Tkool Electronics

IIntroductionLM567isatonedecodingphase-lockedloopintegratedcircuit.Itiscompactindesign,simpleincircuit,andhasawiderangeofapplications.However,ifusingimproperly,itwillbringtroublesindebugging.ThisblogintroducestheworkingprincipleandtipsabouthowtouseLM567tonedecoderforreadersreference.Figure1.LM567ToneDecoderCatalogIIntroductionIILM567InternalStructurePinFunctionIIILM567WorkingPrincipleApplicationIVTipsofUsingToneDecoderLM567Ordering&QuantityIILM567InternalStructurePinFunctionThenameofLM567isphase-lockedlooptonedecoder,itspackageformuses8-pindualin-line,itsinternalstructureandpinfunctionsareillustratedinFigure2.Itsinternalcircuitstructureiscomposedofquadraturephase,detector,phase-lockedloop,amplifier,etc.TheoperatingvoltagerangeofLM567is4.75-9V,theoperatingfrequencycanreach500KHz,andthestaticoperatingcurrentisonly8mA.Thepin③isthesignalinputterminal,whichrequirestheinputsignaltobegreaterthan25mV.Thepin⑧isthelogicoutputterminal.Itcanbeseenfromthefigurethatitisanopencollectortransistoroutput,whichallowsamaximumsinkcurrentof100mA.Theexternalresistanceandcapacitanceofpins⑤and⑥determinethecenterfrequencyf01/1.1RCofICinternalvoltagecontrolledoscillator.Pins①and②areusuallyconnectedtothegroundseparatelytoformanoutputfilternetworkandalooplow-passfilternetwork.Thecapacitorconnectedtopin②determinesthecapturebandwidth.Thelargerthevalueofthecapacitor,thenarrowertheloopbandwidthis.Figure2.TopViewofLM567IIILM567WorkingPrincipleApplicationWhenthetonedecoderLM567works,itsphase-lockedloopinternalcurrent-controlledoscillatorgeneratesanoscillationsignalofacertainfrequencyandphase.Thissignalissenttothequadraturephasedetectortogetherwiththesignalinputatpin③forcomparison.Whenthefrequencyofthesignalfallswithinagivenpassband,thephase-lockedlooplocksthissignal,andatthesametimetheinternaltransistoroftheLM567iscontrolledtobepoweredup,andtheoutputterminaloftheLM567outputslowlevel.The⑤pinofLM567outputstherectangularsignaloftheinternaloscillator,andthe⑥pinoutputsthesawtoothpulse.Thefrequencyofbothisthesameasthecenterfrequencyoftheinternaloscillator.The②pinistheoutputofthephase-lockedloopphasedetector.ThevoltageonisthesignalafterF/Vconversion.Ifthetonesignalisinputtothe②pin,thenthe⑤pinoutputstheFMsquarewavesignalmodulatedbythe②pininputsignal.FromthebasicfunctionofLM567,LM567canbeusedasanoscillator,modulatorordemodulator.Therefore,itcanbeusedasabasicdeviceinthecircuit.TheapplicationofLM567hasthefunctionofdecodingaspecificfrequencyintheinputsignal,anditiswidelyusedincommunication,remotecontrol,measurement,frequencymonitoring,etc.Figure3.LM567ToneDecoderIVTipsofUsingToneDecoderLM567AlthoughLM567hasaverywiderangeofapplications,ifitisnothandledproperlyduringdesignandapplication,itstillfailstoachievetheexpectedresults,andevenbringstroubletothedebuggingoraffectsthereliabilityoftheproduct.Therefore,itshouldbeconsideredfromthefollowingaspectswhenusingit:1.SetOperatingFrequencyandBandwidthofLM567AccuratelyandAppropriatelyWeknowthattheinternaloscillationfrequencyf0ofLM567canbepre-setwithintherangeof0.1KHzto500KHz,anditscorrespondingbandwidthcanalsobedeterminedasrequiredwithinthefieldrangeof7%f0to14%f0.Therefore,afterthedetectedsignalisdetermined,theinternaloscillationfrequencyf0ofLM567shouldbesettocoincidewiththecenterfrequencyofthemeasuredsignal,andthetimingcomponentsRandCconnectedwiththe5and6feetofLM567shouldbeusedwithhighprecision.Amongthem,thesettingofthecenterfrequencycanbedeterminedbytheresistancevalueofthetunerR.Whenadjusting,itisnecessarytopreventRshortcircuitoropencircuit,otherwisetheoutputlevelof⑧pinwillbelowlevelwhetherthereisinputsignalornot.Theexternalcapacitanceofthe②pinofLM567determinesthecapturebandwidth.Thesmallerthecapacity,thewiderthecapturebandwidth.However,thecapacitancecannotbereducedblindlytoincreasethebandwidth,soasnottoreducetheanti-interferenceabilityoreventriggerfalsely,whichaffectsthereliabilityoftheproduct.2.MaketheCenterFrequencyofthePassbandCoincidewiththeCenterFrequencyoftheOscillationAsMuchAsPossibleItshouldbenotedthatthecenterfrequencyofthepassbanddoesnotalwayscoincidewiththecenterfrequencyoftheoscillator,andsometimesitwilldeviateseverely.Thiswillinevitablycauseadecreaseinreliabilityandsensitivity.Therefore,measuresshouldbetakentomakethetwocenterscoincideasmuchaspossible.ThecircuitshowninFigure4canminimizethefrequencyoffsetofthetwocenters.Figure4.CircuitofLM5673.WorkingVoltageofLM567ShouldBeStableThestabilityoftheoperatingvoltageoftheLM567hasafixedresponsetothestabilityofthecenterfrequencyofthetonedecoder.4.AvoidMisoperationWhentheOutputTerminalisPoweredOnLM567outputsalowlevelatthemomentwhenthepoweristurnedon.Therefore,forsomeremotecontrolcircuits,itisnecessarytoaddaCRintegrationdelaycircuittotheoutputendtoavoiderroneousoperationwhenthepoweristurnedon.Thisisespeciallyimportantintheon-offcontrolcircuit.Afterreadingtheblog,haveyoubetterunderstandLM567?Finally,ifyouhaveanyquestionsaboutLM567,pleasedonothesitatetoleaveamessageinthecommentsectionbelow!

SMAJ58CA-E3/61-VISHAY

IIntroductionLM567isatonedecodingphase-lockedloopintegratedcircuit.Itiscompactindesign,simpleincircuit,andhasawiderangeofapplications.However,ifusingimproperly,itwillbringtroublesindebugging.ThisblogintroducestheworkingprincipleandtipsabouthowtouseLM567tonedecoderforreadersreference.Figure1.LM567ToneDecoderCatalogIIntroductionIILM567InternalStructurePinFunctionIIILM567WorkingPrincipleApplicationIVTipsofUsingToneDecoderLM567Ordering&QuantityIILM567InternalStructurePinFunctionThenameofLM567isphase-lockedlooptonedecoder,itspackageformuses8-pindualin-line,itsinternalstructureandpinfunctionsareillustratedinFigure2.Itsinternalcircuitstructureiscomposedofquadraturephase,detector,phase-lockedloop,amplifier,etc.TheoperatingvoltagerangeofLM567is4.75-9V,theoperatingfrequencycanreach500KHz,andthestaticoperatingcurrentisonly8mA.Thepin③isthesignalinputterminal,whichrequirestheinputsignaltobegreaterthan25mV.Thepin⑧isthelogicoutputterminal.Itcanbeseenfromthefigurethatitisanopencollectortransistoroutput,whichallowsamaximumsinkcurrentof100mA.Theexternalresistanceandcapacitanceofpins⑤and⑥determinethecenterfrequencyf01/1.1RCofICinternalvoltagecontrolledoscillator.Pins①and②areusuallyconnectedtothegroundseparatelytoformanoutputfilternetworkandalooplow-passfilternetwork.Thecapacitorconnectedtopin②determinesthecapturebandwidth.Thelargerthevalueofthecapacitor,thenarrowertheloopbandwidthis.Figure2.TopViewofLM567IIILM567WorkingPrincipleApplicationWhenthetonedecoderLM567works,itsphase-lockedloopinternalcurrent-controlledoscillatorgeneratesanoscillationsignalofacertainfrequencyandphase.Thissignalissenttothequadraturephasedetectortogetherwiththesignalinputatpin③forcomparison.Whenthefrequencyofthesignalfallswithinagivenpassband,thephase-lockedlooplocksthissignal,andatthesametimetheinternaltransistoroftheLM567iscontrolledtobepoweredup,andtheoutputterminaloftheLM567outputslowlevel.The⑤pinofLM567outputstherectangularsignaloftheinternaloscillator,andthe⑥pinoutputsthesawtoothpulse.Thefrequencyofbothisthesameasthecenterfrequencyoftheinternaloscillator.The②pinistheoutputofthephase-lockedloopphasedetector.ThevoltageonisthesignalafterF/Vconversion.Ifthetonesignalisinputtothe②pin,thenthe⑤pinoutputstheFMsquarewavesignalmodulatedbythe②pininputsignal.FromthebasicfunctionofLM567,LM567canbeusedasanoscillator,modulatorordemodulator.Therefore,itcanbeusedasabasicdeviceinthecircuit.TheapplicationofLM567hasthefunctionofdecodingaspecificfrequencyintheinputsignal,anditiswidelyusedincommunication,remotecontrol,measurement,frequencymonitoring,etc.Figure3.LM567ToneDecoderIVTipsofUsingToneDecoderLM567AlthoughLM567hasaverywiderangeofapplications,ifitisnothandledproperlyduringdesignandapplication,itstillfailstoachievetheexpectedresults,andevenbringstroubletothedebuggingoraffectsthereliabilityoftheproduct.Therefore,itshouldbeconsideredfromthefollowingaspectswhenusingit:1.SetOperatingFrequencyandBandwidthofLM567AccuratelyandAppropriatelyWeknowthattheinternaloscillationfrequencyf0ofLM567canbepre-setwithintherangeof0.1KHzto500KHz,anditscorrespondingbandwidthcanalsobedeterminedasrequiredwithinthefieldrangeof7%f0to14%f0.Therefore,afterthedetectedsignalisdetermined,theinternaloscillationfrequencyf0ofLM567shouldbesettocoincidewiththecenterfrequencyofthemeasuredsignal,andthetimingcomponentsRandCconnectedwiththe5and6feetofLM567shouldbeusedwithhighprecision.Amongthem,thesettingofthecenterfrequencycanbedeterminedbytheresistancevalueofthetunerR.Whenadjusting,itisnecessarytopreventRshortcircuitoropencircuit,otherwisetheoutputlevelof⑧pinwillbelowlevelwhetherthereisinputsignalornot.Theexternalcapacitanceofthe②pinofLM567determinesthecapturebandwidth.Thesmallerthecapacity,thewiderthecapturebandwidth.However,thecapacitancecannotbereducedblindlytoincreasethebandwidth,soasnottoreducetheanti-interferenceabilityoreventriggerfalsely,whichaffectsthereliabilityoftheproduct.2.MaketheCenterFrequencyofthePassbandCoincidewiththeCenterFrequencyoftheOscillationAsMuchAsPossibleItshouldbenotedthatthecenterfrequencyofthepassbanddoesnotalwayscoincidewiththecenterfrequencyoftheoscillator,andsometimesitwilldeviateseverely.Thiswillinevitablycauseadecreaseinreliabilityandsensitivity.Therefore,measuresshouldbetakentomakethetwocenterscoincideasmuchaspossible.ThecircuitshowninFigure4canminimizethefrequencyoffsetofthetwocenters.Figure4.CircuitofLM5673.WorkingVoltageofLM567ShouldBeStableThestabilityoftheoperatingvoltageoftheLM567hasafixedresponsetothestabilityofthecenterfrequencyofthetonedecoder.4.AvoidMisoperationWhentheOutputTerminalisPoweredOnLM567outputsalowlevelatthemomentwhenthepoweristurnedon.Therefore,forsomeremotecontrolcircuits,itisnecessarytoaddaCRintegrationdelaycircuittotheoutputendtoavoiderroneousoperationwhenthepoweristurnedon.Thisisespeciallyimportantintheon-offcontrolcircuit.Afterreadingtheblog,haveyoubetterunderstandLM567?Finally,ifyouhaveanyquestionsaboutLM567,pleasedonothesitatetoleaveamessageinthecommentsectionbelow!

IntroductionInrecentyears,withthecontinuousdevelopmentofnewtechnologies,storagebatteriesasapowersourcenotonlyplayanimportantroleintransportation(railroad,subway,ship),powergeneration,communications,aerospace,chemical,traditionalautomobilesandotherindustries.Inaddition,batterieshavealsobeguntobeusedinthefieldsofelectricvehicles(EV)andhybridelectricvehicles(HEV)aspowersourcesorpowerauxiliarypowersources.Doyouknowwhatare2featuresofbatteriescomparedwithdisposablerechargeablebatteries?Thatismultiplerecyclingandhighefficiencyandenergysaving.Whenthecarisnotstarted,itmustrelyonthebatterytosupplypowertothestarteruntilitdrivestheenginetorotate.Whenthebatteryvoltageisinsufficientorthebatteryisdamaged,itisdifficulttoprovidesufficientpower,thuscausingtheenginetofailtorun.Therefore,thisblogproposesthedesignofalow-batteryalarmsystemforcarbatteriesbasedonLM741.Ingeneral,whenthebatteryvoltagedropstoacertainlimit,itwillsendoutareminder.Theprincipleofthereminderisthatthecircuitjudgeswhetherthebatteryisworkingnormallybyinstallingasoundandlightsignalalarmsystem.Inthisway,wecanrechargeourcarorreplacethebatteryintime.CatalogIntroductionCatalogIDescriptionofLM741IIDesignoftheSystemIIICircuitDesign3.1SystemHardwareCircuitDesign3.2ReferencePowerSupplyCircuit3.3SamplingCircuit3.4OutputCircuit3.5AlarmPrinciple3.6WiringDiagramoftheSystemIVTestResultsoftheSystemFAQOrdering&QuantityIDescriptionofLM741TheLM741seriesaregeneral-purposeoperationalamplifiers.Itisintendedforawiderangeofanalogueapplications.Thehighgainandwiderangeofoperatingvoltageprovidesuperiorperformanceinintegrator,summingamplifier,andgeneralfeedbackapplications.LM741hasbothinvertinginputsandnon-invertinginputs.Whenthevoltageofthenon-invertinginput(+)ishigherthanthevoltageoftheinvertinginput(-),theoutputofthecomparatorishigh.Ifthevoltageattheinvertinginput(-)ishigherthanthenon-invertingterminal(+),theoutputislow.Theoutputoftheoperationalamplifieristheproductofgainandinputvoltage.IIDesignoftheSystemThelowbatteryalarmsystemismainlycomposedofreferencepowersupplycircuit,samplingcircuit,voltagecomparatorcircuitandoutputcircuit.Thereferencepowersupplycircuitconsistsofavoltageregulatorandacurrentlimitingresistor,whichisaddedtotheinvertinginputofthevoltagecomparatorandprovidesareferencevoltageforit.Thesamplingcircuitiscomposedoftworesistorsinseriestoformaseriesvoltagedivider,whichisusedastheinputsignalofthewholecircuit,andapartofthebatteryvoltageiscomparedwiththereferencevoltage.Thevoltagecomparatorcircuitjudgeswhethertheoutputishighlevelorlowlevelbycomparingthevoltageofthereferencepowersupplycircuitandthevoltageofthesamplingcircuit.Theoutputcircuitjudgeswhetherthelight-emittingdiodeisintheconductingstatebythereceivedoutputvoltagefromvoltagecomparator,therebygivinganalarmsignaltoindicatethebatterypoweristoolow.Figure1.StructureoftheSystemIIICircuitDesign3.1SystemHardwareCircuitDesignThehardwarecircuitoflowbatteryalarmsystemisshowninFigure2.ThesystemmainlyincludesvoltagecomparatorLM741,resistor,voltageregulatorandLED.Figure2.HardwareCircuit3.2ReferencePowerSupplyCircuitThereferencepowersupplycircuitconsistsofcurrentlimitingresistorR2andvoltageregulatorVDZ.ThissystemtakesthestablevoltageoftheregulatorasthereferencevoltageofthecomparatorLM741,andconnectsittotheinvertinginputoftheLM741.R2=100k.Thestablevoltageis5V.3.3SamplingCircuitR1andR3areconnectedinseriestoformasamplingcircuit,whichisconnectedtothein-phaseinputterminalofLM741.TheresistancevaluesofR1andR3areequal,taking100ktoformseriespartialvoltage.Theintermediatepointisthesamplingvoltage,thatis,takingpartofthebatteryvoltageasthedetectionvoltage,i.e.theinputvoltage.3.4OutputCircuitTheoutputcircuitconsistsofR4andLED.R4=1K,whichcanlimitthecurrent.AccordingtothevoltagevalueattheoutputofthevoltagecomparatortodeterminedwhethertheLEDisonoroff.3.5AlarmPrincipleWhenthebatteryvoltageishigherthan10V,thatis,thevoltageofsamplingcircuitexceeds5V,theinputsignalvoltageishigherthanthereferencevoltage,thenLM741outputshighlevel,andtheoutputvoltageisbatteryvoltage(10~12V).ItcanbeseenfromFigure4thatthepotentialofpin6ishigherthanthepotentialofpin7.LEDdonotemitlightbecauseofthereversevoltage.Thisindicatesthatthebatteryvoltageisnormalandthealarmfunctionisnotactivated.Whenthebatteryvoltageislowerthan10Vandtheinputsignalvoltage(5V)islowerthanthereferencevoltage,theLM741outputsalowlevel,thatis,theoutputvoltageiszero.Atthistime,thepotentialofpin7ishigherthanthepotentialofpin6,theLEDisturnedonduetotheforwardvoltage.Andthelightindicatesthatthebatterypoweristoolow.Thealarmfunctionisactivated.3.6WiringDiagramoftheSystemFigure3showsthewiringstructureoflowbatteryalarmsystem.Theautomobilebatteryisconnectedtothevoltagecomparisondevicethroughthecarkeyswitch,andprovidespowerfortheautomobilecircuitload(lightingsystem,instrumentsystem,etc.)Whenthebatteryvoltageisnormal,theloadvoltageisnormal.Andthevehiclecanstartnormally.Theinstrumentsystemcandisplayandworknormally.Whenthebatteryvoltageistoolow,thevoltagecomparisondevicewillsendoutalightalarmsignal.Atthesametime,ifthepowersupplyvoltagecannotreachtherequiredvoltagelevelofthesystem,thecorrespondinglighting,instrumentandothersystemswillnotoperate.Figure3.WiringDiagramoftheSystemIVTestResultsoftheSystemItcanbeseenfromtable1thatwhenthebatteryvoltageislowerthan10V,thealarmindicatorison;whenthebatteryvoltageishigherthan10V,thealarmindicatorisoff.Therefore,thecircuitcangiveanalarmwhenthebatteryvoltageislowerthan10V,andstopwhenthebatteryisrechargedtoabove10Vagain.Thealarmsystemdoesnotworkwhentheoutputvoltageofthebatteryisabove10V.Itfullyshowsthatthedesignschemeofthecircuitiscorrectandfeasible.TestResultsoftheSystemBatteryvoltage(V)BatteryvoltagestatusAlarmindicatorstatus6.8toolowon8.1lowon9.6lowon10.3(Aftercharging)normaloff12.8(Aftercharging)normaloff13.6(Aftercharging)toohightoffFAQWhatislm741opamp?AnLM741operationalamplifierisaDC-coupledhighgainelectronicvoltageamplifier.Ithasonlyoneop-ampinside.AnoperationalamplifierICisusedasacomparatorwhichcomparesthetwosignal,theinvertingandnon-invertingsignal.WhyOpampiscalled741?The741OpAmpICisamonolithicintegratedcircuit,comprisingofageneralpurposeOperationalAmplifier.ItwasfirstmanufacturedbyFairchildsemiconductorsintheyear1963.Thenumber741indicatesthatthisoperationalamplifierIChas7functionalpins,4pinscapableoftakinginputand1outputpin.Howdoesa741opampwork?ThemostcommonOp-Ampisthe741anditisusedinmanycircuits.TheOPAMPisaLinearAmplifierwithanamazingvarietyofuses.Itsmainpurposeistoamplify(increase)aweaksignal-alittlelikeaDarlingtonPair.TheOP-AMPhastwoinputs,INVERTING(-)andNON-INVERTING(+),andoneoutputatpin6.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhydoestheIC741requiredualpowersupply?Operationalamplifiershavetwopowersupplyrailsbecausetheyusuallyneedtoswingbipolar-outputvoltagesthatgoeitherpositiveornegativeinresponsetothenormalrangeofinputsignals....Withoutthedualsuppliestheoutputsignalwouldclipatthegroundpotential.HowdoIcheckmy741IC?Testinga741ICThecircuitiscommonlycalledasvoltagefollower.Avoltageisappliedtopin3oftheop-ampthroughthevariableresistor(10K).AllweneedtodoistoverifywhetherthevoltagesV1andV2areexactlysameornot.Checkthemusingamulti-meter.WhatisIC741?Anopampisacomplexelectronicdevice,whichconsistsofresistors,capacitors,transistorsanddiodes.Itiscommerciallyavailableinintegratedcircuitform.MostcommonlyavailableandusedopampICisIC741.TheIC741isasmallchip.Itcompriseseightpins.Whatisgainbandwidthproductof741?Gain-BandwidthProduct:ForanOp-Ampthegain,Gisdefinedasthegainwhenasignalisfeddifferentiallyintotheop-ampandnofeedbackloopispresent....ItisgenerallygiveninV/s,andforthe741op-ampissomethingcloseto1v/s.WhatarethefeaturesofIC741?Shortcircuitandoverloadprotectionprovided.Intheory,thedcoutputvoltagewillbezeroifboththeinputsofthe741ICareconnectedtotheground.Lowpowerconsumption.Largecommonmoderejectionratio(CMRR)anddifferentialvoltageranges.Noexternalfrequencycompensationisrequired.Whichop-amp(LM356orLM741)isthebetterchoiceforhigherfrequencyapplications?Um,theLM356isanaudiopoweramplifierwitha300KHzbandwidth.TheLM741isanoperationalamplifierwithatypicalunitygainbandwidthof1MHz.Inotherwords,theyareentirelydifferentsortsofthingsandnotatallinterchangeable.Neitherisverygoodathigherfrequencies.YoumightbethinkingoftheLF356,whichisaJFETinputoperationalamplifierwithaunitygainbandwidtharound5MHz.MuchbetterpartinalmosteverydimensionthantheLM741.CanweuseanLM324insteadofanLM741forconstructinganop-ampintegrator?Yes.Itwilllikelyperformslightlybettertooasithasaslightlybetterspecification(frequency,slewrate,etc),plusyougetfouridenticalopampsinasingle14pinpackage.IntroductionTheLM386isapoweramplifierdesignedforuseinlowvoltageconsumerapplications.Thegainisinternallysetto20tokeepexternalpartcountlow,buttheadditionofanexternalresistorandcapacitorbetweenpins1and8willincreasethegaintoanyvaluefrom20to200.Theinputsaregroundreferencedwhiletheoutputautomaticallybiasestoone-halfthesupplyvoltage.Thequiescentpowerdrainisonly24mWwhenoperatingfroma6Vsupply,makingtheLM386idealforbatteryoperation.CatalogIntroductionCatalogIHowdoesLM386InternalCircuitWork?1.1Inputstage1.2VoltageAmplifierstage1.3Outputstage1.4FeedbackNetworkIILM386ApplicationCircuit2.1CircuitofInfraredalarm2.2CircuitofAutomobileVoiceHorn2.3CircuitofMicrocomputerStereoPowerAmplifierFAQOrdering&QuantityIHowdoesLM386InternalCircuitWork?TheprincipleofLM386internalcircuitisshowninthefigure.Theinternalcircuitisbasedonatypicalaudiopoweramplifierconfiguration,oftenreferredtoasLintopology.LM386internalcircuitisdividedintoinputstage,voltageamplifierstage(VAS),outputstage(OPS)andfeedbacknetwork.Figure1.LM386InternalCircuit1.1InputstageThefirstmoduleisthePNPemitterfolloweramplifier(Q1,Q3).ItsetstheinputimpedanceanddefinestheDCoperatingpointtoraisetheinputvoltagefromtheground,sothecircuitwillacceptthenegativeinputsignalto-0.4V.Both50Kinputresistors(R1,R3)haveestablishedpathstothebasecurrentground,andtheinputsneedtobecoupledtoavoidinterferingwiththeinternalbias.Sotheinputimpedanceisdeterminedbytheseresistorsandissetto50K.Analysisofvoltagegain:Thegainoflongtailpair(Q2,Q4)ofdifferentialamplifierisregulatedbytwogainsettingresistors1.35k+150(R5+R5).Externalpins1and8canadjustthegainfrom20(minimum)to200(maximum).Thevoltagegaincanbecalculatedunderstaticconditions(withoutinputsignalapplied)asfollows:Figure2.AnalysisofLM386voltagegainThevoltage(vdiff)atbothendsofR4andR5isonlythedifferentialinputvoltage(VIN),becausethebaseemittervoltagedropofPNPtransistors(Q1,Q2,Q3andQ4)onbothsidesofLTPisthesame.ThecurrentmirrorformedbyQ5andQ6producesequalcurrentonbothsidesoftheLTP.ThecurrentismarkedasI.Duetothecurrentmirror,thecurrentintensitythroughR8isequalto2I,whileignoringthecurrent(i7)throughthetwo15Kresistors(R6,R7).thesetworesistorshavealargerimpedancecomparedtotherestofthecircuit,thereby:Inthefigureabove,itiseasytoseethatifi7=0,then:Theformulacanalsoberewritteninamoregeneralway:Z1-5andZ1-8aretheimpedancebetweenthecorrespondingpins.Withoutanyexternalcomponents,thegainisGV=2x15k/(150+1350)=20(26dB).Useacapacitor(orshortcut)betweenpin1and8,thenitsgainofGV=2x15k/150=200(46db).1.2VoltageAmplifierstageThecommonemitteramplifier(Q7)amplifiesthelowamplitudeinputsignaltotheappropriateleveldirectlycoupledtotheoutputstage.1.3OutputstageItisclassABpoweramplifier,thatis,push-pullconfiguration.Eachtransistoramplifiesitscorrespondinghalfwave.BecausethegaindifferencebetweenQ9andQ10ofPNPtransistorsisinacompoundPNPtransistorconfiguration,TOTAL=Q9XQ10.Dividercompensation:DiodesD1andD2areusedtocompensateforcrossdistortion.Infact,inapush-pulltopology,thetransistordoesnotstartconductinguntiltheinputsignalbeginstoexceeditsforwardvoltage(Vbe).Theforwardvoltage(VBE)isthevoltageatthebaseemitterjunction(usuallyabout0.6V).Inordertooffsettheminimumconductionlimit(Vbe)ofthetransistors,theyneedtobebiasedsothattheiridlingvoltagewillneverbelowerthantheforwardvoltage(Vbe).Acertainamountofcurrent(calledabiascurrent)willcontinuouslyfeedintothebaseofthetransistortoensurethattheymaintainthesacrificialefficiencyofconduction.Itisprovedthatusingdiodesisoneofthebestsolutions.Itprovidesatemperature-dependentpressuredrop.Andbymatchingthethermalcoefficienttothetransistor,thebiascurrentcanbekeptfairlystable.Ifaccurateheattracingisrequired,installthediodesonthesameheatsinkasthepowertransistor.Sinceonediodeisusuallynotenough,amplifiersusuallyusemultiplediodejunctions1.4FeedbackNetworkAnegativefeedbackisappliedfromtheoutputtotheemitterQ4viatheresistorR8.ThefunctionoftheDCfeedbackistostabilizetheoutputDCbiasvoltagetohalfofthesupplyvoltage.ThefunctionsofDCfeedbackareasfollows:IfforsomereasonVOincreases,thecorrespondingcurrentincrementwillflowthroughR8andintotheemitterofQ4.Therefore,theincreaseofcollectorcurrentofQ4leadstothepositiveincreaseofbasevoltageofQ7.ThisleadstoanincreaseinthecollectorcurrentofQ7,whichreducesthebasevoltageofQ7,thusreducingVo.IILM386ApplicationCircuit2.1CircuitofInfraredalarmFigure3.CircuitofInfraredalarmFigure3showsthecircuitofinfraredalarm.ThecircuitiscomposedofanANDgatecircuit,amonostabledelaycircuit,afour-wayinfraredtransmittingandreceivingcircuit,atriggerandatwo-colorlight-emittingcircuit,andanaudioalarmcircuit.FourpairsofwarninglinesfortransmissionandreceptioniscomposedofHF1~HF4(infraredlight-emittingdiodes)andBG1~BG4(infraredreceivingpairingtubes).Ifsomeonecrossesthewarninglineandtheinfraredbeamisblocked,thecorrespondingmatchingtubewillbecutoff.AndtheinputofthecorrespondingNANDgateishighlevel.Itmakesthetriggerterminalpin2ofIC3(555)obtainanegativedifferentialpulse,thatis,theoutputterminaloftheANDgatecomposedofD1~D4.Therefore,the555isset,andthehighlevelisoutputfrompin3whichmakesBG5saturatedandturnedon.ThechipIC4(KD-9562)ispoweredonandanalarmsoundisgiven.ThedelaywidthofIC3monostablecircuittd=1.1Rw1R3determinesthesoundtime.Thedelayalarmtimecorrespondingtotheparametersinthefigureisabout100seconds.Atthesametime,thecorrespondingtimecanbechangedbychangingthevalueofWandCaccordingtothespecificsituation.ThevoltagestabilizingtubeDWadopts2cw7or2cw10,andthevoltagerangeisabout3VtoprotectthemusicintegrationKD-9562,soastopreventitfromburningduetoover-voltage(highvoltage).ThechipKD-9562isaneightanalogsoundintegratedcircuit,whichcanselectthecorrespondingmusicaccordingtotheusesituationandpurpose.LM386isasinglepoweraudiopoweramplifierintegratedcircuit,whichisusedtoexpandtherangeofalarmsound.F1-1~F1-6,F2-1~F2-6usesixinverterCD4069.Two-colorlight-emittingdiodesLED1~LED4adopt2EF303.Undernormalconditions,theyemitgreenlight,andwhensomeonecrossesthewarningline,theysendoutredwarninglight.2.2CircuitofAutomobileVoiceHornFigure4.CircuitofAutomobileVoiceHornTheleftsideofthedottedlineinFigure4istheoriginalcircuitdiagramofthevehicleelectrichorn.SListheelectrichornbuttonswitchonthesteeringwheel.S2isanewlyaddedSPDTSwitch,whichisusedforswitchingbetweenelectrichornandvoicehornoftheoriginalvehicle.WhentheswitchS2issetto2,presstheswitchSl,thecapacitorClischarged,thetransistorsVTl,VT2turnon,therelayJlpullsin.J1-1isclosedandheldfor15secondstosupplypowertothecircuit.IClisadedicatedvoiceintegratedcircuitHL-169A.Sinceitsworkingtimeis2.8seconds,theself-excitedmultivibratoriscomposedoftransistorsVT3andVT4.Every3seconds,ahighlevelisoutputasatriggersignal,sothatICloutputsavoicesignalevery3seconds,andsendsittoIC2foraudiopoweramplification,andthespeakerBLemitsvoice.2.3CircuitofMicrocomputerStereoPowerAmplifierBecausetheaudiosignalamplitudeofthelineoutputofthesoundcardistoolarge,theLM386canbedriventopushthespeaker.Inaddition,duetotheinterferenceofvideosignalwhenplayingVCD,itisnotgoodtoconnecttheVCDaccordingtothetypicalcircuit,soitisnecessarytoaddsomecomponentsanddebugthecomponentvalues.TheschematicdiagramisshowninFigure5.Figure5.CircuitofMicrocomputerStereoPowerAmplifierLM386hastwoinputterminals,3pinin-phaseinputand2pininvertinginput.Theinputsignalcanbeinputfromanyendandtheotherinputterminalcanbegrounded.TheinputendisconnectedwithcapacitorC4inordertofilteroutthevideointerferencewhenplayingVCD.Thevaluecanbeincreasedappropriately,butitcanbeusedwithorwithoutC4whenplayingCD.Thepin1andpin8aregaincontrolterminals,whicharecomposedofC2andW2.Thesmallertheresistance,thehigherthegain.ItismoreappropriatetoadjustthegainofW2toabout150.Ifthegainistoohigh,itwilleasilycauseself-excitation.Pin7isconnectedtoa10capacitor.ThehighfrequencycomponentattenuationcircuitiscomposedofR2andC6toeliminatethecrashsoundfromtheloudspeaker.ThecapacityofC6canbeadjustedaccordingtotheactualeffect.Pin6isconnectedtothegroundwitha0.1capacitor,whichactsasafiltertoeliminatethestatichumoftheamplifier.Pin5isconnectedtothecouplingcapacitorC3.Ifonlyoneconespeakerisconnectedtoonechannel,C3capacityshouldnotexceed470,otherwisetheloudspeakerwillbeblockedwhenplayinglowmusic.Ifhigh-frequencyandlow-frequencycrossovertechnologyisadopted,thecapacityofC3canbeincreasedtomakethebassfullyreflected.W1isusedtoadjusttheoutputvolume,whichisparticularlyconvenientwhenplayinggamesorlisteningtoCDs.FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?

SMAJ58CA-E3/61-VISHAY

IntroductonLM386isalowvoltageaudiopoweramplifier.LM386adopts8-pindoublein-lineplasticpackagewithworkingvoltageof4V-15V.Whenthepowersupplyvoltageis12V,300mWoutputpowercanbeobtainedonan8load.VariousoscillatorscanbeeasilyproducedwithLM386.CatalogIntroductonCatalogISimplestOscillatorIIBlockingOscillatorIIIElectronicPianoIVSquare-waveOscillatorVSinusoidalOscillatorFAQOrdering&QuantityISimplestOscillatorFigure1.CircuitofSimplestOscillatorInFigure1,theoutputendandin-phaseinputendofLM386areconnectedbypiezoelectricceramicchipHTD.Theamplifierformspositivefeedbackandgeneratesoscillation.HereHTDisbothafeedbackcapacitorandasound-generatingdevice.Componentparametersinthefigure:D1~D4are1N4001,C1=220pF,HTDispiezoelectricceramicsheetwithauxiliaryacousticcavity.IIBlockingOscillatorFigure2.CircuitofBlockingOscillatorAsshowninFigure2,asimpleoscillatorconsisitofLM386,C3,C4andloudspeakers.RPandC2makethisoscillatorproduceblocking-oscillation.Afterconnectingthepowersupply,LM386doesnotworkbecausetheinitialterminalvoltageofC2iszero,andthepowersupplychargesC2throughRP.WhenC2chargingvoltageishigherthanacertainvalue,LM386oscillatorstartstovibrate.Astheamplitudecontinuestoincrease,thecurrentconsumptionoftheoscillatoralsoincreases.ThiscurrentflowsthroughRP,anditsvoltagedroponRPalsoincreases,causingtheLM386powersupplyterminal6pinvoltagetocontinuetodrop.EventuallytheLM386cannotworkandtheoscillatorstops.ThepowersupplyrechargesC2viaRPagain,causingthevoltageatC2torise.WhenthevoltageatC2risestoacertainvalue,theLM386oscillatorstartsagain.Inthisway,theoscillatorwillproduceblocking-oscillation,andthespeakeremitsbeep,beep,beepsound.Componentparametersinthefigure:D1~D4are1N4001,C1=C3=220F,C2=47F.C4=0.01F,surface mount resistor codeRP=4.7K.IIIElectronicPianoFigure3.CircuitofElectronicPianoFigure3isasimpleelectronicpianocircuit.Onthepin3ofLM386,theintegratedcircuithasa10Kresistortoground.Thisbuilt-inresistorandtenscaleresistorsRP1~RP10constitutethetimingresistoroftheoscillator.C2isthetimingcapacitor.ByadjustingthevaluesofRP1~RP10,thespeakerscansequentiallyemitmusicalsoundsfromlowoctavedo,re,mitohighoctavedo,re,mi.KI~K10arekeyswitches.Componentparametersinthefigure:Cl=C3=220F.C2=2200FIVSquare-waveOscillatorFigure4.CircuitofSquare-waveOscillatorFigure4showsasquare-waveoscillatorcomposedofLM386.R1isthetimingresistor.C2isthetimingcapacitor.R2andR3providevoltagebiasforLM386in-phaseinput.BecausethevoltageattheC2terminalcannotchangeabruptly,theinvertinginputterminalpin2oftheLM386islowlevel,andpin5isthemidpointoftheinternalOTLoutputstageoftheamplifier.Itis1/2Vocinstaticstate,anditissuppliedtothethird-phaseinputpin3afterdividingpressureviaR2andR3.Obviouslythepotentialofthispinishigherthanthesecondpin.Therefore,pin5outputshighlevel.ThishighlevelchargesC2viaR1.WhenthevoltageofC2terminalishigherthanthepotentialofpin3,pin5outputslowlevel.C2dischargestopin5viaR1.WhenC2isdischarged,thepotentialofpin2dropsandislowerthanthepotentialofpin3.Pin5outputshighlevelagain.Inthisway,thecircuitformsoscillation,andtheoscillationsignaldrivestheloudspeakertosoundthroughC3.Componentparametersinthefigure:C1=C3=220F,transistors testC2=0.33F.R1=22K,variable capacitorR2=1K.R3=9.4KVSinusoidalOscillatorFigure5.CircuitofSinusoidalOscillatorFigure5isasinusoidaloscillatormadeofLM386.ThecircuitadoptsWienbridgeoscillationmode,andtheoutputsignaldistortioncoefficientofthecircuitisverylow.TheflashlampHandtheresistorR3formanegativefeedbackcircuit,whichkeepstheamplitudeoftheoscillatoroutputsignalstableandhaslowdistortion.WhenthevaluesofcapacitorsC1andC2arethesame,theoscillationfrequencyofthecircuitcanbeobtainedbytheformulaf=1/2C1R1R2.Inactualproduction,Hcanuse3V,15mAflashlamp.FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?IDescriptionThisblogusesLM386integratedblockasthecoredevicetomakeasimplesoundamplifier.Itsproductioncostisrelativelylow.Thisblogissuitableforbeginnerstolearnaboutpowertubes,integratedoperationalamplifiers,speakers,languagechipsandothercomponents.Sowecanmastertheprinciples,characteristicsandusageofthebasicamplifiercircuitandpoweramplifiercircuit.Figure1.LM386CatalogIDescriptionIIIntroductiontoLM3862.1Features2.2InternalStructureIIIWorkingPrincipleofLM386SoundAmplifierIVLM386SoundAmplifierDebuggingVConclusionFAQOrdering&QuantityIIIntroductiontoLM3862.1FeaturesLM386isakindofaudiointegratedamplifier.Ithastheadvantagesoflowpowerconsumption,adjustableinternalchaingainadjustment,largepowersupplyvoltagerange,fewexternalcomponentsandlowtotalharmonicdistortion.Therefore,LM386iswidelyusedinrecordersandradios,mainlyinlow-voltageconsumerproducts.LM386featuresare:BatteryOperationMinimumExternalPartsWideSupplyVoltageRange:4V12Vor5V18VLowQuiescentCurrentDrain:4mAVoltageGainsfrom20to200Ground-ReferencedInputSelf-CenteringOutputQuiescentVoltageLowDistortion:0.2%(AV=20,VS=6V,RL=8,PO=125mW,f=1kHz)Availablein8-PinMSOPPackageBasedonthecharacteristicsshownabove,lm386componentsarewidelyusedincommunicationequipment,smallradios,andwalkie-talkiecircuits.Itisalsocalleduniversalpoweramplifiercircuitbythemajorityofelectronicenthusiasts.2.2InternalStructureLM386adopts8-pindualin-linepackage.SeeFigure2forthepinarrangementdiagram.Figure2.LM386PinArrangementPin6isconnectedtothepositivepoleofthepowersupply;Pin4aregrounded;Pin2invertinginputterminal;Pin3non-invertinginputterminal;Pin5istheoutputterminal;Pins1,7,and8areusedtoimprovetheperformanceofthecircuit.Theexternalcomponentends,andtheinternalcircuitisathree-stageamplifiercircuit:The1ststageconsistsofVT1~VT6toformadifferentialamplifiercircuit,The2ndstageiscomposedofVT7voltageamplifiercircuit,The3rdstageiscomposedofVT8~VT10toformacomplementarysymmetricalOTLoutputcircuitthatcaneliminatecrossoverdistortion.R5,R6,andR7formanegativefeedbacknetwork.IIIWorkingPrincipleofLM386SoundAmplifierThecoreoftheLM386soundamplifieristheLM386poweramplifierintegratedcircuit.AsshowninFigure3.TheelectretmicrophoneB1convertssoundsignalsintoelectricalsignals.Thissignalisveryweak,howtoamplifyit?WecanaddthecouplingcapacitorC1tothebaseofVT1,andVT1formsacommonemitteramplifiercircuittoamplifythesignal.Also,thesignalisoutputfromthecollectorofVT1,andaddedtotheinvertinginputterminalofLM386viacouplingcapacitorC2topin2andpin3isgrounded.AfterthesignalisamplifiedbytheinternalthreestagesofLM386,thesignalisoutputfrompin5,andthenpassesthroughthecouplingcapacitor.C3issenttothespeakers.Aftergoingthroughtheseprocesses,itcanmakeasound.Figure3.LM386SoundAmplifierFigure4.LM386AudioAmplifierCircuitThenhowtoadjustthesignalmagnificationofLM386?Here,wecanconnectanadjustableresistorR5andcapacitorC6topin1andpin8toformaseriesRCnetwork.WhenR5=0,thevoltagemagnificationis200.Pin7isconnectedtocapacitorC5topreventLM386fromgeneratingself-excitation.Inaddition,pin5isgroundedthroughR4andC4tomakethespeakersoundsofter.IVLM386SoundAmplifierDebuggingAfterthecircuitisassembled,weshouldcarefullycheckforerrorsorfalsesoldering.Ifthereisnoabnormalityaftertheinspection,turnonthe6Vpowersupplyfordebugging:Step1:Dontpickupthemicrophonefirst.Whenthereisnoinputsignal,testthequiescentcurrentofthewholemachine,whichisabout7mA.Step2:TestthestaticvoltagevalueofeachpinofLM386,asshowninFigure2.Step3:Afterthevoltageandcurrentarenormal,placetheRPvolumeregulatorinthemiddleandtouchthebaseofVT1withascrewdriver.Thespeakerwillemitaclickclicksound,indicatingthatthecircuitisnormal.Step4:ConnectthemicrophoneB1,andthenfine-tunetheRP.Ifnothinggoeswrong,speakintothemicrophone,thespeakershouldhaveamplifiedsound.Ifthereisnosound,checkwhetherthemicrophonecableisconnectedincorrectlyorthequalityofthemicrophoneisdefective.Step5:Whenusingasoundamplifier,donotplacethemicrophoneandspeakertooclosetogether.Iftheyareunfortunatelytooclose,thespeakerswillmakeaharshsound.Therefore,itisbesttouseshieldedwireforthemicrophonelead-out.Figure5.LM386VConclusionThroughthedesignofthisblog,wehaveanessentialunderstandingoftheworkingprincipleofLM386.Wehavemasteredthepinfunction,internalstructurecircuitandworkingprincipleofLM386.Inaddition,thesoundamplifiermadebyLM386hasthecharacteristicsofsimplecircuit,convenientdebugging,andcompletefunctions.Afterreadingthisblog,haveyoubetterunderstandLM386?FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?Introduction74LS04containssixindependentgateseachofwhichperformsthelogicINVERTfunction.Theoutputsignalsofthesixinvertersareoppositetotheinputsignals.CatalogIntroductionICircuitofRingOscillatorIISymmetricalSquare-waveOscillatorIIISimpleself-excitedMultivibratorIVCircuitofCrystalOscillatorandFrequencyDividerVFMWirelessMicrophoneFAQOrdering&QuantityICircuitofRingOscillatorFigure1.RingoscillatorTheexperimentalcircuitofanongateringself-excitedmultivibratorwithRCdelaycircuitisshowninthefigure.TheoscillationcircuitiscomposedofnongateIC1,IC2,IC3andtimingcircuitelementsRPandC.TherectangularwavesignalisoutputbyIC3.R1isaprotectiveresistortoavoiddamagetoIC3gatecircuitwhentimingcapacitorCisreversedischarged.NotgateIC4makestheoscillatoroutputrectangularwavewithbetterwaveform.Oscillationfrequencyestimationf1/2.3RCT2.3RCTheresistancevalueoftimingresistorisselectedintherangeof100-10002.ThetimingcapacitorChasalargevaluerange,fromseveralhundredpicofarads(pF)toseveralhundredmicrofarads,whichcanmaketheoscillationfrequencyrangefromseveralmegahertztoseveralhertz.Replacethetimingresistorwithapotentiometer(1.5k92),whichcancontinuouslyadjusttheoscillationfrequencyandhasalargercoverage.Thechipusedis74LS04.IISymmetricalSquare-waveOscillatorThefigureshowstheexperimentalcircuitofnon-gatesymmetricalsquare-waveself-excitedmultivibrator.Becausethecircuitissymmetrical,thedutycycleofoutputoscillationwaveformis1:1,whichissquarewave,soitiscalledsymmetricalsquarewaveoscillator.Intheoscillationcircuit,theoutputofnongateIC1iscoupledtotheinputofnongateIC2viaatimingcapacitorC2.Also,theIC2outputiscoupledtotheIC1inputviaC1.Twonongatesarecoupledwitheachotherthroughcapacitorstoformapositivefeedbackclosed-loopcircuit,whichcanproducesquare-waveoscillation.WhenR1=R4=R,C1=C2=C,theestimationformulaofoscillationfrequencyisasfollows:f1/RC.TheoscillationperiodTRC.Figure2.SymmetricalSquare-waveOscillatorIIISimpleself-excitedMultivibratorThefigureshowsasimplenongateself-excitedmultivibratorexperimentalcircuit.Itiscomposedofnon-gateoscillatorIC1,IC2,inverterIC3,redandgreenlight-emittingdiodesandpowersupplysystemGB.IC1andIC2aretheswitchinglinksoftheoscillator.R1andCtimingcircuitsproducedelaypositivefeedbacksignalstocontroltheswitchtoturnonandoffperiodically,sothatIC2outputsrectangularwave.TheinverterIC3makestheredandgreenLEDsandtheoscillatorflashalternately.Figure3.Simpleself-excitedmultivibratorIVCircuitofCrystalOscillatorandFrequencyDividerFigure4.CircuitofCrystaloscillatorandfrequencydividerVFMWirelessMicrophoneWirelessmicrophonesareavailableeverywhereonthemarket,buttheircircuitsareallmadeupofLCoscillatorsorquartzcrystaloscillatorcircuits.Asweallknow,theNANDgatehasthefunctionofmagnificationandphaseinversion.Therefore,aslongasthreeNANDgatesareconnected,aringoscillatorisformed.CoupledwiththeFMcircuit,itcanalsobemadeintoawirelessmicrophone.Figure5.FMwirelessmicrophone74LS04isaTTLintegratedcircuitwithsixsingle-inputNANDgates.Theauthorusesthreeofthemtomakeanoscillator.Whenthesupplyvoltageis5V,theoscillationfrequencyisabout90mhz.Whenthepowersupplyvoltagedecreases,thefrequencydecreases;whenthesupplyvoltageincreases,thefrequencyalsoincreases.Ofcourse,itsoscillationamplitudewillalsochange,buttheeffectisnotsignificant.Inthisway,theauthorusesthemethodofchangingthepowersupplyvoltagetochangethefrequency(thatis,toachievefrequencymodulation).ThespecificmethodistousetheoutputofBA328,anaudioamplifierintegratedcircuit,asitspowersupply.BA328isanamplifyingcircuitofrecordinghead.Whenitisusedfortapesignalcompensationandequalization,anRCseriesparallelnetworkshouldbeconnectedbetweenthefirstandthesecondpins,butitisusedforlinearamplification,soonlya100kw-130kwresistorisneeded.Thevoltageoftheoutputterminal(pin)ofBA328shouldbeequaltoone-halfofthevoltageofthepin(powersupply).Ifthepowersupplyvoltageis12V,thereshouldbea6Voutput.Ifitisnotcorrect,theresistanceshouldbeadjusted.Inaddition,the1kWresistorinthefigureisusedtoadjustthemagnification.Ifitisreduced,thegainwillbeincreased.Whenspeakingtoanelectretmicrophone,thevoltageattheoutput(PIN)canchangerapidlyfrom5.8vto6.2V.Thisvoltageissenttothefootof74LS04tomakeitgenerateFMsignal,whichisamplifiedandisolatedbythefourthNANDgateandsenttotheantenna.FAQWhatis74LS04?74LS04isamemberof74XXYYICseries.The74-seriesaredigitallogicintegratedcircuits.74LS04IChassixNOTgates.TheseNOTgatesperformInvertingfunction.HencenameHEXINVERTINGGATES.Whatisthefunctionofic74ls04?74LS04HexNOTGateIC.74LS04isa2inputquadruple8-bitNOTgateIC.InverterinlogicconvertersisanelectronicsdevicewhosebasicfunctionsaretoinverttheincominglogicweatheritisHIGHorLOW.TheyarealsoknownasNOTgates.Whatisahexinverter?Ahexinverterisatypeofanintegratedcircuitthatcontainssixinverters.Manysophisticateddigitaldevicesuseinverters,includingmultiplexers,decoders,andstatemachines.Aninvertercircuitsmainfunctionistooutputthevoltagerepresentingtheoppositeleveltoitsinput.WhyisNOTgatecalledaninverter?ANOTgate,oftencalledaninverter,isanicedigitallogicgatetostartwithbecauseithasonlyasingleinputwithsimplebehavior.ANOTgateperformslogicalnegationonitsinput.Inotherwords,iftheinputistrue,thentheoutputwillbefalse.

SMAJ58CA-E3/61-VISHAY

Description74LS04containssixindependentgateseachofwhichperformsthelogicINVERTfunction.Theoutputsignalsofthesixinvertersareoppositetotheinputsignals.Theinvertercanreversethephaseoftheinputsignalby180degrees.Thiscircuitisusedinanalogcircuits,suchasaudioamplifier,clockoscillator,etc.Inverterisoftenusedinelectroniccircuitdesign.74LS04-HEXInverter-TruthTableExampleCatalogDescriptionCADModelsFeaturesApplicationPinoutCircuitDiagramPackageParametersElectricalCharacteristicsProductComplianceComponentDatasheetProductManufacturerFAQOrdering&QuantityCADModels74LS04FootprintFeaturesSupplyvoltagerange:+4.75Vto+5.25VMaximumsupplyvoltage:+7VMaximumcurrentallowedtodrawthrougheachgateoutput:8mATotallyleadfreeTTLoutputsMaximumRiseTime:15nsMaximumFallTime:15nsOperatingtemperature:0Cto70CApplication▪Indifferentlogiccircuit▪Indifferentservers▪Indifferentstoragemoduletostoredata▪Indifferentdigitalreluctancescircuitsandinstruments▪IndifferentnetworkingsystemsPinoutPinNumberDescriptionINPUTOFINVERTINGGATES11A-INPUTofGATE132A-INPUTofGATE253A-INPUTofGATE394A-INPUTofGATE4115A-INPUTofGATE5136A-INPUTofGATE6SHAREDTERMINALS7GND-Shouldbeconnectedtoground14VCC-ShouldbeconnectedtopositivevolatgeOUTPUTOFINVERTINGGATES21Y-OUTPUTofGATE142Y-OUTPUTofGATE263Y-OUTPUTofGATE384Y-OUTPUTofGATE4105Y-OUTPUTofGATE5126Y-OUTPUTofGATE6CircuitDiagramPackageParametersTechnologyFamilyLSVCC(Min)(V)4.75VCC(Max)(V)5.25Channels(#)6IOL(Max)(mA)8IOH(Max)(mA)-0.4ICC(Max)(uA)33InputtypeBipolarOutputtypePush-PullFeaturesHighspeed(tpd10-50ns),InputclampdiodeDatarate(Mbps)70ElectricalCharacteristicsProductComplianceECCNEAR99USHTS8542390001ComponentDatasheetDatasheet74LS04DatasheetProductManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.FAQWhatis74LS04?74LS04isamemberof74XXYYICseries.The74-seriesaredigitallogicintegratedcircuits.74LS04IChassixNOTgates.TheseNOTgatesperformInvertingfunction.HencenameHEXINVERTINGGATES.Whatisthefunctionofic74ls04?74LS04HexNOTGateIC.74LS04isa2inputquadruple8-bitNOTgateIC.InverterinlogicconvertersisanelectronicsdevicewhosebasicfunctionsaretoinverttheincominglogicweatheritisHIGHorLOW.TheyarealsoknownasNOTgates.Whatisahexinverter?Ahexinverterisatypeofanintegratedcircuitthatcontainssixinverters.Manysophisticateddigitaldevicesuseinverters,includingmultiplexers,decoders,andstatemachines.Aninvertercircuitsmainfunctionistooutputthevoltagerepresentingtheoppositeleveltoitsinput.WhyisNOTgatecalledaninverter?ANOTgate,oftencalledaninverter,isanicedigitallogicgatetostartwithbecauseithasonlyasingleinputwithsimplebehavior.ANOTgateperformslogicalnegationonitsinput.Inotherwords,iftheinputistrue,thentheoutputwillbefalse.Whatarethe7basiclogicgates?Therearesevenbasiclogicgates:AND,OR,XOR,NOT,NAND,NOR,andXNOR.TheANDgateissonamedbecause,if0iscalledfalseand1iscalledtrue,thegateactsinthesamewayasthelogicalandoperator.ThefollowingillustrationandtableshowthecircuitsymbolandlogiccombinationsforanANDgate.IntroductionAcircuitordevicethatchangesthephaseofasignalby180,asrequiredforfeedingapush-pullamplifierstagewithoutusingacouplingtransformer,orforchangingthepolarityofapulse;atriodeiscommonlyusedasaphaseinverter.Alsoknownasinverter.Thefollowingisanintroductionto74LS04andothersimilarICchips.CatalogIntroductionI74LS04VS.74LS141.1BriefIntroduction1.2Differencebetween74LS04and74LS14II74LS04VS.74LS08III74LS04VS.74HC04IV74LS04VS.54LS04FAQOrdering&QuantityI74LS04VS.74LS141.1BriefIntroductionBoth74LS04and74LS14arenotgatesofthe74series.74LS04isaHexInverter.74LS14isaHexSchmidttrigger.The74LS04gatecircuithasathresholdvoltage.Whentheinputvoltagerisesfromthelowleveltothethresholdvoltage,ordecreasesfromthehighleveltothethresholdvoltage,theconditionofthecircuitwillchange.74LS14isaSchmidttrigger.Itisaspecialgatecircuit,whichisnotcompatiblewiththesimplegatecircuit.Schmidttriggerhastwothresholdvoltages(positivethresholdvoltageandnegativethresholdvoltage).1.2Differencebetween74LS04and74LS14◾Output:Theoutputof74LS04and74LS14arethesame.Ifthesamemanufacturer,theoutputparametersarethesame.◾Input:Thedifferencebetweenthetwoisthattheinputisnotthesame.74LS04inputisTTLlevel,while74LS14inputisSchmidtinput(withhysteresischaracteristics).Becausetheinputisdifferent,theapplicationofthetwochipsisalsodifferent.74LS04ismostlyusedfornoncontrolofgeneraldataontheboard,while74LS14isgenerallyusedforsignalshapingorsignalbufferingofcriticalsignals.Inmostcases,74LS14canreplace74LS04.II74LS04VS.74LS08The74LS08devicecontains4independent2-inputANDgates.Thelogicfunctionexpressionof74LS08is:Y=ABorY=/(A+B),positivelogic.74LS08iscommonlyusedindigitalcircuitsystems.74LS0474LS08VCC(Min)(V)4.754.75VCC(Max)(V)5.255.25LogiclevelTTLTTLPin/Package14PDIP,14SO,14SOIC,14SSOPPDIP14,SOIC14,SOP14,SSOP14III74LS04VS.74HC0474HC04isahexinverterofCMOScircuit,andtheworkingvoltageis2V-6V.Both74LS04and74HC04areinverters,butLSstandsforlow-powerSchottkyandHCishigh-speedCOMS.LSisslightlyfasterthanHC.LSadoptsTTLlevel.HCisCMOSlevel.74HC04iseasytounderstand.Inputlowlevel,outputhighlevel.Inputhighlevel,outputlowlevel.74LS04containssixindependentgateseachofwhichperformsthelogicINVERTfunction.Theoutputsignalsofthesixinvertersareoppositetotheinputsignals.Theinvertercanreversethephaseoftheinputsignalby180degrees.Thiscircuitisusedinanalogcircuits,suchasaudioamplifier,clockoscillator,etc.IV74LS04VS.54LS0454LS04containssixindependentinverters.Itischaracterizedforoperationoverthefullmilitarytemperaturerangeof-55℃to125℃.74LS0454LS04TechnologyFamilyLSLSVCC(Min)(V)4.754.5VCC(Max)(V)5.255.5Bits(#)66Voltage(Nom)(V)55F@NomVoltage(Max)(Mhz)3535ICC@NomVoltage(Max)(mA)0.0330.033tpd@NomVoltage(Max)(ns)2222IOL(Max)(mA)88IOH(Max)(mA)-0.4-0.4SchmittTriggerNoNoRatingCatalogMilitaryOperatingTemperatureRange(C)0to70-55to125Pin/Package14PDIP,14SO,14SOIC,14SSOP14CDIP,14CFP,20LCCCFAQWhatis74LS04?74LS04isamemberof74XXYYICseries.The74-seriesaredigitallogicintegratedcircuits.74LS04IChassixNOTgates.TheseNOTgatesperformInvertingfunction.HencenameHEXINVERTINGGATES.Whatisthefunctionofic74ls04?74LS04HexNOTGateIC.74LS04isa2inputquadruple8-bitNOTgateIC.InverterinlogicconvertersisanelectronicsdevicewhosebasicfunctionsaretoinverttheincominglogicweatheritisHIGHorLOW.TheyarealsoknownasNOTgates.Whatisahexinverter?Ahexinverterisatypeofanintegratedcircuitthatcontainssixinverters.Manysophisticateddigitaldevicesuseinverters,includingmultiplexers,decoders,andstatemachines.Aninvertercircuitsmainfunctionistooutputthevoltagerepresentingtheoppositeleveltoitsinput.WhyisNOTgatecalledaninverter?ANOTgate,oftencalledaninverter,isanicedigitallogicgatetostartwithbecauseithasonlyasingleinputwithsimplebehavior.ANOTgateperformslogicalnegationonitsinput.Inotherwords,iftheinputistrue,thentheoutputwillbefalse.

SMAJ58CA-E3/61-VISHAY

DescriptionTIP122isanNPNDarlingtontransistor.Darlingtontransistormeanstherearetwotransistorinonepackageconnectedtoincreasegainatoutput.TIP122transistorhasalotofgoodfeatureslike5Acollectorcurrent,maxemitter-basevoltageis5V,maxcollectordissipationis65watt,minimummaximumcurrentgainisequalto1000.Thistransistorisdesignedtouseasaswitchandforamplificationpurposes.CatalogDescriptionTIP122ComponentDatasheetTIP122PinoutTIP122FeaturesTIP122ApplicationsTIP122EnvironmentalandExportClassificationsTIP122ParametersWorkingofTIP122HowtoSafelyLongRuninaCircuitDarlingtonCircuitSchematicWheretouseTIP122HowtouseTIP122TIP122ReplacementandEquivalentComplementofTIP122TIP122AlternativeNPNTransistorsTIP122SameFamilyTransistorsAdditionalResourcesFAQOrdering&QuantityTIP122ComponentDatasheetResourceTypeLinkDatasheetsTIP120-22TIP120-22,TIP125-27TO220B03PkgDrawingPCNObsolescence/EOLMultipleDevices19/Jun/2009MultDeviceEOL19/May/2017PCNDesign/SpecificationHeatsinkDesingChanges24/Feb/2014Logo17/Aug/2017PCNPackagingTapeandBox/ReelBarcodeUpdate07/Aug/2014MultDevices24/Oct/2017HTMLDatasheetTO220B03PkgDrawingTIP122PinoutPinNumberPinNameDescription1BaseItgovernsthebiasingofthetransistorandworkstoturnONorOFFthetransistor.2CollectorCurrentflowsinthroughcollector,usuallyconnectedtoload3EmitterCurrentcomesoutbytheemitter,itisusuallylinkedtoground.TIP122FeaturesHighDCCurrentGainhFE=2500(Typ)@IC=4.0AdcCollectorEmitterSustainingVoltage@100mAdcVCEO(sus)=60Vdc(Min)TIP120,TIP125=80Vdc(Min)TIP121,TIP126=100Vdc(Min)TIP122,TIP127LowCollectorEmitterSaturationVoltageVCE(sat)=2.0Vdc(Max)@IC=3.0Adc=4.0Vdc(Max)@IC=5.0AdcMonolithicConstructionwithBuiltInBaseEmitterShuntResistorsPbFreePackagesareAvailable*TIP122ApplicationsAudioAmplifierAudioAmplifierStagesAudioPreamplifiersSwitchingLoadsUnder5ATIP122EnvironmentalandExportClassificationsAttributeDescriptionRoHSStatusRoHSnon-compliantMoistureSensitivityLevel(MSL)1(Unlimited)TIP122ParametersBaseProductNumberTIP122CategoryDiscreteSemiconductorProducts-Transistors-Bipolar(BJT)-SingleCollector-BaseVoltageVCBO100VConfigurationSingleCurrent-Collector(Ic)(Max)5ACurrent-CollectorCutoff(Max)500ADCCurrentGain(hFE)(Min)@Ic,Vce1000@3A,3VDescriptionTRANSNPNDARL100V5ATO220ABDetailedDescriptionBipolar(BJT)TransistorEmitter-BaseVoltageVEBO5VFactoryPackQuantity200Height9.4mmLength10.67mmManufacturerONSemiconductorManufacturerProductNumberTIP122MaximumCollectorCut-offCurrent200uAMaximumDCCollectorCurrent5AMaximumOperatingTemperature+150CMinimumOperatingTemperature-65CMountingStyleThroughHoleMountingTypeThroughHoleOperatingTemperature-65C~150C(TJ)PackagingBulkPartStatusObsoletePower-Max2WProductTypeDarlingtonTransistorsSeriesTIP122SubcategoryTransistorsTransistorTypeNPN-DarlingtonUnitWeight0.042329ozVceSaturation(Max)@Ib,Ic4V@20mA,5AVoltage-CollectorEmitterBreakdown(Max)100VWidth4.83mmWorkingofTIP122Thistransistorisrecognizedforitshighercurrentgainwhichis1000andhighercollectorcurrent5amperes,therefore,itisusuallyusedtoswitchThistransistorhaslessbaseandemitterVoltageofthemerely5VhenceforthcanbeeffortlesslyorganizedbyaLogicinstrumentsuchasamicrocontrollerThoughprecautionhastobeengagedtocheck,ifthelogicinstrumentscanfontupto120mA.ThoughTIP122hasextraordinarycurrentatcollectorandcurrentgain,itisimpartiallymodesttoswitchtheexpedientmeanwhileithasanEmitter-Basevoltage(VBE)oftheonly5VandIbofmerely120mA.HowtoSafelyLongRuninaCircuitTogetbetterperformancewiththisdarlingtiontransistorwesuggesttoalwaysstayingbelowitsmaximumratings.Donotoperateitincircuitsusingmorethan100V.Donotprovideloadmorethan5A.Alwaysuseasuitablebaseresistortoproviderequiredcurrentatitsbase.Useasuitableheatsinktosaveitfromoverheatinganddostoreoruseitintemperaturebelow-65centigradeandabove+150centigrade.DarlingtonCircuitSchematicWheretouseTIP122Thistransistorisknownforitshighcurrentgain(hfe=1000)andhighcollectorcurrent(IC=5A)henceitisnormallyusedtocontrolloadswithhighcurrentorinapplicationswherehighamplificationisrequired.ThistransistorhasalowBase-EmitterVoltageoftheonly5VhencecanbeeasilycontrolledbyaLogicdevicelikemicrocontrollers.Althoughcarehastobetakentocheckifthelogicdevicecansourceupto120mA.So,ifyoulookingforatransistorthatcouldbeeasilycontrolledbyaLogicdevicetoswitchhighpowerloadsortoamplifyhighcurrentthenthisTransistormightbeanidealchoiceforyourapplication.HowtouseTIP122AlthoughTIPhashighcollectorcurrentandcurrentgain,itisfairlysimpletocontrolthedevicesinceithasanEmitter-Basevoltage(VBE)ofonly5Vandbasecurrentofonly120mA.InthebelowcircuitIhaveusedtheTIP122tocontrola48Vmotorwhichhasacontinuouscurrentofabout3A.Thecontinuescollectorcurrentofthistransistoris5Aandourloadconsumesonly3Awhichisfine.Themaximumbasecurrentisabout120mA,butIhaveusedhighvalueof100ohmresistortolimititto42mA.Youcanuseevena1Kresistorifyourcollectorcurrentrequirementisless.Thepeak(pulse)currentofthistransistoris8Asomakesureyourmotordoesnotconsumemorethanthat.Thisisjustamodelcircuitdiagramthatshowstheworkingonthistransistoritcannotbeusedassuch.So,similarlyyoucancontrolyourloadinthesameway.TIP122ReplacementandEquivalentTIP132,TIP102,NTE261,NTE263,2N6045,2N6045G,2SD2495,BDT65B,2N6532,BDT63B,BDW43,TIP142T(PinconfigurationofsometransistorsmaydifferfromTIP122,checkpinconfigurationbeforereplacinginacircuit)TIP22isadarlingtionpairtransistormanufacturedinTO-220package,itsagoodtransistortouseasahighgainswitchoramplifier.ComplementofTIP122ThecomplementoftheTIP122transistorisTIP127.TIP122AlternativeNPNTransistorsBC547,BC548,BC549,BC636,BC639,2N2369,2N3055,2N3904,2N3906,2SC5200TIP122SameFamilyTransistorsNPNFamilytransistorsareTIP120,TIP121,TIP122,andPNPFamilyareTIP125,TIP126,TIP127(PNP)AdditionalResourcesAttributeDescriptionOtherNamesTIP122FSTIP122FS-NDTIP122FS-NDRTIP122OSFAQWhatisTIP122transistor?TIP122TransistorisanNPNDarlingtontransistor....TIP122Darlingtontransistorhasalotofgoodfeatures,like5Acollectorcurrent,maximumemitter-basevoltageis5V,maximumcollectordissipationis65watt,andsoon.Thistransistorismanufacturedtouseasaswitchandforamplificationpurposes.WhattypeofpackageisusedforTIP122transistor?TheTIP122isasiliconNPNDarlingtontransistorinaTO-220typepackagedesignedforgeneralpurposeamplifierandlow-speedswitchingapplications.HowdoyoutestatransistorTIP122?Harvino.Theproperwaytotestistosetyourdmmtodiodetest(usually2ksettingontheohmscale).Transistorshavethreelegs;anemitter,abase,andacollector.HowdoIknowifmytransistorisblown?Connectthebaseterminalofthetransistortotheterminalmarkedpositive(usuallycolouredred)onthemultimeter.Connecttheterminalmarkednegativeorcommon(usuallycolouredblack)tothecollectorandmeasuretheresistance.Itshouldreadopencircuit(thereshouldbeadeflectionforaPNPtransistor).Whatarethe3terminalsofatransistor?Abipolartransistorhasterminalslabeledbase,collector,andemitter.Asmallcurrentatthebaseterminal(thatis,flowingbetweenthebaseandtheemitter)cancontrolorswitchamuchlargercurrentbetweenthecollectorandemitterterminals.HowtomakeminiaudioamplifieruseTIP122/TIP127transistor?

IntroductionLM339(Quaddifferentialcomparator)consistoffourindependentvoltagecomparators.Itisacommonintegratedcircuitandismainlyusedinhigh-voltagedigitallogicgatecircuits.UsingLM339caneasilyformvariousvoltagecomparatorcircuitsandoscillatorcircuits.CatalogIntroductionCatalogICircuitofSingleLimitComparatorIIOverheatDetectionandProtectionCircuitIIIHysteresisComparatorIVOver-voltageDetectionCircuitVDoubleLimitComparatorVIUsingLM339toformanOscillatorFAQOrdering&QuantityICircuitofSingleLimitComparatorFigure(a)showsabasicsinglelimitcomparator.AddtheinputsignalUIN(i.e.voltagetobecompared)tothein-phaseinputterminal,andconnectareferencevoltageUrattheanti-phaseinputterminal.WhentheinputvoltageUinUr,theoutputishighlevelUOH.Figure(b)showsitstransmissioncharacteristics.Figure1.CircuitofSingleLimitComparatorIIOverheatDetectionandProtectionCircuitItispoweredbyasinglepowersupply.Afixedreferencevoltageisaddedtotheanti-phaseinputterminalof1/4LM339,anditsvaluedependsonR1andR2.UR=R2/(R1+R2)*UCC.Thevoltageatthein-phaseterminalisequaltothevoltagedropofthethermistorRT.Whenthetemperatureinsidethemachineisbelowthesetvalue,the+terminalvoltageisgreaterthanthe-terminalvoltage,andUoisahighpotential.Whenthetemperaturerisesabovethesetvalue,the-terminalvoltageisgreaterthanthe+terminal,andtheUooutputisatzeropotential,whichcausestheprotectioncircuittooperate.AdjustingthevalueofR1canchangethethresholdvoltage,whichsetsthetemperaturevalue.Figure2.OverheatDetectionandProtectionCircuitIIIHysteresisComparatorThehysteresiscomparatorcanalsoberegardedasasinglelimitcomparatorwithpositivefeedback.Inthesinglelimitcomparatordescribedabove,iftheinputsignalUinhasslightinterferencenearthethreshold,theoutputvoltagewillproducecorrespondingundulation.Thisshortcomingcanbeovercomebyintroducingpositivefeedbackintothecircuit..Figure(a)showsahysteresiscomparator.ThefamiliarSchmidtcircuitisacomparatorwithhysteresis.Figure(b)showsthetransmissioncharacteristicsofthehysteresiscomparator.Figure3.HysteresisComparatorItisnotdifficulttoseethatoncetheoutputstateischanged,theoutputvoltagewillbestableaslongastheinterferencenearthejumpvoltagevaluedoesnotexceedthevalueofU.Accordingly,itcomestoareductioninresolution.Forthehysteresiscomparator,itcantdistinguishtwoinputvoltageswhosedifferenceislessthanU.Thehysteresiscomparatorwithpositivefeedbackcanacceleratetheresponsespeedofthecomparator,whichisoneofitsadvantages.Inaddition,sincethepositivefeedbackaddedbythehysteresiscomparatorisverystrongandmuchstrongerthantheparasiticcouplinginthecircuit,thehystericcomparatorcanalsoavoidtheself-oscillationcausedbytheparasiticcouplingofthecircuit.IVOver-voltageDetectionCircuitFigure4showsthepartofover-voltagedetectioncircuitinaninductioncookercircuit.Whenthegridvoltageisnormal,1/4lm339u42.8v,thecomparatorturnsover.Theoutputis0VandBG1iscutoff.ThevoltageofU5iscompletelydeterminedbythepartialvoltagevalueofR1andR2,whichis2.7V.ItmakesU4largerthanU5,whichmakesthestateafteroverturningextremelystableandavoidstheinstabilitycausedbythesmallfluctuationofgridvoltageneartheover-voltagepoint.Duetocertainhysteresis,afterovervoltageprotection,theinductioncookerstartstoworkagainwhenthegridvoltagedropsto242-5=237vandU4U3.Figure4.Over-voltageDetectionCircuitVDoubleLimitComparatorThecircuitinFigure5consistsoftwoLM339toformawindowcomparator.WhenthecomparedsignalvoltageUinisbetweenthethresholdvoltages(UR1UinUR2),theoutputishighpotential(UO=UOH).WhenUinisnotbetweenthethresholdpotentialrange,(UinUR2orUinUR1)theoutputislowpotential(UO=UOL),andthewindowvoltageU=UR2-UR1.Itcanbeusedtojudgewhethertheinputsignalpotentialisbetweenthespecifiedthresholdpotential.Figure5.DoubleLimitComparatorVIUsingLM339toformanOscillatorFigure6showsthecircuitofanaudiosquarewaveoscillatorcomposedof1/4LM339.ChangingC1canchangethefrequencyoftheoutputsquarewave.Inthiscircuit,whenC1=0.1uF,f=53Hz;whenC1=0.01uF,f=530Hz;whenC1=0.001uF,f=5300Hz.LM339canalsoformahigh-voltagedigitallogicgatecircuit,andcandirectlyinterfacewithTTLandCMOScircuits.Figure6.LM339OscillatorFAQWhatisLM339?LM339isavoltagecomparatorICfromLMx39xseriesandismanufacturedbymanyindustries.Thedevicesconsistoffourindependentvoltagecomparatorsthataredesignedtooperatefromasinglepowersupply.WhatisthedifferencebetweenLM324andLM339?TheLM324hasacomplementaryoutputwhiletheLM339isopencollector.Inthecomplementaryoutput,currentcanflowineitherdirectionasrequired(eithersourceorsink)whiletheopencollectoroutputcanonlysinkcurrent.HowdoesLM339comparatorwork?TheLM339isaquadopampcomparator.Acomparatorworksbyasimpleconcept.Eachopampofacomparatorhas2inputs,ainvertinginputandanoninvertinginput.Iftheinvertinginputvoltageisgreaterthanthenoninvertinginput,thentheoutputisdrawntoground.Whatiscomparatoric?Acomparatorisanelectroniccircuit,whichcomparesthetwoinputsthatareappliedtoitandproducesanoutput.Theoutputvalueofthecomparatorindicateswhichoftheinputsisgreaterorlesser.Pleasenotethatcomparatorfallsundernon-linearapplicationsofICs.WhatisthereplacementforLM339?LM311,LM324,LM397,LM139,LM239,LM2901Whatisacomparatorcircuit?Acomparatorcircuitcomparestwovoltagesandoutputseithera1(thevoltageattheplusside;VDDintheillustration)ora0(thevoltageatthenegativeside)toindicatewhichislarger.Comparatorsareoftenused,forexample,tocheckwhetheraninputhasreachedsomepredeterminedvalue.WhatistheuseofLM339?LM339isusedinapplicationswhereacomparisonbetweentwovoltagesignalsisrequired.Inadditionwithfourofthosecomparatorsonboardthedevicecancomparefourpairsofvoltagesignalsatatimewhichcomesinhandyinsomeapplications.DescriptionULN2003AisaDarlingtontransistorarraywithhighvoltageandhighcurrent.ItconsistsofsevenNPNDarlingtonpairswithahighvoltageoutputandacommoncathodeclampdiodeforswitchinginductiveloads.CatalogDescriptionULN2003APinoutULN2003ADocumentsandMediaULN2003AECADModelULN2003AFeaturesULN2003AAdvantagesWheretouseULN2003HowtouseULN2003ULN2003AApplicationULN2003APackageInformationULN2003ARepresentativeSchematicDiagramProductManufacturerFAQOrdering&QuantityULN2003APinoutULN2003ADocumentsandMediaResourceTypeLinkDatasheetsULN2003A,ULQ2003AHTMLDatasheetULN2003A,ULQ2003AULN2003AECADModelULN2003ADR2GSymbolsULN2003ADR2GFootprintsULN2003AFeaturesTheULN2003isknownforitshigh-current,high-voltagecapacity.Thedriverscanbeparalleledforevenhighercurrentoutput.Evenfurther,stackingonechipontopofanother,bothelectricallyandphysically,hasbeendone.Generallyitcanalsobeusedforinterfacingwithasteppermotor,wherethemotorrequireshighratingswhichcannotbeprovidedbyotherinterfacingdevices.ULN2003Mainspecifications:500mAratedcollectorcurrent(singleoutput)50Voutput(thereisaversionthatsupports100Voutput)IncludesoutputflybackdiodesInputscompatiblewithTTLand5-VCMOSlogicULN2003AAdvantagesTheULN2003AisanarrayofsevenNPNDarlingtontransistorscapableof500mA,50Voutput.Itfeaturescommon-cathodeflybackdiodesforswitchinginductiveloads.ItcancomeinPDIP,SOIC,SOPorTSSOPpackaging.InthesamefamilyareULN2002A,ULN2004A,aswellasULQ2003AandULQ2004A,designedfordifferentlogicinputlevels.TheULN2003AisalsosimilartotheULN2001A(4inputs)andtheULN2801A,ULN2802A,ULN2803A,ULN2804AandULN2805A,onlydifferinginlogicinputlevels(TTL,CMOS,PMOS)andnumberofin/outputs(4/7/8).WheretouseULN2003ULN2003ICisoneofthemostcommonlyusedMotordriverIC.ThisICcomesinhandywhenweneedtodrivehighcurrentloadsusingdigitallogiccircuitslikeOp-maps,Timers,Gates,Arduino,PIC,ARMetc.Forexampleamotorthatrequires9Vand300mAtoruncannotbepoweredbyanArduinoI/OhenceweusethisICtosourceenoughcurrentandvoltagefortheload.ThisICiscommonlyusedtodriveRelaymodules,Motors,highcurrentLEDsandevenStepperMotors.Soifyouhaveanythingthatanythingmorethan5V80mAtowork,thenthisICwouldbetherightchoiceforyou.HowtouseULN2003TheULN2003isa16-pinIC.IthassevenDarlingtonPairsinside,whereeachcandriveloadsupto50Vand500mA.ForthesesevenDarlingtonPairswehavesevenInputandOutputPins.AddingtothatwecanagroundandCommonpin.Thegroundpin,asusualisgroundedandtheusageofCommonpinisoptional.ItmightbesurprisingtonotethatthisICdoesnothaveanyVcc(power)pin;thisisbecausethepowerrequiredforthetransistorstoworkwillbedrawnfromtheinputpinitself.ThebelowcircuitisasimplecircuitthatcanbeusedtotesttheworkingofULN2003IC.InthecircuitconsidertheLEDtobetheloadsandthelogicpins(bluecolor)asthepinsconnectedtotheDigitalcircuitorMicrocontrollerlikeArduino.NoticethatthePositivepinoftheLEDisconnectedtothepositiveloadvoltageandthenegativepinisconnectedtotheoutputpinoftheIC.ThisisbecausewhentheinputpinoftheICgetshightherespectiveoutputpinwillgetconnectedtoground.SowhenthenegativeterminaloftheLEDisgroundeditcompletesthecircuitandthusglows.Theloadsconnectedtotheoutputpincanbemaximumof50Cand500mAeach.Howeveryoucanrunhighercurrentloadsbuycombiningtwoormoreoutputpinstogather.Forexampleifyoucombinethreepinsyoucandriveupto(3*500mA)~1.5A.TheCOMpinisconnectedtogroundthroughaswitch,thisconnectionisoptional.Itcanbeusedatestswitch,meaningwhenthispinisgroundedalltheoutputpinswillbegrounded.ULN2003AApplicationTypicalusageoftheULN2003Aisindrivercircuitsforrelays,lampandLEDdisplays,steppermotors,logicbuffersandlinedrivers.AULN2003installedinabreakoutboardtobeusedasaunipolarsteppermotordriverwitha28BYJsteppermotorontheleft.ULN2003APackageInformationULN2003ARepresentativeSchematicDiagramProductManufacturerONSemiconductor(Nasdaq:ON)isdrivingenergyefficientinnovations,empoweringcustomerstoreduceglobalenergyuse.Thecompanyoffersacomprehensiveportfolioofenergyefficientpowerandsignalmanagement,logic,discreteandcustomsolutionstohelpdesignengineerssolvetheiruniquedesignchallengesinautomotive,communications,computing,consumer,industrial,LEDlighting,medical,military/aerospaceandpowersupplyapplications.ONSemiconductoroperatesaresponsive,reliable,world-classsupplychainandqualityprogram,andanetworkofmanufacturingfacilities,salesofficesanddesigncentersinkeymarketsthroughoutNorthAmerica,Europe,andtheAsiaPacificregions.FAQWhatistheuseofuln2003a?TypicalusageoftheULN2003Aisindrivercircuitsforrelays,lampandLEDdisplays,steppermotors,logicbuffersandlinedrivers.Whatisthefunctionofuln2003driverininterfacingofsteppermotor?Knownforitshighcurrentandhighvoltagecapacity,theULN2003givesahighercurrentgainthanasingletransistorandenablesthelowvoltageandlowcurrentoutputofamicrocontrollertodriveahighercurrentsteppermotor.WhatisaDarlingtonarray?Darlingtondevicesarehigh-voltage,high-currentswitcharrayscontainingmultipleopen-collectorDarlingtonpairsormultipleDarlingtontransistorswithcommonemitters,andintegralsuppressiondiodesforinductiveloads.HowtousetheULN2003ATransistorArraywithArduino?

I.DescriptionTheroleofanalog-to-digitalconversion(AD)istoconvertcontinuousanalogquantitiesintodiscretedigitalquantitiesthroughsampling.Itiswidelyusedincircuitdesign,suchasthedigitizationofanalogquantitiessuchasimage,voltage,andcurrent.ThefunctionoftheADchipistocompletetheanalog-to-digitalconversionfunction.TherearemanykindsofADchips.ThisarticletakesADC0804asanexampletoelaborateonthesoftwareandhardwaredesignmethodsoftheADconversioncircuit.CatalogI.DescriptionII.ADC0804IntroductionIII.CircuitConnectionDiagramIV.ADC08904TimingAnalysis4.1ADC08904StartConversionTimingAnalysis4.2ADC0804ReadDataTimingAnalysisV.ADC0804Analog-to-digitalConversionTestProgramVI.ConclusionFAQOrdering&QuantityII.ADC0804IntroductionADC0804isastep-by-stepcomparisonADconverter,usingCMOSmanufacturingprocess,20pins,8-bitresolution,theinputanalogvoltagerangeis0-5V,andthetypicalconversiontimeis100us.Thechipcontainsathree-statedataoutputlatch,whichcanbedirectlyhungonthedatabusofthemicrocontroller.III.CircuitConnectionDiagramFigure1CircuitconnectiondiagramThecircuitconnectiondiagramisshowninFigure1above,whichmainlyincludesAT89S52single-chipmicrocomputer,ADC0804and8light-emittingdiodes.The31-pinoftheone-chipcomputerisconnectedtohighlevel,thepurposeistomaketheone-chipcomputerstarttoexecutetheprogramfromtheinternalROMafterpower-on.ThefollowingfocusesontheperipheralcircuitdesignoftheADC0804chipandtheconnectionbetweenthecorrespondingpinsandthemicrocontroller.The20thpinofADC0804isconnectedto5Vforpoweringitself,andpin0isthepowerground.Pins11-18aretheconverteddigitalsignaloutputterminals,whicharerespectivelyconnectedtoP1.7-P1.0ofthesingle-chipmicrocomputerandconnectedtotheanodesof8light-emittingdiodes(LED1-LED8).Thefunctionofconnectingthelight-emittingdiodeistointuitivelytestthecorrectnessofthecircuitdesignandprogrammingbyobservingthechangeofitson-offstate.Thedetailswillbegivenlater.Pin1CSisthechipselectionterminal,connectedtopinP3.5ofthemicrocontroller,andthelowlevelisactive.OnceCSisactive,ADC0804isreadytostartworkingimmediately.Pin2RDisthereadsignalinputterminal,connectedtopinP3.7ofthesingle-chipmicrocomputer,lowleveliseffective.3pinWRisthewritesignalinputterminal,connectedtothesingle-chipP3.6pin,thelowlevelisvalid,andtheWRisvalid,theADconversionisstartedimmediately.The19-pinCLKRistheexternalresistanceendoftheinternalclockgenerator.TheRCoscillatorcircuitisformedbya10Kresistoranda150pfcapacitor.Theoscillationsignaloutputbytheoscillatorcircuitisconnectedtothe4-pinCLKINastheclockpulseofADC0804.Thepulsefrequencyis1/(1.1R*C),ifthecapacitorisselectedtoomuch,theconversionratewillbeaffected.Pin5INTRistheinterruptsignaloutputterminal.Whenitoutputsalowlevel,itindicatestheendofanADconversionandpromptsthecontrollertodothecorrespondingprocessing.Thisarticledoesnotusetheinterruptmode,sothepinisleftfloating.6-pinVIN+and7-pinVIN-formapairofanalogdifferentialsignalinputterminals.Amongthem,pin6VIN+isconnectedtoanadjustableresistorthrougha10Kcurrentlimitingresistor.Byadjustingthesizeoftheadjustableresistor,avoltagebetween0-5Vcanbeobtained.Sincepin7VIN-isgrounded,thevoltageisItistheanaloginputvoltageofADC0804.ThetaskofADC0804istoconverttheanalogvoltageintoan8-bitdigitalquantity,therangeis0x00-0xFF.Pin9VREF/2isthereferencevoltageinputterminal.Thereferencevoltageis2.5V,whichisobtainedbydividingthe5Vvoltagethroughtwo1Kresistors.IV.ADC08904TimingAnalysis4.1ADC08904StartConversionTimingAnalysisFigure2ADC08904startconversiontimingdiagramAccordingtotheADC0804startconversiontimingdiagram(Figure2),itcanbeseenthattheADC0804startstheconversionthroughthefollowingseriesofprocesses:first,clearCS,thatis,changeCStolowlevel,afteraslightdelay,changeWRfromhighleveltolowlevel,andthenchangeWRtohighlevelafteraslightdelay,andtheADconversionisofficiallystarted.After1-8ADconversiontimeperiods,theanalog-to-digitalconversioniscompleted,andtheconversionresultisautomaticallystoredintheinternallatch.Atthesametime,theINTRinterruptoutputterminalbecomeslowleveltoinformtheMCUofthisADconversionjunction,andtheMCUthentakesoutthedatabyreadingforsubsequentprocessing.4.2ADC0804ReadDataTimingAnalysisFigure3ADC0804readdatatimingdiagramAccordingtotheADC0804readdatatimingdiagram(Figure3),itcanbeseenthattheADC0804readdataoperationneedstogothroughthefollowingseriesofprocesses:firstclearCS,thatis,CSbecomeslow,andafteraslightdelay,RDchangesfromhightohighLowlevel,afterTacctime,thedataonthedigitalsignaloutputterminal(digitalsignalafterA/Dconversion)canbestabilized.Atthistime,themicrocontrollercanreadthedataonthedigitalsignaloutputterminal,andthenpullRDtoahighlevel.V.ADC0804Analog-to-digitalConversionTestProgramThisarticlewritesacompleteADC0804analog-to-digitalconversiontestprogram,asshownbelow,andgivestheprogramfunctioncommentslinebyline.TheprogramiswrittenstrictlyinaccordancewiththeADC0804start-upconversiontimingandreaddatatiming.ItsfunctionistoobtaindifferentvoltagesbyadjustingtheadjustableresistorR2inFigure1.ThisvoltageisusedastheanaloginputofADC0804,whichisconvertedto8-bitdigitalquantitybyADC0804,anddrives8-bitlight-emittingdiodesrespectively.Differentvoltagesareconvertedintodifferentdigitalquantities,sothatthebrightnessofthe8-bitLEDisdifferent.Observingthisphenomenonindicatesthatthedesignoftheanalog-to-digitalconversioncircuitinthisarticleiscorrect.VI.ConclusionInthispaper,8051single-chipmicrocomputerisusedasthecontroller,theADC0804-basedanalog-to-digitalconversioncircuitisdesigned,theworkingprincipleofADC0804isdiscussed,andacompletetestprogramisgivenandannotated.Throughtesting,thecircuitcanworknormally,layingagoodfoundationforfurtherresearchinthefieldofcircuitdesigninthefuture.FAQWhatisadc0804?TheADC0804isacommonlyusedADCmodule,forprojectswereanexternalADCisrequired.Itisa20-pinSinglechannel8-bitADCmodule.MeaningitcanmeasureoneADCvaluefrom0Vto5Vandtheprecisionwhenvoltagereference(Vrefpin9)is+5Vis19.53mV(Stepsize).Whatisthedifferencebetweenadc0804andmax1112?ADC0804isusedforparallelADCandMAX1112isusedforserialADC.Whichpinoftheadc0804indicatesendofconversion?PIN-5Interrupt(INTR)ThispinautomaticallygoeslowwhenconversionisdonebyADC0804orwhendigitalequivalentofanaloginputisready.PIN-6Vin(+)connectinputanalogsensorpin/inputvoltagetothispin.WhatisADCandDAC?ADCstandsforAnalogtoDigitalConverter,whichconvertstheanalogsignalintothedigitalsignal.DACstandsforDigitaltoAnalogConverteranditconvertstheDigitalsignalintoananalogsignal.Whatistheresolutionof8bitADC?Forexample,anADCwitharesolutionof8bitscanencodeananaloginputtoonein256differentlevels(28=256).Thevaluescanrepresenttherangesfrom0to255(i.e.asunsignedintegers)orfrom128to127(i.e.assignedinteger),dependingontheapplication.IDescriptionThisblogintroducesatemperatureacquisitionandalarmsystembasedonAT89S52microcontrollerandDS18B20temperaturesensor.Here,wehavedescribedthefollowingindetail:schemedesign,componentselection,hardwarestructureandsoftwaredesign,etc.CatalogIDescriptionIIIntroduction2.1Introductiontotemperaturemeasurementsystem2.2IntroductiontoDS18B202.3DS18B20TemperaturemeasurementsystemIIISystemschemestructuredesignIVSelectionofmaincomponents4.1Processor4.2DigitaltemperaturesensorDS18B20VSystemhardwaredesign5.1Powermodule5.2Temperatureacquisitionmodule5.3Displaymodule5.4Alarmmodule5.5ButtonmoduleVISystemsoftwaredesign6.1Instructions6.2Initializationsequence6.3Buswritetiming6.4Busreadtiming6.5TemperatureacquisitionprogramVIIExperimentaltestVIIIConclusionFAQOrdering&QuantityIIIntroduction2.1IntroductiontotemperaturemeasurementsystemTemperaturemeasurementsystemsarewidelyusedinthefollowingfields:grainstorage;medicalcare;transportation;smarthomesandgreenhouses;powertelecommunicationsystems;Moreover,thesystemwithanalarmfunctioncanalsoreducetheriskoftemperatureaccidents.Atpresent,thetemperaturevaluescollectedbythetemperaturemeasuringdevicearestillmainlyanalogsignals.However,themicroprocessorcanonlyprocessdigitalsignals,andA/Dconversionisrequiredfirst.Thismakesthedevicestructurecomplexandlowprecision.However,theemergenceofdigitaltemperaturesensorscansolvethisproblem.2.2IntroductiontoDS18B20ThenewdigitaltemperaturesensorrepresentedbyDS18B20integratestemperatureacquisitionandA/Dconversiondirectlyoutputsdigitalsignalsandhasasimpleinterfacecircuitwiththesingle-chipmicrocomputer.DS18B20hasthefeaturesofasinglebus,smallsize,highresolution,stronganti-interference,etc.Ithasapplicationsinthemeasurementofhighwaysubgradetemperaturefieldandbearingtemperaturedetectioninfrozensoilareas.Moreover,thesensorhasaunique64-bitserialnumber,andmultipledevicescanbeconnectedtoasinglesignallinetoachievelong-distance,multi-pointdistributedtemperaturemeasurement.2.3DS18B20TemperaturemeasurementsystemThisbloguses51single-chipmicrocomputersastheprocessingcore,usesDS18B20toformatemperaturemeasurementmodule,plusabuttonmodule,adisplaymodule,andanalarmmodule,etc.,todesignadigitaltemperaturecollectionalarmsystemsuitableformultipleoccasions.Itisdesignedtorealizemultiplefunctionsofsynchronouscollection,display,alarm,andcontrolofspecifiedtemperature.ThetemperaturemeasurementalarmsystemhaspassedthesimulationtestofthePROTUSsimulationplatformandsuccessfullyverifieditsfunctionwiththecircuitboard.Thedevicerunsstably,withagoodtemperaturemeasurementeffectandsmallerror.IIISystemschemestructuredesignThesystemincludesthefollowingparts:ThecoreAT89S52microcontrolleranditsperipheralcircuits;Temperaturemeasurementmodule(DS18B20digitaltemperaturesensor);Powermodule;Displaymodule(drivecircuit,multi-digitLEDdigitaltube);Buttonmodule;Alarmmodule(buzzer;LEDlight-emittingdiode).WecantakealookatdetailsshowninFigure1.Figure1.BlockDiagramoftemperaturemeasurementsystemWhenweusetheDS18B20intelligenttemperaturesensor,itoutputsdigitalsignalswithoutprocessingandconversion.AslongasthereadandwriteasequenceofDS18B20isstrictlyfollowed,thereal-timetemperaturecanbeaccuratelyread.Eventhoughthesystemhashighprecisionandrelativelycomplicatedprocedures,thecircuitissimpleandsmall,whichisconducivetotheintelligentizationandlightweightofthesystem.WithmultipleDS18B20sconnectedtoasinglebus,themicrocomputercancommunicatewithmultipleDS18B20swithonlyonedataline.Inthisway,itcanalsomeettherequirementsofmulti-pointtemperaturemeasurement.IVSelectionofmaincomponents4.1ProcessorThesystemprocessorusesanAT89S52single-chipmicrocomputer.AT89S52isahigh-performance,low-power8-bitCMOSmicroprocessorfromAt-mel.Its8KsystemprogrammableFLASHmemorymakesitsdownloadcircuitsimpleandcanrealizeonlineprogramminginserialandparallelmode.Thereare316-bittimer/countersinsidetheAT89S52chip,1full-duplexserialport,4I/Oports,and256bytesRAM,whichisconvenientforprogramdebugging.4.2DigitaltemperaturesensorDS18B20TheDS18B20temperaturesensorisaone-linesmartdigitaltemperaturesensorproducedbyDALLASSemiconductor.Inaddition,DS18B20isalsotheworldsfirsttemperaturesensorsupportingasingle-wirebusinterface.Ithasthecharacteristicsoflongtransmissiondistance,smallsize,andsimpleinterface.TheDS18B20ismainlycomposedofthefollowingcomponents:Temperaturesensor,configurationregister;64-bitROM;HighandlowalarmtriggersTHandTL.Amongthem,lithographyROMisthekeytorealizingmulti-pointtemperaturemeasurement.Afterthetemperaturemeasurementisconverted,itisoutputintheformof16-bitsign-extendedtwoscomplementandstoredintheDS18B2028-bitRAMs.VSystemhardwaredesignThehardwarecircuitofthesystemismainlycomposedofthefollowing5modules:Temperaturemeasurementmodule,powersupplymodule,displaymodule,alarmmoduleandbuttonmodule.TheoverallcircuitschematicdiagramisshownasinFig.2.AT89S52single-chipmicrocomputerisconnectedtoa11.0592MHzcrystaloscillatorcircuittoprovideanexternalclock,andtheresetterminalRESETisconnectedtothewatchdogcircuittoformaminimalsingle-chipsystem.Thesystemcanachievethefollowingfunctions:DS18B20collectstemperature,andthemicrocontrollerisresponsibleforthecommunicationandcontrolofthesensor;Thedisplaymoduledisplaystheprocessedtemperaturevalueinrealtime;Thealarmmodulemonitorsthetemperaturerange.Whenthetemperatureexceedstheupperandlowerlimits,LEDdiodesandbuzzersareusedtogeneratealarmsignalstoreminduserstotakemeasures;Thebuttonmodulesetsthealarmvalueasrequiredtoimprovethepracticality.5.1PowermoduleThecircuituses+5Vworkingvoltagetosupplypowerforthesingle-chip,acquisition,andalarmcircuits.Inaddition,anindependentpowermoduleneedstobeaddedduringhardwareproduction.5.2TemperatureacquisitionmoduleDS18B20utilizesthecharacteristicofasinglebusline,connectsthetemperatureoutputendDQandP0.3mouththrougha4.7kpull-upresistor.Thesingle-chipmicrocomputerinitializesthesensorandcompletesthetemperaturecollectionthroughthewire.TheGNDofthesensorisgrounded,andVDDcanbepoweredbyadatalineoranexternalpowersupply.Inordertoimprovetheanti-interferenceability,thisdesignusesanexternalpowersupplymode.Figure2.Hardwarecircuitstructure5.3DisplaymoduleInordertosavethehardwareinterface,adynamicscanningdisplayschemeisadopted.Dynamicscanningisacyclicshiftmethodthatusesthepersistenceofthehumaneyetoachievetheeffectofcontinuousdisplay.Thisdesignusesa6-digit8-segmentcommoncathodedigitaltubewithadecimalpointtodisplaythetemperaturevalue.Amongthem,thefirstdigitisthepositiveandnegativesigndigit,thesecond,third,fourth,andfifthdigitsrespectivelydisplaythehundreds,tens,onesanddecimalplacesofthetemperature,andthelastdigitdisplaysthetemperatureunit℃.TheP2portofthesingle-chipmicrocomputer(P2.0~P2.7total8bitscorrespondingto8fields)isconnectedwiththesegmentselectioncommonsignallineofthenixietubethroughthedriverchip74LS245.P3.0~P3.5ofP3portareconnectedwiththebitselectionsignallineofthedigitaltubetorealizebitselectioncontrol.5.4AlarmmoduleInordertoincreasethesafetyfactor,thealarmcircuitadoptsanalarmmethodwithsoundandlightdoubleguarantee.Thisincludesabuzzerand2LEDsofdifferentcolors.Thecollectedtemperatureisconstantlycomparedwiththesettemperaturethreshold:Whenthetemperatureishigherthantheupperlimitthreshold,thebuzzerofportP3.7sendsoutahigh-frequencyalarmsignal,andtheredLEDlightofportP0.6islitatthesametimetogivehightemperaturealarm.Whenthetemperatureislowerthanthelowerlimitthreshold,thebuzzersendsoutalow-frequencyalarmsignal,andatthesametimelightsuptheblueLEDlightofportP0.7togivealow-temperaturealarm.5.5ButtonmoduleWecanrealizehuman-computerinteractionthroughbuttons,adjustthetemperaturethreshold,andmakethesystemsuitableformoreoccasions.Thismoduleiscomposedoftwoparts,onepartisthecontrolbutton(K1~K4),theotherpartistheindicatorlight,whichoccupiestheportP1.0~P1.5ofthesingle-chipmicrocomputer.Fordetails,wecanseeFigure3below.WhenK1ispressed,theredlightison,indicatingthattheupperlimitsettingstateisentered,andthetemperatureisadjustedthroughthebuttonsK2(+)andK3(-).Atthesametime,thedisplaymoduledisplaysthetemperaturevaluesettingsynchronously.Aftertheadjustmentiscompleted,pressK1againtoexit.Thelowerlimittemperaturevalueadjustment(K4)processisconsistentwiththeupperlimit.VISystemsoftwaredesignTheDS18B20hardwarecircuitissimple,andrelativelycomplicatedsoftwaredesignmustbeusedtoprovidereasonablelogictimingtoensurereliableandaccuratework.DS18B20mainlyincludes3kindsofoperations:initialization,busread,andbuswrite.Thesethreeoperationsmuststrictlyfollowthetimingrequirements.Inthefollowing,wewillconductanin-depthanalysisofthesethreeaspects.6.1InstructionsAccordingtothecommunicationprotocolofDS18B20,thesensormustusetheROMinstructionandmemoryRAMinstructionprovidedbyittooperate.Andthesetwokindsofinstructionsappearintheprograminthehexadecimalformof8bitwordlength.CommonlyusedcodesandspecificmeaningsareshowninTable1andTable2.Eachtemperatureconversiongenerallygoesthroughthreesteps:resetoperation,sendROMcommand,sendRAMcommand,andthenreadthetemperature.6.2InitializationsequenceInitializationisoneofthebasicoperationsatthebottomoftheDS18B20,whichisequivalenttoestablishingacommunicationbridgebetweenthemicrocontrollerandthesensortoprepareforthesubsequentoperations.TheinitializationpulseincludestheresetpulsesentbytheCPUandtheresponsepulsesentbythesensor.TheinitializationpulsesequenceisshowninFigure3.Figure3.DS18B20initializationsequenceThehostfirstsendsoutaresetpulse(low-levelsignal)of480-960sandthenreleasesthebustoenterthereceivingmode(RX).WhenDS18B20detectstherisingedgewhenthebusisreleased,itwaitsfor15-60s,andthensendsoutalow-levelresponsepulsewithadelayof60-240s.Atthistime,theDQofthesensorissetto1,andthehostisalsosetto1,andtheinitializationprocessiscompleted.Atthistime,thesensorisinastatewhereitcanbereadandwritten6.3BuswritetimingWritingdatatoDS18B20isthebasicoperationofsendinginstructionsanddata.Therightshiftoperationisusedtorealizebit-by-bitwritingwithlowbitinfrontandhighbitinback.Itmainlyincludestwotimings:writing0andwriting1.Thewritesequencestartswhenthehostpullsdownthebusformorethan1s,andsendsthesignaltobesenttotheDQwithin15s,waitingforthesensortosampleit,andthesensorcompletesthedatacollectionwithin45s.Duringdatacollection,ifthebusishigh,writelogic1;otherwise,writelogic0.ItcanbeseenfromthewritesequenceinFigure4thatonewritecyclerequiresatleast60s,andtheremustbeanintervalgreaterthan1sbetweentwowritecycles.Figure4.WritetimesequenceofDS18B206.4BuswritetimingWritingdatatoDS18B20isthebasicoperationofsendinginstructionsanddata.Therightshiftoperationisusedtorealizebit-by-bitwritingwithlowbitinfrontandhighbitinback.Itmainlyincludestwotimings:writing0andwriting1.Thewritesequencestartswhenthehostpullsdownthebusformorethan1s,andsendsthesignaltobesenttotheDQwithin15s,waitingforthesensortosampleit,andthesensorcompletesthedatacollectionwithin45s.Duringdatacollection,ifthebusishigh,writelogic1;otherwise,writelogic0.ItcanbeseenfromthewritesequenceinFigure4thatonewritecyclerequiresatleast60s,andtheremustbeanintervalgreaterthan1sbetweentwowritecycles.Figure5.ReadtimesequenceofDS18B206.5TemperatureacquisitionprogramTakethetemperatureacquisitionprogramasanexampletobrieflyexplainthesourcecode:VoidConvert_18B20(Void){RST_18B20();WR_18B20(0xcc);WR_18B20(0x44);}IntRead_18B20(Void){RST_18B20();WR_18B20(0xcc);WR_18B20(0xbe);Temp_8[0]=RD_18B20;Temp_8[1]=RD_18B20;return(Temp_8);}VIIExperimentaltestThetesttemperaturevalueisshowninTable3.Thesystemerrorislessthan0.5,andthetestresultsshowthatthesystemhashighaccuracyandstrongpracticability.VIIIConclusionThisarticledesignsatemperatureacquisitionalarmsystembasedonAT89S52single-chipmicrocomputerandDS18B20digitaltemperaturesensor,anddetailsthesoftwareandhardwaredesign.Thedesignhastheadvantagesofsimplestructure,highprecisionandgoodstability,andissuitableforthefollowingfields:granary,electricmachineroom,bearing,airconditioner,refrigerator,industryandagriculture,etc.TheDS18B20singlebusandmulti-pointtemperaturemeasurementfeaturestrengthensitsscalabilityandhasabroadmarketprospect.FAQWhatisDS18B20temperaturesensor?TheDS18B20isa1-wireprogrammabletemperaturesensorfrommaximintegrated.Itiswidelyusedtomeasuretemperatureinhardenvironmentslikeinchemicalsolutions,minesorsoiletc.Theconstrictionofthesensorisruggedandalsocanbepurchasedwithawaterproofoptionmakingthemountingprocesseasy.HowdoestheDS18B20work?Itworksontheprincipleofdirectconversionoftemperatureintoadigitalvalue.IsDS18B20athermistor?Athermistorisathermalresistor-aresistorthatchangesitsresistancewithtemperature....Thermistorshavesomebenefitsoverotherkindsoftemperaturesensorssuchasanalogoutputchips(LM35/TMP36)ordigitaltemperaturesensorchips(DS18B20)orthermocouples.HowaccurateisDS18B20?TheDS18B20readswithanaccuracyof0.5Cfrom-10Cto+85Cand2Caccuracyfrom-55Cto+125C.Whatisds1820?TheDS18B20isonetypeoftemperaturesensoranditsupplies9-bitto12-bitreadingsoftemperature....Thecommunicationofthissensorcanbedonethroughaone-wirebusprotocolwhichusesonedatalinetocommunicatewithaninnermicroprocessor.HowdoIconnectmyDS18B20tomyRaspberryPi?OnceyouveconnectedtheDS18B20,powerupyourPiandlogin,thenfollowthesestepstoenabletheOne-Wireinterface:1.Atthecommandprompt,entersudonano/boot/config.txt,thenaddthistothebottomofthefile:2.dtoverlay=w1-gpio.3.ExitNano,andrebootthePiwithsudoreboot.WhatistheworkingprincipleofDS18B20?TheDS18B20DigitalThermometerprovides9to12-bit(configurable)temperaturereadingswhichindicatethetemperatureofthedevice.Itcommunicatesovera1-Wirebusthatbydefinitionrequiresonlyonedataline(andground)forcommunicationwithacentralmicroprocessor.Inadditionitcanderivepowerdirectlyfromthedataline(parasitepower),eliminatingtheneedforanexternalpowersupply.ThecorefunctionalityoftheDS18B20isitsdirect-to-digitaltemperaturesensor.Theresolutionofthetemperaturesensorisuser-configurableto9,10,11,or12bits,correspondingtoincrementsof0.5C,0.25C,0.125C,and0.0625C,respectively.Thedefaultresolutionatpower-upis12-bit.WheretouseDS18B20Sensor?TheDS18B20isa1-wireprogrammableTemperaturesensorfrommaximintegrated.Itiswidelyusedtomeasuretemperatureinhardenvironmentslikeinchemicalsolutions,minesorsoiletc.Theconstrictionofthesensorisruggedandalsocanbepurchasedwithawaterproofoptionmakingthemountingprocesseasy.Itcanmeasureawiderangeoftemperaturefrom-55Cto+125withadecentaccuracyof5C.EachsensorhasauniqueaddressandrequiresonlyonepinoftheMCUtotransferdatasoitaverygoodchoiceformeasuringtemperatureatmultiplepointswithoutcompromisingmuchofyourdigitalpinsonthemicrocontroller.HowconnectDS18B20toArduino?FirstplugthesensoronthebreadboardtheconnectitspinstotheArduinousingthejumpersinthefollowingorder:pin1toGND;pin2toanydigitalpin(pin2inourcase);pin3to+5Vor+3.3V,attheendputthepull-upresistor.OnanATMega328P,whyisaDS18B20temperaturesensorreturningincorrecttemperaturevalues?Severalpossibilities:1.Ifitisjustreadingalittlehigh,itmightbecausedbyselfheating.Addaheatsinkand/ormakemeasurementslessfrequently.2.Especiallyifthevaluesarereallywhacky,itmightbecodewitherrorsormis-wiring.Useapublishedsketchtocheckoperation.3.TheDS18B20mightbedefective.Tryanother.4.Itsaccurateto0.5C.Areyouexpectingittobemoreaccurate(likedowntotheLSBofthereadvalue)?

IDescriptionSometimes,ifyoucanusetheinexpensiveLM386anduseittomakeastereopoweramplifier,theeffectshouldbeconsideredideal.Here,thisblogwillintroducethemethodsandexperienceofusingLM386tomakeamicrocomputerstereopoweramplifier.CatalogIDescriptionIIIntroduction2.1LM386schematic2.2HowtouseLM386IIIInstallationandcommissioningOrdering&QuantityIIIntroduction2.1LM386schematicLM386isalow-powerhigh-gainpoweramplifiercircuit.ItsencapsulationformisshownasinFig.1.Figure1.LM386PinoutBecausetheaudiosignalamplitudeofthelineoutputofthesoundcardislarge,itcandrivetheLM386andthenthespeaker.AndbecauseitwillbeinterferedbythevideosignalwhenplayingVCD,itisnotgoodtofollowthetypicalcircuitconnection.Atthistime,weneedtoaddsomecomponentsanddebugcomponentvalues.TheschematicdiagramofLM386isshownasinFig.2.Figure2.LM386SchematicLM386pinfunctionsareasfollows:LM386hastwoinputterminals:non-invertinginputterminal3thpinandinvertinginputterminal2thpin.Theinputsignalcanbeinputfromanyend,theotherinputendisgrounded,theinputendisconnectedinparallelwiththecapacitorC4,thepurposeistofilteroutthevideointerferencewhenplayingVCD.Thevaluecanbeincreasedappropriately,butitcanbewithorwithoutC4whenplayingCD.Pins1and8arethegaincontrolterminals,andthegaincontrolnetworkiscomposedofC2andW2.Thesmallertheresistance,thehigherthegain.Figure2SchematicdiagramW2ismoreappropriatetoadjustthegaintoabout150,andthegainistoohightocauseself-excitation;Connecta10capacitortopin7toavoidself-excitationwhenthegainistoohigh;R2andC6formahigh-frequencycomponentattenuationcircuittoeliminatethecracksoundfromthespeaker.Amongthem,thesizeoftheC6capacityisadjustedaccordingtotheactualeffect;A0.1capacitorisconnectedtothe6thpintogroundtofilterandeliminatethestatichumoftheamplifier;The5thpinisconnectedtothecouplingcapacitorC3.Ifonlyoneconespeakerisconnectedtoonechannel(theauthorusesaconespeakerwithadiameterof120mm,impedance8ohms,andoutputpowerof1W),theC3capacitycannotexceed470.Otherwise,thespeakerwillbeblockedwhenplayinglowmusic.Ifthehighandlowfrequencycrossovertechnologyisadopted,theC3capacitycanbeincreasedtofullyreflectthebass.W1isusedtoadjusttheoutputvolume,whichisespeciallyconvenientwhenplayinggamesorlisteningtoCDs;theworkingvoltageis10volts,andabridgerectifierfiltercircuitcanbemadebyyourself.2.2HowtouseLM386LM386isanaudiopoweramplifierICwidelyusedinelectronicproductsandhomeamateurproduction.ItstypicalapplicationcircuitisshownasinFig.3.Figure3.LM386CircuitSo,howshouldweuseLM386correctly?1.Self-excitedhowlingcausedbyexcessiveinputsignal.Forthehowlingcausedbytheexcessiveinputsignal,aresistance-capacitancenetworkcanbeaddedbetweenthe1and8pinsofLM386.Inbatchapplication,theresistanceofRcanbedeterminedbyexperiments,orRcanbereplacedbyatrimmingpotentiometerW.Ifthesignalisstilltoostrong,LM386pins1and8canbesuspended.2.Highfrequencyself-excitation.Theprincipleofanti-highfrequencyself-excitationcircuitisshowninFigure4.Forhowlingcausedbyhigh-frequencyself-excitation,a4700pF~0.22Fceramiccapacitorcanbeconnectedbetweenthesignalinputterminalandtheground,anda1000~4700pFcapacitorcanbeconnectedbetweenthe8thpinandtheground.Whenmakingsingle-endedinput,theidleinputterminalshouldnotbegrounded.Figure4.LM386Circuit3.Lowfrequencyself-excitation.Forhowlingcausedbylow-frequencyself-excitation,youcantrytoconnecta68~22kresistorbetweentheinputterminalandtheground,increasethefiltercapacitorofpin8to1000F,andmaketheLM386ascloseaspossibletotheoutputterminalofthepowersupplywhenmakingtheprintedboard..4.Whenusingotherbrandproducts(suchasGL386,KA386,etc.),someICswillaffectthesensitivityofhigh-frequencyaudio.A0.1Fceramiccapacitorcanbeconnectedbetweenits7thpinandground,anda0.1Fceramiccapacitorcanbeconnectedbetweenthe4thand6thpins(note:differentfromthe8thpintoground).IIIInstallationandcommissioningAccordingtotheschematicdiagramshowninFigure2,wecanmaketwoidenticalpoweramplifiercircuits,whicharecombinedtoformastereopoweramplifier.Becausetherearefewcomponents,itisbettertousedouble-coreshieldedwireswithoutmakingprintedcircuitboards.Then,connectthestereoplugtothetwoamplifiers,andusetheshieldwireasthegroundwire.Donotconnecttheamplifiertothesoundcardaftersoldering.Atthistime,weshouldfirstcheckthattheweldingiscorrectandthenturnonthepower,andthentapthetwoinputendsofthestereoplugwithmetaltweezers.Ifthetwospeakerscanknockoutnormally,itindicatesthattheamplifierisworkingproperly.Atthistime,afterturningoffthepoweroftheamplifierandthemicrocomputer,wecanconnectittothesoundcard.Theconnectionmethodistoinsertthestereoplugintothelineoutputjack(LineOut)ofthesoundcard.Finally,itisemphasizedthatyoushouldavoidunpluggingandpluggingthestereoplugwhenthepowerison(microcomputeroramplifier),orweldingthecircuitwhentheamplifierisconnectedtothesoundcard,soasnottodamagethecomputer.FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?FAQWhatisl293d?L293DICisadualH-bridgemotordriverIC.OneH-bridgeiscapabletodriveadcmotorinbidirectional.L293DICisacurrentenhancingICastheoutputfromthesensorisnotabletodrivemotorsitselfsoL293Disusedforthispurpose.Whichisbetterl293dvsl298n?L293DDriversOperatesat4.5Vto36VwhereasL298NcanbeOperatesatupto46V.Maximum600mACurrentcanbedrawnthroughbothchannelsofL293DwhereasL298NMotorDrivercandrawupto2Afrombothchannels.WhatistheuseofEnablepininl293d?L293DhasanenablefacilitywhichhelpsyouenabletheICoutputpins.Ifanenablepinissettologichigh,thenstateoftheinputsmatchthestateoftheoutputs.Ifyoupullthislow,thentheoutputswillbeturnedoffregardlessoftheinputstates.HowmanyDCmotorscanbecontrolledbyanICl293d?TheL293Disa16-pinMotorDriverICwhichcancontroluptotwoDCmotorssimultaneously,inanydirection.HowdoIconnectmyArduinotol293d?Connect5VtoEnable1,Vss,andVsontheL293D.Connectdigitaloutputpins(wereusing6and7)toinput1andinput2ontheL293D.ConnectyourArduinosGNDtobothGNDpinsonthesamesideoftheL293D.Finally,connectoutput1andoutput2oftheL293Dtoyourmotorpins.WhatisHbridgeinl293d?H-BridgeCircuit.AHbridgeisanelectroniccircuitthatallowsavoltagetobeappliedacrossaloadinanydirection.H-bridgecircuitsarefrequentlyusedinroboticsandmanyotherapplicationstoallowDCmotorstorunforwardbackward.WhatisthefunctionofHbridge?AnH-bridgeisanelectroniccircuitthatswitchesthepolarityofavoltageappliedtoaload.ThesecircuitsareoftenusedinroboticsandotherapplicationstoallowDCmotorstorunforwardsorbackwards.Whatisl293dmotordrivershield?L293DshieldisadriverboardbasedonL293IC,whichcandrive4DCmotorsand2stepperorServomotorsatthesametime.Eachchannelofthismodulehasthemaximumcurrentof1.2Aanddoesntworkifthevoltageismorethan25vorlessthan4.5v.HowdoIusethel293dmotordrivermodule?Connect5VtoEnable1,Vss,andVsontheL293D.Connectdigitaloutputpins(wereusing6and7)toinput1andinput2ontheL293D.ConnectyourArduinosGNDtobothGNDpinsonthesamesideoftheL293D.Whatisthedifferencebetweenl293dandl298n?L293isquadruplehalf-HdriverwhileL298isdualfull-Hdriver,i.e,inL293allfourinput-outputlinesareindependentwhileinL298,ahalfHdrivercannotbeusedindependently,onlyfullHdriverhastobeused....Hence,heatsinkisprovidedinL298.。how to read resistor

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