proyectos divertidos para estudiantes de electronica

5/27/2018 Proyectos Divertidos Para Estudiantes de Electronica

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rurProlcGBlr tlnhoilmomtl

Duringmore han20years,he author,sacollaboratorithAmerican,

EuropeanndLatinAmericanlectronicsagazines*,aspublishedlarge

assortmentfpracticalircuits singommonarts.

Nowmanyfthose

projects

rencludedn thisvolume,mostofwhich

ou

canbuildnoneevening.heprojectsangerom un ypes hroughractical

typeso amusementypes.Of course,hereareotherdeviceshatcan be

used oteachousomethingbout ircuits r components.

An mportanteaturefhesesrojectsrehe deasoExplore,ntendedor

studentsookingorprojectsnscience ro use npracticalesearch.

Wecanconsiderhisbookas a source ookoftheeasiest ndun-to-mak

of hehundredsf

projects

reated nd

published

y

heauthor uringhese

lastyears.

But,astheprojectsren a wideangeof types,weshould eparatehe

electronicsxperimentersnto wogroups:heoneswhowant oimprove r

expandomeotherareaof theirelectronicsnterest, uchascomputers,

radio,nstrumentation,udio, ecurity ndevengames;ndhe oneswho

want olearn omethingboutelectronicircuits nddevices rwantnew

ideasousen sciencerojects.

Most fheprojectsescribedereinanbestand-alonesndividualcces-

sories;hereverossiblehecircuitsave een esignedo hatheyanbe

gangedithoneormore therrojects.orexample,anyrojectsf audio

etfects rgeneratorsanbegangedithaudio mplifiersrhigh-powerut-

putstages.

Allheprojectsresimple,ithew ow-costomponentshatcanbemaden

oneevening fwork.

Tomake t easyor he readero chooseheprojectseaddedodes fter

eachitle o ndicatehekindofexperimenterforhomheyarentended:he

codeP(Practical)ndicatesprojectuilt orpracticalse.Thecode

E'

(Experimental)ndicateshat heprojects intendedorheexperimentero

teach omethingboutircuits r devlces.



trolr

Of course,oucanalsoindprojectswithboth codesEand P)whichan

dtherbe mountedo teachsomethingrkndbe used orapracticalnd.

Thepresentationsf theprojectsrepractical.lectronicsomponentsre

listedwitheachcircuitdiagram.utsecondaryartssuchas sockets,has-

sis,enclosures,iscellaneousardwarend soon, are notspecified, in

the readersfree ochoose hesenon-criticaltemsaccordingohisprefer-

encesand demands.

Themanner nwhich hecircuitsworkandcan be modifiedsexplainedn

practicalermsso the readeranacquireomeknowledgefpracticallec-

tronicsas heprogresseshroughhe book.

Althoughmanyof theprojectsweenjoyedonstructings heyaredescribed

here,oumayhinkofpossiblemodifications.eustrecommendhatyougo

aheadand modifyhe circuitsoyourpersonalnds.There sawideatitude

incircuitmodificationsndmostofthemwillbe ofvalueothe experiment

whowantso see howhingswork,even hougheachproject's rimaryntent

is orhebuilderwhodesires functionaltemof equipments heresultf his

work.

Asthebookncludesasy-to-buildrojects,heauthorhopes twill helpyou

to learnmanyof the undamentalsf electronicsnaneasyandunway,and,

ifyou'rea student,rovidesource orschoolprojects.

NewtonC.Braga

.Mini-Projectsshe itleof a columnublishedy heauthoruring ever

yearsnaBrazilianlectronicsagazineamedEletr6nicaTotalTotalElec-

tronics).



frnFdocahlhclnulmtmol

MlcRo-PowEREDFLASHERE/P)

A simpleLED lasheran be builtwithaTLC7555 imerusedas alow-

frequencyscillatornddrive o anLED.C1 uns n alow requencyeter-

mined yR?R3andC1.Frequencys n heange etween.1and5Hzbut

youcanaltert bychanging l.Thiscapacitoranangerom1to10uF.

Duty yclesdeterminedyR2/R3ationds mportantnapplicationshere

youneed eductionfenergy onsumed.Thoughigure showsixedesis-

torsor R2andR3,youcanuse rimmerotentiometersfyouprefer.he

potentiometers,fcourse, rehandyoralteringherequencynddutyycleof theoscillator.

Rl values ependponhepowerupplyoltage.Withpoweruppliese-

tweenand6volts,R1s 470ohms.Withpoweruppliesetweenand9

volts,Rl is560or680ohms.Withpoweruppliesn he ange etweenand

12volts,l must e1,000hms.Theircuit rains nly50uArom 6-vo

powerupply.

FigureshowsheschematiciagramorheMicro-Power

EDFlasher.

theheart f hecircuits Ol,a 555imer.

Usehepartsplacementiagram saguidewhenassemblingheMicro-

Power EDFlasher. omponentslacement,singterminal tripas chas-

sis,s shownn Figure2.

Take pecial arewithpositionsfpolarizedomponents,uchastheLED

andelectrolyticapacitor.

Afterouaresurehatyouhavewiredall hecomponentsorrectly,uthe

batteriesnhebatteryolder. heLEDshouldlash.



R1

560s,

c1

4.7pF

Dl Rg

1N914 4KT

FigureI

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Figure2

I



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II'

PartsList- Micro-PowerEDFlasher

lC1 -TLC7555CMOS ntegratedircuitTimer

LEDI-Commoned,greenoryellowLED

D1 -1N914generalurposeilicon iode

Rl -560ohm,114W,5%esistor

R2 -1,000,000hm,114W,5%esistor

Rg -4,700ohm,114W,5%esistor

C1 -4,7 uF,6M/DCelectrolyticapacitor

C2 -10UF,2W\/DCelectrolyticapacitor

81 -6to 12VAA cells,9Vbatteryorpowersupply

ldeas oExplore

learnmoreabouthe circuitand devices:

oAlterR2andR3(minimumaluesre1,000 hmsorboth)andsee

how helashing atechanges.Of course,fyouwant,youcanreplace

R2andR3 with1,000,000-ohmrimmerpotentiometers.

oExplainow he astable 55works n this circuit.

oAlterC1n arangebetween and100uF andobservelashingate

alteration.xplainwhathappens.

oWhatsduty-cycle?



FroFGtllmPomrlMmfic

Sciencexperimentsithhe clrcuit:

oLED sa monochromaticightsource.Youcanperformomeex-

perimentsnopticsusing hiskindof lightsource.Chromaticiltersan

be used nsomeexperimentsnvolvingEDs.TrytoseLEDsof diffe

entcolorsred,yellow,reenand, fpossible,lue).

. Light lashes,s theonesproducedy thiscircuit,an beused n

hypnoticxperiments.

oThecircuitcanbe usedo indicateoperationfotherelectron

devices.Wiredothepowersupplyofamonitoredevice,heblinke

LEDwillndicatetsoperation.

Rememberhathe heoryn hisbook sspecificallyelatedo theassociatexperimentsndprojects.Thisook sdesigneds an ntroductionotas an

in-depthreatmentf electronics.fyouare interestednfindingout more

about hesubjectsouchedoninthisbook,severalextscanbefoundor

furthereading.



Ffd0crzsH-i$fff,l

Thecircuitmustbepoweredya S-voltegulatedowerupplys tusesa

TTLC.Currentequirementsangeypicallyrom5 to15mA.

Componentslacementna smallrinted-circuitoardsshownnFigure.

Experimentsike hiscanalsobeperformednwhatelectronicsxperimenerscall

breadboards".Thesereboardsnwhichhepartsof experimen

canbe emporarilyssembled.yusingreadboardst isnotnecessaryo

teo\/7$1"

t'\ttffin

FigureI

Figure2

r8



Frndrctrffithe halmffil

solderhecomponents.hisswhy heyarealsocalledsolderless

boards"

Thecircuitanbeusedoteachmuchaboutlip-flops,sedn computerss

countersndnmemoriesndmanyotherapplications.

Observation:ndigitalelectronicsnelectricalignals eitherhighorlow.

Thesewostatesaleusedorepresentinarybits1and0.Sincedigitalogic

lOs operaterom asingle-endedowersupply,ahigh staterepresents

voltageearhe supplyoltagendalowstateepresentsvoltageear0V'

PanrsLsr- SET-RESETUP-FIoP

fC1 -74OOTLIntegratedircuit

LEDs -Red,greenoryellowommonEDs

R1,R2 -330ohm,114W,5Y"esistors

51 -SPDTtoggleswitch

ldeasoExPlore

Toearnmoreabouthecircuitnddevices:

oThecommonlip-flopsafundamentalounterircuit.Mountther

unitsikehisandusehemo explainowcountersndmemorie

workn computerircuits.achlip-flopanstoreabit.

. Findheditferencesetween-SandJ-Klip-flopsndhowhey

areusednogicircuits.

Sciencexperimentsndprojectssinghiscircuit:

oReplace1bya-magneticreed)witchr amicroswitchnduse

thiscircuitsa one-eventemoryn experiments.t candetectnd

memorizehena Switchn anure,alarm,rmechanicalrocesss

closedoramoment.

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MIN|-METRONOMEP)

Heresa dandywo-transistoretronomehichoucanbuildntoasmall

plasticase.Youcanusean oldnonworkingransistoradio ohouse his

gadget.n mostcaseyoucanmerely emovehemaincircuitryutretain

someparts,uchas the on-otfolume ontrolotentiometer,peaker nd

batteryolder.fyouhavedone his,youhaveusteliminatedhe ollow

items:PKR,1,and81.

Thecircuit anbepoweredith woorfourAA ellsnddrains bout0mA.

Assoonas 31isclosed,hemetronorfletbrtq lacking.yadjustingoten

tiometer1youind hebeat'or

frequencyf clackingouwish o set.

Tocalibrate,ouhave nlyo synchronizeourmetronomeitha commerci

typeor anyknown ource.

FigureshowsheschematiciagramorheMini-Metronomet heheart

ofthecircuit reQ1andQ2,as atwo-stageirect-coupledmplifier,hich

allowshecircuitogeneratentervalledulses.

Figure2showsamechanicalviewfthemetronome,singterminal t

aschassis

for hesmallomponents.

Position fthepolarizedomponents,uchas Gl, C2andhe transis

should eobservedn hemounting.

rt



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Q1

R1

10K

*_J

Q 2

| s t \Bc5s8| t

t lc2d I

100pFT II t ?

l a r :| 3/6VT-

SPKR

4l8A

+ r \

c1

lOpF

R2

1K

P1

1M

Ftgure1

Figure2\

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HftFCIFfrilTtrlffiHT----

PartsList- MiniMetronome

Q1 -8C548 NPN ransistor

Q2 -8C558 PNPransistor

51 -SPSTtoggleor slideswitch

81 -3Vor 6V-two orfourAA cells

SPKR 4 or Iohm,2to4-inchoudspeaker

P1- 1,000,000hmPotentiometer

Rl -10,000hm,1l4W,5oloesistor

PA -1,000hm,114W,5%esistor

C1 -10pf,6VVVDClectrolyticapacitor

C2 -10Uf,6WVDCelectrolyticapacitor

ldeasoExPlore

Toearnmoreabouthecircuitanddevicesrtogetbetterperformanc

oReplace1by anycapacitorntherangeetweenand10pF.

Observehatwillhappeno thebeatate.Explaint'

oReplaceransistor2withaTlP32ona smalleatsinkndpower

thecircuitroma 9Vor12Vpowerupply.You'llaveextraoweror

yourexperimentaletronomendcanusetinargerlaces.

o.RemovePlandouchwithyouringershepointswheretwas

wiied.Willhecircuitperate?anyouexplainhatsgoingn?

-

2a



Prtlm8thl-ilrtrr

Science xperimentsndditferentses or hecircuit:

oThemetronomeanbe used ngymnasticxercisesrnrunni

to findhecorrecthythm.hemetronomeanbehousedna small

plasticox,poweredycellsandeasilyarried ithhe unner.

oBiologicalxperimentsithsoundsanbemadewith hisdevice;

experimentsnanimalonditioning,orexample.

n



filnH.f0c03ffisrhoilm

PENDULUM LARM (E/P)

Anymovementhatswingshependulumensorriggershisalarm,nablin

arelay.

Thecircuitanbeusedoprotectars,arge bjects,omesndotherlaces

ashesensoranbe usedo detectnymovement.hisdeviceanalsobe

usedorscientificxperiments,s suggestedttheendofthesection.

Therelayandrivepowerfuloundystems,uchas sirens,orns,amps,

etc.Thecircuitanbepoweredyal2-voltbatterywhenusedncars,or

instance)rapowerupply.urrentrainsvery owabout00uA)whenhe

relaysdeenergized,xtendingatteryife.

TheschematicircultfhePendulumlarmsshownn Figure.Thecircui

hasasitsheartan SCRSiliconontrolledectifier),hichenergizeshe

relaywhenhesensoretectsnymovement.

A mechanicaliewofthecircuitmounting,singterminaltripaschassis

is shownn Figure2.

Relay oilvoltages chosenccordingo thepowerupplyoltage.ou an

useaminiDPDTAMiniRelayRadiohack75'249)r,orheavyoads,10AminiSPDTelayRadiohack75-248).Theseelays reratedo12

VDCand drainonly38 mA(theiroilresistances about320ohms).As

equivalentypes anbeused,oushouldakecarewith erminalayout.

Reset anbemadewithamomentary-typ6witchPush-On)iredetween

theSCRanodendcatode,r byusingheon-otfwitch.

Positionsfpolarizedomponents,uchasthe SCRanddiode,houlde

::t::r :tairsareatsoivenn Fisurc2.Noricehatoperationccurshen

theverticalorhorizontal)arewireouchesheringduringnymovement

2l



fl0l0c|Peniluluml

(sEETEXT)

X1R1

scRTtc106

FigureI

Figure2

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PartsList- Pendulum larm

SCR -TlC106requivalentiliconontrolledectifier

D1 -1N914 requivalenteneral-purposeilicon iode

K1 -12V elayseeext)

S1 -SPSTlideoroggle witch

Rl -22,OOOhm,114W,5%esistor

R2 -10,000 hm,114W,5%esistor

X1 -Pendulumensorseeext)

ldeas oExplore

To earnmoreaboutircuit nddevices:

oReplaceelaywitha12Y 200mA ncandescentamp.Doeshe

circuitwork?

oExplain hatDlisdoingn hiscircuit.st necessaryf he elays

replacedyanncandescentamp?

oExplainowanSCRworks

Sciencerojectsndditferent sesor hiscircuit:

oReplace1 by a reedswitchogetan alarmriggered yamag-

neticensor.Youanalsoeplace 1bf amicroswitchr otherindof

momentarywitch.

oInbiologicalxperimentshe alarmcanbe usedo detectmall

movementsn animalrapsor cages.

t0



Frfhct?oildumllr

oReplacinglby wometalwiresenableshecircuitobe riggered

by water.Watereveldetectorsanbe madeusinghis kindofsensor

and tcanbe used nmanyexperimentsndpracticalpplication

olnstallednyourcar, hiscircuitanbe usedas an

alarm,drivinghehornor asiren.

oBy replacing1withalargemetalplate,hecircuitanbe usedo

detectwind.Airlowcanmoveheplatesothathebarewireouching

the loopcauseshealarm otrigger.



runPnFctlollhEnul

MEDIUM-WAVEFPRESELECTORP)

Thesensivityfmostmoderately-pricedMeceiversspoorn hemedium-

waveand.orseyet,selectivitylsodropstfsharplyithinheupperart

ortn"band,makingnereceiv-erighlyusceptibleoimages,oiseand

annoyingeterodYnes.

Evenhebestantennandagoodboostermplifieran'tmakep orhese

deficienciesna commoneceive/srontend.But,usingnRFpreselecto

b;trd;theantennandheeceiver'sntennanputerminalsillgiveou

realncreasenhereceptionuality.

Thisircuitmatchesheantennampedanceithheeceive/sntennanput

accordingherequencyftheunedtation'

FigureshowschematiciagramftheMedium-wavereselector'

Figure2showsnexplodediewofthecircuit,whichanbehousedn a

smalllasticox.

Llisormedy urnsfNo.28enameledire,woundna5/16-incherrite

form.apsremadeach15or20urnsandtsnumbers notcritical'he

numberftaPsanbealtered.

Attachourantennandgroundothenputerminalsfthepreselecto

Tuneothedesiredtationnyoureceiver,nd,bychoosinghebest.pos

tionofthealligatorliponhetripanOyadjustingVfindhebestsignal

Theequiredntennaill

dependponhestationouwantotune'Aran-

domengthfwiiewillgiveairlygoodperformancehroughheA{ band'

Antennasithengths-etweensano150eetareecommendedorbest

performance.

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ToReceiver

FigureI

Figure2

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PartsList- Medium-WaveFPreselector

L1

CV

X1

-Medium-Waveoil-seeext

-

365pFminiatureariableapacitor

-Alligatorlip

-2-positionarriertriP

ldeasoExPlore

Toearnmoreabouthecircuitnddevices:

oExplainhemportancefagoodgroundonnectionn hiscircu

Whats hemeaningf"impedance"?

oUseanewcoilwith20urnsandapseveryturnsotuneshor

wavestations.

oMakeseoondoil20urns)nhesameerriteod oplughe

antennandground.



ftnFillectiffimmlhleilcr

ELECTRONICISHINGURE(P)

Thiscircuitmitateshesoundfwetbugsmillingbouthesurfaceo attra

curiousish.

Thecircuits basicallyHartleyudiooscillatorperatingnafrequen

between00and2,006Hertz.PoweredyanAAcell,t canhousedn aclean

emptyeanututterarwithhebuzzerircuitrymountedpside-downnhe

.ofti.Voumustbecarefullotodrilln suchawayasoallowwateroeak

tnrougnhecap.iliconubberanbeusedoclosenywatereak'

CapacitorClouldive resonantfrequencyofpproximately,000Hz'but

p1wouldiveawid6ariationnsignaltoneeneratednheaudioange'

Youanalsousealow-impedancearphonesatransducer,onnectit o

thesecondoiloutput) ftheransformer'

Tooperate,nscrewhecap,hrowS1ON,puthecoverackon,anddro

theishurentohewatern nevicinityfwhereouwillbeishing'llow0

minuteseforeeelinghemn.fnecessary,diustP1oanewsignalone

FigureI showshe schematiciagralfortheFishLure.observehathe

se-condaryoilofthesmalludioransformersnotusednhiscircuit

constructionetailsftheElectronicishingure,singterminaltripas

chassis,s shownnFigute2.Theexactocationsfcomponentsno

critical.

T1salsonotcritical.ny500:8r1,000:8ransistor

ransformerithente

tappedrimaryanbeused.wecanalsosuggesthatanysmallransi

transformeranbeexperimentedith'

EO



Pnm0 $oe[cnhHshlun

S1

1.5V

(')SEETEXT

R1

1K

Figure1

Figure2

It



Fr}Idccufor[nHrcilmEmGl

PartsListElectronic ishingLure

Q1 -8C548 general-purposePNsiliconransistor

T1 -500:8or 1,000:8ransistorransformer

(RadioShack2TS-1380s suitableor hisask)

P1 -100,000hmrimmerotentiometer

R1 -1,000hm,114W,5%esistor

C1 -0.01uFmetal ilmor ceramicapacitor

S1 -SPSToggler slide witch

BZ -Piezoelectricransducerr crystalearphone(Radiohack273-073r equivalent)

81 -1.5V AAcell

ldeasoExplore

To earnmoreabouthecircuit:

oReplaceBZbyalow-impedanceweeter r small oudspeakeon-

nected o the transformer econdaryoil.

oChangeC1values nthe rangebetween .001and0.22uF.Ob-

servewhat hapenswith onepitch.A higher-valueapacitorivesa

lower one.

oThe circuitalsooperatesroma3Vor6Vpowersupplywithout

makingnychanges.

ft



PloloclHGGtorlcHrill

Science nd ditferentsesorhedevice:

oYouanmake everalexperimentsnanimalconditionncludin

theoneshat ive n the water. ryoalterhe RC networkP1,R1 and

Cl) to

get

onesof ditferent

itch.

ryo usediodes, mall ranscoilsand otherpassiveomponentsn thisexperiment.oundsike

thoseproducedysongbirds anbegeneratedithafewcomponen

arranged n thecorrectway.Canyoudiscoverhowo doit?

oRemovehepiezoelectricransducerndwireelectrodesn tsplace.

Thedevice an be useas a nervstimulator. xperimentsithanimals

andplantscan be made.Whatphysiologicalunctionsre atfected?

Cancircadian hytmsrinternaliologicallocksbe atfected y con

tinuousexposureo sounds?

oElectrodeslacedntowaterand wired nplaceof the transdu

willproducecurrent ield.You anpedormnterestingcientificork

relating ow ishandotherWatereings eact o thecurrentield.Can

the current ieldsaffectphysiologicalunctions?fyouexperimentith

plants,electafastgrowingouseplant.

80



ftnrdccEhr[tcHnilmms

FREE-POWERM RECEIVERRE)

Thisprojectusesa strangeway ogettspower.tusespowerextracted

fromhe unedtationogiveothe amplifierransistor.ithareasonab

strongppliedmodulationnvelope,hisypeof detectorroducesstron

demodulatedutput.

Naturally,hecloserouareo a strongtation,hemore urrentouradio

willbeableo supply.

Forbestesults,oumustoeverythingossibleo deliverstrongignalto

the ransistoretector.erecommendgoodantennandground,heat-

terpreferablyeingmadeo awateripeor solidxternalroundomposed

of apipedriventeastfeetntomoistarth.hiss mportantorensurin

maximumignalickup. I

lfyouhavelentyf spacevailable,heongerheantennaupo about00

feet),hebetterheresults.

Figureshowshe schematiciagramf theFree-PowerMreceiver.b-

servehat heheartofthecircuitsagermaniumransistorhatworks sa

detectorndaudiomplifier.

Gomponentslacementn aterminaltripusedasa chassiss shownn

Figurc2.The erminaltripanbeixed nanexperimentoardhatcanbe

constructedsingome ommonoolsandmaterials.

Qlisanygermaniumransistor,uchsGE-2 r2N107.Youanindgerma-

nium ransistorsnoldnonworkingM ransistoradioeceivers.onwork

AMradios analsosupplyhevariable apacitorndheoopstickferrit

rod).

Earphoneust eahigh-impedancerystaltype.ow-impedancearphone

don'tunctionn hiscircuit.

_



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FigureI

s-4^o

Figurc2

t8



frn?nfffihrucmlffi--

PartsList- Free-PowerM Receiver

Q1 -NPNorPNPgermaniumransistorseeext

XTAL-CrystalarPhone

L1 -LooPstickseeext

CV -365pFvariableapacitorseeext

Rl -12,000hm,114W,57esistor

C1 -1 uF,25WVDClectrolyticapacitor

ldeasoExPlore

Toearnmorebouthecircuit:

oReplacel by15urnsofNo.28 wire,woundnaferriteod,o

tuneshort'wavetations.

oBy eplacinglwithagermaniumiodendemoving1andC1you'litransformhisadiontoa simplerystalet'

oAlterR1n arangeetween,7}Oand7,000hmsogetbetter

performance,ependingnheransistorsed'

oReplaceheransistorithasiliconype,uchshe8C548'What

willhaPPenithsensivitY?

sciencerojectnvolvinghecircuitnd,uncommonses:

oExplainowrystaletsunctionndellaboutadioistory.fyou

arenterestednmoreadioistoryeveralextsanbeoundnthe

publicibrarY.

olfyouwantoearnmoreboutadioeceivers,ryoindnform

tionabouteterodynendsuper-hereterodyneypes'

-

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HEFfdffiffnrffilmrbl

DUAL-LEDLASHERE,P)

Thiscircuitsesaone-gatescillator,itha4093CMOSG,oproduce

50%duty-cyclelashern twoLEDsor a bi-colorED. he circuitanbe

poweredya 3to 12-voltowerupplynds usefulnseveralxperiment

andpracticalpplications.Youanuset aspartof alarms,arning ystem

games,oys, ndsomecientificxperiments,swewilldescribeere'

R2andR3values ependponhepowerupplyoltage, ccordino the

followingable:

Power Supply

3Volts

5Volts

6Volts

9Volts

12Volts

R2, R3

220ohms

330 ohms

470 ohms

820ohms

1,000 hms

Formore utputoucanusea transistorizedutputtagerivingncandes

centamps.Experimentso observeightetfects n animalsndplantsan

beconductedith hiscircuit.

Pl andC1determinelash ate.Flashatecanbe adiustedyP1,butCl

alsocanbealteredn alarge ange fvalues,ccordingo theapplicatio

yountendor hedevice.

Schematiciagramor heDual-Ledlashersshownn Figure1.Onegate

of a4093C s usedasoscillatornd heotherwoareusedasnverters

Componentslacementn aPCboardsshownnFigure2.Youanalso

useabreadboardr solderlessoardo mounttas anexperimentalircuit

Positionfhepolarizedieces,uchasLEDs, letrolyticsndC,shoulde

observed.

tf



,,trmAlld.|nm*o

P1 R1

tM 100K

cl

1pF

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z ' i

I

, l

- . \-, \-_

LEDl

Figure1

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12V

ov

c1

3 E

nD r

Figure2

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IunPlolectsol thcDttrcfimcntot

PartsListDual-Ledlasher

lC1 -40938CMOSntegratedircuit

LED1-bi-colorrredandgreenommonEDs

(RadioShack276-012l

R1 -100,000hm,114W,5%esistor

R2,3 -resistor ccordingopowersupplyoltage seeext

P1 -1,000,000 hmpotentiometer

C1 -1uF,25WVDCelectrolyticapacitor

ldeaso Explore

Toearnmoreabouthe circuitnddevices:

oReplaceC1with capacitorsn therangebetween1 and47 uF.

Observeowhigheraluesalterheflashate.

oInfraredEDs anbe usednsomeexperiments.ochangen he

originalircuits necessary.

Sciencenddifferentsesor hecircuit:

oRemoveP1 andR1 andwireat thispontatouchsensorr elec-

trodes.oucancontrolheflashatebytouch.Abio-feedbackevice

canbemadehiswaY.

oBy wiringhelC spin1 to anexternalircuit,heflasheran be

controlledy a logicevel.CMOScircuitsanbe usedo controlhe

flasher.

il



, ,Pnmlmu+nnm

oMountheLEDsnplacef heenses,.ffiflashateanbeadjustedo makenhypnoticrrelaxingLtfecom-binehiswitha touchensorndyouhavenuncommonio-feebackevice.Youanalsousehiscircuito makexperimentsncirca

dianhythmsr internaliologicallocks,eterminingowheycanbealteredy ightpulses.ariousheoriesaveeenproposedboutthissubject.

. Psychiatristsreusingphototherapyo helpsomepatients.anyouindsomeapplicationorhecircuitnhisield?

. Plalsoanbereplacedyresistiveransducers,uchas LDRsrNTCs,ogivea light-r emperature-dependentlash-rateircuit.x-

perimentsanbe madewithconductivityf materialsyconnecprobesnserieswithR1.Replacelwithheprobesnhiscase.

g l



IunProfcctsorstGrDcIlmGntGl

6VX 1A POWERUPPLYP)

Inorder operformxperimentsndprojectsnvolvinglectricityouwillneeda sourceofvoltage. oltage equirementsorcommonprojects,uchas the

onesnhisbook, ependpon heirapplications,ndtypicallyange roma

few milliampereso one or two amperes.

lnsteadf usinga batteryoucan usea circuit alledapowersupply.

Thepowersupplyweshowherecan be used oprovideVx 1A regulated

outputothe experimentalndpracticalircuitsdescribedn thisbook.The

outputvoltage s fixedbythe lC.

Figureshows he schematiciagramorhispowerupply.Ol is a voltag

regufator,7806.The"06"

indicateshatt isa6-voltegulator.

Figure2showshecomponentsayout, singaterminaltripas chassis.

Thecompleterojectan be assembledna smallplasticox.The ntegrate

circuit hould emountedn a heatsink. oucanalsoaddan LED n series

witha470ohm resistor, ired n theoutputof the circuit o indicahat t ison.

External ircuitsan be connectedo thepowersupplywithalligator li

Position f thepolarized ieces,uchas diodes,he lC,and electrolyta-

pacitors,mustbe observed.

The ransformersn'ta criticalartofthisproject.ypeswithasecondaryoil

rangingrom7.5 to 12 voltsand currents etween00mAand14can be

used.

5f



trolrctg 8u llPil0tsuil

D2

1N4002

c2100pF

tl_

TI

I=

T1

12+'l2Y

1A

louc1

1000pF

FigureI

Fiaure2

t

55



mFrtmctrtrtrHilffi

PartsList- 6-VoltPowerSupply

lOl-7806positivehree-terminalegulator

T1 -Transformer:rimary17VACseconda

y

12+12Y 1A

D1,2-50Vx 1A 1N4002requivalentiliconectifieriodes

C1 -1,000F,25WVDClectrolyticapacitor

C2 -10uF,12WVDClectrolyticapacitor

S1 -SPST witch

ldeaso Explore

Toearnmoreabout hecircuit r alter heperformance:

oReplaceC1bya 7805, 809or7812fyouwanta 5V 9Vor 12V

powersupply. oumayalsohaveochange he transforma117:15+1Vusing 7812.

. Explain owhecircuitworks.

oWhat s theditference etweenn ACanda DCcurrent?

Science nduncommonpplications:

oThispowerupply anbe usednchemicalxperiments,uchas

theoneshat nvolveurrentlowhroughubstances.xperimentinvolvinglectrolysisndelectroplatingre wo hatcanbesuggested.

A variable ound-wireotentiometer100ohms, watts) houl

wirednseries ith hepowerupply utputo imiturrentlow hroug

theoad.Youanalsouse heLightDimmerescribedn hisbookor

this ask.

a



Plrflctg 0urlt Pilil $ut

o6V200mA smallncandescentamps an be supportedythis

powerupply.heseamps re excellentightsourcesoworkwith

microscopes.

oSmallmotorsndampsnexperimentsnvolvinghysics,echan-

icsandoboticsanbepoweredrom hispowerupplywithadvan-

tages.oudon'thave o spendlotofmoney ncellsorbatteries.

oAllcircuitsescribedn hisbookwhichequire 6Vsupplyanbe

poweredy hispowerupply.

oThecircuitanbeusedas anexcellentowerdapteroryoui6V

equipment,uchas smalladios,alculators,tc.

o6Vamps anbe usedn experimentsnvolvinglantgrowth.e-lectafastgrowingouselantnduse.a arkroomrcardboardox

to coverthem.ampsitholoredilters anbeusednanexperimen

involvingrowthnddevelopment.

oCircadianhythms analsobe studiedsinganimalsrplants

Lamps anbepowerednatnightndotfatday.Whatphysiolog

functionsouldbeatfected?

5t



mFilncNsfffirHrufinrm

rNsEcTREPELLENTP)

Some ontinuousoundsan epelnsectsandalsoattract).he requencyand ntensityependspon heapplicationnd ypeof insectndcan be

foundhroughxperimentation.

Thecircuithown eregeneratescontinuousoundhatcanbeused o

repelorattract)omeypesfnsects,r nscientificxperimentsnvolvi

animals.

Our nsectepellentanbepoweredy9Vbatteries,woM cellsor ourAA

cells,and ts owcurrent equirementsillextendhe ifeof thoseellsorbatteries.

Figureshowsheschematiciagramfthe nsectRepellent.heheartf

thecircuitsa 7555 C,aCMOSimerwiredsanaudioscillatornddrivin

apiezoelectricransducer.

Thecomponentslacementna homemaderinted-circuitoardsshownn

Figure2.Exactplacements nothatcritical.

All hecomponentsnd hepowerupply anbehousedna smalllasticox.

TransducerZsa crystalarpiecerapiezoelectricransducer,uch s he

Radiohack 73-073.

Positionf thepolarizedieces,uchasc2 and hepowerupply,mustbe

carefullybserved.

Using he nsectepellents veryeasy. ouonlyneedoadjustherimmer

potentiometer1 oproducesoundwithhesamepitchas the nsectouintendorepel.xperimentationhouldemadentilyouindhebest ound

to repelspecificnsect.

60



E ledl0In$octidh

R2

4K7

cl0.047p.F

Figure1

Figure2

01



ftrF||f|Gilthlhsuh |m

PartsList- InsectRepellent

c1

BZ

R1

R2

P1

c1

c2

S1

B1

-TLC7555MOSntegrated-circuitimer

-Crystalrpiezoelectricransducer

RadioShack73-073r equivalent-10,000hm,114W,5%esistor

-4,700hm,114W,5%esistor

-100,000hm rimmerotentiometer

-0.047F metalilmorceramicapacitor

-10uF,12WVDClectrolyticapacitor

-SPST lideor dgglewitch

-3V(2AAcells),V(4M cells),V(battery)

ldeaso Explore

Toearnmoreabouthecircuitrgetbettererformance:

. Powerfulutputanbeobtaineditha transistorizedutputtage

as shownn Figure3.Thepowerransistorhoulde mountedna

heatsink.Theransducersa ow-impedanceoudspeaker:angingrom

4to8 ohms.

oExperimentsithultrasoundahbe madewithhiscircuit:educe

Cl to 1200Fanduseapiezoelectricweeters ransducer.emovethesmallransformersedn heseweetersndplugheransduc

directlyo thecircuitutput.utputsnrequenciess highas40,000

Hzcanbeproducedy hiscircuit.

oExplainowsoundsanbeproducedyelectronicransduce

suchasheoneused nhisproject.



?nhdl0 InrstirDd

oWhatareultrasounds?

Sciencendditferentpplications:

a Ofcourse,oucan esthe realetfects fthis deviceonseveral

kinds fnsects. n attractiveiologicalxperimentanbeconducte

based nhiscircuit.

oEtfects f sounds nplantgrowthr developmentan becon-

ducted singhiscircuit.Cansoundsqrultrasounds)lter hecirca-

dianhythms fplantsndnsects?

oThecontinuousoneproducedy hiscircuit anbeusednalarms

orwarning ystems.iceandother mallanimalsrerepelled y

powerfulltrasounds.

oReplace2byanLDR.Theircuitowbecomeslight-depend

oscillator.xperimentsith ightandsounds annowbe conducte

usinghedevice.

6 to12V

Figure 3

08



HnPnlmts||]mHlo|lmeml

ULTRASONICENERATORE/P)

Dogs,mice, atsandothernimalsanhear oundsithrequenciesp o

4O,O0Oz.There reseveralinds finsectshatcanalsohearorreacto

thesesounds.he circuitweproposeereproducescontinuousound

emissionn frequenciesbovehehumanimit,or arange etween8,000

and40,000Hz.These oundsrecalledultrasoundsndcanbe usedn

severalxperimentalndpracticalpplications.

Thedeviceedescribeereanbeusedo scareogs ndothernimals,n

biologicalxperiments,ndmany thernterestingpplications.

Therecommendediezoelectricransducerasts maximumutputower

between00 and 3,000Hz, butt alsowill operatethigherrequenci

emittingesspower.

Theecommendedowerupplys ourM cellsor a9-voltattery.

Ourprojectunsbetweenpproximately8,000nd40,000Hz,butyoucan

easilylterhisange ychanging1,n arange etween70pFand0.001

uF.FrequencyanbesetbyP1n herange eterminedy C1.

Rememberhat he40938C willoscillaten requenciesp o 500kHz.

Thecompleteircuitfthe Ultrasonicenerator,singheourgatesof a

40938ntegratedircuit,s shownn Figute1.

Componentslacementn aprinted-circuitoards shownn Figurc2.

Thecircuitanbehousedn a smallplasticoxandhe ransducerillbe

fixedn herontpanel.

Take arewith hepositionf thepolarizedarts,uchasthetransis

electrolyticapacitorndpowerupply.

Forcontinuousperation, 1shouldemountedn aheatsink'

The ransformers nota criticalart.Any ransformerithasecondaryoil

rangingrom100 o 500mAcanbeusedn hisproject.

-

00



F.lect luftmmlcecmnt

Figure I

Figure 2

0t



HiFrrN.Gt3ffimmdlmrfit]

PartsList- UltrasonicGenerator

lC1 -40938CMOSntegratedircuit

Ql

-

8D135medium-powerPN iliconransistorBZ -Piezoelectricransducer

RadioShack73-090requivalent

Tl -Transformer:rimary17VAC;econdaryVx100mA



Pl -100,000hmrimmerotentiometer

C1 -4,700Fceramic rmetalilmcapacitor

C2 -100uF,12 M/DCelectrolyticapacitor

S1 -SPSToggle r slide witch

81 -6Vor 9V-AAcellsor battery seeext

ldeas o Explore

To earnmoreabouthecircuit rogetbettererformance:

oYouaneplacehepiezoelectricransducerya commonweeter.

Remove1andBZandplacehe weeteretween 1andQl'scol-

lector.Canyoumeasurehegeneratedltrasoundower?

. Thecircuit analsogenerateoundnheaudibleange. eplace

Cl byacapacitornheangeetween .02and0.1uF.

oExplain ltrasoundsndhow heyreproducedyelectronicrans-

ducers.

0l



P'rhct ttUhffuh8emn0r

oWhat sapiezoelectricaterial?

Science ndditferentpplications:

oSeveral xperimentsanbe madesing ltrasounds.ouanex-

perimentithdogconditioning.singhisoscillatoroucancalla dog

using nnaudibleoundinaudibleo humans)

oGhoose capacitoretween.01and0.047 F oproduceounds

both nthe audio angendultrasoundange. ouannowconduct

experimentsodetermineheexactupper-limitrequency eardby

humans.Youlso anconductxperimentsithanimals.twillbe m-

portanto have frequencyounter n hando do hiswork.

oReplaceZbyelectrodes.hecircuitwillgeneratehigh-volta

outputhatcanbeusednnervetimulation.sea 10,000hmpoten-

tiometeroadjust utput oltaget hispoint.ulsesaneacheaks

as highas400volts.

oToget pulsesfornervetimulationnd otherexperiments)ou

onlyhaveo replace1witha1uFcapacitorndP1witha1,000,000

ohmpotentiometer.ulsesn he rateangeetween.1persecond

to 10persecond anbegeneratedith hischange.

oThisircuit analsobeused safluorescentampnverter.com-

mon luorescentamp 4to 20 wafts) nplaceof the ransducer

glow,venone hatsweakenougho not unctionnheACpower

line.

00



Hr PnhG[slorl[cilmmt

DCLAMPDIMMERE,P)

Thiscircuitanbeusedo controlthemountfcurrentn anncandesce

lampandalsoaDCmotor.fyouchangeheamountfcurrenthrough

lampyouchangets brightness.ndfyouchangehe amountf curren

throughDCmotorouchangetsspeed.nputoltageanangerom6 to

12voltsandcurrentrainn theoutputsupto2A.Youcanalsousehis

circuitn the outputfa 6Vor12Vixedpowerupply,onvertingt intoa

variableto 6voltor0to12voltsupply.

Thepowerransistorhouldemountednaheatsink.hecircuitanbe

housednasmalllasticoxandheheatsinkithhe ransistorixednthe

outside.

Thecircuitanbe usedo controlrightnessfa car'spanelamps ndn

roboticso controlDCmotor peedlongwideangefvalues.lso,ev-

eralexperimentsnvolvingurrentlowcontrolanbeperformedsinghis

circuit.

Thecircuitctsasavariableesistorrrheostatith heprincipalurrent

flowinghroughheransistorndhecontrol urrentlowinghroughhepo-

tentiometer.urrenthroughhepotentiometers onlyafewmilliamperes

TheschematiciagramftheDC dimmers shownn Figurct.Qlis an

NPNpowerransistorndheprincipalomponentsedn thisproject.

Componentsayouts shownn Figure2.Thetransistoroesnot showon

theheatsink,owever.

Equivalentransistorsanbe used,utakecarewithhemaximumurrent

theycan control.ypes uchasTlP31andTlP41can beusedo contr

lampsupto 2 amperes.lso,afurthermodificationn Rlvaluemustbemadeoensurehat,whenP1s setnearts minimumalue,hatcurrents

flowinghroughheamP.

lfequivalentransistorsreused,akecarewithheirerminalositions

theycanbeditferent.

-

AD



Prrfoct2 DG mr Iilmmu

FigureI

F1

5A

Q1

2N3055

+12V

IN

oul

I:

Figure2

t3



Hr]||Fc0tffimDculmffir

PartsList- DCLampDimmer

Q1

P1

R1

F1

-2N3055 SiliconNPNpowerransistor

-4,700ohmpotentiometer

-470ohm,2W,.5 /esistor

-5Afuse

ldeas o Explore

To earnmore bouthecircuit rtogetbettererformance:

oYoucanuseaPNPpowerransistor,nvertingnputpolarizat

Explainhy hiscircuit anonlycontrolDCcurrents.

oA Darlingtonransistoranbeusedo reduce urrentlow hroug

thepotentiometer.eplace 1witha 100,000 hmcommonotenti

ometernd Rlwitha10,000 hm,1/4watt esistorhenusinga

Darlingtonowerransistor.lPl10canbe usedn hiscase.

oWhat s a rheostat?

Sciencenduncommonpplications:

oYoucan usehiscircuito control rightnessf microscopeight

sources. 6Vampcanbe usedor hat askandhiscircuitwillbe

wiredbetweenheampanda 6Vpowerupply.he 6Vregulated

powerupply escribedn hisbooks dealor hisapplication.

oExperimentsnelectrolysisndelectroplatinganbecurrent-f

controlledy usinghiscircuit.

a Thiscircuit anbe used ocontrol mallmotorsn roboticsin

physicsxperiments.

tl



ffi|m nmllmDllmmei

oTheamountof currentncurrent ieldscanbe controlled y us

thiscircuitand aDCpowersupply.Experimentsnvolvinglectrotr

pismcan be attempted. ry oput plantswithina coiloobservehe

influencefthe magneticieldon theirgrowthanddevelopment.e-

memberhat theresa magnetic ieldarounda coil ofwirethatis

carrying current.

Figure3showshow his experimentan be arranged.

Thecoils formedby 10 to50turnsof commonNo.1to 22wirearounda

cardboard oxor wood orm.Anammeternserieswithhe coilcircuit anbe

used o control he amountof currentusednthe experiment.

Rememberhat too muchcurrentwillcause he coil and the transo

overheat.t isagooddeao add a lamp nserieswithhe coil circuit.he

lampwilladd resistanceo the coilcircuit,educingurrentlowto a safe

level.

Figure3

t5



IunPiilcctsfuhscilmmu

AUDrOOSCILLATORE)

This ow-powerxperimentalscillatorangenerateudibleignalsnthe

range etween00and2,000Hz,drivingsmalloudspeakerra low-im-

pedancearphone.hecircuit anbepoweredy2 twoorourAAcellsor a

fixed6voltpowerupply.urrentequirementsor hiscircuitependpon

thepowerupplyoltage nd heoudspeakermpedancendrange ypi-

callyrom10o 300mA.

Potentiometer1 adjustshe operatingrequencyndcan be setwithin

large ange fvalues.otentiometersp o1,000,000hmscanbe used,changinghe requencyangeowerimitoabout10Hz.

C1canalsobealtered,ndvalues etween.01andO.22uFresuitableor

experimentation.argeC1valuesillproducerequenciesn he owerart

ofheange.

Thecircuit anbe usedaspartof alarms,ames,oysand olearnmore

aboutransistorizedscillators.

Figureshowsheschematiciagramf theAudio-Oscillator.1andQ2

forma directed-coupledmplifierndRl/Cl is heclosedoop hatakeshe

signal ackrom heoutputo thenput..

,

Figure2showsheayoutfhecomponents,singterminal tripaschas-

sis.All hecomponentsndpowerupplyanbehousedn a smallplastic

box.

Thekeysatelegraphomemade-typewitch,utyou analsouseanSPSTtoggle rslide witchorcontinuousperation.keys recommendedfyou

want o useheoscillatorsaMorseCodeendern demonstrationrprac-

tice.Youcanwire hepointsA andB to the contacts fa relayo use he

circuit spartof an alarm.

tt



Pf.lcct 8 ftllroso

cl

0.047pF

B1

3TO6V

FigureI

k-\

Figure2

t0



mFmf0cilsffmHrulmdu

PartsList- AudioOscillator

Q1 -8C548 eneral urposePNransistor

Q2

-

8C558 eneralurposeNPransistor

SPKR 4or 8 ohmsmalloudspeaker

K -Telegraphicey See ext

81 -3to6volts twoor ourAAcells

Ri -10,000 hm,114w,5 esistor

R2 -1,000hm,114W,5 esistor

Cl -0.047 Fmetalilmor ceramicapacitor

ldeas o Explore

To earnmorebout hecircuit r ogetbettererformance:

oChange1ora capacitornhe angeetween.01and0.22uF.

Therequencyangef theproducedonewillbealtered.With0.01

uForlower aluesorCl,thecircuitwillproduceltrasounds.sea

tweeterr apiezoelectricransducern hiscase.

. Replace1withaTlP32orTlP42ndpoqerhecircuitwitha12

voltsupply.You'lletmuchmorepowern heoutput.

. Explainwhyoscillators eedaclosedoopo thesignalo work.

Sciencerojectsndother pplications:

oExperimentsnacousticsanbemadewith hisdevice.hecircuit

canproduceny onebetween0and20,000Hz,andeven igher.

tt



;nlrcr l3|latrIscffia.

oA telegraphtationanbe simulated ithhiscircuit.ouanind

MorseCodenanybookabout elegraphy.

oBy eplacing witha reedwichwiredopointsandB, hecircuit

willoperates an alarm.

oExperimentsnvolvingonductivityfmaterialsanbemadewith

probesluggedopointsandB.

oConnectesistiveransducerss LDRs ndNTCstpointsand

B togetalight-dependentr emperature-dependentscillator.

a Usingwo metalodsas sensors,hecircuit anbe useas alie

detector r bio-feedbackevice. eplace

l

with

a 0.22or 0.47uFcapacitorndadjustPl togetseparatedulsest thespeaker.he

pulseatewillbealtered hen heskinonductivityf he nterroga

personhangeshilena stateof strainue o a lieorstress.

oA 117V+V x 250mA ransformeran eplacePKR oproduce

high-voltageulsesn nervetimulationxperiments.hegenerated

pulsesaneacholtagesshighas 400Vpp.

oExperimentsnanimalhysiologyanbeconductedsing ound

orhighvoltages describednotherprojects.rowth fplantsub-

mittedo high-poweroundsrhigh-voltageieldsan be observe

usinghiscircuitwithpracticalxperiments.

oAC ieldsanbegeneratedy eplacinghespeaker itha 2O-turn

coil.Theplantsr animalsanbepositionedithinhecoil'slectric

field.See hesameexperimentsingheDCDimmerorcoilandex-

perimentetails.

tl



IunPnfmtrfimH|Oilmmr

AUDIOSWTTCHE/P)

Thisaudio ontrolledelay asa large umber f applicationsnds nterest

ing o heexperimenterhowishesoexploreheworkingniversefrelays

andaudio r sound ontrolledircuits.

Anaudioignaln heamplitudeange etween Vppand5Vpp riggershe

relay,oweringnhedevice,iredetweenointsandB.

Relay alues determinedypowerupply oltage. ora 12voltpowerup-

plyyoumustusea12volt elay.urrentrainependspon hepowerup-

plyvoltagendalso heelaysed.Using 12Yx38mA Radiohack75-

248'1relay,hecurrent rains owenougho allowheuseof commonellsn

thepowerupply.

Clcanangeetween.01and1.0uF,anddetermineshesensitivityfhe

circuitn heaudioange. arge aluesivemoreensitivityt owrequen-

cies.

Thiscircuitasahigh-impedancenputandneedsstrong udio igo

operate.

Figureshowsheschematiciagram f heAudioSwitch. bservehat heheart f hecircuits a commoneneral-purposePN ransistorhatactsas

aDCamplifier.

lnFigure2we showayoutf componentsorhisproject.hecomponen

canbesolderedna terminaltripused schassis.Theerminaltrip anbe

flxed n a wooden oard.

Positionf thepolarizedomponents,uchas hediodes,owerupply nd

capacitor 2,mustbeobserved.

Touse hisaudioelayouhaveowirepontsAandBto the outputf an

audioamplifierminimumowerequireds5watts) ndadjusthevolume

controlorbestoperation.

Asmallransistorutputransformerhould eusedooperatehe elaywith

low-impedanceignals,uchas heonesromheoutput f audio mpli



Fofeot flullr ilftG

D2

1N914

D1 R1

1N914,t0K

(.)sEETEXT

B1

6OR9V

Figure I

Figure 2

05



mrilffi||rrhsll|mmr

Figure3showshowo use his ransformer.

R,depends nheoutputowerftheamplifierndsgivenelow:

OutputPower

0to 1 watt

1to10watts

10o 25watts

25to50watts

I

47ohms,1/4watt

100ohms,'ll4watI

220ohms,ll2watt

PartsList- AudioSwitch

Q1 -8C548general-purposePNsilicon ransistor

D1 -1N914eneral-purposeilicon iode

D2 -1N4002iliconectifier iode

Kl -6Vor 12Vrelaysee ext

R1 -10,000hm,1/4W,5% esistor

Cl -metal ilmor ceramicapacitorseeext

C2 -100 uF,12WVDCelectrolyticapacitor

81 -6V or12Vcells,powersupplyor battery

t0



;TrMlf rilm nilH

ldeaso Explore

To earnmoreabout hecircuitnddevicesr ogetbettererformance

oReplace

lwithaDarlingtonransistorsuchas a BCS17)ndresistor1 with100,000hms. hecircuitwill ncreasensensitivi

oExplainowC1 unctionsnhiscircuit.

Science nddifferentpplications:

oConnecthecircuitoanaudio mplifierutput, itha mioophon

pluggedo theamplifiernput.You'llavesound-operatedwitch.

oThiscircuitwithamicrophonendanaudio mplifieranbeusedto closea trap withsoundactivationrtoactivate recordinith

sounds.

Youcan alsouse ttophotographnexplosionr the crashof an

objecty riggering flashwithheproducedound.

oTheaudiooutput famultimediaystemna computeranbe

used ocontrolxternal evices ithhiscircuit.

R;

l-----+x

FRoM IIF ro

AMPLTFTER3lE

AUDlos\

ourPUT|

''l

L._--_-{'Y

8:1000

o

Figure3

tt



IunPnlos lol UrG nilmomcr

6VOLTSFROM12VBATTERTESP)

Withhisadapteroucanpower6voltupo 1A)devices,uchasrecordersCDplayers,alculators,adios, atteryhargers, tc., romyourcar battery.

Thecurrentadapter spluggednto the vehicle ightersocketand is small

enoughobehoused na verycompactlasticbox.

Onlyourcomponentsre used.ThelC determineshe outputvoltageand

shouldbe mountedn aheatsink.apacitors repolarizedomponents,o

youmustobserveheirpositionwhenmounting.Theuse s very mportantn

order oprotecthedeviceand car wiringagainst horts.

Output ariesaccordingo thedeviceouareapplyingowero. DCexten-

sioncableswithplugso fit thedevice o bepoweredhouldbe used.Take

care with theoutputpoles.Checkfyourdevicehas apositivernegative

polen thecentralerminal.

Theschematic iagramf the12Vo6Vx 1Aconvertersshown n Figure 1

Theprincipalomponents lC1,a6Vvoltage egulatorhatoperateswith

inputvoltages angingromto35volts.

Componentsayout sshownnFigure 2. Allhe componentsan easilybe

housedn aplasticbox.

The ntegratedircuit an be changedo alter heoutput oltage.Youan use

a7809or9Vx 1Aoutput r a7805or5Vx 1Aoutput.

It is very mportanthat nopartsof the componentssednthiscircuit ouch

one another. he lC hasshort-circuitndhermalprotection.

t



?nhcr 5olrilsFmlzummi

Figure 1

Figure2

gl



m?nmffimsu||nomcr

PartsList- 6 VoltsFrom12VBatteries

lC1 -7806ntegratedircuit

C1 -1,000uF,16WVDCelectrolyticapacitor


Fl -2A fuse

ldeaso Explore

To earnmorebouthedevicerogetbettererformance:

oReplacehe ntegratedircuitlOl)witha7805or 7809 ogetout-

putvoltagesf 5V and9V.

oExplainheditferenceetweenhis inearoltageegulatornda

switch-modeegulatorsed ncomputerowerupplies.

oThisircuit analsobeusedn nonregulatedoweruppliesoget

aregulatedVx 1Aoutput.

olt'spossibleogeta negativeegulatedowerupply yreplacin

the7806witha7906C.Doasearchor nformationboutthishange

inheproject.

Sciencerojectsnduncommonses:

a YoucanusehisdownconverteropowerourAAcell-power

circuitsroma12Vbatterynsciencexperiments.

o6Vlampsusedaslightsourceor microscopesanbepowered

fromhecar batterysing hisdownconverter.ieldworksing mi-

croscopeanbe conductedsinghiscircuit.

t2



tmF|ObGElnso ldmmol

oNE-COMPONENTRANSMITTERE)

Here s aprojecthatshoulde constructedythosewithnopatienceor

electronicsuilding. nlyonecomponentsusedo builda completeire-

less ransmitter

Ofcourse,his s hesimplestay ogenerateadioignals.t isa CW con-

tlnuouswave) ransmitterndspowerfulnoughoplunkdowna signal

anywheren he550kHz o7MHzband.

The undamentalrequencyependsponowerupplyoltage nds n he

range etween00kHzand1 MHz,uthere restrongarmonicseaching

up o7 MHz.

Figure showsheschematiciagram fhissimpleramsmitter.syoucan

see,we haveonlyonecomponent:4049CMOSC thats formed y six

inverters.n thisprojectnlyive nvertersreused.

ThecircuitspoweredromAAcellsor battery ndcurrent rains veryow.

As an experimentalroject oucanplaceheCon a universalolderles

board.heantennas a singlewire2 to 5 feetong.

AcommonM(mediumaveorshortwave) eceiversplacedear he

transmitter. signalanbeuned n romdistancesp osomeeetaway.

Therearewoways otune he ransmitter,howninFigure2.

In heirstase,s herequencysvoltage-dependent,echangehepower

supplyoltage. sea12voltpowerupply ndadjusthevoltagen theC

withP1. n hesecond ase,we nclude variableapacitorn heeedback

loop o alter herequency.

PartsList- One-Componentransmitter

lC -4069or4049CMOS ntegrated ircuitonlyhis )

(Andapowersupply,f course)

30



PnftGt0 FGmnmilTnmillt0l

lC1=4O49B

l*1 oe

FigureI

Figure2

-

0t



n;||FdFilDgnntr

l&astoErplore

To earnmoreabout hecircuit nddwice:

oExplain owadioignals regeneratedndWhywedon'tneeda

tunedircuit.

oWhyshouldn evennumberfgatesbeusednthiscircuit?Will

anoddnumberwork?

oWhycanyouunenhesignalsnmorehanonepointfthedial?

Sciencerojects:

oSend elegraphignalshrougrh wallusinghiscircuitas ransmitterandan AM radioasreceiver.

oExplain owcomputerircuits angonerateadiosignalsnoise)

usinghiscircuits an example.

It



Itm tdcctsffi$rHnilmcnu

WIRELESSMTRANSMITTERE/P)

Theseircuitsavealways eenpopularorbothutility ndentertain

purposes.

TheFMransmitterescribedere sbuiltwith ewomponentsosave pace

andcost.hecircuit asonlyone ransistorndspoweredy woor ourAA

cells.

Thebroadcastingrequencyf theunit,ntherangeetween8 and 108

MHzFMband),sdeterminedyLlandhevariableapacitorV(a2Oor

30pFrimmer apacitor).1consists foururnsof No.22wire,woundna

singlelose-spacedayern a 112-inchorm.hecoilscenterappedhere

it swiredo heantennaerminal.

Anypiecef stitfwirewillserve s heantennandwillgivegoodoverage

Forbetter peration,ntennaength houlde between and15nches.

Tryoutyourunit at anyconvenientead potonhe heFMband.djustCV

to thebest ignal.hesignals anbe uned ndistancesp o150 eet.

Aschematiciagram f the FM ransmittersshownn Figure1.Onlyone

transistors usedas a high-frequencyscillator.nysmallRFNPN ransis

torcanbe usedorhe ask.

Componentslacementn aprinted-circuitoardsshownn Figure2.Ca-

pacitorsre critical omponentsnd shouldethe types ndicatedn the

partsist.Don'tusemetal ilmcapacitorsnsteadf the ceramic apacit

whichrecalledorn hepartsist.

Youanalsouseaterminaltripas chassissshownn Figure3,butkeep

allhecomponenterminalsndwiringhort o avoidnstability.

Thecircuit anbehousednd smalllasticoxalongwithhepowerupply.

Avoidheuseof metaloxeso househecircuit.

Takearewithpositionf thepolarizedieces,uchas the electretmicro-

phone,lectrolyticapacitorndpowerupply.

r02



trdOct ttrlnlcss ;ilTnns||ffi

R2

10K

c1

lOpF

Q1 \

8F494

R4

47

Figure1

, {

Figure2

ilt



IunFrrlrctsolho x|Dafimml

PartsList- WirelessFMTransmitter

Q1 -8F494RFsilicon ransistor

MIC -two-terminallectretmicrophone

L1 -coil-seeext

CV -trimmer apacitor20o50pF)

R1,3 -4,00ohm,114W,5%esistor

R2 -10,000hm, 114W,5%esistor

R4

-

47ohm,1l4W,5% esistor


C2 -0.01 uF ceramicapacitor

Cg -4.7pFceramic apacitor

C4 -0.1 uF ceramic apacitor

S1 -SPST lideortogglewitch

81 -3V or 6V-twoorfourAAcells

A -antennaseeext

ldeaso Explore

To earnmoreabout hecircuitor togetbetterperformance:

oReplaceransistorQ1witha2N2218andpowerhe circuit roma

9V battery.Theignalswillbe uned n romdistancesp o 1,500 eet.

oThecircuit anbe usedas abug

to hearsecretconversatio

||f



Ffdcctl ilnlffi Iil In

Figure3

Placehe circuit nsidea falsebook on a deskopickup conversa

tions.

oExplain ow he transmitter orks.

oWhatareradiowavesor electromagneticaves?

oWhat s FrequencyModulationFM)andAmplitudeModulatio

(AM)?Explain he ditferences.



IunPlolectsolu|errcr|memcl

Sciencerojectssing his ransmitter:

oTheransmitter an be usedopickupremoteounds.oucan ix

it in animalensorailso monitorhem emotely.

oThe mikecan beplacedn the focusof aparaboliceflectoroconcentrateounds.irdsndother nimalsn he orest r otherplaces

canbeheardusing hissystem, s suggestedn Figure4. An nteres

ingstudy anbemade nvolvingocalongbirds.

oYoucan use his ransmitteroran experimentalroadcastnyour

schoof.However, on't use ong antennas becauFCC rulesare

severeegardingstrongillegal radioemissionsn theFMband.

Figure 4

100



IunPtol0Glsu $e ffIeilmcmor

HIGH-POWERUDIOOSCTLLATORE)

Thishigh-powerersionf anaudioscillatorroducesstrongudibleone

usingapiezoelectricransducer.ll fourgatesexistingnthe 4093 Care

used n hisprojectodrive he ransducerithagoodaudioignal.

Thecircuitan be used nalarms,oys,asa standalonerojecto teach

about scillatorspecifically,r inexperimentssing ontinuousoundsn

the requencyangeetween00and10,000z.

Therecommendediezoelectricransducermitsmaximumutputpower

between00and3,000Hz,but t willalsooperatenother requencieith

lesspower.

Powerupply oltageangesbetweenand12volts.Currentequirement

depend pon hepowerupply oltage,angingrom10 o50mA ypically.

Pladjustshe tonerequency.lcan be alteredwithina large angeof

valuess ndicatednheschematiciagram,hownn Figure.

Componentslacementn aprinted-circuitoards shownnFigurc2.Youcanalsomounthecircuitsing solderlessoardorexperimentalpplica-

tions.

Alltheomponentsnd hebatteriesifusedspowersupply)anbehoused

ina smallplasticox.

BZcanbe replaced ithacommoniezoelectricweeter.ut, n thiscase,

youshould penhe weeterndemovehesmall ransformerrom nsidet.

Thenheoutputf hecircuit houldeconnectedirectlyo hesmalliezo-electricransducer.

lt



Ptrhct 0 lbhPmllulh0scl

+5Vo+12V

tc1-40938

Figure1

trr-. 9

\\ .J.J

P1

o

o

Figure 2

ttl



mmhmffilrHnhorm

PartsList- High-PowerudioOscillator

lOl-40938CMOSntegratedircuit

BZ -Piezoelectricransducer

(Radiohack 73-090r equivalent)

P1 -100,000hmpotentiometer

Rl -10,000hm,114W,5%esistor

C1 -1200pFo0.047 Fceramicrmetalilmcapacitor

ldeasoExplore

To earnmoreabout omponentsnddevices:

oThiscircuit analsoproduceoundnheultrasoundand.Using

a1,200FcapacitororC1, he rangewillreachn upperimitof

about00,000z.

oExplain owapush-pullutput tageperates.


oThiscircuitanbe usedoranimalonditioningrnexperiments

involvingounds.

oBy eplacinglwithensors,uchsLDRsLightDependente-

sistors)rNTCsNegative-Temperatureoefficientesistors),one

frequency illbe ight-dependentr temperature-dependen

- oByreplacing l withouchensorsr electrodes,ecanusehe

circuitsliedetectorr bio-feedbackevices.hesoundpitchwill

depend pon kin esistance.

fl2



PnfccrE lllti-'lrdlilllr

oThecircuitcan also be usedasa fishattractorrinexperiments

involving ateranimals ndsounds.eplacing Zwithwiresmmersed

intowaterwillgeneratelectricurrent ieldsorexperimentalorks

involvinghe nfluence f theseieldsonfishor otherbeings.

oSomeanimals,uchasmiceandats,rescared ffbyultrasound

Thecircuitcan be usednexperimentsodeterminehefrequencies

that are moreetfective or this task.

Seeotherprojectsnvolving oundsor new deas oexplore.

1t8



Itn P10l0ct3u ha Euoilmomcr

TIMERE/P)

Smallomeppliancesndcircuitsanbeurned natter timedelayang-

ing romsecondsominutessing hissimpleimer.

School nd

hobbyis

experimentsanbeime-controlledy usinghiscircuit.

Theunithasa constant-currentourceocharge l.Cl andPladjusthe

time ange.YouanalterC1withinrangef 100nd1000F ochangehe

time ange.

Using1ampereelayoucancontrol C oadsp o 100wattswiredohe

117VACowerine.

Tooperateheunit, onnecthe oad othe relayontactspointsandB,

usedasa switch) ndadjustP1o thedesiredimedelay. ress2dodis-

chargeCl completelyThenloseSl tostart.Afterheadjustedimedelay,

the elaywillclose, nd he oadwillbepoweredN.

Conversely,yusingheNC Normallylosed)ontactsf heelayoucan

turnadeviceOFFafterheadjustedime.

Touse heunitagainoumustpress2todischarge1 beforetarting.

Figureshows heschematiciagramf the lmer.Observeheditferen

componentssednthisproject:unijunctionransistorUJT)ndanSCR

(Siliconontrolled ectifier).

Anmechanicaliew sshownn Figureusing terminaltripaschassis

Allhecomponentsndpowerupplyanbe housedna smalllasticox.

Takearewith'positionsf criticalomponents,uchas the UJI,SCR,di-

odesanddlectrolyticapacitors.

The elayependspon hepowerupply oltagendvoltagerop hroug

theSCR. hisdropsabout volts,oyouneed ouse6to 7.S-voltelays

witha9-voltowerupply.

TheSCRneedn'temountedn aheatsink,s hecurrentrain s ow.

r10



Ftdoct1g llnFl

D1

1N4002 +\or < B

lrt

Ir.l

c2

1O0pF

SCR

Ttc106

(.)sEE

TEXT

R2ej 12Oa

8C558

"3,1'+l-*.

FigureI

e e rOO

Figure2

UseAAcellsora transformeropowerhis imer.Rememberhatcurrent

drain sowonlywhenherelays notenergized.



IunEofcctsor n trnel|mcmcr

PartsListTimer

Q1 -8C548NPNgeneral-purposeiliconransistor

Q2 -2N2646nijunctionransistor

SCR -TlC106iliconontrolledectifier

D1,2-1N4002iliconiodes

R1 -47,OOOhm,1/4W,5%esistor

R2 -Lz}ohm,1/4W,5%esistor

R3 -100ohm,1/4W,% resistor

P1 -100,000hmpotentiometer

C1,2-100uF,12WVDClectrolyticapacitors

K1 -Relaysee ext

51 -SPST lideortogglewitch

S2 -Normallypenmomentarywitch

81 -9V-sixAAcells

ldeaso Explore

To earnmuchabout ircuitnddevicesr togetbettererformance:

a Explainowa constant-currentourceoperates.

oExplainowa UJTandSCRoperate.

oAlterC1 ogethigherimedelays. ryvaluesp o1,000F.

tl0



?rutct g fhtr

Sciencerojectsnduncommonsesorhisdevice:

oAll experimentshatneed ime-delayontrol anuse hisdevice,

as ongasthe imedelayneededalls n the range fthis imerbe-

tweenafewseconds ndminutes).sea commonatchasrefer.

enceo make scaleor hepotentiometer.

a Thecircuit anbeused o activate angerousxperimentsitha

safe ime-delayllowingheexperimentero reach afedistance.

oTraps anbe armedaftera time-delay,othe experimenteran

avoidhe raphimself.

oChemicalrocessesanbe controlledsing his imer.nyaudio

oscillatorescribedn thisbookcanbe useaswarning ircuitwhen

wired o theelayutput.

110



lunPilcrahr[nmrdmotmcl

MrcRoAMRADIOE/P)

ThismicroAM adiowilltunetrong tationsn he requencyange etween

530and1,600 Hz.

Thecircuitsesonlyoneransistorstheamplifier ndwitha transfor

drives smalloudspeaker.shecircuitsverypoornamplificationt needs

alongwireantenna.heantenna houlde rom15 o50eet ong orbest

results.goodgroundonnectionsalsomportant.

Of course,hissa smallnexpensiveransistoradiowith ow isteninol-

ume,particularlyn aweakstation.f thestationstoo weak, eplacehe

SPKR y alow-impedancearphone.

Thepowerupplys ormedy woorourAAcellsandcurrent rains very

low,extendingheirife. hecircuit rains nly ewmicroamperes.

L1 s a tappedoopstick,onnectedo variableapacitor V.These tems

canoftenbeound nnon-workingransistoradios,swellasthe speaker

and ransformer.

Figureshowsheschematiciagramorhisproject.iodeDlactsas a

detector ndQ1as an audioamplifier.1 isa commonransistor u

transformer.

ln Figure2 we show he componentsayout. ll thecomponentsan be

housedna smalllasticox.Aterminaltrip s used schassisnanexperi-

mentalversion.

T1 isatransistorransformer1,000:8)nd heSPKRs aminiatureype.But,fyouhavean unworking Mradiooucangethesepartswithoutpend-

inganymoney.

To use,closeSl and une o the desiredtation y adjusting V.Youcan

adjustR1 or hebestesultsccordingoyourransistorain.

r22



ngcctz0 ffiGfrilf

c1O.1pF

FigureI

Figurc2

n8



lilmhG8ffimffifipror

PartsList- MicroAM Radio

Q1 -8C548 eneral-purposePNransistor

D1

-

1N34

eneral-purposeermanium

lode

L1 -loopstick seeext

CV -365pFvariableapacitor

T1 -Transistorransformer,000:8

SPKR I ohms2in.miniaturepeaker

R1 -2,200,000hm,114W,5%esistor

Cl -0.1uFceramicr metalilmcapacitor

Sl -SPSToggle r slldewitch

81 -3 or 6V-twoorourAAcells

ldeas o Explore

To earnmorebouthecircuit r ogetbettererformance:

oReplacelwithaDarlingtonransistor,uch saBC517, ndind

a betteralueor R1.Valuesntherangebetween,200,000nd

10,000,000hms anbe used.

oReplace1by20 urns f No.28wireonaferriteodandry uning

short-wavetations. sealongwireasantenna.ositionfheL1 ap

mustbecarefullytudiedogetbest electivityndsensibility.

oExperimentitha crystalearpiecen heplacefT1andSPKR.

10,000hm esistorhould ewired nparallelithheearpiece.



Fnllcr20ffilrilmlh

oExplainowcrystaletsor direct-detectioneceiversperate.

oDefineheermselectivitt''.

oWhatsagalena-crystal?

Sciencerojects:

oThis receiveranbe usedo demonstrateowantiqueadioe-

ceiversperatedhenadiowas irstnvented.tcanbepresenteds

amodern

versionf a crystalrgalenaeceivern a demonstrati

Aninterestingxhibitanbemadewith hisset,he ree-powerM

receiverdescribedn hisbook),nda crystalet.

a The circuitanalsobeusedas anRFsnitfe/',detectingadio

signalsroducedyexperimentalircuitsn heAMorshort-waveand.

Replacel witha1,000 Hchokendemove1ogetasensitive

RFsnitfer.

r2[



t{nEofoGB.r htInoilmmll-

TOUCHSWITCHE)

Smallppliances,ampsndmotorsanbecontrolledya simpleouchwit

thisexperimentalircuit.

oadsreONduringheimeadiustedyPlfora

fewsecondsomorehan10minutes.onversely,yusingheNC normal

closed)ontactsoucanalsournotfanappliancefterheadjustedime.

Thesensorsformedy wosmallmetallates,ndshouldn'teplacedar

fromhecircuit.hemetallatesreinger-touchedthesamemoment-

Thecircuitanbepoweredroma6-or12-voltowerupply,ependingn

theelaysed.Donotuseransformelessoweruppliesithhisproiect'o

avoidhocksrdangerous

horts.ransformerlessoweruppliesrenot

isolatedromheAc-powerineandepresentdangeroushockazard.

K1 s arelaywith6-or12-voltoilands energizedycurrentp o 50mA'

WithelaysnthisrangeoucanpowerheouchwitchromAAcells6

volts)rsmallPoweruPPlies.

A schematicfheTouchwitchs shownnFigurc.Thecircuitses555

lCimerastsheart,ndimedelays determinedyadjusting1'

circuitmounting,singsmallomemaderinted-circuitoard,sshownn

Figure2.fyou:dikeoetchyourownboardsehispartsplacementia-

gramsguide.

ln Figure3wehowhesensorhatcanbemadewithwosmallmetallates

ona-plasticrwoodase.Wiresohesensorhouldn'teong.maximum

lenghtf10eetsrecommendedoavoidrraticperation.

Pos16nfthepolarizedomponents,uchasheelectrolyticapacitorsnd

diodes,houldeobserved.oads connectedo terminalsandB.Re-

memberhatherelayctsasa switch.

Don'towerhiscircuitromransformerlessoweruppliesoavoidanger

ousshocksndshorts.

Asensitivityontrolanbeaddedothiscircuitn asimplemanner.sea

1,000,000hmpotentiometerorhisask.

: t

nt



Ffdrcr 2l luGnil|

B1

a12V

l\^r < B

lfi

a28C548

c2lOO f

R1

100K

Q1

8C548

R3

10K

(.)sEE TEXT

Figure 1

t2t

Figure 2



HrFrdrctsol hoDndmomcl

PartsList-TouchSwitch

lC1 -555ntegratedircuit,imer

Q1,2 -8C548general-purposePN ransistors

D1 -1N914 iliconiode

Kl -relay seetext

Rl -100,000hm,114W,5%esistor

R2 -47,OOOhm,114W,5%esistor


R4 -1,000hm,1l4W,5oloesistor

P1 -1,000,000hm,114W,5%esistor

C1 -10 o470uF,12WVDCelectrolyticapacitorseeext


S1 -SPSToggleor slideswitch

81 -6 or12VM cells,batteryorpowersupply

ldeaso Explore

To

get

more

performancero learnmore bouthecircuit:

oSensitivityanbencreasedy eplacinglwithaDarlingtonran-

sistor,uch saBC517.

oByconnectingreed witchetweenointsandXyoucanuse

thiscircuitodetectmovement.ixa smallmagnetnhepieceo

acton hereedwitch.

rtllu



frrfcct2l frrcDSffi

'3

Figure3


. Thiscircuit anbe usedo closetrap.he ouch ensorwillde-

tectwhenheanimal ntersherap.

oProjectshatneeda way o detectmovements,witchingnyoad,

canbemadewith hiscircuit. everalindofsensors,ikemicroswitch

pendulumensors r anyothermomentary-typewitch anbe used

inhis ircuit.

oConnectnLDRbetweenointsandB.Alsoonnect100,000

ohmpotentiometeretween andhenegativeoleofhepowerup-

ply.ou'll ave light-operatedelayrremoteontrol.flashof ight

producedy a lantern r evena cigaretteighter anclose herelay,

poweringhe oad. hecircuit anbeusedodetectlashesfightn

science xperiments.ixheLDR ntoa telescopendyoucandetect

meteorallings.

a Experimentsnvolvinghunderstormstnightcanbeconducte

automaticallysinghiscircuit.he irst lashofightninganbeused

topowerON heequipment.

t8l



IunPruiectsor ielrDollmcmel

SIMPLELUORESCENT

LAMPTNVERTERE/P)

Thiscircuitwill ightacommonluorescentubefromto 4Owatts)roma 6-or12-voltowersupply, uchasni-cadells,D cells,car battery r ot

source,without eedof a chokeor starter.ven heoldubeswhichno ong

function t allonACpowerineswillightwhenusedor hispurpose.Some

ofthem, hough,maybeoo weak olightwhen he circuitspoweredrom6

or12volts.You hould xperimenteforehand.)

Youcan usehedevice s an emergencyight, ntrailers, ignalintc.

Bypoweringhe fluorescentampwitha transformerowersupplyyouin-creasesafetyactorof an experiment,voiding angerous hocor short

Currentrain, ypicallyangingrom 100 o800mA,depends nthe charac-

teristics f thelampused,hepowersupply oltage, ndhe transform

The ampwillbrighten ccordingo the drained urrent.xperimentshould

bedonewithsome ditferentransformers nd oscillatorrequenciesoget

betterperformanceut ofthecircuit.

Basicaly,he circuitsalow-frequencyscillator rivingatransformerigh

voltages obtainedrom he ransformero'lightfluorescentight.

The rimmerpotentiometerllowsrequency djustmentogetbetterperfor

mance.

Schematiciagramf the Fluorescentamp nvertersdisplayedinFigure

1.Asyousee, he circuit onsistsf alow-frequencyscillatorithapairof

complementaryransistors.

Componentsayout,singaterminal tripaschassis,s shownn Figure2,

Componentslacements notcritical.

Transistor2should emountedn alargeheatsink.Tlsa 6Vx450mAor

12Yx 450 mAtransformer.fa CT(center-tappedecondary oil)trans-

former syoushoulduseonly wo ofthe threesecondary'sires.



Fof0ct22$mjollutsctmlmffil

I

FigureI

BE

Figure2



IunPnf0cFful[oH$lmilu

Experimentsith ransformersithsecondaryurrentsrom300o 800mA

andvoltagesetweeenand15Vcanbemade ogetbettererforman

Warning:he luorescentampspoweredithhighvoltageshatcanbe

dangerous.ake areofthewires'nsulationsndwhenhandling

onnec

tionso thedevice.

PartsList- SimpleFluorescentampnverter

Q1 -8C548 generalurposeNPNsiliconransistor

Q2 -T,P42PNPpowerransistor

T1 -Transformer:17VAC;6Vx 450 mA or12Yx 450mA

Xl -Fluorescentamp seeext

P1 -470,000hmstrimmerpotentiometer

R1 -10,000 hms,1/4-watt,% -resistor

R2 -1,000ohms,114-watl,5%resistor

C1 -0.047uF-metalilm caPacitor

ldeaso Explore

To earnmoreabouthecircultr togetbettererformance:

oTry o useaferriteransformernplaceof T1.Thecircuiterfor

mancewill ncrease.

oExplainow ransformersorknhiskind f circuitndwhy rans-

formers onotwork n DCcircuits.

Sciencerojectsnduncommonpplications:

oReplacelbyansmallltravioletfluorescentamp ndyou'llave



Prolcct 2SlMcHurlr$mtlrmtl

amineralrluorescent aterialsearcher.anymaterials,ncludin

theoneswithahighpercentagefcalcium,illglowwhen llumina

by ultraviolet.anyexperimentsnd demonstrationsanbe made

involving inerals,lantsndluorescent aterials

oAn nterestingxperimentithplantss ostudyheetfect f ultr

violet adiationnditferentlants'growthrgermination.rradiateev-

eralbatches fvariouseeds, uchas tomato, een, quas

withUV andhenplant.ecausefncreasingVadiationeaching

theearth ue o depletionf heozoneayer,heetfect fhis adiatio

onplantife sof concerno usall.

oComparetfects f ditferentightwavelengthso seedgermina

tion.Thewavelenghtsfincomingolaradiationange rom200 o3,000nanometersnm).UVradiationsbetween 80and400 nm.

Selecteeds romcommonlantsndexpose itferrent ato

UVand/or ommonightredoblue).Whathappens lth hediferen

seeds uringermination?oualsocanconducthe experimentot

onlywithseeds, utplantsndnsects.

oHigholtageresentnthe117Vransformeroilcanbe usedn

nerve timulationxperiments.leasedda10,000hmpotentio

etertocontrolhe appliedvoltagefthe circuits intendedo be usedonhumans Theoltagenthe ransformeraspeaksshighas400V

oFluorescentight analsobeusenexperimentsithnsects.ome

kindsofinsectsreattracted y ightvisiblendultraviolet )nsect

trapsanbeconstructedsinghiscircuit s base.

oFishandother nimals anbeattractedy luorescentight.A cir-

cuitpoweredycellsor batterys mportantor ieldwork.

oAlternate ethodsfarmpestontrol anuseight, isible swell

as radiationn heultravioletartof hespectrum.nsectraps anbe

constructedith luorescentampnverters.or urthernformati

The nternationalllianceorSustainablegriculture

1701UniversityvenueE

Minneapolis,N55414 (612)31-1099

tft



tunPtoiGctsor ln Hmilmrmel

TOUCHON/TOUCH FFRELAY(P)

AO-poweredppliances,uchaslamps,mallhomeappliances,oolsand

othertems,can be controlled yyouringertipssinghis circuit.Also, est

equipmentndexperimentsanbe controlledy hiscircuit.Youanurnonanyoad byfirstouchingimesensorX1, then urn itotf bytouchingXl

again.There snoshockhazard,sthecontrol ircuitscompletelysolated

fromhe ACpowerine.

The control ircuitspoweredrom ouror eightAAcells,or,fyouprefer,

powersupplyangingrom6lo 12 voltsaccordingotherelaycoil.

Don'tuse ransformerlessowerupplies ecauseheyarenot solatedrom

the ACpowerineand can causesevere hocksand shorts.

Theschematic iagram ftheTouchOnffouchOffRelay sgivenn Figure 1.

Thecircuituseswo lOs.The555timerworksas a monostable,roducin

one controlulsewhen he sensor s touched. he4013 saflip-flophat

controls herelayby atransistor.

Componentslacementn ahomemaderinted-circuitoardsasshown n

Figure2.Componentayouthouldbe alteredf the relayusedn theproject

isan equivalentf the ype ndicatednpartsist.

Relaycoilvoltage s determined y thepowersupplyvoltageand theload

currentequirement.oucan use amini1A DPDTRadioShack275-2491

12V,280hm,43 mA,andwire tas shownnheigure,r useanotherype

of relay, epending n theload equirements.

A 10A SPDTmini-relayRadioShack275-278)ssuitableor heavyduty

appliances.

As a simpleule,youcan use a 6- or12-volt elaywithcoil currentsangin

from 10 o 100mAandcontacts po 10A,accordingo the askyouhave n

mind.

Positionsfthepolarizedomponents,uchas he diode,electrolyticapaci-

tors and ransistor, houldbe observed.

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Figure2

Sensorrehe Samesthe'TouchSwitch"Qectdescribednhisbook.

Don'tusemetallicboxto househe device,asthere arepartsconnecte

directlyothe ACpowerine.Be surehat herearenopowerine contac

with helowvoltage ircuito avoidshocksanddangeroushorts.

Theoadsconnecteds shownn Figure 3,to be ONwhen herelaycoils

energized.oucanalsousehenormally losedcontactso turnotf aload

when herelaycoils energized.

Rememberhatcurrentequirementsrehighwhen herelaycoilsener-

gizedandowwhen heransistorQ2is otf(relayoilnonenergized)hats

animportantactoroconsiderfyouare usingbatteriesopowerhe unit.

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