TH1 Courtesy: RCA electronicfor example. equipment, you If you can reduce the size/weight make room for additional control factors of TRANSISTORS:PARTS LIST 138,R7-any 12-22K, resistance 0.5w 0 to 250 ohms functionsmentation.is of special and makesignificanceWhen the aircraft the computer came into being, in space travel or in missile safer to fly and to fly in. its value to the air- instru- This DIODES: D3DI,Q2,Ql. -1N3737 2-2N32284-2N26143-2N3241A SCR MISCELLANEOUS:R13-470R11-5.R10-680R9 -15K 6K ohms pot, 2w, linear taper processedever,ingcraft course, industrycomputer by computer altitude, was size obvious, and etc. relayed has been so vastly reduced that With the integratedand circuit, to this how- day, pilots use data to them in flight concern- the pilot CAPACITORS:C3-200C2*C1-10D4, 5,-50 mfd, mfd, mfd, electrolytic, electrolytic, electrolytic, 6, 7-1N3754 15v6v 15v TH1-thermistor,1500temperaturevariationperature ohms coefficient, over range desired from operating 150 to negative tern - resistance tips,can have rather computer than Becausedepend services onthe pilot must act on the radio -relayedin the information. cabin right at his finger- information provided,having the hu- computer (and RESISTORS:R5-180R4*R2-270RI, -33 3-47K, ohms 2w *IndicatesPb,F1-10 J1 -3 optional amp-wireceptacle latchingAC plug (see -circuit and text) re- fromthereforemanthe error computeraircraft the is furtheraircraft instruments is locked eliminatedcontrols) into is the directly by such as "roll," the rotation locked into theaircraft's computer, controls. For ex- coupled. Information of an and R6, 14-150 ohms components flightcomputerwing,aircraftample, characteristicthe takeon actionpilot its a movementlongitudinal corrects Herethis for is is thea 40- pilotaxis. to 400 -Hz motor done automatically,this leaving by adding one aileron -controlto circuitconcern suitable himselfShould a wind gust lift a control. By with. less for 108 systems,such action. this circuit may Also, for those readers be used as a servo amplifier. involved with servo 109 10V DC AT 17 ma H.S. +18V DC AT 20 ma H.S. it. A moment spent in studying this circuit will probably Cotrtesy: RCA 52 ma F.S. C5 Q1 47 a +18V F.S. photoelectricnurture some other ideas. components and ignoring For example, by using only the the neon lamp circuits +5.6V R5 .5 V R6 1.7V Q2 youasa small flashlight,alight -actuated switch,can make any forsmall instance. size motor To make react the to anyphotocell light-from mount it inside a deep black -painted func- C4: +5V 1 +18 V R7 6V P-Pl +1.1VR11 tube, so if you own a blender, you that stray or ambient light will not be a handy adjunct. Mount the neon lamp are aware that a timer for activate it. thisand 0.18V p -p -- +1.2 1.2V R10 D1 Tr5(12.° photocellappliance incan such a way that only the light from the neon lamp 40-400 AT C21 +0.4V 15V P -P Re,R9 R12 +1.1V\ P40V -P 500 -°"LOAD thecan blenderfall on the photocell.will Withnot run. the switch but the 100K resistor and the In the time position, the blender in the off position, 100-mfd capac- / + 1.7 V runs as usual, R1 C3 +0.5V 29 X 100 Q3 dumpsofitor the charge. neonthe capacitor lamp, it into lights, When the capacitor is charged to the firing point the triggerthe circuit, motor. keeping it from activating the photocell. This EFFICIENCY OFOF POWERPOWER STAGE STAGE AT AT 40 80-400 Hz Hz = 21 X 100 8585 = 25%= 34% recharging, and stopping MOTOR TRANSISTORS:PARTS LIST RESISTORS: R1C2-.1 -4.7K, mfd 1w AC117V DIODE:IC: G1-CA3020Q2,Ql, 3-2N3772 4-2N3053 R11,R6,R5,R3,R2-5 12-.5 4-27010-22K, ohms, ohm, ohms, lw lOwlw lw 7, 8, 9-470 ohms, lw CAPACITORS:Cl,D1-1NI763Atrolytic, 3, 4, 10v5, 6-100 mfd, elec- TRANSFORMER:T1-StancorR13 -470K, P-8358,lw0.245 amp, 29w at 80 to 400 Hz 120v RMS, TRANSISTORS:PARTS LIST C3-.033 mfd Courtesy: RCA DIODE:PHOTOCELL:Q2-T143Q1-T1C21D1PC -1N2070I-Amperex B873107 (see text) RESISTORS:R2R 1-10KR4R3 -100K -33K-100K pot, semi -log taper ploysactIt's asana standardphotoelectric interesting photocell, point that others have Thyristor Photocell Timer sensors. While this circuit actually em- many solid-state junctions will simply used uncased CAPACITORS:C2-.1C1-100 mfd, mfd, 300v electrolytic, 150v MISCELLANEOUS:R5I1-NE-2H -500K pot (see text) transistors,I so1 0 that light could fall on the junction and activate LOAD2 AMP MAX J1 IN CREASESPEED R2 SCR Speed Control Pi introl,control Thistriggering the silicon oroperating lamp the controlled KD2100dimmer. speed rectifieris As determined SCR. a modelcircuit car is and/oradaptable train as by the delay involved achieveda motor con- inRl. time,afterparallel, Because the in turn, startoutput the ofloadis eachcontrolled and half the voltage is available at the load -cycle of AC input voltage. siliconby adjustment controlled of potentiometer rectifier Actual control is only when Delay are Courtesy: PARTS LIST RCA is resultsclockwisethedecreased, SCR in is maximum rotation, not the current maximum conducting. When R1 is set to its speed. When the potentiometer through R1, R3, and R8 delay in triggering the SCR maximum charges setting DIODES:TRANSISTORS:Q2-KD2102Q1-KD2101D1 to D4-KD2103 R6-15R5-470R4-150R3-5.R2, 7-1K 6K ohms ohms slightlyduction,transistorcapacitor andless switch. Cl thethan more LFt Theone droprapidly switchvolt across whento then the the the triggering potential oftriggers the 2 - the SCRoutput into terminals con- drops topot is in the maximum CAPACITORS:C1-1D6-KD2100D5-KD2104 mfd, 200v SCR isv MISCELLANEOUS: R8R11-74.R10-100R9-1 -15K, ohm, 7Klw ohms 5w SCRofage counter thefrom approaches SCR the -clockwise onpotential -and aBecause steady -off position. DC C2 levelserves determined an on C2 so the capacitorperiods. cannot D5integrating isolates the function, anode theof the output volt- by the duration discharge RESISTORS:R1C2-50 -100K, mfd, 2w electrolytic, linear PI,F1-3 J 1 amp -3-w fuse ire plug and receptacle beenprovidesofthe througheach triggeredanode input voltageathe parallel half intoSCR falls -cycle.conduction. when discharge to R7it is zero and turns off the SCR at thetriggered endhelps stabilize into conduction. SCR operation Hence, and path for Cl after the SCR hasR2 limits current through SCR Overload Protector betoamps,the buildbetter bridge should adevice off, rectifier a suchshortMany tooccur experimenters the across the take a final as this into its end use function. maximum allowable value of 2 application view and tend output terminals. You'll if Whenorand the drill will suffer unless you turn offyou the try power to hogyour quickly. out electric too much drill atis once,going into some resistant material either the material 112numberyou put of controlthis in afunctions separate box where it and have a more versatile about the house. can betool, used however, with a aluminum.The same thing can happen when you are drilling This device senses the presence of an overloadinto soft 113 uotentialijoineter.currentance that detects increasing atis highwhich enough this switch toR1 in combination make Q2's basewithwill negative conductcurrent is set by to the the poten- load. When R6 forms a sensing resist- with re- this Ri3 andspeetto D5 by the epower source. switch is derived its emitter, the from its baseswitch more conducts. negative The voltage across C4, When whichthe switch is charged conducts, through with respect to C2 is R8 it bypassed.itsturnsnoninductively. emitter. on Q1 by making or R6 is When Q1 conducts, the chargingScramblehomemade -wind this byon windingany 10 convenientfeet of #22 form. wire path for Courtesy: RCA R10 TRANSISTORS:PARTS LISTQ3-KD2102Ql, 2-KD2101 R3,R2, 10-1509, 11-470 ohms ohms CAPACITORS:DIODES: Cl,D6,D1 to 7-KD2100 D5 -1(D2103 SCR 2, 3-10 mfd, electrolytic, R13-1.R12R8R6-.165R5-270R4, -6.8K, 7-4.-1K 5K ohms ohms7K, 2w 2w (see text) offby readingthe powerRESISTORS: excessive to the drillcurrentR1C4-10015v before-50 drawn-ohm mfd, trouble pot, electrolytic, through 2w canlinear theoccur. I2v line. MISCELLANEOUS:P1,F1-10 J1 -3 -wireampceptacle AC plug and re- It turns placedchargebiasedcharged across byon through the the power loadHere's duringsource. how this On it halfworks:the following cycle When is also half switch applied -cycle, S1 to the is closed, C2 is R7 triggers the andgate of D2 and D4 when the diodes are forward - SCR D7. The voltage C2 is overloadastheThe transistor nextcombination residual half condition Q1-cycle.charge isof notis Thison sensed. conducting, this process capacitor continues which triggers is to to repeat say when as long ne D1, R4, and Cl, causing Cl to charge. SCR D6 during switch114 to conduct,When an overloadcurrent drawn condition by the is load present. causes the regenerative The 115 will have a plus sign, or the letters POS. The ground otherterminal,wire,connectionlated or wireusually connected is generally "hot" side,uninsulated. will to the horn, made with a heavy piece As a furthercan check, tell whichhave a length of the starter motor, side is grounded. heavily insu-the positive of braided etc. Fromgram.g you these connections,TOhave IGNITION a Ifyou negative your system is positive grounded system, use ground, use the TS the upper dia- lower one. LIGHT CONTROLLING CIRCUITS DEFEAT 0 S1 NORMAL SP TO LIGHT R2 FORSYSTEMSGROUND NEGATIVE IGNITION - TO IGNITION DEFEAT DI T1 SP Car Light Minder TO LIGHT 0 R2 POSITIVE - This circuit actually performs somewhat like a NOR gate used Courtesy: PARTS LIST RCA SYSTEMSGROUNDFOR IGNITION keyignitionin iscomputers. turned key off must Itwith senses bebe the offon lights the andand presence thethe still carcar on, lights of the two changemustoff. conditions. be in on, the or di- The the If the ignition TRANSISTOR:Q1Q -2N217 LA -2N647 RESISTORS:TRANSFORMER:R1R2-680 -15K ohms inThisareintorection other times oscillation. circuit ofcircumstances whenyou current may S1 be flow willprovides used where wantis alsosensed thea operating defeatto lights detectby D1,position, on voltagesundesired andthus the triggeringbecause ignitionare there Q1off. DIODE:CAPACITORS:D1C2-30C1-0.22 -1N34 mfd, (observe mfd 15v electrolytic, polarity) 25v T 1-audio-outputondary;400equiv. -ohm primary, Lafayette 11 transformer;-ohm#99R6209 sec - or here,lificationscorrectOr itone maybe forperformance where negative modifiedYou the will operationand of tonotice another.thesuit othermanythat of onetwopositive automated deviceseparate battery isindustrial schematics vital grounds. to theamp- are provided will116openTo be ascertain themarked hood which andwith look asystem minus at the issign, battery. in use or intheOne letters of the batteryNEG. Theposts your own automobile, 117 Light Flasher SCR Light Switch You'veThecuit.cillators, flashing undoubtedly but rate here is isdeterminedseen an electronicneon light by Cl. flashersswitch With typethe flasher Each time the switch turns itself on, the light flashes, or relaxation os- cir- Ql and Q4 act as an electronic switch triggered by the con- need.valuethe rate somewhat, is about once the flash a second. rate Of can be adapted to a specific course, by varying the value shown, predeterminedheredrivesductionis designedwired the of SCRsilicon remotely toillumination. operate into conductioncontrolled is the KD2106 rectifier (PC1), D5. shown The sensor whichand connected bywhen J1-Pl. ambient This lightcircuit levels fall below TRANSISTORS:PARTS LISTQ2-KD2102Q1-KD2101 RESISTORS: R2R1 -25K,-2.5K 1wpot, 2w linear DIODES:PHOTOCELL:D6-KD2104D5-KD2100Dl to D4 -KD2103 SCR MISCELLANEOUS:R6-33R5-470R4-150R3 -3K, ohms ohms 5w (see text) TRANSISTORS:PARTS LISTQ1-2N438A Courtesy: Radio Shack CAPACITORS:C2-50C1-50PC1-KD2106 mfd electrolytio,electrolytic,text) 15v150v (see F1-3P2,P1, J2J1-Amphenol amp -3 -wire fusejackceptacle AC 80-2 plug plug and andre - RESISTORS:CAPACITOR:C1-3Q2 -2N565 mfd electrolytic, 15v MISCELLANEOUS:BATTERY: B1R3R2 -820K-1K-6v theandplugalamp ambient lightTo intolevels set theup are theload such unit, socket. that you When would evening want the lamp place the sensor so it faces a window, falls, and ponentsOr if you in want a metal toThe have box circuit fun so with they would can't make see athe handy accompanying R1-100 ohms your friends, mount the com- signal for the car or boat. I1-#47 lamp thecausedto seeturn lampmorning, that the does the lamp lamp notice to comesturn that off. onthe again. increased ambient light on, adjust potentiometer go off, and then recheck the following night If it has not, readjust R1 untilR1 until the lamp lights. has toIn batteriescandescentcircuitry.118 should They'll lamp! last wonder a long howtime. you built a flasher with an in- Current drain is very light, so a set of keeppromised the lightby R6 Toon and onceuse C2, the the which circuit circuit function in has this been infashion, a triggered latching omit into the network com- mode to the 119 eludeanon condition.instantaneous these components. light source to keep the light off, then If you have applications where you would want in.. down,cidentand thelight gate and the increased current through on-cathode the photocell path of increases, the silicon controlledits resistancethe rectifier photocell, goes R5, F1 1 P1 currentwill trigger through the switch. When the switch R3 is applied to the gate of the SCR, becomes saturated, and it is P2 S1S switchvoltage withiniggered into dividier R3 and R6 keeps limits conduction.when it is not conducting. This completes the load circuit. the potential across the References 60 120VHz PC1 hereand are,Q2. As long as light of course, to the transistor early in eachremains AC input above the required level, half -cycle by means ofswitch formed by the switch SENSITIVITYR1 INCREASE theis retriggered current from Cl, and the SCR, in turn, R2 is retriggered. V READSWHEN( LOAD PC1 18.5 CURRENT IS VOLTS UNPLUGGED FLOWS) Si DIA D2Y MAX.21tOWLOAD J2 R3 J1 P1 Courtesy: RCA P2 60 Hz120V D3 Du D5 Y A SENSITIVITYIRi NCREASE Light -Activated Switch WHEN PC1 IS UNPLUGGED. 1 CW lightsgarageincreaseThis hitlightcircuit the in that sensor?light provides automatically on Orthe a asensor.control dock goes light thaton when forturns a automobileboat that head- Applications? How about a a lamp on with an can be Courtesy: PARTS LIST RCA RESISTORS: R1-2. 5K pot, 2w linear ( NO LOAD CURRENT)READS 18.5 VOLTS. V shouldavoidturned triggering onbe mountedwhenThe a by flashlight lightdeeply ambient level in is lightaat playedflat which black onthis it circuitfrom the deck? To during the day, theapplies sensor power to the load -painted tube. TRANSISTORS:DIODES: Q2Q1-1(132101 -1(D2102 R4-150R3R2R6-180R5-470 -25K,-3K, ohms5w 1w ohms R2,tentialrectifiedis adjustedand determined Cl current act by as potentiometer from aby power the the settingKD2103 source Rl. of When forbridge potentiometer photocell switch S1 KD2106. Rl. is closed, charges C1 to a po- R1, PHOTOCELL:CAPACITORS:PCD5-KD2100D1C1-50 1-KD2106to D4-KD2103 mfd electrolytic, 150v MISCELLANEOUS:R7-33 ohmsP2,P1, (see J2 -3 text) -wireconnector AC plug J1-Amphenol 80-2 plug and and re- levelR1 should that 120will be settrigger so the the ambient 2 light won't -stage electronic switch. charge Cl to a As in- C2 -50 mfd electrolytic,(see text) 15v, F1-3 amp fuseceptacle 12 1 When the light falls below the minimum required level, the eventhecircuitrydropsresistance diagram, after below formed light theofwill falls PC1triggering bykeep belowC2increases, the and value,circuittriggering R7, the shownand thelevel. from latchedcurrent (keeps from the switch "A" to capacitoropens. load The otel Silicon tiveAs to a lightchanges sensor in lightthis circuit Photovoltaic Light Sensor intensity (amplitude) and Q1 is unique. PC1 is highly servessensi- andnectexample,additionalofas useareadingapreamplifier. microphone this here applicationsacircuit ismotion the and Whileheart of the a light circuit -beam picture optical soundamplifier track, to an ordinaryby applying electric a lamp,little imagination. was designed as a means transmitter. you will find Con- For junctionterrupt"seen"loudspeaker) the which by beam, the is The as exposedand a photovoltaic receiver.the soundto incident will cell sensor, (applied through a suitable (PC1)intelligence consists of can a large be transmitted. silicon PN As long as the light stop. amplifier and can be In- light,ofthephotonsrent electron junctionand flow thehaving thus-holejunction area generatedsufficient pairsand area. create is Two electrical created, the intensitydirectly ofenergy the proportional incident break a valence to the bondnumberan within electron -hole pair. The cur- light energy. Impinging contacts are pro- thewithindevelopedvided light must sothe this issilicon penetrate a currentcomplexThe crystal andability function be of impinging of may be applied to a load.light todepends create an on electron several -holefactors. pair light intensity. The voltage First,Since cellany 122efficiency, reflected orthe transmitted active surface light causes absorbed by the crystal. of the cell is coated with an overall drop in 123 photonssiliconmonoxide must contain to reduce sufficient reflection energy losses. to liberate Secondly, carri Potentiometerlead level (240 wattsRl. maximum) is Control over both and established by the setting halves of the AC olt1 Q2 , operating sine of light).Whereiswithin the Efrequency theis the crystal. photon proportional to the The number of photos is a function of Photon energy is given as:energy, h is Planck's constant, a E = hv wavelength of light (inei light intense throughwoeserving As a are means ofoffers lightthe several outputthe diode setting fixed by SCR D8 network, monit control in theadvantages. photographic The in spite of deviation. D9or tQh. e vstudio photog is andage studio,level, this facedpre - and theThus, intensity, current and flow the wavelength,depends on withthe amount a maximum of absorbed li sensitive withcircuitCourtesy: a choice. RCA He can set his lighting I NCREASE for a goodCM average specified at a particular wavelength. J1 SCR Lamp Dimmer SiFl _ _ _J D Theboys. silicon controlled rectifier opened new vistas to the R In the past, if you wanted to control a great deal of Pt 60 Hz120V PARTS LIST RESISTORS: R1 -100K pot, 2w linear thepensiveofelectricity, SCR complex camevariable electronicalongyou transformer.had and to changedtube have circuitry aall hefty that. with potentiometer all its or an ex- The alternative was the use With the silicon con- failings. Then TRANSISTORS:DIODES:QI-KD2101Q2-KD2102 R3-470R2-150R5R4, -15K, 6-1K ohms lw resultlevelstube.trolled The iswhile rectifier, that SCR thesmall gate unit you amounts can itself have be handlescontrolledalmost of controlling thegreater by equivalent voltages voltage atexertof power levels. The very lowa triode com- CAPACITORS:D7-KD2104D1DS, toCl, D6-KD2103 9-KD2100 2-.01 mfd, lkv MISCELLANEOUS:R8-100R7 -5.6KPI, ohmsJ1 -3 -wireceptacle AC plug and re - hightroluseplete -voltage lowgigantic control -wattage controls. automatedonIndustryfell largepotentiometers Economics amounts. machines upon totheThis were controlwithout SCR, results favored largefor the in it astheenabled well, ability foroperators to to con- necessitypower levels. for keeplatterfor hiseach course, fingers different ascrossed, the subject. results are C3-1 mfd orhe can reset hisF1-10 lights amp fuseMost photographers usually better. This,while you set the lighting, prefer theas needed how- primarythestructive application voltages heat ofthrough were low-level not large being control controls dissipated voltages in meant the form that of de- . More important, feed- large thencheckever, set meansthe the lightmeter lights making again. and the model bake work, you canthe viewing glassIf the model is paying you, bet you won't have in the camera, as when cus- and driftingbeback preset124 circuits occur. and couldautomatically The circuitbe established shown monitor here so themselvesthat is typical the controls of should this: could The any You'retomersing doingthe coming model portrait back(and thisagain. can sometimes go to $25.00On the other hand, if you're pay- per hour! ), 125 by25 the time you get the lights all set,per hour. She's perspired, makeup is running, and your model isn't worth hair therather case of Triacs, over than voltage -sensitive and may require, especially 100 ma for at least a few uses. in properly.lightcomfortable,is stringy. dimmer. Then With andwhenTo getyouthe you're around lightinghave readysufficient these reduced, to problems, shoot, light models to setthe theauthor uses this sortyou close down are always camera of gerswitch.connected toTo provide diode, were developed for this purpose.Two devices, the unijunction transistor this short-termthe gate. current, a capacitor is usually This requires a low -power on -off In theand circuit the trig- oftreatment,the wear diaphragm,lights and down raising tear again,on thethe lightlampsand level only to open up the lights, make the everybody's happy.also, which last a lot shoot, saves a lot exposure, dim This kind of shown,canphasingtical,20 to be with capacitors, 174° themodified conduction for anglelower can loads be variedbyon substituting eachthe from exception half approximately -cycle. a TIC30 of theMost for of the parts are and matched trigger diodes. This circuit 250K potentiometer, matched not cri- Usethe a TI40A4, 2N685A, and theLAMP unit will handle a maximum of 700 watts.and you can increase the wattage to 4000. This full -wave SCR circuit is capable of Thyristor Lamp Dimmer controlling loads up largelyrheostatsto required1000 beenwatts. andbulky replaced transformers and relatively by solid-state of ineffective various devices such In the past, the control of such components which, due types. power levels They have as huge DIODES:PARTS LIST Courtesy: CAPACITORS:Cl, 2-.1 mfd Texas Instruments achangingever,limitedto family their high to relativelyname the -voltage,the general control for a lowhigh group complexion of -power of devices. thyristors of all Two this. have of thesebeen slowly power -handlingvoltages capabilities,at very low levels. "Thyristor" is are the How-were D5,D3,D1, 6-TI40A42-1N20694-TI42 RESISTORS: R2R1 -250K-1K pot tifier,thevariouslyunilateral gate allowing of knownthe thyristor, device.SCR current as conduction the While flow Triac, in oneisQuadrac, triggered direction or by Bilat. or SCR, and the bilateral thyristor, conducting it behaves like a rec- a positive voltage applied to only. The Triac Variable Rate Flasher direction.impedance,voltagehas the advantageof any similar polarity. that to itthe Then can forward be it can conductdrop of acurrent diode. in So either it is The gate of a thyristor exhibits triggered by a gate -to -anode a nonlinear low - lamptype.This is circuitChangingthe an integral operates partvalues at of about ofthe Cl circuit and and is a 60 flashesC2 will per minute. The vary the flashing 12v, 1 amp source.necessary126 for a thyristor to be driven by a low -impedance In other words, the thyristor is current -sensitive cellentrate. timer.With afixed flashing rate of Of course, there are applications 60 per minute, it makes an ex- where you 127 nonofwouldwill -inductivethe not new prefer want electronic a deviceto light, have suchtobeepers. an replace audibleas in a thephotographic indicator. lamp-for You darkroom, example, can use oneanyand MULTI VIBRATOR LAMP AMPLIFIER S1 TRANSMITTER CIRCUITS TRANSISTORS:PARTS LIST RESISTORS: Courtesy: RCA CAPACITORS:C1-25Q4Q3Ql, -2N441-2N2702-2N217 mfd electrolytic, 12v MISCELLANEOUS:BATTERY: B1R5-120R2,R1, -12v 3-100K4-2K ohms Remote Control Transmitter -Receiver C2-100 mid electrolytic, 12v I1 -12v, 1 amp numberHere isof a controlling 27 -MHz transmitter functions, such-receiver as opening system garage doors, suitable for a thefrequencies.transmitterandand inputapplying modulator. (base) is Q3 Q1 basica crystal ofandserves finalcontrols Q2 -controlled asamplifierfunction a to frequency model asQ4. type, oscillator boats -generatingusing and (tone toneairplanes. generator) oscillator, operating The modulating signal is applied directly -modulated The to singisIscoupledat betweeninductivelythe the frequency switchto Q4.the coupled groundspowerThe of output,crystal sourceto the the positiveconsistingXl. antenna and The ground; side oscillator jack, of atherefore,the coaxial battery,is inductively type. depres- of tone -modulated RF, caus- S1 128 ingThe all antenna circuits signalThe to operate. receiver is applied shown to the is collector a direct of-coupled Q1 via antennaregenerative type. 129 C3 R1 R4 R5 R8 L3 R6

12V L2

50 -OHM LOAD C2 L1 50 -MW OUTPUT Cl - L POWER II (6;

Q1 Q2 Q3

-C10 .R10

= C7

X1

S1 R2 L_I_ C5

I

COILS: CAPACITORS: RESISTORS: Ll, 2-Adjustable RF coil (J. W. PARTS LIST TRANSMITTER Cl, 2-.01 mfd R1, 5-6.8K R8, 9-150 ohms Miller #4403 or equiv.) Add 2 C3-. 1 mfd R2 -20K R10 -1K turns of #24 enameled wireon TRANSISTORS: C4,7,8, 9-.05 mfd R3, 4-100K R11-47 ohms cold end. Ql, 2-2N1274 C5-56 pfd R6 -47K CRYSTAL L3-RFC, 15 µh (Delevan #1537- Q3, 4-T1395 CU, 10-33 pfd R7-4. 7K X1-27. 255 -MHz 40or equiv.)

R8

c8 R1 R3

K1 C2 T1 11L2 0

ti C14

C3I C7 Q4 C9 C4 R5 C10 C13

Cl I,

L4 R7

C11 - C12 IL3

R R4 C5

'MC

CA) PARTS LIST RECEIVER R8-270 ohms CAPACITORS:TRANSISTORS:Q2,Q1 -2N2188 3, 4-2N1274 COILS:BATTERY: B1R9-150 -12v ohms C4-18C3-15C2,C1-.001 pfd mfd 7, 10-.05 mfd L2-30Ll-Adjustable mh chokecoldturnsMiller RF (Budend. of #4403 coil#24 CH1227 enameled or equiv.). wire (J. Add 2 oronw Broadcast Band Mini -Transistor C11-40C8,C6,C5, 14-100 12-.002 mfd mfd electrolytic mfd electrolytic 9, 13-5 mfd electrolytic L4-RFC,L3-8.5 15 by uh(Delevan (Stancorequiv.) C1279 1537-44 Or Any broadcast -band receiver will pick up the signal radiated RESISTORS: R3,R2-2.R1 -22K 4-1K 2K MISCELLANEOUS:TRANSFORMER:T1 -10K to 2K or(Thordorson equiv.) TR7 byLituned to any-circuit this circuit. point between 550 oscillator, whose frequency may A single 2N321 transistor frequency. and 1600 kHz. Ll, Cl, To comply with FCC beoperates adjusted as by a and C2 coil Ll. Level control R5 adjustsR7R6-2.R5 -10K -10K7K receiver pot K1-Sigma #11Fequiv. - 2300 -G/SIL or sensitivity to the determinecrystalphonoregulations, or the ceramicThe theoperating desired input cartridge output is sufficient antenna must be keptmicrophone mayis introduced be used, at J1. to drive the circuit, or a under 10 feet long. Ceramic or crystal too. heldconfigurationducts,biasedcontrol in relayto the cut-offsignal. active K1 the pulls and transmitterposition commences in, operating during button to the themustconduct. entire load be depressedcircuit. When and When the signal is present, Q4 is required cycle. no longer Q4 con- In this Courtesy: Radio Shack L1 endtinuesoconclusion.Releasing -of that until -operation once such the A the button latching timeswitch. operation aswill circuita preventreset has could circuitbeen the beactioninitiated, built from around were operated by an it would con-operating to relay K1 PARTS LIST RESISTORS: TRANSISTOR:CAPACITORS:Q1 -2N321 BATTERY:COIL: R4R1,B1 -4.3K 2, -3v 3-10K 132 C4,C3-.05Cl, 2-75 5-.02 mfd pfd mfd ceramic Li-Ferrite loopstickband) (broadcast 133 poTs LIST R3-47R2-1. 2K ohms TgANSISTORS:Q2c21Q3-TA2711 ---2N3866--2N3553 COILS:R5,R4-10R7-50R6-51 8-100 ohms ohmohms pot ohms Sonobuoy Transmitter DIODES;CAPACITORS:D2Di-Varactor -12v Zener L3-3L2-5.5L1-22 turns uh 4h #16 wire,1/2" L 3/16"1/4" ID x ID Sonobuoysthe Navy. are They anti-submarine are dropped warfare from aircraft, (ASW) devicesfloat on used the C2-75C1-0.05C3-32-250C5-2300C4, pfd mfd pfdpfd, 10, 16, 17-3-35 feedthrough mfd pfd L4-5L5-2L6-2 turns 1/4 1/4 #22 turns (closeturns wire,ID #16 xwound) 3/8" L #18 wire, 7/32" wire, 1/4" face,found,andabove. by additional Three triangulation sonobuoys buoys the are are submarine dropped usually droppedto is help located. plotin a its and transmit signals from submarines to the suspect area,If the sub is airplane course. C7-14-150C6,C9-500C8-50 pfd pfd pfd 12, 15-0.01 pfd, feedthrough MISCELLANEOUS:L7,L9-5 8-1.0 turns u.hID #16 3/8"(close wire, L wound) 1/4" ID x tothisWell, electronicuse circuit maybethis as as -typeayou You meansa guide, aren'tscuba will of notice trying wirelessdivers thatto ought communicationlocate this to circuit submarines, be able is basicallyto with devise but a boat. with aa straightforward it seems that some really heads way-up RESISTORS:C13-8-60C11,R1 14-1500-1K pfd X1-Crystal circuitmodulation)applyfortransmitterrupler AM another just modulation, modulated belowusing at type the L8.a final of simplybycrystal modulation an amplifier, FM remove -controlled input. (such R1preferably and asoscillator the high-level inputin the andjack; collector Heising quad- then, If your requirements call Wireless Broadcaster (FM)AUDIO OSC I LLATOR-OUADRUPLERX1 Q DOUBLER Q2 Q3FINAL OUTPUT(50 OHM) 0 The oscillator frequency in this circuit antenna coil and a is determined by 365 -pfd tank R1 I C7 C raL5.1"C24. circuitbroadcastcapacitor.Modulation Ll/L2 band, and is applied and by Obviously, this through a Cl -a ferrite will work with any the "brute force" carbon microphone unit is designed broadcast method.receiver. Q1's base whichfor use acts in likethe force C5C8 R6 voltagedirectofa variableoutput applied passes current oscillations resistor,speech. is applied one to carry the The resultant whose resistanceto the antenna.to the transistor voice intelligence, fluctuating (or varies with theAccordingbase, to causing modulated)along with FCC the Courtesy: D141 RCA CIIL3"41111111111 R5 1111111 + 15V regulations,thethat broadcast a carbon antenna While carrier,microphone the application length must not of this circuit must be used, exceed 10 feet. is limited bythe receiver the factcircuit 1314 135 loudspeaker.can Then, easily be modified by substituting a relay in place of the when the microphone is activated by the 0 sittingwoulddevices,theuser's voice, purposes.also providing make a fine one-wayreceiver wireless can then intercom be operated for baby- to any number of electrical the relay will close. the user with voice control. If a latching relay is used, The circuit Marine Band Transmitter cr wattslopeDCwithThis supply. distortiontransmitteran into overall a 6 -ohm of current will 5%. load. provide Required drain aof 13audio 1.5 -watt amperes modulation 2.185 from -MHz input a13 carrier is-volt 12 It boasts an overall efficiency of 65% with enve- T1 and T2 are close -coupled on -LP 0 Q 000'- 0 closemodeoutputstoroid -coupled crystalforms to theThe and48 in timedgrounded -ohm theare feedbackused transformerinputs. -basefor matching path Colpitts connects from the oscillator base theinterstage oscillator to ground. employs 5 -ohm out- A a series - ...... -+ N ...... + CI) putjunction (30 mw) With to the the driver. leakage The reactance transformer and reflected primary, reactance in con- Z4.1 ca7). CT) ,,,7"" t fromrequired the secondary, collector loading forms theof 770 11 µhohms oscillator provides a loaded Q of coil, and the )1, , -I NX ..- o crystal5 at 2.185 operation between 2.0 and 2.4 MHz and high enough to MHz. The Q is sufficiently low to allow continuous ZICli (1){-I F... Preserve a good waveshape. Complete frequency spread to {4 2.85 MHz -. b.cs' requires retuning. Reducing the Q to less than 5 I -0, z ,.... 1 --,a) 5 ... - distorts the oscillator waveshape and might introduce stability E.cn ZE.w° zc. v. " tn I ' C;4) . -° : °I . I ., - (00 fg 0 0 0, >-1 I= > 7 'F .?., ,1; :, Problems. The common -emitter driver stage provides a somewhat 1 ,c-..' _.,_, cs; Le5 characteristicswhile this provides are superior. less power gain, the upward modulation Both driver and output are col- o 7 ;-.cl 1 u) c..),4 lector -modulated. Driver modulation provides the necessary C.) 0...c vi,..0(NN I F,z,c1:4 F-.- F ...... ,,,q4 1 ,-, x upward peak to provide maximum drive during the upward aOxF...1 .0 .2 -, bottomoutputmodulationexample. -loadednetwork cycle 9. is 5 ofdesigned-foot the output stage. Any change in the 12. 5 -ohm loading-either antenna with a center loading coil, for to work into a 12.5 -ohm load, a The double pi -section re- ti eY'Y'Y's givesultingsistively serious in or envelope reactively-will thought distortion change to the antenna used with this unit. Net- and loss of power. Therefore, the collector loading, re- II U- C-) 65 work capacitor values given are ideal for 2.185 MHz. I I 8 4 =w C40)4 -i" c7.,Qg 40 -Watt CW Transmitter forDesigned many communicationsfor 40 watts CW, inthis the 50 -MHz range. transmitter circuit is suitable As is, adding it's 8) uationsidealclosea modulator for requiringto amateur 50 MHz it isvoice and easily(within othercommunications. adaptable several CW transmissions, MHz),for ham the phone LC or or by If your frequency is combinations other sit- levelseemlationchangedshown modulationmostmethod will accordingly, appropriate: probably will at work Q2. serve of low-levelwith course. the this purpose, transmitter,modulation or LC two immediately If you want a continuously While any standard modu- at Q3, or high-ratios may be -variable II frequency, substitute a VFO for the crystal. If a 138 balancedmay be output connectedThe is required,schematic from the a shows suitableoutput an leg coil unbalanced -capacitor 50 -ohm output. through T1 to ground, network 139 atandusing the perhaps aexisting variable 50 capacitor -ohm as a easier, is to use an impedance output. means of tuning. -matching baiel; Another way poTsTRANSISTORS:Qi 3-2N3118LLST RESISTORS: R3,R2R1, -3.9K 6-5108-2.2 ohms wire -wound AGC stage (Q4).Unique among the transmitter Transmitter power circuits in this book output may be is the revaried Q4Q2-40341 -2N3053 R7-240R5R4-51 -24K ohms ohms quirementsto(and base held station (12 constant) and or 28v) mobile by make the adjusting R9. operation. transmitter readily The circuit's poweradaptable , CAPACITORS:DIODE: Q5Cl-variableDi capacitor,-1N3067-2N3375 90 to 400 COILS: R10-5.6R9L1-I -50K turn pot ohms, (AGCof #16 lwameter, control) wire; 5/16"; length, inner di- 1/8" OSCILLATOR LOW-LEVEL AMPLIFIER DRIVER C3-30C2-51C4, pfd, ceramicmicapfd,through Arco capacitor, 5, 11, #429 or equiv. 14, 19, 1000 pfd 20-feed-1.5 to 20 L3-oscillatorL2-RF choke,woundturns; 1µhform secondary, from#22 having "white wire on dot" coil; 1 3/4 turns;primary, 7 CTC corecoil C6-variableC9,C8,C7-36 10-variable pfd capacitor,micapfd,60 Arco pfd, Arco#402 #404or equiv. or equiv.16, 22-0.02 mfd capacitor, 8 to ceramic L5,L4-5L6-4 7, turns 9, turns 10, ofameter, of#16 Bstock wire; & 5/16"; W length, 11-RF choke, 7µh #3006 coil inner1/2" di- C13-variableC12-91 capacitor,pfd, Vitramon 0.9 #400 or pfd mica equiv. 14 to 7 to TRANSFORMER:TL8-6 1-current turns of transformer #16Arnoldameter, wire; #A4 3/8"; -437 length, -125 -SF, 3/4" inner di-(toroid), or C15-variableC21-variableC18-0.01C17-1000 mfdpfd capacitor, capacitor, ceramicpfd,150ceramic pfd,Vitromon Arco 32 #426#464 oror equiv. equiv. to 250 MISCE LLA NEX1-Crystal, OUS : requiredequiv. frequency OUTPUT(50 OHMS) A Class A linear amplifier 100 -Watt Linear provides a faithful Amplifier reproduction designedofduplicateIf the requirementit inputstrikes into of signal,an youthe amplifier, that input as but strange envelope.not the output envelope bear in mind that it is withoutthat some inefficiency cost in is A typical case be an exact amplified is used to drive often a strictdeliberately efficiency.where this 140 Courtesy: RCA ousaninightbe amplifier wave true (A-3). ofis whenanotherTo a increase the transmitter power, low-leveltransmitter transmitter with a modulated continu- you would 141 tinuousbyalso using have wave ato Class increase A circuit output from the low-level the modulation level such as this, the transmitteras well. modulated on, However may be' componentslatedapplied output directly atCl,You to will the notice that an increase of 100 C2, noinput values of arethis given unit,Ll, andfor and RFC. watts. Similarly, no result in the input a circuitvalues410,14, 500- MHz One -Watt Oscillator tingand arefrequency. the provided RF chokes.A suitable for the power source must also be These outputmust be circuit determined components C3, provided for this at the C4, La opera' anip, This interesting, for the author can amateuralifier, mobileshould and orbe system duemarine to inthe relatively free of ripple. an automobilenature or in of the design, the powerThe unit can be a boat, either used as supply on andrecallmegacycles said the yet, circuit is particularly "I'm sorrytime sir, when a and they never transistor salesman transistors just don't will." Well, perhaps smiled indulgently isn't 500 mega-operate at 500 in a frequencies. cyclessense,"coils"section inare this actuallyCompared to low -frequency -semantically.he's right. After all, schematic. Take a Lecher bars-parallel 500 megaHertzcircuits, looknotice at L3 (see and parts L4. list) there is an unusual brass rods only These that theycuitcritical,1 1/4electric are inductances, inches for for the the output separatedfind Lecher by 3/8" bars in use, long! bars do indeed formthe space betweenYou will also capacitance. spacing. This spacing and their length is athethem two outputserving tankAt as higher frequencies is highly the di- func-cir- yoution oftenfrequencyaphenomenonknown of the frequency Whenelectric you as design for current to travelat which along they arehigh frequenciesthrough"skin effect," you it. the tendency This characteristicoperated. must reckonthe surfacewith of a of a high - was TRANSISTORS:PARTS LISTQl, 2-2N3053 RESISTORS: Courtesy: RCA powerputconductorThermally to wasgood rather usehot, thannot just such that conductors on high -power realizing that theelectrically hot. To get radar systemsbecame where excessively current traveled close around this, hot. the CAPACITORS:Q5-TA2758Q4-40251Q3-40319 RR5R3,4-500 ohms1_, 2-2K5 4 05 toconductorsome the surface unknown and of pumpedgenius, the a conductors, used copperliquid coolant through it. effect, and non- tubing as a Electrical C8-100C7,Cl,C5, 11-.0027 2,6-1 mfd mfd mfd 3, 4-see text COILS: R9-510R8,R7-20R6-12K 10 -100 ohms ohms -ohm pot characteristicsaconducting result of fittingsthis were were technique, unharmed, due to skinused to maintain the nightmares." early radar systems coolant flow. As were often I42 C10-.03C9-1000 mfd pfd, feedthrough RFC1,Ll, 2, 2-see 3-see text text referreda circuit to ofas this"plumber'sAdmittedly, type the 500 -MHz regionis primarily is sparsely of service to UHF populated, and experi- 1 43 465therementers. -MHz is no citizens reason band However, with some additional why this circuit can't befor control and experimenta adapted to 465andThe -MHz thisamateur TV could radio transmitter. serve as an excellent television frequency oscillator/driversignaling applicatiis in this range fo 300/600v Power Supply When you look at transmitter schematic diagrams, it seems Courtesy: RCA glowbuttheythat rarely alwaysbrightly one dodoes tell andthey yousee are give often completely you use a bigtypical out vacuum of supply. keeping tube with rectifiers modern- that what power supply voltages are needed The supplies CAPACITORTRANSISTOR:PARTS LIST Q1S, -2N3553 COILS:RESISTORS:R3-2.R2-75R1-1. 7K ohms 8K (intermittent).daycomplete transistorized supplyS1 controls transmitters.capable AC of to delivering the transformer, 300/600v and at when 330 switchma S1 is This unit makes a rather C3,C2-0.01C1-500 6, 7-variable pfd mfd ceramicto ceramic 20 pfd, disc Arco disc 402 capacitor, 1.or equiv. to L3,LI, 4-parallel 2-RF inchokes, tronicslength, brass 0.22#60ZI89 or 3/16" in equiv. rods, I 1/4" diameter, Lih, Ny- S2inflowingclosed is and used applythe in for thegreen remote powerunit. pilot When switching, to light the S2 transmitter. signifiesis closedwhich thatthemeans The relay primary jumperthat (K1) you power will across can pull is C5-50C4-variable pfd ceramicpfd, capacitor, Vitromondisc 0.9 #400 or equiv. BATTERY:B1 -28v separated by 3/8" diodesismitteruse developed your B+. and microphone capacitors.The by transformera voltage pressBoth doubler -tosupply supplies -talk voltagescircuit switch 300 volts consisting toare control directly,not available oftrans- whilethe 600 volts PlyandB+ceiver300simultaneously to willthevolts theB+. 600 provide filteris With -volt supplied, due formed thecircuitvoltages to relay the which byis relay inungrounded toC11, the powercan hook-up. normallyC12 be a used and numberand With L2 -opentoclosed. theactivateis of disconnected position,relay circuits, theclosed, re-thein- This sup - 144 all-aroundcouplecluding of transmitters, meters bench supplyin appropriate amplifiers, in the laboratory. circuits and with it can the function addition as of an a 145 ,--I 3-, C.- J..# i.., r.., .-.. 0 Go0 I ... _::,C) 2 CO 0 ., .g., w7.) ,L,= C: o: E at I.. a:1 CD I tCD 0co E 10 CI COCD 0"' i ,(;), .il'11 0 0 .2 .-1 -t7to . . 411io" p,c 2 c'/ iii g.= Ca'- '2) 09), ,.a)g. W a)g. 0 ,?, %) 4 . t 3 c.. .-:, 4 g Mobile Power Amplifier 6": 0 ca it1,5 "1, g in c;4 ct- i 1 ..-4 co v 2 o 0 3 co ''' 8 9-- , ,.° 2tttaltsc-,,,,,,2140 , , ;=5 g ,_, :_-_,, ova 0c9.-.621-gc\to- T 0.-wzc.$), -,u2., ,_,A, z g1 c.,-cc,:la z 5' a IT - C) -,0o<,21.71148.4'.:(o`lk21.1 a 'I'' F.z F-; 1,7 4' 1741i"0 4 'p;', ,.ci, ''' .., desiredthatitWhile will the this frequency. operate satisfactorilycoil/capacitor configurationscircuit was intended Obviously, at lower frequencies,for use in the 50 -MHzin light range, of the design para- are changed to providedtune the How- meters,Federalforever,an other example, Communications services, there is no reason why this unit was meant a unit such as provided that power Commission are not the circuitthis forcould amateur notbe builtbe radio use. limitations set by the exceeded. As for citizens adapted marine5band -wattbandsgation) operation, maximum andas possibly well. amateur but on frequencies, set by the FCC. policethe and/or power rating would otherand (after emergency properIt could be used on well exceed the investi-service the heldifalsoity such as tobe a amobileapplicationused minimumThe as 12 a fixed-volt to is avoid made, power transmitting requirement station rig, but with a -base amplifier. the supply voltage AC rippleat once suggests applicabil- suitable supply ithum. Again, be sure If the amplifier could that is is beunmodulatedusedIt applied is asimportant a finalacross signalThe powerthat thebest of the lowemitter way amplifier transistors power. to tune the circuit is to start with a dummy of Q2. doHigh-level not absorb modulation the load, mayit can be driven with an load. but peakingPasserlythem it tuned quicklyclose all the into coilstheto operating frequency. normal fashionthe asantenna. well. andthe capacitors capacitors with for maximuma grid Toward this end, Have the driver prop- When you turn the -dipper to get lamp glow; start by H46 put.then,unit on,Take (more quickly off carefully) the tune dummy do a fine-tuning job for load after shutting down maximum out- the rig and 147 retunestrengthreplace C3 itand meter. with C4 your for maximum antenna. Now output turn as theindicated set on byagain, a field and Again, repeat all the adjustments with the antenna, just to make sure you're on the button. LI L7 50 -Watt Transmitter 50 watts at 50 MHz from a 28 -volt DC supply is is 62% and power supply drain offered by thisbasislargeandis workcircuit.less final signalfor than design theOverallis a network typical to efficiencyproceed synthesis. in a precise, Class3 amps. C Thetransistor combined input/output power gain 27 db. The design approach employs This method permits net- mathematical manner, admittances as a of the driver gainfinalconditionswhilegrounded ofstage providing 8 db. of(Q3) -emitter the isa final bettera 2N3950TO transmitter. representation-60 case.operating The NPN silicon transistor is The large packageThe transistor area in used in the withof thea minimum actual operating power mounted in a dissipationemittercontactsink is -ground recommended. required pathThe sodriverin vitalthe final, stagefor power transistor gain. (Q2) requires power with the RF ground provides a Wakefield FC-502 heat the low -impedance Due to the high handling Courtesy: RCA 6capacities tourationMHz. 6-1/2 prevalent wattsdictated output byin all thewith three typically stages. 18 db power gain The driver also follows the common final stage. The 2N3961 delivers To achieve the desired -emitter config- at 50 CAPACITORS:TRANSISTORS:PARTS LISTQl, 2, 3-40340 COILS: L4,LI, 5, 6-3 1/29/32"1/4" turns ID, ID, 1/4"#18 3/16" longwire, long 2, 3-2 1/2 turns #16 wire, pletedimpedancehigh power directly path. gain, through This the emittermeans the case,the DC ground for even a one is grounded through a low - circuit must be com- feedback to reduce -inch length C11-.2C8,C5,C2,Cl, 3-65-3404-100-550 mfd ceramic pfd pfd 9,6, 7-100010-1800 pfd pfd feedthrough ceramic (L1-3L10-ferriteL7, use General choke,ID,material, 1/2" CeramicsZ long 1/4"-28 Q2 x 3/8") 8, 9-4 turns #14 wire, 3/8" = 450 ohms Powerofacts50 wire MHz, asgain. can the usingcause baseThe a -tosufficient 2N4072,crystal -ground -controlled whichdeliversdegenerative RF path. Colpitts 100 mw.oscillator The crystal (Q1) operates A series resonant cir- at 148 thecuit reactiveis formed portion at the oscillatorof the reflected collector load by impedance Ll, Cl, C2, and of the 149 collector.livered to thedriver and the coil tunesThe 5 - 80 pfd capacitor thecontrols oscillator the collectorpower de- tothestead ratings of resonance. PARTS LIST FM modulation; amplitudeon the final. The circuit may be adapted modulation would exceed to CW keying in- TRANSISTORS:Q3Q2Q 1-2N4072 -2N3950-2N3961 RESISTORS: R2-4.R1C15-.1C14-.02C13-1000 -2K 7K mfd mfd pfd feedthrough CAPACITORS:C1-12C6-.005C4,C3-5-80C2-150 5-1000pfd pfd mfdpfd pfd COILS: R3-750L3-0.L2-0.L1-0.L4-0. 15-0.20ohms05812 22 uh uh uh IL h C11-15C10-5-50C9-9-180C8-62C7-30C12-1.5-15 pfd pfd pfd pfd MISCELLANEOUS:RFC3,RFC1,X1RFC5, -50 4-3.92-5.6µh 6-Q-MHz zener diode helps solve a current -voltage charac- number 153 and you probably won't even miss tion.rentstheteristic voltage up has to the acrossa sharp maximum the break diode value at remainsabout at the 0.1 allowablealmost ma. Beyond constant power this dissipa_for The voltage characteristic is flat, like that of a point, gas_cur: transmitteritis It until youreducedshould beby notedthe need it.or amplifier, that the voltageamount between of protectiveThen voltage you'll wish you be obtained by subtracting the platehad and it! cathode Vd. The re - the pro- notlators.oftube voltages need regulator. In firing addition and Powervoltage lower to these regulatorcurrent higher advantages, thanranges diodes the than provideregulating power do gas a regulators wider voltage,-tube choiceregu_ asdo mitterproperheattectivesuiting chassis.biasoperatingbias Vd Zener from thediode may grounded dissipation sinking, the diode and voltage Vd. Maximum should be mounted on the trans-cathode operating bias. For is the product of total diode dissipation do the gas -tube types. PARTS LIST atcathode a specific current TUBE TYPEcase 807 temperature can MAX DISSIPATION = 25 w be obtained from the case DIODE: D1 -Z en er VdE,gE, -= = 750300-32 vv FROM TUBE CHARACTERISTIC CURVES 1 d = 21_w750 = 33 ma CAPACITORS:C3-330C2-470C1-.1 mfd mfdpfd TUBE TYPE 6146 E,gE, = = 600 200 v MAX DISSIPATIONId = = 25 w 25 w 41.7 ma COIL:RESISTOR S: R2R1 -500K-5K pot TUBE TYPE 813Vd = -43 v FROM TUBE CHARACTERISTIC CURVESPOWER DISSIPATION = 125 w 600 Courtesy: Texas Instruments L1 -20h, 15 ma VdEigE = 300-22v ,v = 1600 v TOTAL OPERATING CURRENT ,------200 ma Id = 125 w1600 =7B ma Courtesy: Texas Instruments B Zener Protection for Power Amplifiers RFC1 amplifierWhen excitation tube, or drive is removed from a final or power it can take off on its own and build up very In SERIES1N1816 destroyfromadditionquickly happeningan to expensiveto levels allowing by beyond tube. throwing off -frequency the tube'sprotective plate emissions, bias dissipation on youthe tube canrating. easilywhen The circuit shown here keeps this V Vd - PROTECTIVE - OPERATING BIAS BI AS zenerexcitation154 adds ceases. nothing of its own to the range or quality of the It's somewhat like buying insurance-the I 55 temperature vs power dissipation curve on the data sheet terminal transmitter operating frequency are not always the popularzenermaycomes be is tubewith theused onlytypes,the with diode. component usingother outputthe 1N1816 tubes, audio The chart shows added, a parts list is not series zener.parameters for or RF. Since included, Zeners three that the torsame,circuittriothose and coil remember!and A design glance your ownlisted in the chart is needed, youvalues and specifications. at LCthe values.chart will give you capaci- If a frequency other can use the basic +6.8V'+10V r C11 R4 FET VFO Li C2Cl C3 - Cut TC5 =DS R2 L2 C7 A field effect transistor serves as the heart of this variable - TC6 OUTPUT tofrequency importantreplace oscillatora thatcrystal you oscillatorselectcircuit. a Since range compatible with the crystal circuit in a transmitter, a VFO is most often usedit is 'ADJUST FOR 2V PEAK OUTPUT J1 RCA frequencies being replaced; the Tuned Circuit Data crystal frequency and the PARTSTRANSISTORS: LIST C12-0.025 Courtesy: mfd, 50v ceramic Circuit Component 3.5 - 4.0 Frequency of Operation (MHz) I 5.0 - 5.5 J Q1 -3N128 FET RESISTORS: disc Cl Component Value100 (C = picofarads) 50 8.0 - 9.0 50 DIODE: Q3Q2-40245D1 -2N3241 -1N914 R2R1-12R3 -22K -12K to 47K;peak select output for level2 -volt C4C3C2 390100 25 None390 25 None 25 CAPACITORS:Cl-double-bearingorpacitor, equiv. variable ca- Millen 23100 or(See 23050 Table for value.) R6-240R5R4-820 -47K ohms C6C5 680 680 560560270 C3,C2-25 4, 5,pfd, 6-silver-mica airtor,marlund trimmer, (See APC-25Table capaci- Ham- for or value.)equiv. COILS: L2-2.5L1-inductance mh; miniaturecharacteristics) RF choke, Millen J300-2500 or (See Table for WireNumber size of turns L1: 171 20 14-3/4 20 1 11-1/22 18 C9-0.C8-0.05C7-2200 1 pfd, pfd, 50v, ceramic disc silver50v, mica ceramic disc feedthrough MISCELLANEOUS: equiv.iron core, connector, chassis DiameterTurns per (inches)inch 16 1 16 1 18 C10, 11-1500 typepfd, J1-coaxial mounting 156 2 I B & W 3014,3015, Polycoils 1746,1748, AirAir Dux Dux 816T, or equivalent. 808T, or equivalent. 157 Ci SP SPECIAL AUDIO CIRCUITS RI. Electronic Metronome Courtesy: Radio Shack graphicthatauthor,Electronic mechanical darkroom. for example,metronomes metronomes has found this device useful in With the metronome set for may be used for just about anything are used for, and more. The one -secondthe photo- Multiplex Demodulator everythingwiringclickcouldn'tintervals rate is see checks fromtheexactly, anyway! connection about out OK,three Just and from tocount 250the the offunit transformer the still doesn't it eliminates the need for a clock that per second. The only critical clicks. R1 varies the secondary. work, just you If chanicsauthorAt the was timeMagazine employed that stereoin Chicago. as FM electronics editor for Popular first made its appearance,The big news in hi-fi The addition of reverbera- the pre- Me- the Ittry is reversing important the also blackPARTS to observeand LIST green wires from the correct polarity of Cl. transformer. viousers,ingeration" echoyear seemed hadchambers, wasn't been to open reverberation.easily coupled up " and having been so recentlymarketable. Along came the sound. with L -pads to the "wing" But the word "reverb- "multiplex," burned by speak- CAPACITOR:TRANSISTOR:C1-10Q1 -2N507 mfd electrolytic, 15v TRANSPDR1V1EBATTERY: RB1R2 -10K-3v whichfrighteningor "multiplectors, is a much words,The easier theZenith industry Corp. invited the press to witness mouthful. wisely settled on the first"stereo stereo FM," They were 158 RESISTORS: R1-1 meg pot, linear T1 -500 -ohm primary,secondary 3.2 -ohm goingFMmum broadcast, to specifiedtry to get and foron soon approval the exciting by the air as soon after the FCC had passed. word was out. the legal time We waited mini- 159 COMPOSITE R1 R24 LEFT, PARTS LIST R12,R11 17-5K -1.5K pot CHANNE INPUT CI Q1 C4 C5 03 ST OUT R13 PUTL isANSISTORS:Q7Q1 -2N408to Q6-40359 R20R19-8.R18 -10K-15K 2K pot R2 Cf. R3 C8 - N1 C10 N2 N1 I 116 DIODES: D1 to D6 -1N295 COILS: R22-820 ohms C2 N4 I 3 DI Q4 C12 R14 CAPACITORS:C1-0.33 mfd LI-10 mh, QThompson = 46 at -67 Ramo - Wooldridge kHz; Q2 N4 D5 R15 1 OUTPUTCHANNELRIGHT C2-560 pfd #E0 -14039-R1 or equiv. 19 kHz; 1 C3-300 pfd (adjust for optimum L1 C31 R4 R7 8 L4D2 R9 L5 )101 C13i R161117 C4-1000 pfd,separation) part of L2 L2-69 mh, WooldridgeQ equiv.N1/N2= 93 at = 5.66; Thompson-Ramo- (includes C4) #E0 -15484-R3 or TO T118 C6-1000C5-10 pfd pfd, part of L3 93 at 19 kHz; -12V AGCTUNER R19 R20 R23 Q7 R25 C10-390C8-1000C7, 9-0.47 pfd, mfd part of L5L4 L3-69 mh, WooldridgeQequiv.N1/N2 = (includes = 40.2; Thompson-Ramo- C6) #E0 -15486-R3 or R18 R21 RESISTORS:C16,C15,C11, 12, 17-1.018-0.02 mfd rrid 13, 14-7500 pfd, +5% L4-69 mh,Wooldridge QN3/N4N1/N2 - 88 =at - 5. #E0 24, -15360-R9 2; Thompson-Ramo- N1/N3 = 19 kHz; 5.21, or Qse R22 Courtesy: RCA R4R3-6.R2R1 -120K-91K-1K 8K L5-41 mh,N1/N2equiv. (includes= C8) 11.62, Q = 108 N1/N3 at 38 kHz; = 19.8, roombreathlessly, filled with the glorious excitedly, and at the stroke of the three-dimensional sound. minute,the The R8-510R7,R6,R5 -18K ohms 9,13, 14, 16, 21-3.3K 15, 23, 24, 25-10K MISCELLANEOUS:II-stereo lamp,Wooldridge 14equiv.N3/N4 ma, (includes= 10v 2; #E0 -15361-R7 C10) Thompson-Ramo- or similarmajorNewdifferences,question York FM to was this, equipmentCity daylighton so everybody'shad that beatsaving manufacturers people who had bought us out. time,lips, but all workedto no avail. against Shortly thereafter, many were producing units mono FM tuners Time zone us, and R10-220 ohms pensiveplugimplicationofturers,could salesat unit the realizing adaptpotentials to back plug was them chassis in,thatthat forand stereoall labeledthere or markets, simply addedstereo. you would have to buy was wasan inex- on the way, but notUnfortunately, some manufac- "Multiplex Adapter." The an unconnected yet sure Line -Operated Phono Amplifier verttunerfacilities it. around that that'sare Today,built still most FM tuners Or if you're building right in. However,operating if mono, this circuit will con- are already equipped with stereo a tuner from scratch, as youyou were! you have an older fortransistorsFETsMoreIf a there's andconvenient operate thanat low an inputAC supply. voltages, making batteries one fly in the solid-statehigh -voltage ointment, transistors it's the factto provide that AC operation This circuit combines 160castadapter.well ismight being I1, be thereceived. if stereo you read this book, be sure to include this light, will turn on when a stereo broad- ask yourself Veryabout often, design when you think in terms ofsimple phonographs, phono amplifier. you parameters and what can you get 16I he'dman)for a have tookdollar. ato different spend to stand. get good He wanted quality! to knowThe big how The designer of this circuit (a very practical factor, LITTLE of suppliestakendirectlyfirst turned low on, voltage from while filter for capacitor the capacitor FET Cl which is Cl. charging. Ahas resistance a 50 -volt divider break- Q2's Vcc is transformerlessdowncostaddscourse, germanium a pointsfew is to bucks eliminate well power circuits. to under the thetransistors cost. 100 power volts, usuallytransformer, precluding have voltagewhich their Unfortunately, available 101,,,, usuallybreak,use in trol.ceramicfilterdown. capacitor Due cartridge toThe theis amplifierportion needed.is low connected current FET acrosscurrentdrain is a ofthetwo will the 1 -stage meg not3N126 exceed volumedirect FET, -coupled7 con- ma. Theno field type. effect A transistor is operated common -drain 0 3N126 Q2 used(like aas cathode a bias potentiometer -follower) and for the the source audio load output resistor transistor. is also U R4 T1 S therefore,ohms at thequiteThe bias satisfactoryoutput conditions transistor sinceused. has theThe an R5 coupling input bias resistancecontrol efficiency will of is, about 150 CARTRIPHONCERAM DGE 0 C E notmaryThe be outputadjusted to a 3. transformer 5 to-ohm less secondary. than is a about 3 -watt Using 1K unit for an with normal 8 -ohm a 2000 operation. speaker -ohm pri-T1 R1 DI +30V DC former.acrossswings The theabout output tone 4000 control transformer ohms to consists the primary.collector of R6 Whilewith and this C2,the output effects trans- are placed PARTS LIST C R3 Courtesy: Motorola prettymust severe, be tailored this tois suita matter individual of engineering needs. judgment and DIODE:TRANSISTORS:D1Q2-MJE340Q1 -1N4004-3N126 FET RESISTORS: R4R3R2R1-330 -1K-10K,-3K, potohm, lw 5w 2w CAPACITORS:C3-100C2-0.1C1-100 mfd mfd,mfd electrolytic, electrolytic,400v 3v150v TRANSFORMER:TI-ThordarsonR7-33R6R5 -100K-5K ohm pot pot 24S53 Stereo Balancer rectifier isoperated a MotorolaThe directlypower 1N4004 supply from surmetic theshown 115 siliconhere -volt is AC rectifier.a conventional line. half -wave The fiddlebalanceaVery lotpretty with more often, controls panelthe convenient. controls stereo to are having equipmentbyset Channels an accurate Amanufacturers and B prefer to have ear, but you'll find"flat," a balance they may meter not be. You can one. As a result, whenon the schematic con- marginsopurposes.330 the -ohm audio at (R1)"high output resistor line" transistor conditions. in series has with aThe breakdown the resistor rectifier alsovoltage has will several safety burn It limits the DC rectifier voltage to about 120 volts lookceivednect1 toelsewhere theat both stereo sides, system'sma thetype, needle with will a zero be center. When equal levels are re- in this book, you'll find a square -wave gen- loudspeakers. The meter is a 0- straight up. If you cuit.open162 Also, in the it limits event surgeexcessive through current the diodeis drawn when through the unit the 15 cir- You'veerator circuit.got an on Use -the that in conjunction with this -money team to make stereo adjustments! circuit, and 163 You may find one small difficulty with this balancing cir- cuit, and here's how to get around that: High -efficiency loud- speakers require less power from the amplifier to produce sound of a givenlevel. As a result, there may not be suffici- entdrivefrom the amplifier to move the meter pointer suffici- ently to obtain readings.If you raise the volume level enough to obtain a reading,the sound from the speakers can be Audio Mixer

RI DI

R2 With this mixer circuit, you can connect a microphone and a CHANNEL

A guitar, or two microphones, or two guitars to a single amp- lifier or a tape recorder input. The jacks used should be se- lected to match the jacks and plugs on the equipment, and the CHANNEL entire unit should be mounted in a shielded, grounded metal box to reduce hum pickup. While you can mix signals with- B Courtesy:Radio Shack out an amplifier, you will find that this sort of device enables PARTS LIST you to properly balance the sound from each source. What's more,it permits proper coupling into the amplifier or tape DIODES: D1, 2-1N34A deck. RESISTORS: Another excellent application for this circuit is sound motion RI to R4-330 ohm picture production. With the advent of magnetic striped film MISCELLANEOUS: and relatively inexpensive sound projectors, people are be- M1-0-1 ma, zero center coming more and more involved in this activity.In the be- deafening. So, instead connect noninductive resistor dummy ginning, most settle for a spoken narrative, but soon they loads to the speaker terminals. Of course, with low -efficiency want a bit more. Using a stereo tape recorder, first record speakers, you'll have no problem. Another solution isto the dialog on one track, then add the background music to the build a small stereo amplifier, and feed the stereo balancer other track.Connect track 1 output to J1 and track 2 output from the speaker terminals through the small amplifier. Be to J2.Connect J3 to another tape recorder, and make a sure to calibrate the pointer first by adjusting the auxiliary single tape consisting of a combination of tracks one and two. amplifier level controls. Now record the combined music and sound -track tape onto track one of the stereo recorder. Rewind it to the start, and then, as it plays back track one, on which the music and dia- log are recorded, record the sound effects on track two, us- ing sound -on -sound techniques.Then connect the device as before, J1 to track 1, J2 to track 2, and J3 to the sound pro- jector audio input. By running the sound -striped film through the recordingprojector,you will blend all three sounds-dia- log, background music, and sound effects on the film stripe. The result will bea professional sounding job.

164 165 J1 Cl C3 j3 theoneham More practically, first toinvolvingradio, find aswitching need the forfastest from this finger receive game amateur radio operators probably were circuit. to transmit was a problem, in the world. You had In the early days of R5 13+mitter,to throw beforethe antenna you could talk. cut off the receiver B+, and turn on the switch from the receiver to the trans- Then, happily, the coaxial relay transmitter J2 C2 Courtesy: Radio Shack TRANSISTOR:PARTS LISTQ1 -2N104 BATTERY:R6-2.4R5R3, -22K 4-100K meg RESISTORS:CAPACITORS:R1,Cl, 2-500K 2, 3-.5 pot mfd MISCELLANEOUS:J1,B1-1. 5v ment 2, 3-jacks to match equip- D5 C3 TERMINALSI NPUT PARTS LIST C4-10 to 100 mfd electrolytic; to Courtesy: O RCA SCR Voice Control DIODES:TRANSISTOR:D1Q1-KD2101 to D4-KD2103 RESISTORS: R3-270R2,R1 -5K 4-4.7K, ohmspot, 2w, 2wincrease linear release time. 12v byThis the soundaudio -actuatedof your voice. switch can be usedYou'll to control need about a volt to drive any device CAPACITORS:D7,D5,C3-0.1Cl, 8-KD21006-1N34A 2-10 mfd, mfd SCR 200v, electrolytic, any type 15v MISCELLANEOUS:R5-470F1-10J1, P1 ohms amp-3 -wire fuseceptacle AC plug and re- remotely!aboutveryonlyampit, thingshowever, these betweenhave With that units. practical tickle thesothis Shooters bemike unit,people sureuses, and you liketo about theythe canuse input can shooting (usinga small beterminals. lots Vox boxes not the idea of controlling power transistorizedguns, delight pre them - of fun, too. The hangwasreceivethaton invented, theonto switching mike mode.the and mike,as withaSwitches by push for throwing the to-to relay.release with-talk only locksswitch) it one would helped, switch you put were (usuallyyoubut youableback toin But this meant that you had to still hadlocated do all the onelay166 system)syllable! control the mightiest of motors, just by speaking a master/slave re- triggerswhichto flip thesolved the switch. relay. all theThen problems. along came The the first voice syllable -actuated you speakrelay By varying the value of C4, the circuit 167 switchingrelease time during is increased short pauses or decreased or brief to interruptions. prevent premature The T1.J R4 C3 S1B forcircuit any may of a alsodozen be other used applications.to turn a tape recorder on and off or Q2 Q3 B1 1+- 72 -.1".1 S2A The intercom circuit shown here is essentially Intercom SP2 9_1140. B2 S2B Courtesy: Radio Shack isFollowingspeaker,speakeramplifier in the "talk"serveswith with the thecircuit aposition, theslightly switches dual diagram, sophisticated T1function determining feeds you the ofwill switchingmicrophonebase observewhat of thatQ1 thatcircuit. throughfunction and when loud- Ci.S1 is, a 3 -transistor Each SP1 does indeed serve as a microphone.TRANSISTORS:PARTS LISTQl, 2-2N107 R2, 4-4.7K RESISTORS:CAPACITORS:C3-30Cl,Q3 -2N2702-10 mfd electrolyticmfd electrolytic TRANSFORMERS:BATTERIES:Ti,Bl,R5, 2-AF 2-9v6, 7-150output, ohms 500 -ohm CT Withfeedingfrom theQ3's the circuit signalemitter operatingAt to theScircuit P2 same which in is thistime, connected then fashion, S1B functions is connectedwhateverto transformeras a loudspeaker.R1, is so 3-470Kspoken that T2 the output signal primary, 3.2 -ohm secondary feedingitreverseinto to oscillateSP1 the the willamplifier process. andbeThe heard"howl." remote output at unitSP2.signal consists By back reversing onlyto the of input, SP2,switch S2,causing Si, and you B2. S2 also provides a calling signal by Additional first168remote one, unitsusing may 4 -conductor be added, cable. connecting them the same as the 02 81 1 TO RECEIVER R4 R5 Si SPECIAL RECEIVER CIRCUITS AVC LINE Courtesy: Rad ic Shack S -Meter receiverAn S -meter AVC indicates circuit. relativeThis circuit signal will level work and with operates communi- in the Beat Frequency Oscillator Q2,orcations CB you units. receivers,effectively hamnull thereceivers, reading marineon the meter, -band or receivers, establish By balancing potentiometer R6 between Q1 and becauselongtheIf you hissing and ever short the soundowned carrierdashes resulting a short-wave andused from at the hamreceiver, transmitter CW you may dots come across as hissing transmissions.key. The is just that-aThis mode of have heard sounds RESISTORS:TRANSISTORS:PARTS LISTQ1, 2 -2N109 BATTERY:R6R4,B1 -5K 5-10K -9v pot bandTooperationearrierbeingadded. hear operation this is interrupted calledas will a continuous soundA-1, by or garbled theinterrupted tone,telegraph until a local the BFO signal This is the function of the BFO. carrier wave (ICW). Also single -side - is turned on must be 1N34the relative diode inreading each input or zero leg and-point. recalibrating By installing the scale, a simple there R2,R 1 -10K 3-270K pot MISCELLANEOUS:M1-0-1 milliammeter to RPisrestore connected signal tone Inthewhich to thecircuit beats signal.receiver shown with antenna the here, incoming C2terminals varies signal audible tone only when the tone pitch. and injects an The circuit in theincoming IF is 170well.no reason why the unit could not be used as a VU meter as carrierstages, isproducing present. an 171 C3 ventional performance automobile antenna is improved with a short-wave stubs just won't antenna.work Con- too well. band re - CONNECTDO NOT u the circuit is to be used with an X1 AC broadcast ANTENNATO RECEIVER'S TERMINAL J1 iCi 4 Qi Cu (--,_ J2 Si TO RECEIVER'S 1RFC1 GROUND TERMINAL - 81 TRANSISTOR:PARTS LISTQ1 -2N544 RESISTORS: R2R1-4. -10K 7KCourtesy: Radio Shack S1 Courtesy: IC, Radio Shack CAPACITORS:C3-.001C2-15Cl-. pfd01 mfd mfd trimmer TRANSFORMER:BATTERY:T1-IFB1-1. 5vtransformer CRYSTAL FREQUENCY CAR RADIO 5000 - 6050 RANGE TUNING KHz 44505500 KHz6450 71006050 - 7100- 8050 Short Wave Converter 7 5008550 80509100 - 9100- 10150 used)tachedThey it used isto possiblean to automobile say "tuneto pick inradio upthe police (dependingworld," calls, and on withhams, the frequenciesthis or uniteven at- TRANSISTOR:PARTS LISTQ1 -2N247 L2-22 turns B#3016around & W L2 miniductor aretennaforeignThe selected, terminal. auto broadcasts antenna so Bycheck changingwhen is onconnected whatatmospheric crystals particular to J1the conditionsand desired frequencies J2 to frequencies the are radio you'dright. an- RESISTOR:CAPACITORS:C1-100R1C3,C2-100 -390K 4-.001 pfd pfd trimmer ceramicmfd ceramic MISCELLANEOUS:BATTERY:RFC1-2.5X1-seeB1-4 1/2v mhchart Dchoke cells jack 172crystaltunedlike to the hearfrequency same before as chart youbefore go list without several and the buy converterpossible crystals. ranges. in The radio is place. The COILS: L1-9 turns hookup wire wound J2-femaleJ1-auto radio coax antenna connector S0239 173 ingcanbeceiver, watch a bit your dangerous. step in connectingAgain, it-a mistake in pay particular attention ground, to oneconnectingtime,And antennathat to simplygoes avoid length toone havingthedisable of whentuning the broadcast leadsthe receiver's ferrite you use this with a transistor capacitor. -your best bet is to remove signals come in at the antenna by dis_ receiver. same the C curtesy: Radi c Shack onIn an communications amplitude modulated work, noise Noise Limiter is the result of random spikes PARTSCAPACITORS:DIODES: LLST C1-.02D1, 2-1N625 mfd RESISTORS:R4R2,R1 -500K-270K 3-500K pot cludingnoiseinan aAM spikes socket, noisy receiver. thatspark or createeven Thereplugs inare an a sewing machinesquitter, motor static,with orsignal. interference manyin sources of such noise, automobile,in- aloose light bulb It is the presence of these worn C2, 3-.01 mfd R5, 6-1 meg orsource,andtionbrushes. impossible, find between or the when source. the isWhenthe AGCa correctioncircuit noise and receiverlikeproblems process this is This noise limiter circuit is Only when it is impossible to locateare present, the it is always best to try audio amplifier. designed for installa- extremely involved includingway.limiterinnoise which may in theallcase be amplitude receivercoming it's far fromcircuiteasier modulation several and broadcast This circuit is adaptable to to install this dual -diode noise eliminate thea number problem of that sourcesapplications, simultaneously,necessary. However, or short-wave izednoreceivers, power,174 receivers. it ishigh-fidelity especially suitable tuners, for etc. inclusion As the circuit requires in transistor- 175 --.17operation. But there are other advantages as well. Sparkbecause there is a lesser tendency of pitting AUTOMOTIVE ACCESSORIES plugsandtor, lastlongerresiduedistributor accumulation; points, in fact, etc. -seems to last longer. the entire system-capaci- Transistorized Ignition System Battery Charger (distributor)A standard and automotive a coil to ignitiongenerate system a high uses-voltage a circuit spark. breaker By Basically,isprovide done aby constant abattery means voltage of charger a step-down source consists at a transformer,given a of a system designed to current level. This rectifying theforesurely,coil,inserting vapor a more you and mixture canapositive transistorthe generate higher to -acting burn. amplifierfrequency a higher one. betweenfrequency enables allthe spark, combustibles distributor and there- and in This results in more efficient Plugs fire better and more device,quirements,achargesystem, trickle and is a charge. reachedvoltagea meansincluding Thesetwo regulator orof ofeitheran reducingSCR cutting of some sort,circuits a circuit possess -protecting andall ofzener these diode re- for regulation. the applied current level to off the supply when full TO DISTRIBUTOR batteryInPARTS each hasLISTcase, reached an indicator full charge. lamp is used to indicate when the PARTSTRANSISTORS: UST R1 Ll 12V DC TRANSISTORS: KD2101 R3-150 ohms DIODE: D1Q2Q1 -2N3055-2N3054-90v, 50w =120 mA Dl CAPACITOR:DIODES: D5-KD2100D1D6-1(1)2104 to D4-KD2103 Zener TRANSFORMER:R6-33R5-1.R4-470 8K ohms ohms RESISTORS: R2-7.5R1-100 ohms,ohms, 25w5w P01DISTRIBUTION NTS RE R1-10KC1-50SI-40s:Rmfd pot, 2w linear electrolytic, 15v MISCELLANEOUS:T1F1-1 -120v amp to 24v fuse (12v)14v (6v) or 120v to COIL:176 Li-ignitionR3-1 ohm, 100wcoil Courtesy: RCA R225-w (6v) 20w (12v) or 2 ohms, P1Il-G.E. -3 -wire 1448 AC (12v) plug or #47 (6v) 177 Well -insulated heavy -gauge (at least #4 or 6) stranded cable . R2 11 7tiould wiresh is moreon. flexible, particularly at the cable sizes in ques-If you arebe building used to connecta charger, the what charger are commonlyto the battery called Stranded Fi R3 ofpurpose',jumper each cablenicely cables" and (available connect theat any cables auto to supply the charger. store) serve the if you remove the insulated clips from one end NOCURRENT CURRENT D4 6 -Vol t Charger Courfresy: RCA Fi I1 P1 60120V Hz NOCURRENT CURRENT Courtesy: RCA 178 12 -Volt Charger 179 (.; if)> - C.) a) °.-I" -2' ,.; 117 .a , oa) 1 a) :3 .. Q Q) .'.... 1.4 C.,i ocq N CIg 1:L)9 LT) CO dN 1:14'. 1.-1 I 71 .11 .. LO1-10 ra -I CO C` OI I . 0 . X c.i 1 E cl) kA N ,-. I ] tr) 0F. ,4 g .. . ) ,- rz,tr .may -.1 I -I ,-1 I -4 f:4 19E-'cn CrINIC)°>Z r; .1. i:: g,_, '4(44u : ,1 In t- FA , I 40E..4rn -to'7 1-4 C4 CO" ",); Lf; CC; - ,- 1.-1 m -I a; FLII 4 co , c:,.., H E-1w I DIFFERENTIAL, ANDINTEGRATED, COUNTER CIRCUITS ra, Eg CY cy 6 c) ou=wgrzzazzrzzpc(711 40 Low -Noise Differential Amplifier Ira (Q5)ingThis two high provides direct -impedance -coupled a constant circuit differential total consists emitter stages. of four current A transistors fifth for transistor the form- first - CC points.inputstage of-base eachpair feedback (Q1 and stabilizes Q4). Output the transistor -collector DC-to -opposingoperating To keep AC signal components from lowering input emit- A/NA (4\ Et-"AN-4/ impedance, shunt capacitors are used in the first stage 4- teralsotrolled circuits. raises by output the input -collector impedance. -to -input To -emitterestablish feedback, DC operating which Overall AC voltage amplification is then con- illL.) -.- stageconditions,180 collector first current adjust ofthe 30 10K kia, pot then (R8) adjust for athe combined other 10K pot first 181 computer(R11)action for can zeroapplications, occur, differential recheck this output circuit the voltage.first (and pot. variations Because of some it) senses inter- Used extensively in Courtesy: RCA RB +13V thebalanceand relationship produces with the abetween differential power twosupply voltage or standard reflecting(or current) (B1). balance conditions or un- +270 V C3 R4 Cu C5 C2 ))) M I C. Cl = DRIVER TRANSMITTER CONREMOTE TROL C7 TRANSFORMER Linear Integrated Remote Control System (RELAYWONTROL 1 CONTROL 11 RELAY Apply an input signal of about 40 kHz to the mike, and you can SOLENOID SOLENOID ADDITOCHANNELS TIONAL oidremotely functions control as needed. a series The of 40 devices kHz required by adding to controloperate solen-this Li! 11 T Ll factorstillunitsignal isfallsis the frequency.just withinability above ofthe the your audio range audio range, of components human technically. hearing. to reproduce However, the it For example, if the microphone cuts off The limiting J!L_ CONTROL FUNCTIONS_ cations.nal,thatmikeat theyou12 tokHz,audio can the use youintegratedequipment thisaren't unit goingcircuit! can for and a to numberBut willget once anyhandle of signalthe interesting thefact at40 is all -kHzestablished fromappli- sig- the PARTSTRANSISTOR: LIST Q1-use suitable type RESISTORS: R2R1-depends -100K on Q1 maticslidestor with intoslide a synchronizeda projector."show"One such presentation applicationtape. Here's and is how putautomatic them it works: in control Sort ofthe a slide projec- Record the narration on Cape so that your auto- CAPACITORS:IC: G 1-CA3035C2-.01C1--4700 mfd pfd R5R4-150R3-1R8R7-4.R6 -33K -10K-1Kmeg ohms7K change,eachyour ownslide record voice in detail. a (and40 -kHz background signal from music a small if you oscillator. like) explains When you are ready for the slide to (You C6,C5-.0022C4-.03C3-.022C8-depends 7-10 mfd mfdmid mfd electrolytic on QI ytic TRANSFORMER:COIL: T1-driverLl-depends transformer, on onQ1 Q1 depends phoneconnectedmight182 placed even to try near your a silent the automatic tape dog recorder's whistle slide projector, for speaker, this!) andWith you're its this micro- all unit C9-.05 mfd 183 set. to REGISTER complishuseyourbe changed a equipmentmanual the this pushbuttonsame unitis incapableend. will -operated of handling 40 -kHz the 40 kHz, The tape recorder will pick up the signal from the tape, start, and when the slide is transmitter to you can ac- if TRANSISTORSWITCHING NO N Shift Register or Ring Counter enableThe shiftthe count register to proceed is used from in unit consecutive counting circuits to to unit, from decade to TRANSISTORS:PARTS LIST RESISTORS:R1 -1K (or 680 ohms, 1w) Courtesy: RCA completefire.decade. 0-10 counter can be constructed. The By extending the circuit, andEach input pulse causes the next using a "nixie" tube, a adjacent lamp to shift register CAPACITORS:DIODES:Ql,D1,Q3, 2, 5, NA -2N404 2, N -1N34 4, N -2N1302 R6,R5,R4R3R2-27 -1K ohms (or 330 (or ohms) 12 ohms, 1w) 9,8, NNA -2.2K -560 (or ohms 680 (orohms) 180 usedplaysareisouts. able tovalueless.an Aconvert importantto computer communicate electronic The rolecan shift indo the informationregister theall results productionof its of is, in a sense, a transducercomputation,to man, the butcomputations unless it into a form for human computer read- C2,C1-100C3-1 4, mfd, mfd (or electrolytic, trolyticmfd),25 mfd), 50v 25v ceramic 6v elec- 5, N-0.05 mfd (or 0.1 MISCELLANEOUS:R7,Il, 10, 2, N-M9NB -150ohms, or82 1488ohms, ohms, 1w) 2w)lw (or shownterutilization. is identical by dotted withIn lines. the the schematic "n" you will observe that the second stage regis- When the first switching transistorstage register. It is coupled as cuitoperation as shown at many is designed different for output an output -current -current level 12v; E2 = 9v). Transistor types and componentvalues levels. This cir-of 40 ma allsucceedingIlWhenstage the will lamps isextinguish,a secondtriggered havepulse pulse willand with causetheenters the second the firstthe following base gone on and then off. lamp, 12,pulse, will light.lamp Il will light. of the first transistor,Then, the sequencelamp to light until Each tionshown(Elto = atan anin ordinary outputparentheses -current Theoctal "nixie"indicate base level tube, tubeof the 3 exceptchangesamps mentioned (El that necessary = it is has a tube 11 for base similaropera- pins. in appearance 27v; E2 = 24v). that 184anddesiredis repeated. Al. and In addition, may be made regenerative byThe connecting shift register points A the basic circuit can be may use as many stages as adapted for ainlookingdownThese ring. pins lead on to the terminals top of the placed tube youaround see thethe tube, so The tube is evacuated and back -filled with neon gas. terminals as 185 theWhenspot. gas a Thisfiringbetween tube voltage isthe supplied isterminals placed with between ionizes, a bezel two forming on adjacent which a thebright numbers terminals, red thatstate the by on the state cipher is signified byzero. the number one a zero, then moving left, and the off the playapplied0-9 the are spot engraved.to underthe triggering the As number you terminal. can equal see, to thea shift amount register of impulses will dis- number one,four,Starting and so on,at the right, place followed by the number two, doubling the number 8 4 2 followed by theeach time. 1 0 useAsourindicate youthe numbers numbercan an see, off mode.this can 64 32 under the key numbers, as1 to indicate anon situation, 16 To write the number 82 then,be extended endlessly. Now we follows: the cipher 0 will we place will Bistable Multivibrator The binary number 64 1 32 0 16 which 1represents 82 would 08 40 2 1 be 10100100.01 0 causeThis it 1 provides -MHz flip-flop output iseither the heart in an of on computer or off mode, easily circuitry be- observingelectronictheatadjustable the flopped schematic, twoswitches,to mode, binary traces "0" these readouts.and simultaneouslyappears reverse.they havewhereWhen Such been indicated."I"on units oscilloscopes, isused present make as However, a meansasexcellent shown too. ofin doesn'tanotheror "ten" really system,system. beginWe and areto the showaccustomed depth up of until our to involvementdealing with withnumbers "tens" in the decimal A typical example is the American who you expose yourself to PARTS LIST Courtesy: RCA catedtemandtravels pounds.called onthefactthat to Great "binary" Britain arithmetic.electronics and gets Thecan snagged countingeasily on reproduce shillings,system issteady- predi- In electronic counting, we use a base two sys- pence, DIODES:TRANSISTORS:Ql,D1 2-2N404 to D6 -1N126 RESISTORS: R2,RI,C2, 4-4308-5.1K7-1.2K pfd mica, 24v be186thatstate either are systems. ondiametrically or off.A switch opposed. can either be on or off. A lamp can There are two steady-state conditions Consider then, the theory CAPACITORS:Cl, 3-180 pfd mica, 24v R4.R3, 6-11K5-2.7K 187 If we used a row of lights under the key numbers then, we doughnuts.andeithercould another easilyis or A Os.moves wiresignalIn computer moves horizontallyin binary vertically work, code a matrix through is formedeach of through each, with a dough- any number at all, many small ferrite doughnut using willmagnetizingeachnut atcause intersection each the intersection.voltage doughnut diagonally. to any at pair the of Asintersection vertical and horizontal Another wire is threaded you can see, applying of those wires through wires to a system.arethesenetizing.magnetize. magnetized, doughnuts The andsimply third reading by wire out is the used information for resetting in The computer itself then can store determining whether or not information in or thedemag- binary they Decimal Counter usesThis logic system circuits employs to convert flip-flops from inbinary to decimal. NOR a binary count, and then Qcs, U leftback0-9gates of through readout.the are second used 500 forFeedbackand -pfd this third capacitors purpose from theand rightneon sidelamps of the last directly to the base on the output flip-flop goes are used in the thirdchangedmal flip-flops. -counting before unit this must condition be is fed back to the second and If this is not done, the feedback flip-flops. delayed so the last stage is fully The feedback in a deci- signal will In 0E 188additionaltheinterfere DCU, with delaythe theflip-flops is original required. have signal The sufficient maximumand cause a malfunction. delay, thereforecounting no frequency Courtesy: Texas Instruments 189 is about 200 kHz. It could be increased by lowering oftorminimumthe reducingthe temperaturevalues unit hfe theThe steering lowest operating temperature of the triggering capacitorsand the to highest by maximumincreases, Icbo. hfe increases resistors from 15K to about 3.9K. is chiefly determined by andabout the 200transistors pfd, and As transis-

1:1 go - 0.O PARTS LIST 0 "cl TRANSISTORS:DIODES: Ql, 2, 3-use an appropriate type R4,R3,R5, 8-75K7-10K 6-1.2K CAPACITORS:RESISTORS:D1,R1,C2,Cl, 2, 3, 4-1002,3-1N659 5-5009-15K pfd pfd MISCELLANEOUS:R15R14RIO,I1-NE-2 -31K-68K 11, 12, 13-22K curs,mode.itare maycapacitors. saturated. it prove can difficult This can to bring a If such a redesign is attempted, be corrected by using larger value call for more triggering voltage, transistor out of the storage and the problem oc- triggering and 190 191 EXPERIMENTAL CIRCUITS Courtesy: RCA DIODETRANSISTOR:PARTS : LISTQ1 -2N647 RESISTOR: R1 -220K Photographic Slave Flash CAPACITOR:PHOTOCELL:C1-100SCD1-1N34A -photovoltaic mfd electrolytic, cell 25v MISCELLANEOUS:BATTERY:K1I1 -5K -24vB1-22 relay bulb 1/2v theproducesanswerused,Anyphotographer photocell how isshadows. a do onslave. you the getWhenslavecan them tell the you both flashbulb that to fireusing at the However, if more than one flashbulb is on the camera goes off, a single light source same time? The lifiedbywillat the seealmost by flash ittransistor as the fromlight sameIn Q1thefrom this andtime,master circuit,two actuates unit. the light-sensitiveThis causes thecertainly slave to close fire sources.itsenough lamp- so the film photocell (SC) is triggered current is then amp- An automatic keyer operates with a transmitter or an oscil- Automatic Keyer circuitYouvoltagehadswitches beencan is across moretest collectingconnections the thanthe slave socket,adequate a betweenchargeby causing for fromB1 and thethe Cl. flashbulb closing S1 and observing Il. use with conventionalrelay flash- RY. The relay then The capacitor,battery, which dumps its to go off. This totransmissions.wordslator charactersform to per automaticallyforma dash minute. are andOne self Usually,release important -completing. dots the a built-in keyandfeature Thatbeforedashes speaker of is thistheatto speedssay, dash circuitmonitors hasup is tobeen that the60 if you start ment.192bulbs, but is not sufficiently fast for electronic flash equip- findformed, the tone Breakingwill continue the circuit until the down dash to isits completed. componentmultivibrators, stages, you flip-flops or gates, and amplifiers. will 193 pARTS LIST R13,R11, 21-15K19-33K DIODES:TRANSISTORS:Q9Q3,Ql, -2N647 2,6-2N1302 4, 5, 7, 8, 10, 11-2N404 R25-68R24R17R15,R14, -100K-68K ohms 23-27018, 30, ohms 32-27K CAPACITORS:D7D3,D1,Cl, -1N2861 2-1N34A 3-1 mfd, paper (or Mylar), 4, 5, 6-1N2858 R34-6.R31,R28R27-1.R26-560 -50K 33-10K 8K2K ohms pot C6,C5,C4,C2-0.47 9-3308-5607-0.01200v mfd pfd mfd ceramic, ceramic, ceramic, 25v 600v 50v TRANSFORMERS:R41R37,R36,R35-8. -10K, 38-47K39, 2K 40-15K lw C15-16C13,C12-0.1C10, 11-0.0214-2000 mfd mfd electrolytic, ceramic,mfd mfd15v ceramic, electrolytic, 50v 50v 150v T2T1 -push-pull-power transformer, outputPS8415,or (14Kequiv. transformer toPS8421 V.C.), or Stancor equiv. #A3496, Stancor Of RESISTORS: R5,R4,R3,R2,R1R7, -39K, 29-10K16-18K6-51K 10-22K 0.5w pot 9, 12, 20-3.9K MISCELLANEOUS:Si-VibroplexIl-indicatorFlK1 -fuse, -DC relay; lamp keyer,2.5K; #47 or operating equiv. current -4 ma 1 amp coil resistance - Cr) 0 k R8, 22-180 ohms 11 nectedorThese, together appliedin such in numerousina wayother that configurations, applications. when the key canRelay is functionin itsK1 active can separately be mode, con- tors.pulltrolmoved,the transmitterforaudio themutingthe amplifierformed built-in power receiver.loudspeaker is applied by R28 the which functions finaland receiverpairis driven ofas 2N404a volumepowerby the transis- push-is con- re- Courtesy: RCA 194 195 Electronic Theremin

The theramin is, perhaps, the original electronic musical in- accompanying"antennas,"strument.The unit is It placed is oneschematic "played" controlling behind byshows an hand AMpitch, the movementreceiver basic the other oscillator which in volume. relation picks circuits. uptotwo the If you want a completely The -J whips.tectorindependentsignals and The radiated audio standard musicalLl amplifier. byand procedurethe instrument,L2 antennas. are Variloopsticks is to all have you one need antennaand is athe diode vertical,antennas de- are simple 121 u PARTSTRANSISTORS: LISTQ2,Q1 -2N1097 3-2N1264 RESISTORS: R2,R1 -180K 3-51K C.) the otherhorizontal. With the unit behind an AM receiverCAPACITORS: and C5,C3,Cl, 2-2004-2006-.01 mfdpfd trimmer COILS:BATTERY: Ll,B1 -9v2-Variloopsticks throughthepacitorceiver otherloopstick (C3) thenear 200 speaker. at the-pfdcores J1 center untilcapacitor screwed aof hissing the (C4) about band noiseat halfandJ2 untilis adjustway heard. a in, whistle the tuneNow 200 thecomes adjust-pfd re- ca- Do not retune the receiver. Go back Wv cr hands196and resetaround Cl the for antennas. the lowest pitch, and then start waving your 197 dropsCollector of about current 0.4 volt should when thealternate from zero circuit is switching 50 amps. to some peak toemitterflectedvalueacross 1.75 determined backjunctions volts the baseto when the areby-to primary the driven-emitter supply byon off. junctions, thetovoltage V transformer. BE(sat) No protection is and providedthe impedance that the re- back and back -biased The base -to - required CONVERTER -INVERTER CIRCUITS bias is kept below 15 volts. R5 Low -Voltage High Current Converter The output of low -voltage sources, such as solar cells, often This unit PARTS LISTCourtesy: Motorola VIN usestransistorvoltageandmust high-performance can be ofswitchconverted isthe driven 2N2728 currents to with higherpower is as aless highforced voltagestransistors than as gain 500.1 to volt ofbe(Q1, 10. useful.at 2)50 to amps do this; if the amps. The saturation TRANSISTORS:CAPACITORS:Ql, 2-2N2728 TRANSFORMERS:T1-Phoenix PX2127N2-100N1-8 turns, turns CT atinofsistance approximatelythe#12 feedbackwire of lesslessBy thanthanwinding, adjusting1 kHz. 0.002a foot this ohms,thelong! circuitfeedback or is is equivalent designedvoltage with to to oscillate aa 1length -ohm resistor (R5) The circuit operates at maximum This is a re- RESISTORS: R5-1R3,R1,C2-10,Cl, 3-202-0.754-7.5 ohm, 000 mfd, ohms, 5wmfd,ohm, 6v 6v 5w T2-Phoenix PX2126N6-4N5-4N4-8N3-12 turns turns theofasefficiency output 20the ohms load transistors greater theresistanceThe power than collector do output70% not is decreased, saturateat -to begins60 -emitter watts. andto butdecrease.Output beginvoltage at a powerto critical in Atheat. this this increases circuit valuepoint, should swing voltsstartingcurrent appear of resistors. the across transistor,The total When starting current in theaddition resistors transistorof the to feedback R3the andcurrent R4.secondary through includes the is driven off, 3.75 When the base the ing4 volts198 resistances peak -to and -peak the if transistor there were saturation no losses. result However, in voltage wir- voltagesthem.transistors Base across are currents drivenR3 and are on,R4) the R3 and sum and that of R4 200 have ma 1.5 (resulting volts across below the zero reference from 199 withwhich aforced would gain be 2.5 of amps;20 to 50 therefore, the transistors are driven an50 efficiencyamps, the loss.transistors Probably do thenot mostfully important saturate, check in in_ amps. At currents in excess of resulting in at:3 angularverter50The amps. loador from converter line 5 voltsfor thisdesign to 50circuit ampsis the was forarea observed switching of load while lineapplications. The safe area of operation of the 2N2728 is operating attraverses. rect- L _ _ _ _ - - - J Frequency Stable 20 -Watt Inverter 200 -Watt 60 -Hz Power Inverter A¢ 11-1 z-I Z z z ismobile Designedrequiring20anfrequency automobile tape to recorders,-sensitive, (A)provide battery, to 200 115v amplifiers, wattsthese AC (B). circuitsfrom a 12vare DCcapable of if a DC -to -AC inverter is to supply Although nottwo-way all equipment radio gear, etc. source, such as operating , itall should types haveof mobile the means of controllingPARTS and LIST A gear (synchronous motors, for example) R2-422 ohms holding the speci- TRANSISTORS:Q6,Q5Q3-2NI038Ql, -2N1302 2,7 -2N511A 4-2N1372 R7-5.R6R5R4-1.R3-4. -50-1K 62K78K64K -ohm pot pot Courtesy: Texas Instruments CAPACITORS:DIODES: D2CID1-1N750A to -100D5 -1N2069 mfd, 15v TRANSFORMERS:T1-MagneticsR10-1R9R8-42.2 -1K ohm, ohms 2w 50181-4AN1-1200 turns #30 wire CT 200 RESISTORS: R1-2.C2-1 15K mfd 12-powerN3-230 transformerN2-150 turns turns #26 #38 wire wire CT CT 201 TRANSISTORS:PARTS LIST B R4R3,R2-422 -1.62K 7-4.64K ohms DIODES: Q6,Q5Q4Ql,D1-1N751A -2N1372 -2N1202,7-2N514A 3-2N1038 R11-42.R9,R8R6R5 -50-1K 10-1 -ohm pot 2K ohm, pot 5w RESISTORS:CAPACITORS:D2R1-100C2,C1-100 to D5 3-4 -1N2069 ohmsmfd,mfd, 15v 10v TRANSFORMERS:T2-powerT1-Arnold transformerEng'g.N3-80N2-40N1-320 3T turns-7189-D4 turns #36#20 #26 wire wire CT CT withfied"chopper"quieter, frequency.these circuits. or vibratorFrequency And, suppliesyou'll stabilities find them of to and more efficient than the familiar that were used to power auto- ± 0. 5% are obtainable be much smaller, mechanical duceddependentmobileoffering voltage, radios theof themanyfollowing whichThese load, years we circuits advantages: can ago. readily are built control, around a square -core 2. the frequency is dependent on in- 1. The frequency is in- and 3. oscillatoris incor- the in- usedporatedherentlowing tooscillator efficiency supplyas the may frequency the circuitprove is high veryIf of you ispower stabilizer, assistance:high.magnetically aren't required. A familiarvoltage coupled regulatorwith squareto its input -core through oscillators, The output of a squareand -corepower amplifiers are the fol- theisa squaretransistortheacrosslinear. other -coretheThe coils is transformer changing conducting,transformer. in a magnitude flux primary the in supplyproportional voltage If the circuit is oscillatingthe coreand induces a voltageand inthe rate of flux change to the turns ratio. is dropped Courtesy: Texas Instruments Sinceducedbiasvoltage,Thisthe voltage. biases transformerthevoltages and transistor one biases are of winding reduced, is thethe turning transistors therebyis off, reversed, onreducing causing When the core approaches saturation, other transistor off with a positive the induced voltage across with a negative bias the base drive. a reversal of the in- 202 transistors.bias, and therefore a reversal in the states of the oscillator 203 put.differencewill Where re -shape between a true the It sineaoutput. shouldsquare wave -wavebe is pointed required, and a outsine adequate that most equipment can't tell the -wave supply in- filtering 0 U 0CC.-1 Voltage Regulator In pureHereerence,of potentiometerDC is voltage assuringa voltage from lineR9. regulator 22 regulation to 30 volts, circuit of depending± 1% and onload the It uses a 12 -volt zener diode providing an absolutely regulationas a ref- setting filteredwithin 0.5%. DC. PARTS LIST The circuit is designed for an input of 40-50v DIODE:TRANSISTORS:D1Q4,Q2,Q1 -2N1479-12v 3,6-2N3053 Zener 5, 7-2N3055 RESISTORS:R5-570R2,R3R1 4, -2K-1.2K 6-0.1 ohms ohm 204 CAPACITORS:C2-100C1-1 mfdmfd, electrolytic, paper, 25v 50v R9R8,R7-270 -1K 10-1K pot ohms 205 TUNER DEFLECTION CIRCUITSVERTICAL HORIZONTAL DEFLECTION a HIGH -VOLTAGE CIRCUITS TELEVISION CIRCUITS LNTEGRATED-CIRCUIT SOUND -IF I I. AMPLIFIER AND DETECTOIL Courtesy: RCA IC Sound Amplifier/Detector Color TV Receiver amplificationmentally,aWhile million primarily and oneand intended applicationsno control for functions. TVin other designers, areas asthis well. circuit Funda- has it is an audio preamplifier with straight -through It can be used with Toa concludeschematic this of a transistorized collection of solid-state color TV receiver omitted because of circuits, here is and the its formerbeHowever,crystal included isor a noticeceramic 4.5between -MHz that phono it theinterstage and little cartridges,the boxloudspeaker. coupling marked unit, "amplifier" The the input other trans- must is a or with FM tuners. highlycompleteamplyconsumer(courtesy specialized illustrate parts product Texas list.Instruments).the current statedesign and development in (Thea tuner was construction). To help familiarizeof the art in solid-state competitive market These circuits those the partsturer's2064.5 list-MHz recommended is not ratio included detector component with transformer. this valuescircuit. Since should the beIC used,manufac- a notprincipal acquainted receiver with these circuits, a functions follows. brief description of 207 receivercircuitsrier,coaxial of circuit cablecourse,have notoshownVIDEO theiseffect the IF IF audio STRIP: The amplifier.here,on four it, Along merely amplifiersignal with amplifying the fromstages video the are tunerit. is coupled signal; however, the video IF In the em-car- via tovideobrightness thethe "blackduringcathode level -andB ray &LUMINANCE duringW-white"tube broadcasts. screen colorcastsvideo CIRCUITS:grids. signal and to supplyestablish the the entire correct The luminance circuits amplify Color signals are coupled takeployed. -off point.AGC: TheCapacitor automatic C301 off the first IF stage is the The video carrier is rectified gain control circuit employs three by D102. sound propriateincarriersignal achieving from andcircuits. istheproper COLORtransmitted carrier frequency PROCESSING: and with process and horizontal phase it for in application the sync. color circuits. to ap- The color burst is a small portion of the These circuits remove the color Itis vital gainAGCfromthetransistors. under thetuner.section collectorbase varying AGC to Fromof develop ofsignal the emitterlevels, thus of voltage is Q403.fed also Obviously, to the second Q404, and to the a bias voltage to control Q405, AGC is appliedit is tothe sync inverter stage, purpose of the receiverIF stage, theholdDuring color the black bandpassburst.CONVERGENCE -and -whiteamplifier telecasts, CIRCUITS:at cutoff, due So to that the each absence of the of three elec- the color killer circuits negativeobviousflutterAGCcontrast is andpicture, designedwhen and motor overloadingthewith vehicle tocircuit marked fails. in prevent the consequences of interference, strong signaltearing areas. and While color the interference. The result is frequently preventing changes in its value is quite airplane a tothetron accomplishdotachieve perforated beams on the minor in face this theaperture adjustment plate,function,cathode plate ray of located eachtubes beam. strikebehind the the proper screen. color it is important that they converge ata series of controls is employed To firstD302fier. stageof Twothree circuitry. and IF audio fed stages toAUDIO: the base of The sound signal is The ratio detectoramplifierfollow, stages. then detection in the Q301, the first audio IF picked -off the last video IF output is coupled to the T301/D301- ampli- appearsanyhorizontalpulsecoupled deviation is acrosscompared output.via between C501R501HORIZONTAL with andto the the R502. discriminator AFC and A correction a voltageOSCILLATOR: spike fed Horizontalsync back pulse from and horizontal spike, voltage, corresponding to circuitry. The sync sync is the fied,therectified video of course, detector. videoFIRST andsignal a VIDEOportionis fed to AMPLIFIER isthe and SYNC In this stage the video first videotapped amplifier off and from coupled to SEPARATOR: signal is ampli- The 208oscillatorconstants,the sync separator. circuits. sync pulses V401 functionsare fed the vertical and By appropriate biasing and circuit time as the vertical oscillator. horizontal 209 O

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ro to C230-85C228-0.1 pfd mfd, 400v 11102, 257, 258,312, 259,-1K 317, 323, 432, 449, 418-3.3K 503 C235,C231-2C245-36C243-2C242, 237, x 514-150 0.0015x pfd 238-50.001 mfdpfd pfdmfd R103-24011107,R106-430R104, 108, ohms ohms 113-270 ohms 134, 146, 148, 326, 327, C303,C301-3.3C401-0.005C321-0.C311-120 307-68 pfd 15 pfd mfd pfdmfd R111,11110,11109,11114-1.6K11112-620 120,138-390308-2K 261, ohms404-1.5K 301,ohms 302-8.2K TRANSISTORS:PARTS LIST C409,C408,C406,C403,C410-0.0082 502,420-0.033407-2404-2 504-0.0022 mfd, mfd mfd 10v15v mfd 11115,11117-180R116, 211, 515-15K ohmsohms 118, 121, 122, 147-22 Q104-.SK5009Q103-TIS57Q102Q101-TIS57 -T1557 (3rd(2nd (4th (1st IF) IF) IF) C107,C106-6.8C105,C104-16 108,115-12 pfd pfd pfd 109, 110, 112, 113, C418-0.022C415,C413-0.47C412, 416-0.0015419, mfd 425-0.01,mfd mfd 1000v R123-33011119,R125R124, 223, -2.4K 136, ohms, 227-30K 208, 1w 451-10K Q204Q203Q202Q201Q105 -2N3704 -2N3704 (Burst(2nd (1st(1st Chrom. Video)Keyer)Amp.)Chrom. Amp.) Amp.) 240,134,127,114, 241, 218, 315, 232, 128,116, 129,117, 511,233,130, 512,118, 236, 131,122, 513239,133,123, C424-100C423-18C422-10C421-100C501-2 mfd, mfd,x 51 475v pfd75v50v R128,R127,11126,11131,11129, 135-150K212, 409, 130-100K229-18K 504,440-12K 527-1 pot meg Q301Q208-SK6361Q207Q206Q205 -2N4255-2N3704 -2N3704 (Mixer)(AFC(Osc.)(Sub. (Color Amp.)Car. Killer) Amp.) C121,C120-1.C119-5.6C111, 132,126-10 8 pfd 201, pfd 204,-.01 223-56 mfd pfd C506-680C505-0.047C503-470C508-0.0011C507-1500 pfd mfd pfd mid 11133-1.2K,R132-68011140-22K,R139-500R137-470 ohms ohmohmslw 2w pot Q305Q304Q303-TI408Q302-TI408 -2N3708 (Driver)(1st (IF(Limiter Amp.) C136,C135B-4C135AC125-18C124-5 213, -200 mfd, 411,pfd mfd, mfd, 50v 475v 25v 601, C509-0.0047C516-0.1C515-75C510-0.001 pfd mfd, mfd mfd, 1 KV1KV 11143,R14211141-7.R145 -5K, 144-5K -22K, 5K, 5w 5w 5w pot DIODES: Q404,Q403Q401,Q306-TIP14A -2N3 405-2N3710 402-SK6361 709 (Output) C206,C205,C203, 208,314, 207, 209,319, 312-180 320-820603, 801-.1 pfd pfd mfd 221, 227,414, 417, 302, C520-40C519-45C518-0.022C517-0.01C602-0.082 mfd,pfd, mfd, mfd, 510/ 400vmfd 1 600v KV R20411203,R202,R201,11205, -1K 213-470322-6.2K448-270K 315, (Color 328, Level Pot.) 329, 419, 422 D203-TIV301D201,D102,D101 202, -1N759 301, 401, 302, 402, 501, 403-1N295 502-1N914 C211-320C210, 215, pfd 216,mfd313,304, 244, 305,318-0.02 246-0.001 306, mfd 308, 309, 310, C802B-80C802A,C701-100C604-0.056 803-160 pfd,mfd, mfd 4KV 475v mfd, 250v R209,11207,11206-110K 218,221, 506,309, 533-68K -6.701-4.7K SK 240, 241, 439, CAPACITORS:C101,D803,D801,D601A, 804,802-1N2070202, B, 220-22 C, D -Selenium pfd Rect. 805, 806-1N2069 C219,C217-240C214-25C212, 225-560pfd pfdmfd, pfd 50v 316, 317, 402, 405-2 C808-150C807-1000C806-2C805-0.001C804-100 x 0.001mfd, mfd, mfd, 475v150vmfd 100v 1KV 11216,11215,11214-1K11210, 217,228,511-47K (Hue 255,234,517-22K Pot.) 256, 260, 445, 216 C103-59C102-47 pfd C226-82C222, 224, pfd 229, 234-100 pfd RESISTORS: R101,C809-250 105, 230, mfd, 35v 233. 236, 304, RR219-4.7 220-27528-100K meg 217 R222, 405-27K Blue Horiz. Line T801 -Power R232,R231R226,R225R224, -330K 416-20K303, -39K 235, 417, 318, 446-2.2K 321-2.7K 11518-3.911516-820K,R514R513-10R510R505-6. -100K,-82K. 8K,meg lw lw 2wlw L605L604L801,L606 -Right -Right802, Side Side 803, LinesSideLines 804 -DegaussingR & G Horiz.R & G Vert. MISCELLANEOUS:V101-12GN7AV202-6JH8V201-6JH8V401-6BA11 (R(B ("Y" -Y (Vert. Demod.)Amp.) Osc.) R243-8.R242R238,R237R235, -39K,-15K, 239-270307, 2K, 2w 313,2w 401-5.1K 11524-211519-1011522,11521-1011520-2.2 meg, 523-18 (Horiz.meg meg, lw 5%(Focusmeg, 2w 2w Pot.) Centering Pot.) TRANSFORMERS:T102T101L805 -2nd-1st-Filter Coils VideoVideo Choke IFIF V402-6HE5V501AV403V501CV501B-1/3 -6C4 -1/3 -1/3 (Vert. (Pincushion6U10 6U10 Out.) (Horiz. (Horiz. (Horiz. Correct.) Osc.) Control)Disch. ) R249-1R248-1R246R245,R244-4. -3.9K, meg 247-18K, 7K, (G24w 2w BlueGreen 3w Pot.) Pot.) 11531-10K,11530-1.5K,R529R526-1.11525-1 -1K, 5meg 5w meg, lw (Hv. 1w Adj.5% Pot.) T201-ChromaT104T103T203-Osc.T202 -4th-3rd -Burst Video Tank BandpassTank IFIF V502-6JS6V504-6BK4V503-3AT2X201-3.579545V506-6DW4V505-IV2 (Horiz. (HV(Volt. (Focus (Damper) Output) Rect.) MHzReg.) Rect.) Crystal R306,R305,R252,R251-1R250-1 253,310-11K311, meg 254,412-13K (G2(CRT Red Bias Pot.) Pot.) 501, 502-470K R607-120R602,R601,11534-1K11532-680, 603,606-60 (Pot.) 604, 3w (Pot.) 605-120 (Pot.) T206T205-3.58T204T302T301 -Dual-Quad -2nd-1st MHz 3.58 SoundTrans.Sound MHzTrap IFIF Trap SP301-3.SG1,56015401RC401, 2, -Setup-Convergence3 2 -Spark402 (Speaker) Switch-RC Gap Integrator Socket R325-30,R324,R320-33R319R316R314-120 -82K 408, -10K lw 429, (Vol. 508-33K Pot.) R803R801-Varistor11613-68,R612,R609-60R608-70 -3.5K, 614-82, lw (Pot.)lOw lw T303-Discrim.T401T304T501-Horiz.T402 -Output-Vert. -Pincushion Out. Out. Correct. 13601S70113701 -Yoke -Convergence -Yoke Socket Assy.Plug &Plug Cable Assy. & Cable R411,R410,R407R406R403-1.R402-1. -150K-43K 421-680509, 8K 2K 512, 610, 611-100 COILS: R807-350,R806-82L102-39.75L101,R805-10, 105-41.25 lOw 2w MHz MHzTrap Trap R423R420,R415-300R 414-5KR413, -5.1K, 424-750 535, lw 804-220K L109L108-268L107-4.5L106-10L104-1.1L103-47.25 -Delay ,Lh uhMHzoh MHz&Line S.T. 15KTrap TrapCoil 11433,R431,R428R427,R426,R425-500 -750K 438-330K507, 430-82K436-2.2 (AGC 808-1.5 (Vert. meg Adj. Hold meg Pot.) Pot.) L201,L113-550L112-220L111-1L110 209 -Peakingmh-Ferrite uh uh & 12K SleeveCoil R443-270,R442,R441R437-4R435,R434 -4.7K, 702,802-Thermistor meg-1.5K 1w703-220 1w(Vert. (Vert. Size Lin. Pot.) Pot.) L501-Horiz.L208L205,L202, -2nd 203,206, Chroma 204-18207-696 Osc.by 22K Inductor uh uh shunted Amp. Load 218R450-9.R447-3.R444-10, 1K9K 2w (Vert. Cent. Pot.) L603L602L502,L601 -Red-Green 503 -Blue -DamperConvergence Convergence Convergence Choke Yoke Yoke Yoke 219 rOther 4144 TAB BOOKS of Interest HOBBY & EXPERIMENT BASIC TECHNOLOGY 542 -TRANSISTOR PROJECTS FOR HOBBY- 538 - COMPUTER CIRCUITS & HOW THEY ISTS & STUDENTS. Steckler.192 pages, 140 WORK. Byron Wels. 192 pages. 134 illus. $4.95 ilfus. $4.95 530 - BASIC ELECTRONICS PROBLEMS 537 - 125 ONE -TRANSISTOR PROJECTS. SOLVED. D. A. Smith. 192 pages, 100 illus. $4.95 Rufus Turner. 192 pages, 125 illus. $3.95 528 - PULSE & SWITCHING CIRCUITS. 524 - 104EASY PROJECTS FOR THE Harvey Swearer. 256 pages, 200 illus. $4.95 ELECTRONICS GADGETEER. Robert M. 510- HOW TO READ ELECTRONIC CIRCUIT Brown. 160 pages, 104 illus. $3.95 DIAGRAMS. Brown & Lawrence, 192 pages, plus 487 - 64 HOBBY PROJECTS FOR HOME & 64 -page schematic foldout section, 140 illus. $3.95 CAR. Brown & Olsen. 192 pages, 111 illus. $3.95 112 - LEARN ELECTRONICS BY BUILDING. 486 - 104 SIMPLE ONE -TUBE PROJECTS. 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