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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.

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.

IIntroductionInthisblog,wecomparetheLM339andLM339NproducedbyTI.Thecontentofcomparisonincludescomponentparameters,packaging,applicationareas,andtheircircuitdiagrams,etc.HopethisblogishelpfultothoseinterestedinLM339orLM339N.LM339NCatalogIIntroductionIIComponentDatasheetIIIDifferenceBetweenLM339andLM339NIVParametersVFeaturesVIApplicationsVIIPinoutFAQOrdering&QuantityIIComponentDatasheetComponentDatasheet1LM339NDatasheetComponentDatasheet2LM339DatasheetIIIDifferenceBetweenLM339andLM339N◾LM339Nisaquadvoltagecomparator.Itadoptsdualin-line14-pinpackage.Themaximumoperatingvoltageis18Vandthepowerconsumptionis265mW.Itisusedininductioncookersandotherproducts.◾LM339(Quaddifferentialcomparator)consistoffourindependentvoltagecomparators.Itisacommonintegratedcircuitandismainlyusedinhigh-voltagedigitallogicgatecircuits.LM339commonmoderangeisverylarge,from0vtothepowersupplyvoltage-1.5v;widesupplyvoltagerange:singlepowersupplyis2-36V;dualpowersupplyvoltageis1V~18V.IVParametersParametersLM339NLM339Numberofchannels(#)44OutputtypeOpen-collector,Open-drainOpen-collectorPropagationdelaytime(s)0.70.3Vs(Max)(V)3630Vs(Min)(V)22Vos(offsetvoltage@25C)(Max)(mV)55Iqperchannel(Typ)(mA)0.20.2Inputbiascurrent(+/-)(Max)(nA)25050Rail-to-railOutOutRatingCatalogCatalogOperatingtemperaturerange(C)0to700to70FeaturesStandardcomparatorStandardcomparatorVICR(Max)(V)3428.5VICR(Min)(V)00Approx.price(US$)1ku|0.241ku|0.05VFeaturesLM339NLM339WideSupplyVoltageRangeLM139/139ASeries2to36VDCor1to18VDCLM2901-N:2to36VDCor1to18VDCLM3302-N:2to28VDCor1to14VDCVeryLowSupplyCurrentDrain(0.8mA)IndependentofSupplyVoltageLowInputBiasingCurrent:25nALowInputOffsetCurrent:5nAOffsetVoltage:3mVInputCommon-ModeVoltageRangeIncludesGNDDifferentialInputVoltageRangeEqualtothePowerSupplyVoltageLowOutputSaturationVoltage:250mVat4mAOutputVoltageCompatibleWithTTL,DTL,ECL,MOS,andCMOSLogicSystemsWideSupplyRangesSingleSupply:2Vto36V(Testedto30VforNon-VDevicesand32VforV-SuffixDevices)DualSupplies:1Vto18V(Testedto15VforNon-VDevicesand16VforV-SuffixDevices)LowSupply-CurrentDrainIndependentofSupplyVoltage:0.8mA(Typical)LowInputBiasCurrent:25nA(Typical)LowInputOffsetCurrent:3nA(Typical)(LM139)LowInputOffsetVoltage:2mV(Typical)Common-ModeInputVoltageRangeIncludesGroundDifferentialInputVoltageRangeEqualtoMaximum-RatedSupplyVoltage:36VLowOutputSaturationVoltageOutputCompatibleWithTTL,MOS,andCMOSOnProductsComplianttoMIL-PRF-38535,AllParametersAreTestedUnlessOtherwiseNoted.OnAllOtherProducts,ProductionProcessingDoesNotNecessarilyIncludeTestingofAllParameters.VIApplicationsLM339NLM339High-PrecisionComparatorsReducedVOSDriftOvertemperatureEliminatesNeedforDualSuppliesAllowsSensingNearGNDCompatibleWithAllFormsofLogicPowerDrainSuitableforBatteryOperationIndustrialAutomotiveInfotainmentandClustersBodyControlModulesPowerSupervisionOscillatorsPeakDetectorsLogicVoltageTranslationVIIPinoutLM339andLM339NsharethesamepinoutdiagramFAQWhatisLM339?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.IDescriptionThisblogmainlydiscussesandsolvesthefollowingproblem:HowtouseLM339voltagecomparatortomakeareservoirwaterlevelgauge?Accordingtowaterlevel,thisdesignperformssignalprocessingandcontrolsthepotentialofmultiplevoltagecomparators,sotheoutputwillchangeaccordingly.Therefore,underitsdrive,LEDcannotonlyemitlight,butalsoachievetheeffectofindicatingthewaterlevel.Figure1.LM339CatalogIDescriptionIIIntroductionIIIWokingPrincipleIVDeviceselectionandComponentProduction4.1deviceselection4.2PartProductionVInstallationandDebugging5.1DetectionPart5.2DisplayPartVIConclusionFAQOrdering&QuantityIIIntroductionDuetoinsufficientwatersupplyinsomeresidentialareas,pumpworkersmustfirststorewaterinthereservoirandthensupplywaterinaregularmanner.Inthisway,thepumpworkermustknowthewaterlevelofthereservoiratanytimeinthepumproom.Inthepast,electrodessuchascopperrodsorstainlesssteelwereusedtodetectthewaterlevelofthepool.However,duetoelectriccorrosion,thefunctionoftheelectrodeislostsoonafteruse.Forthisreason,thisblogusesLM339voltagecomparatortomakewaterlevelgauge.Thisnotonlyeliminatesthepainofoftenchangingelectrodes,butalsosimpleandeasy.Howsimpleisit?Onlytwowiresneedtobeconnectedfromthereservoirtothepumproom.Aftermorethantwoyearsofoperation,itsperformancehasbeenstableandreliable,achievingtheexpectedresults.IIIWokingPrincipleThemaincircuitofthewaterlevelgaugeiscomposedof4LM339voltagecomparators.Thiskindofintegratedcircuithasthecharacteristicsofeasypurchase,lowprice,singlepowersupplyoperationandwidedifferentialrange.EachLM339has4independentvoltagecomparators(15inthisdesign).Aslongasthepotentialdifferencebetweenthepositiveandnegativeinputterminalsis10mV,theoutputterminalcanbereliablyswitchedfromonestatetoanother.Whenthepositiveinputterminalis10mVhigherthanthenegativeinputterminal,itsoutputterminalishigh;Whenthenegativeinputis10mVhigherthanthepositiveinput,itsoutputislow.Inaddition,LEDscanbedrivendirectly.ThenhowtomaketheoutputendofLM339havehighandlowlevelchanges?Inspecificuse,anappropriateresistanceisgenerallyaddedbetweentheoutputterminalandthepositivepowersupply.Thisresistoriscalledapull-upresistor.Thatis,whentheoutputterminalofLM339isinahighimpedancestate,thepotentialoftheoutputterminalispulledupbytheresistor.Figure2.BlockDiagramofWaterLevelGaugeTheprincipleblockdiagramofthedeviceisshowninFigure2.Thevoltagesignalmeasurementconsistsofareedswitchandavoltagedividerresistor.Theringmagnetssuspendedinthewaterareindifferentpositions.Duetotheprincipleofelectromagneticinduction,notonlythecorrespondingdryreedswitchnormallyopencontactsareclosed,butalsothecorrespondingvoltagedividerresistorisconnected.Therefore,thecircuitwillpickupdifferentvoltagesignals.Thepotentialofthenegativeinputterminalofthecomparatorisformedbyafixedvoltagedividerresistor.Themeasuredvoltagesignaliscomparedwiththesetpotential.TheresultofthisisthattheLEDdisplaysthewaterlevelwhendriven.Inaddition,analarmisissuedwhenthehighestwaterlevelisreachedtoremindthepumpertostopwaterinjectiontopreventwateroverflow.TheconcretecircuitisshownasinFig.3.Figure3.WaterLevelGaugeCircuitDiagramInFigure3,thepowersupplyis+12V,andthedepthofthepoolisdividedinto15segmentsfordisplay.Inthispicture:A1~A15arevoltagecomparatorscomposedofLM339;GK1~GK15aredryreedswitches,thenormallyopencontactisclosedwhentheringmagnetisclosetoacertaindryreedswitch;ThevoltagedividercircuitcomposedofresistorsR1toR15determinesthepotentialofthepositiveinputterminalofeachcomparator.ThevoltageofthepositiveinputterminalofLM339changesduetothedifferentpositionsofthemagneticsteel.ThevoltagedividercircuitcomposedofresistorsR01~R030determinesthepotentialofthenegativeinputterminalofeachcomparator.Thepotentialofeachnegativeinputterminalisfixedafterdetermination.Whenthemagneticsteelfloatingonthewatersurfaceisclosetoacertaindryreedswitch,duetothepartialpressureofR1,R2,,R15,thepositiveinputterminalsofthecomparatorsA1,A2,,A15havedifferentinputs.Afterthissignaliscomparedwiththepotentialsetatthenegativeinputofthecomparator,therewillbeacorrespondingoutput.FromFigure3,whenGK1pullsin,itisequivalenttoholdingthemagneticsteelfloatattheupperlimitwaterlevel.Thepositiveinputofeachcomparatorisequaltothegroundpotential,whichislowerthantheirnegativeinput.Therefore,theoutputterminalsarealllowlevel,sothatallLEDsarelit.Atthistime,theoutputofA1dropsfromhighleveltolowlevel,andNE555istriggeredthroughcapacitorC.NE555isconnectedasamonostablecircuit.Oncetriggered,its3pinwilloutputahighlevel,whichwilldrivethebuzzertoalarm.ItsdurationisdeterminedbytheRCcomponentsconnectedtothe6and7pins.WhenGK2isclosed,LED2~LED15shouldbeonandLED1shouldbeoff.Atthistime,thepotentialofthepositiveinputterminalofeachcomparatorishigherthanthepotentialofthenegativeinputterminalofA1andlowerthanthepotentialofthenegativeinputterminalofA2~A15,andsoon.IVDeviceselectionandComponentProduction4.1deviceselectiona.SetthenegativeinputpotentialofeachcomparatortoVsh.Thenegativeinputpotentialofeachcomparatorissetartificiallyaccordingtothenumberofsegmentsdividedintopowersupplyandwaterdepth.Becausethepooldepthhasbeendividedinto15segmentsfordisplay,startingfrom2.0V,thedifferencebetweeneachadjacentnegativeinputterminalis0.4V.AsshowninthefirstrowinTable1.b.Selecttheresistancebetweenthenegativeinputterminalofeachcomparatorandthepowersupply,thatis,thevoltagedividerresistanceR01=R03==R029=20k,settoR.c.CalculatethegroundresistanceR02,R04,...,R030,whichisRr.SupposetheresistanceofthenegativeinputterminaltogroundisRr,andthepotentialofeachnegativeinputterminalisVsh,accordingtocircuitdiagram3:(1)Fromthisformula:(2)Forexample,tomakethepotentialofthenegativeinputterminalofthevoltagecomparatorA1Vsh=2V,accordingtoequation(2),wecangetAsshowninthesecondrowandthefirstcolumninTable1.TheselectionoftheotherresistorsR04,R06,,R030canbecalculatedaccordingtotheaboveformula(theresultisatheoreticalvalue,seethedatashowninthesecondrowinTable1fordetails).d.DeterminethenominalresistanceRbfromRr.Infact,thenominalvalueofcommerciallyavailableresistorsisdifferentfromthiscalculatedvalue.Inspecificapplications,anominalresistanceRbwithasimilarresistancevaluecanbeselected.ThespecificvalueisshowninthethirdrowofTable1.e.DeterminethepotentialVofthenegativeinputterminalofeachcomparatorAbyRb.WhenthenominalvalueofresistanceRbisselected,usethefollowingformulatocheckthepotentialVgeneratedbythisresistance.(3)Thespecificpotentialvalueisshowninthe4throwofTable1,comparedwiththesetvalueinthe1strow,aslongasitdoesnotexceed0.1V.f.DeterminetheresistancesR1,R2,,R15ofthepositiveinputterminalsofeachcomparatorandsetthemasRzh.FirstfindR1,setthepositiveinputpotentialofeachcomparatorasVzh,whenGK1pullsin,itcanbeseenfromTable1that2VVzh2.4V,setVzh=2.2V,R=20k,accordingtoformula(3),itcanbelistedThesolutionisthatRzh=R14.5k.Thisresistanceisnotthenominalvalue.Chooseasimilarnominalvalueof4.8k.ThenfindtheotherresistancesR2,R3,,R15,whichcanallbecalculatedbythismethod.Theresultisthetheoreticalvalue,whichhasaslightdeviationinpractice.Aftercorrection,thevalueisshowninthefifthrowofTable1.Aftertheaboveparametersareselectedinthisway,itcanbeensuredthatwhenthewaterlevelinthepoolreachesthelowestlimitandthefloatholdingthemagneticsteelsinkstothelowestposition,themagneticsteelseparatesfromallthereedswitchesandtheLEDsareallextinguished;AndwhenthefirstreedswitchGK1isclosed(equivalenttothewaterlevelinthepoolreachesthehighestlimit,thefloatholdingthemagneticsteelrisestothehighestposition)LEDsareallon.Whenthefloatisatacertainpositioninthemiddle,thecorrespondingLEDandtheLEDsbelowareallon,andtheLEDaboveitisoff,toshowthewaterlevel.Aftertheabovecalculation,thespecificdatashowninTable1isobtained.4.2PartProductionItisnecessarytomeasuretheheightfromthelowestwaterlevelofthereservoirtothelimitwaterlevel,anddividethisheightinto15segments.Thedistanceofeachsegmentislessthan200mm,thisdistancecanensurethatthemagneticsteelcanalwaysattractanadjacentdryreedswitch,soastoavoiddisplaybreakpoints.Thatistopreventthemagneticsteelfromnotattractingtheupperdryreedpipeorthelowerdryreedpipeduringoperation,sothattheLEDdisplayisallextinguished,causingtheillusionofwaterlessness.FortheconnectionsofGK1,R1~GK15,R15,firstsolderthemtoasmallprintedcircuitboardwithawidthlessthanorequalto20mm,andthenusewirestoconnectthematadistanceoflessthanorequalto200mm,andencapsulatethemina25mmhardplastictube..Theupperandlowermouthsofthepipeshouldbetightlysealedtopreventwaterleakage.Thetubeiscoveredwitharing-shapedmagnet.Afterdroppinganon-ferromagneticheavyobjectonthelowerendofthehardplasticpipe,theplasticpipeisverticallysunkintothebottomofthereservoir.Aringfloatisplacedunderthemagneticsteelandissleevedonthetube,andtheupperendofthetubeisfixedontheobservationportabovethereservoir.Duetothefunctionofthefloat,themagneticsteelisalwayssuspendedonthewatersurface,risingandfallingwiththewatersurface.Notethattheplaneofthemagneticsteelshouldalwaysbeparalleltothewatersurface,andtheplasticpipeshouldbeverticaltothewatersurfacetopreventthemagneticsteelfrombeingstuckbyfrictionwiththepipewallwhenthewaterlevelrisesandfalls.VInstallationandDebuggingThewholedeviceconsistsoftwoparts:Itisadetectionpartcomposedofareedswitchandvariousvoltagedividers;ItisthesignalprocessingdisplaypartcomposedofLM339.5.1DetectionPartBeforeencapsulatingtheplastictube,putsomesilicagelinthetubetoabsorbthemoistureinthetubeandpreventthelineinthetubefromgettingdamp.Ifring-shapedmagneticsteelisusedasthedetectionelement,thereedpipeconnectedinseriesintheplastictubeshouldberealizedbytwostaggeredreedpipes.Accordingtotheelectromagneticinductiontheory,theanalysisofthemagneticfieldlinesofthemagneticsteelshowsthatthereareasmallsectionofmagneticfieldlinesparalleltotheplaneofthemagneticsteelattheupperandloweropeningsofthemagneticsteel.Whenthissectionisclosetothereedswitch,thedirectionofitsmagneticfieldlineisperpendiculartothedirectionofthereedofthereedswitch.Atthistime,althoughthereedswitchisveryclosetothemagneticsteel,thecontactisstillreleasedanddisconnected,whichwillmakealltheLEDsgoout.Iftwostaggeredreedpipesareusedinstead,theproblemcanbesolved,andthestaggereddistancecanbedeterminedinexperiments.5.2DisplayPartThewaterlevelofeachsegmentisdisplayedbygreen10LED,andthelimitwaterlevelisdisplayedbyeye-catchingredLED.IftheLEDsarearrangedneatlytogether,thewaterlevelinthepoolcanbeclearlyseenaccordingtotheonoroffoftheLEDs.Equippedwithabuzzer,itwillgivethepumpworkeraclearerreminder.Note:Fromthedetectorinthepooltothecircuitboardofthepumproom,itisbesttouseshieldedwiretopreventinterferencesignalsfromentering.Weshouldalsonotethatthepowersupplymustberegulated.Fugure4.lm339VIConclusionThenegativeinputpotentialofthevoltagecomparatorA1~A15composedofLM339shouldbesetaccordingtoacertainrule,andthepotentialintervalbetweeneachotherdependsonthedepthofthecell.Ifthewaterlevelisdeeper,theintervalcanbesmaller,andthenumberofsectionscanbeselectedmore.Thepotentialdifferencebetweenadjacentcomparatorsisgenerally0.4V.Ifthepotentialdifferenceislarge,theselectionoftheresistanceiseasy;ifthepotentialdifferenceissmall,becausethenominalvalueintervalofthegeneralresistanceislarge,itisnecessarytouseanadjustableresistortoadjustthepotential.Ofcourse,inthecaseofsmallintervals,thesmallestpotentialdifferencebetweeneachothershouldbegreaterthan10mV,otherwisetheinputcharacteristicsofLM339willnotbeabletodistinguishthepotentialbetweeneachother.Inaddition,thevoltageofthepowersupplyandthenominalvalueofeachresistancemustbeconsidered.Thismethodcanalsobeappliedtootherfields.Suchasmonitoringthewaterdepthofrivers,rivers,lakes,andbays,theoillevelofgasstations,andthedepthofwatertanksinwaterplants.FAQWhatisLM339?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.

LM5020

I.IntroductionThe74HC595isan8-bitserial-inorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.74HC595withthecharacteristicsofhighspeed,lowpowerconsumptionandsimpleoperation,canbeeasilyusedinMCUinterfacetodriveLEDoperation.ThisarticleintroducesthecircuitdesignofLEDdisplaydrivedby74HC595.CatalogI.IntroductionII.BasicDescription2.1LEDDisplay2.274HC595III.CircuitDesign3.1HardwareCircuit3.2DisplayDriverIV.ConclusionFAQOrdering&QuantityII.BasicDescription2.1LEDDisplayA7SegmentLEDDisplay,alsoknownasLEDdisplay,hasbeenwidelyusedinvariousinstrumentsbecauseofitslowprice,lowpowerconsumptionandreliableperformance.TherearemanytypesofLEDdriversonthemarket,andmostofthemhavemultiplefunctions,butthepriceiscorrespondinglyhigher.Ifusedinasimplesystemwithlowcost,itisnotonlyawasteofresources,butalsoincreasesthecostofproducts.Using74HC595chiptodriveLEDhasvariousdisadvantages.Highspeed,lowpowerconsumption,unlimitednumberofLEDs.ItcancontrolboththecommoncathodeLEDdisplayandthecommonanodeLEDdisplay.Thecircuitdesignedwith74HC595isnotonlysimple,butalsolowinpowerconsumptionandstrongindrivingability.Itisalowcostandflexibledesignscheme.2.274HC595The74HC595isan8-bitserial-in/serialorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.Boththeshiftandstorageregisterhaveseparateclocks.Thedevicefeaturesaserialinput(DS)andaserialoutput(Q7S)toenablecascadingandanasynchronousresetMRinput.ALOWonMRwillresettheshiftregister.DataisshiftedontheLOW-to-HIGHtransitionsoftheSHCPinput.ThedataintheshiftregisteristransferredtothestorageregisteronaLOW-to-HIGHtransitionoftheSTCPinput.Ifbothclocksareconnectedtogether,theshiftregisterwillalwaysbeoneclockpulseaheadofthestorageregister.Datainthestorageregisterappearsattheoutputwhenevertheoutputenableinput(OE)isLOW.AHIGHonOEcausestheoutputstoassumeahigh-impedanceOFF-state.OperationoftheOEinputdoesnotaffectthestateoftheregisters.Inputsincludeclampdiodes.ThisenablestheuseofcurrentlimitingresistorstointerfaceinputstovoltagesinexcessofVCC.Figure1.74HC595FunctionalDiagramFigure2.74HC595LogicSymbolIII.CircuitDesign3.1HardwareCircuitFigure3isadisplaypanelcircuitdesignedwithAT89C2051and74HC595interface.Figure3.CircuitofDisplayPanelTheP115,P116,andP117oftheP1portareusedtocontrolthedisplayoftheLED,andtheyareconnectedtotheSLCK,SCLKandSDApinsrespectively.Threedigitaltubesareusedtodisplaythevoltagevalue.Onthecircuitboard,LED3isonthefarleftandLED1isonthefarright.Whensendingdata,firstsendthedisplaycodeofLED3,andfinallysendthedisplaycodeofLED1.ThebrightnessoftheLEDiscontrolledbytheresistanceofPR1toPR3.2.2DisplayDriverUseDISP1,DISP2,andDISP3tostoredisplaydata.AftertheCPUinitializationiscomplete,calltheLRDISPsubroutinetocleartheregisterof74HC595.ThereisnoneedtocalltheclearsubroutinebeforecallingthedisplaysubroutineDISPLAY.Nowwritethetwosubroutinesasfollows.①CLRDISP:MOVR2,#24CLRBIT:CLRSCLKCLRCMOVSDA,type of transistorsCSETBSCLKDJNZR2,photonic integrated circuitsCLRBITRET②Display:CLRSLCKMOVR3,surface mount resistor code#3MOVR0,types of transistors#DISP3DISP1:MOVA,variable resistor symbols@R0MOVR2,smd resitor#8DISP2:CLRSCLKRLCAMOVSDA,CSETBSCLKDJNZR2,DISP2DECR0DJNZR3,DISP1SETBSLCKRETIV.ConclusionItcanbeseenfromtheaboveexamplesthattherearenocomplicatedtechnicalproblemsinthedesignofhardwareandsoftwarewhen74HC595isusedtodesignLEDdrivercircuit.Inaddition,74HC595canbeusednotonlytodriveLEDdisplays,butalsotodrivelight-emittingdiodes.Each74HC595candrive8LEDssimultaneously.Thissolutionisidealwhenthevolumerequirementsoftheproductarenothighandwanttoreducethecost.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.DescriptionLED,asthefirstbasicfunctiontobecompletedinMCUlearning,playsaveryimportantroleinMCUlearners,whichalsocalledmagiclampbyMCUlearners.IbelievethateveryoneseesmostandthesimplestLEDcircuitisthefigureshownbelow.Asshowninthefigure,notonlythecircuitissimple,butalsoitsoperationisverysimple.GiveselectricalleveltoI/OcorrespondingtoeightLEDs,andthecorrespondingLEDcanbeonoroff.Figure1.simpleLEDcircuitCatalogDescription74HC595Drives8BitsLEDSFAQOrdering&Quantity74HC595Drives8BitsLEDSButnotallLEDcircuitsaresosimple.Somecircuitswilluse74HC595chiptodrive8LEDsordrivethe8-bitdigitaltubesegmentcode,asshowninthefigurebelow.Figure2.74HC595drives8LEDsWhyisasimplecircuitsocomplicated?Thereasonisobvious.BeforetheeightLEDneedeightI/O,nowonlythreeI/OcandriveeightLED.Letsbrieflyintroduce74CH595anduseitsuccessfullytodriveeightLEDlights.The74HC595isan8-bitserial-inorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.Boththeshiftandstorageregisterhaveseparateclocks.Thedevicefeaturesaserialinput(DS)andaserialoutput(Q7S)toenablecascadingandanasynchronousresetMRinput.SIisitsserialdatainput.Q0toQ7aredataoutput.SCK,istheclockfortheshiftregister.The595isclock-drivenontherisingedge.Thismeansthatinordertoshiftbitsintotheshiftregister,theclockmustbeHIGH.Andbitsaretransferredinontherisingedgeoftheclock.RCK,isaveryimportantpin.WhendrivenHIGH,thecontentsofShiftRegisterarecopiedintotheStorage/LatchRegister;whichultimatelyshowsupattheoutput.Sothelatchpincanbeseenaslikethefinalstepintheprocesstoseeingourresultsattheoutput.SQHisserialdataoutput.Whatwewanttoachievenowistomovethe8-bitsdataofSIinto74HC595onebyoneundertheactionofSCKandRCKandpresenttheminparallelonQ0-Q7.Figure3.How74HC595ShiftRegisterworksWheneverweapplyaclockpulsetoa595,thebitsintheShiftRegistermoveonesteptotheleft.Belowisitscode.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.Whatisadigitaltube?Lightemittingdiodeconnectstheanodetogetherandthenconnectedtothepowerofpositiveiscalledcommonanodedigitaltube,lightemittingdiodeconnectedtothecathodeandthenconnectedtothepowerofthecathodeiscalledcommoncathodedigitaltube.Whatisthedifferencebetweenshiftregisterandcounter?Inashiftregister,theinputofelementNistheoutputofelementN-1,andallelementsusethesameclock.Inacounter,theinputofelementNistheinverseofitsoutput,andtheclockofelementN+1istheoutputofelementN.IDescriptionDoyouknowwhattheDigitalTubeDisplayneeds?Thedisplayofthedigitaltuberequiresadigitaltubeandacontrolcircuitofmultipledigitaltubes.Takethesingle-chipmicrocomputercontrolcircuitofan8-bitdigitaltubeasanexample.Thesingle-chipmicrocomputerneedstoprovidean8-bitsegmentcodeandan8-bitcode.Thus,weusuallychoosetwoofthefourparallelI/Oportsinthe51single-chipmicrocomputertoprovidesegmentcodesandbitcodesrespectively.Althoughthiscircuithardwareconnectionandsoftwareprogrammingarerelativelysimple,therearealsoproblems.Thatis:ToomanyI/Oportsareoccupied,whichaffectstheoveralluseofthemicrocontroller,andisnotconducivetotheaccessofotherdevices.Howtosolvethisproblem?Wecanuseatypeofshiftregisterforauxiliarycontrol.Here,thisblogusesthe74HC595chip.Figure1.74HC595CatalogIDescriptionIIIntroductionto74HC595III74HC595DisplayControlofMulti-digitDigitalTube3.1HardwareConnection3.2SoftwareProgramming3.3SimulationDebuggingIVConclusionFAQOrdering&QuantityIIIntroductionto74HC59574HC595isaCMOSshiftregisterwithopen-drainoutput.Theoutputportisacontrollablethree-stateoutput.Itcanalsocontrolthenext-levelcascadedchipserially.Itsstructureisusuallya16-pinDIPpackageorSOpackage.The74HC595pinoutisshowninFigure2,andthecorrespondingpinfunctionsareshowninTable1.Figure2.74HC595PinoutThemainfeaturesof74HC595are:8-bitserialinput/8-bitparallelorserialoutput;Three-stateoutputregister(three-stateoutput:agatecircuitwiththreeoutputstatesofhighlevel,lowlevelandhighimpedance);High-speedlow-powerconsumption,high-speedshiftclockfrequencyFmax25MHz.Table1.74HC595PinFunctionPinNumberPinNamePinFunction15,1~7Q0~Q7Paralleltri-stateoutputpin8GNDPowerground9Q7Serialdataoutputpin10/MRClearendofshiftregister(activelow)11SH_CPSerialdatainputclockline12ST_CPOutputmemorylatchclockline13/OEOutputenable(activelow)14DSSerialdatainputline16VCCPowerendIII74HC595DisplayControlofMulti-digitDigitalTubeHere,thisblogtakesthesingle-chipmicrocomputercontrolmulti-digitdigitaltubeasanexample.Tousethechipcorrectly,youmustfirstcorrectlyunderstandthetimingdiagramortruthtableofthechip.Thetruthtableof74HC595isshowninTable2.InputPinOutputPinDSSHCP/MRSTCP/OEHQ0~Q7outputhighimpedanceLQ0~Q7outputeffectivevalueLClearshiftregisterLRisingEdgeHShiftregisterstorelowlevelHRisingEdgeHShiftregisterstorehighlevelFallingEdgeHShiftregisterstateretentionRisingEdgeStatevalueinoutputshiftregisterFallingEdgeOutputmemorystateretentionItcanbefoundthattheserialdataisconnectedtotheDSpin,butitisonlyinputtotheshiftregisterwhenSH_CPisarisingedge,andentersthestorageregisterwhenST_CPisarisingedge.Ifthetwoclocksareconnectedtogether,theshiftregisterisalwaysonepulseearlierthanthestorageregister.Theshiftregisterhasaserialshiftinput(Ds),aserialoutput(Q7),andanasynchronouslow-levelreset.Thestorageregisterhasaparallel8-bit,three-statebusoutput.WhenOEisenabled(lowlevel),thedataofthestorageregisterisoutputtothebus.3.1HardwareConnectionSincethe8-bitdigitaltubeneedstoprovideatotalof16bitsofsegmentcodeandbitcodeatthesametime,itcannotberealizedbyusingone74HC595.Tosolvethisproblem,weusetwo595chipstocascadeseriallytoprovidean8-bitsegmentcode(providedbyU2)andan8-bitcode(providedbyU3).ThesimulationhardwarecircuitisshowninFigure3.Theinputsignalof595isconnectedtothethreeI/OportsofP2.0~P2.2respectively.Amongthem,P2.0providesserialinputsignals,P2.1andP2.2provideoutputandinputclocksignalsrespectively.Figure3.SimulationHardwareCircuitDiagram3.2SoftwareProgrammingHere,weuse2piecesof74HC595chipsforserialcascading.Therefore,youmustpayattentiontothesequenceofserialdataoutputwhenprogramming.Theusualpracticeisasfollows:First,writethedata(iebitcode)ofthe74HC595chipatthenextlevel;Then,writethedata(iesegmentcode)ofthefirst-level74HC595chip;Finally,releasetheparalleloutputpinstogetheratonce.Thesampleprogramisasfollows(partial):voidOneLed_Out(uchari,ucharLocation){ucharj;OutByte=Location;for(j=1;j=8;j++){DS=Bit_Out;SH_CP=0;SH_CP=1;SH_CP=0;OutByte=OutByte1;}OutByte=~Segment[i];for(j=1;j=8;j++){DS=Bit_Out;SH_CP=0;SH_CP=1;SH_CP=0;OutByte=OutByte1;}ST_CP=0;ST_CP=1;ST_CP=0;}3.3SimulationDebuggingWecandrawthehardwarecircuitdiagramontheProteus7platform,andthenwritethesoftwareprogramontheKeil4.0platformandcompileanddebugit.Then,loadthegeneratedHEXfileintothesimulationchipandrunthesimulation.Ifallgoeswell,theresultswillbedisplayedcorrectly.Accordingtothedisplayrequirements,itcanrealize8-bitdigitaltubeshiftdisplayor8-bitdigitaltubesimultaneousdisplay.ThesimulationresultsareshowninFigures4and5.Figure4.ShiftDisplayof8-bitDigitalTubeFigure5.SimultaneousDisplayof8-bitDigitalTubesIVConclusionThetestresultsofthisblogshowthattherearemanyadvantagestothedisplaycontrolofmulti-digitdigitaltubesthroughthecascadeof74HC595chips.Thesebenefitsaremainlyreflectedinthefollowingaspects:Itcangreatlyreducethedisplaycontrolofthesingle-chipdigitaltube;ItcangreatlyreducetheoccupancyoftheMCUI/Oportline;Thecircuitissimpleandeasytoprogram.Themethodintroducedinthisblog,whetheritistoconductsimulationteachingonacomputer,ortobuildactualhardwarecircuits.Ingeneral,Thecurrent74HC595chipiscost-effective,andthecostofbuildingacircuitislow,makingitverysuitableforgeneraluse.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.Whatisadigitaltube?Lightemittingdiodeconnectstheanodetogetherandthenconnectedtothepowerofpositiveiscalledcommonanodedigitaltube,lightemittingdiodeconnectedtothecathodeandthenconnectedtothepowerofthecathodeiscalledcommoncathodedigitaltube.Whatisthedifferencebetweenshiftregisterandcounter?Inashiftregister,theinputofelementNistheoutputofelementN-1,andallelementsusethesameclock.Inacounter,theinputofelementNistheinverseofitsoutput,andtheclockofelementN+1istheoutputofelementN.

LM5020

IDescriptionTheinstrumentationamplifiercircuithasthefollowingfeatures:HighInputImpedance;HighCommon-modeRejectionRatio;LowDrift;...Theabovefeaturesmakeitwidelyusedinfieldsofsmallsignalamplificationofsensoroutput.Thisblogwillintroduce4implementationoptionsofinstrumentationamplifiercircuits.These4optionsaredesignedbasedondifferentelectroniccomponents.Andtheyarealsoonthebasisofexplainingthecircuitstructureandprincipleoftheinstrumentamplifier.Theelectroniccomponentsdiscussedinthisbloginclude:LM741,OP07,LM324,AD620.Wewillsummarizefeaturesofthe4circuitthroughtesting,analysisandcomparison.Ibelievethisblogcanprovideacertainreferenceforcircuitdesignbeginners.WhatAreInstrumentationAmpilfiers?CatalogIDescriptionIIIntroduction2.1InstrumentationAmplifierOverview2.2InstrumentationAmplifierStuctureandPrincipleIIIInstrumentationAmplifierCircuitDesign3.1LM741CircuitOption3.2OP07CircuitOption3.3LM324CircuitOption3.4AD620CircuitOptionIVPerformanceTestandAnalysisFAQOrdering&QuantityIIIntroduction2.1InstrumentationAmplifierOverviewThesignalsinputbysmartmetersthroughsensorsgenerallyhavethecharacteristicsofsmallsignals:Thesignalamplitudeisverysmall(millivoltorevenmicrovoltmagnitude);Oftenaccompaniedbyloudnoise.Forsuchsignals,thefirststepofcircuitprocessingisusuallytoamplifysmallsignalswithaninstrumentationamplifier.Themainpurposeofamplificationisnottogain,buttoimprovethesignal-to-noiseratioofthecircuit.Atthesametime,fortheinstrumentationamplifiercircuit,thesmallertheinputsignalthatcanberesolved,thebetter;thewiderthedynamicrange,thebetter.Therefore,theperformanceoftheinstrumentationamplifiercircuitdirectlyaffectstherangeoftheinputsignalthatthesmartinstrumentcandetect.2.2InstrumentationAmplifierStuctureandPrincipleThetypicalstructureoftheinstrumentamplifiercircuitisshownasinFig.1.Itismainlycomposedoftwo-stagedifferentialamplifiercircuit.Figure1.StructureofInstrumentationAmplifierAmongthem,theoperationalamplifierA1,A2arein-phasedifferentialinputmodes.Non-invertinginputcangreatlyincreasetheinputimpedanceofthecircuit.Atthesametime,itcanalsoreducetheattenuationofweakinputsignalsbythecircuit;Differentialinputcanmakethecircuitonlyamplifythedifferentialmodesignal,andonlyfollowthecommonmodeinputsignal.Inthisway,theratiooftheamplitudeofthedifferentialmodesignaltothecommonmodesignal(ie,thecommonmoderejectionratioCMRR)senttothesubsequentstageisimproved.Inthisway,inthedifferentialamplifiercircuitcomposedofoperationalamplifierA3asthecorecomponent,undertheconditionthattheCMRRrequirementsremainunchanged,theaccuracymatchingrequirementsforresistorsR3andR4,RfandR5canbesignificantlyreduced.Asaresult,theinstrumentationamplifiercircuithasbettercommonmoderejectioncapabilitythanasimpledifferentialamplifiercircuit.UndertheconditionsofR1=R2,R3=R4,Rf=R5,thegainofthecircuitinFigure1is:G=(1+2R1/Rg)(Rf/R3)ItcanbeseenfromtheformulathattheadjustmentofthecircuitgaincanbeachievedbychangingtheRgresistance.IIIInstrumentationAmplifierCircuitDesignAtpresent,theimplementationmethodsofinstrumentationamplifiercircuitsaremainlydividedintotwocategories:Thefirstcategoryiscomposedofdiscretecomponents;Thesecondcategoryisdirectlyimplementedbyasingleintegratedchip.Intheblog,withsingleopampLM741andOP07,integratedfouropampLM324andmonolithicintegratedchipAD620asthemainelectroniccomponents,4kindsofinstrumentationamplifiercircuitoptionsaredesigned.3.1LM741CircuitOptionConsistsofthreegeneral-purposeoperationalamplifiersLM741toformathreeoperationalamplifierinstrumentamplifiercircuitform.Andsupplementedbyrelatedresistorperipheralcircuits.Atthesametime,addthebridgesignalinputcircuitofthenon-invertinginputterminalsofA1andA2,asshowninFigure2.Figure2.SingleOpAmpInstrumentationAmplifierA1~A3inFigure2canbereplacedwithLM741respectively.Theworkingprincipleofthecircuitisexactlythesameasthatofatypicalinstrumentationamplifiercircuit.3.2OP07CircuitOptionComposedof3precisionoperationalamplifiersOP07,thecircuitstructureandprinciplearethesameasinFig.2(3OP07sareusedtoreplaceA1~A3inFig.2respectively).3.3LM324CircuitOptionTakeafouroperationalamplifierintegratedcircuitLM324asthemaincomponent,asshowninFigure3.Itscharacteristicistointegrate4functionallyindependentoperationalamplifiersintothesameintegratedchip.WhataretheadvantagesofusingLM324?Thatis,itispossibletogreatlyreducethedifferenceindeviceperformanceofeachopampduetodifferentmanufacturingprocesses.Inaddition,theuseofaunifiedpowersupplyisconducivetothereductionofpowersupplynoiseandtheimprovementofcircuitperformanceindicators.Andthebasicworkingprincipleofthecircuitremainsunchanged.Figure3.LM324InstrumentationAmplifier3.4AD620CircuitOptionThecircuitconsistsofamonolithicintegratedchipAD620asthemainelectroniccomponents,asshowninFigure4.Itischaracterizedbyasimplecircuitstructure:anAD620,againsettingresistorRg,andaworkingpowersupply.Therefore,thedesignefficiencyisveryhigh.ThecircuitgaincalculationformulainFig.4is:G=49.4K/Rg+1.Figure4.AD620InstrumentationAmplifierIVPerformanceTestandAnalysisThefouroptionsoftheinstrumentationamplifiercircuitalladopttheformofabridgecircuitcomposedof4resistors,whichchangesthedouble-endeddifferentialinputintoasingle-endedsignalsourceinput.Theperformancetestismainlytocarryoutsimulationandactualcircuitperformancetestfromthefollowingaspects:1.ThemaximuminputofthesignalsourceVs;2.VsminimuminputofsignalsourceVs;3.Themaximumgainofthecircuit;4.Commonmoderejectionratio.ThetestdataareshowninTable1andTable2.Amongthem,themaximum(small)inputofVsreferstothemaximum(small)inputofthesignalsourcewhenthecircuitoutputisnotdistortedundergiventestconditions.Themaximumgainreferstothemaximumgainvalueofthecircuitthatcanbeachievedwhentheoutputisnotdistortedunderthegiventestconditions.ThecommonmoderejectionratioiscalculatedbytheformulaKCMRR=20|g|AVd/AVC|(dB).Note:fisthefrequencyofVsinputsignal;Thevoltagemeasurementdatainthetableareallexpressedbypeak-to-peakvalue;Duetothesimulationdevice,thesimulationofoption3withMultisimfailedintheexperiment,and-inTable1indicatesthefailuredata;Options1to4inthetablerespectivelyrepresenttheinstrumentationamplifiercircuitcomposedofLM741,OP07,LM324andAD620respectively.FromthemeasureddatainTable2,wecanseefromit:Foroption2,ithasthebestperformanceintermsofsignalinputrange(thatis,themaximumandminimuminputofVs),circuitgain,andcommon-moderejectionratio.Intermsofcomponentprice,itisalittlehigherthanthecostoftheLM741option1andtheLM324option3,butitismuchcheaperthantheAD620option4.Therefore,amongthefouroptions,option2ofOP07hasthehighestcostperformance.Foroption4,inadditiontoitsrelativelysmallmaximumgain,itsotherperformanceissecondonlytooption2.option4hastheadvantagesofsimplecircuit,superiorperformance,andsavingdesignspace.However,thehighcostisitsbiggestdisadvantage.Foroption1andoption3,thereislittledifferenceintheirperformance.option3isslightlybetterthanoption1,andtheyalsohaveabsolutepriceadvantages,buttheirperformanceisnotasgoodasoption2andoption4.Basedontheaboveanalysis,option2andoption4aresuitableforoccasionswithhigherperformancerequirementsforinstrumentamplifiercircuits.Amongthem:Option2ofOP07isthemostcost-effectiveOption4ofAD620issimpleandefficient,butthecostishigh.Option1ofLM741andOption3ofLM324aresuitableforoccasionswhereperformancerequirementsarenothighandcostsavingsareneeded.Accordingtospecificcircuitdesignrequirements,differentoptionsareselectedtoachieveoptimalresourceutilization.Figure5.InstrumentationAmplifierICInaddition,afterthecircuitdesignplanisdetermined,thefollowingaspectsshouldbepaidattentiontointhespecificcircuitdesignprocess:1.Payattentiontotheselectionofkeycomponents.Forexample,forthecircuitshowninFigure2,thereareafewthingstopayattentionto:MakethecharacteristicsofopampA1andA2asconsistentaspossible;Whenselectingresistors,resistorswithalowtemperaturecoefficientshouldbeusedtoobtainthelowestpossibledrift;TheselectionofR3,R4,R5andR6shouldmatchasmuchaspossible.2.Payattentiontoaddingvariousanti-interferencemeasuresinthecircuit.suchas:Thepowersupplydecouplingcapacitorshouldbeaddedatthelead-inendofthepowersupply;RClow-passfilteringshouldbeaddedtothesignalinputterminalorhigh-frequencynoisecancelingcapacitorsshouldbeaddedtothefeedbackloopoftheoperationalamplifierA1andA2;ThePCBdesignshouldbecarefullylaidoutandroutedreasonably,andgroundwiresshouldbehandledcorrectly.FAQWhatislm324?LM324isaQuadop-ampICintegratedwithfourop-ampspoweredbyacommonpowersupply.Thedifferentialinputvoltagerangecanbeequaltothatofpowersupplyvoltage....Generally,op-ampscanperformmathematicaloperations.Whichisthedifferencebetweenlm324andlm339?TheLM324hasacomplementaryoutputwhiletheLM339isopencollector.Inthecomplementaryoutput,currentcanflowineitherdirectionasrequired(eithersourceorsink)whiletheopencollectoroutputcanonlysinkcurrent.Whatisopampusefor?OperationalamplifiersarelineardevicesthathaveallthepropertiesrequiredfornearlyidealDCamplificationandarethereforeusedextensivelyinsignalconditioning,filteringortoperformmathematicaloperationssuchasadd,subtract,integrationanddifferentiation.Howdoesanopampwork?Whatislm324usedfor?LM324ICApplicationsTheapplicationsofICLM324includethefollowing.ByusingthisIC,theconventionalop-ampapplicationscanbeimplementedverysimply.ThisICcanbeusedasoscillators,rectifiers,amplifiers,comparatorsetc.I.IntroductionAsweallknow,theionnitridingprocessrequiresrelativelyhighcontrolofthepressureinsidethefurnace,sothispaperdesignsagasflowcontrollerbasedontheL298NchipdrivenDCmotorcontrol,whichcanbeusedtocontrolthegasflowofthereactor.Soletsfirstunderstandtheionnitridingtheory.CatalogI.IntroductionII.IonNitridingTheoryIII.SystemFlowandPressureMeasurementandControlBlockDiagramIV.L298NChipIntroductionV.ControllerPrincipleVI.ConclusionFAQOrdering&QuantityII.IonNitridingTheoryNitridingisachemicalheattreatmentmethodtostrengthenthemetalsurface.Itistoplacemetalpartsinanactivenitrogenmedium,andatacertaintemperatureandholdingtime,thenitrogenelementcanpenetrateintothemetalsurface,therebychangingthechemicalcompositionofthemetallayertomakeithavehighwearresistance,fatiguestrength,corrosionresistanceandburnresistance,etc.,soitiswidelyusedinindustry.Ionnitridingiscarriedoutinalow-temperatureplasma.Thelow-pressuregasisionizedundertheactionofanelectricfieldtoproducehigh-energyionsandhigh-energyneutralatoms.Thesehigh-energyparticlescanimprovethestructureoftheinfiltrationlayer,promotethechemicalreactionprocess,andacceleratethenitridinglayerformation.Ionnitridingiscarriedoutinglowdischarge.Intheprocessofionnitriding,thepressurecontrolaccuracyofthefurnaceisrelativelyhigh,andthecontroldeviationreachesseveraltensofPa.AccordingtoPaschensLaw:Amongthem:Pisthegaspressure;Disthedistancebetweenparallelplateelectrodes;Visthecathodesecondaryelectronemissioncoefficient;BisStolevsconstant;Aisaconstant.Takingthederivativeofformula(1),thebreakdownvoltageexpression(2)canbeobtained:Itcanbeseenfromformula(2)thatthebreakdownvoltageVisrelatedtothegaspressureandd,andingeneralexperiments,disfixed,soionnitridingisextremelyimportantforpressurecontrol.III.SystemFlowandPressureMeasurementandControlBlockDiagramTheflowmetercontrolsthegasflowattheinlet.Whentheinletandexhaustflowsarebalanced,thefurnacepressureremainsstable.Duetotheinternalinfluenceoffurnacegasleakageandotherinterferencefactors,theinternalpressureofthefurnacefluctuatesupanddown,andthesystemdeviatesfromtheequilibriumstate,whichaffectstheplasmaprocessinseverecases.WeuseanordinaryDCmotortodrivetheDCmotorthroughtheL298N,andthemotordrivestheconetorotatethroughthereductionlever.Whentheconeisscrewedin,thegaspumpedoutperunittimeisreduced;whenitisscrewedout,thegaspumpedoutincreases,sothatthepressureinsidethefurnaceisstabilizedattherequiredvalue.Thechangeoffurnacepressureismeasuredbythepressuresensorandpassedthroughthetransmitter,whichsendsthegasflowcontrollertothefeedbackvoltage.Theelectricvacuumbutterflyvalveusedforthesuctionportisexpensive,asshowninFigure1.Figure1BlockdiagramofsystemflowandpressuremeasurementandcontrolIV.L298NChipIntroductionL298NcanacceptstandardTTLlogiclevelsignalVSS,andVSScanbeconnectedto4.5~7Vvoltage.4pinVSisconnectedtothepowersupplyvoltage,andtheVSvoltagerangeVIHis+2.5~46V.Theoutputcurrentcanreach2.5A,whichcandriveinductiveloads.Theemittersofpin1andpin15areseparatelyledouttoconnectthecurrentsamplingresistortoformacurrentsensingsignal.L298candrivetwomotors,OUT1,OUT2andOUT3,OUT4canbeconnectedtoeachmotor,thisexperimentaldevicewechoosetodriveonemotor.Pins5,7,10and12areconnectedtotheinputcontrolleveltocontroltheforwardandreverserotationofthemotor.EnAandEnBareconnectedtothecontrolpotentialenergyendtocontrolthestallingofthemotor.Figure2istheL298Nfunctionallogicdiagram,Table1istheL298Ninternalfuntionalmodule.Figure2L298NfunctionallogicdiagramEnAIn1In2OperativeCondition0Stop110Rotatingforward101Inversion111Brake100StopTable1L298NinternalfunctionalmoduleThefunctionalmoduleofIn3andIn4isthesameasTable1.ItcanbeseenfromTable1thatwhenEnAislowlevel,theinputlevelhasaneffectonmotorcontrol.WhenEnAishighlevel,whenEnAishigh,theinputlevelisonehighandonelow,andthemotorrotatesforwardorreverse.Iftheyarebothlowlevel,themotorwillstop,andiftheyarebothhighlevel,themotorwillbrake.V.ControllerPrincipleFigure3istheschematicdiagramofthecontroller,composedof3dashedblockdiagrams:Figure3TheschematicdiagramofthecontrollerThefollowingarethefunctionsofthe3dashedblockdiagrams:(1)Thedashedblockdiagram1controlstheforwardandreverserotationofthemotor,U1AandU2Aarecomparators,andVIcomesfromthevoltageofthefurnacepressuresensor.WhenVIVRBF1,U1Aoutputshighlevel,U2Aoutputhighlevelturnsintolowlevelthroughinverter,andthemotorrotatesforward.Similarly,whenVIVRBF1,themotorreverses.Theforwardandreverserotationofthemotorcancontroltheflowofgasextractedbytheairextractor,therebychangingthepressureinsidethefurnace.(2)Inthedashedblockdiagram2,twocomparatorsU3AandU4Aformadual-limitcomparator.WhenVBVIVA,itoutputslowlevel,andwhenVIVA,VIVB,itoutputshighlevel.VA,VBaretheupperandlowerlimitsofthevoltageconvertedbythefurnacepressuretransducer,thatis,thecontrolrangeofthereactionfurnacepressure.Accordingtoprocessrequirements,wecanspecifythevaluesofVAandVBbyourselves,aslongasthefurnacepressureiswithintherangedeterminedbyVAandVB,themotorstops(notethatVB<VRBF1<VA,ifitisnotinthisrange,thesystemisunstable).(3)Thedashedblockdiagram3isalongdelaycircuit.U5Aisacomparator,Rs1isthesamplingresistor,VRBF2isthemotorovercurrentvoltage.ThevoltageonRs1isgreaterthanVREF2,themotorisovercurrent,andU5Aoutputslowlevel.Itcanbeseenfromtheabovethatblock1controlstheforwardandreverserotationofthemotor,andblock2controlsthesizeoftherippleofthefurnacepressure.Whenthefurnacepressureistoosmallortoolarge,themotorturnstoafixedpositionatbothendstostop,accordingtothesteady-stateoperatingequationoftheDCmotor:Amongthem:Фisthemagneticfluxofeachpoleofthemotor;Ceistheelectromotiveforceconstant;Nisthenumberofmotorrevolutions;Iaisthearmaturecurrent;Raisthearmatureloopresistance.WhenthenumberofrevolutionsofthemotorNis0,thecurrentofthemotorincreasessharply,andthemotorwillburnoutifthetimeistoolong.Butwhenthemotorstarts,thecurrentinthecoilinthemotoralsoincreasessharply,sowemustseparatethesetwostates.Thelongdelaycircuitcandistinguishthesetwostates.Theworkingprincipleofthelong-delaycircuit:WhentheRs1overcurrentU5Ageneratesanegativepulseandisdifferentiated,thepulsetriggerspin2of555,thecircuitisset,andpin3outputshighlevel.Becausethedischargeterminal7pinisopen,C1,R5andU6Aformedasanintegration,thenstartworking,thechargingvoltageonthecapacitorC1riseslinearly,andtheintegrationconstantofthedelayoperationalamplifieris100R5C1.WhenthechargingvoltageonC1,thatis,thevoltageonpin6exceeds2/3VCC,the555circuitresetsandoutputsalowlevel.Themotorgenerallystart-upinlessthan0.8s,andtheC1chargingtimeisgenerally0.8~1s.TheoutputlevelofU5AisORedwiththeoutputlevelofpin3of555viaU7.IftheoutputlowlevelofU5AislongerthanthechargingtimeofC1,U7outputslowlevelafterC1ischarged.TheANDgateU8inputstothe6pinENAterminalofL298N.Themotorstops.IftheoutputlevelofU5AislessthanthechargingtimeofC1,pin6willnotactandthemotorwillstartnormally.Thelongdelaycircuitabsorbsthemotorstart-upovercurrentvoltagewaveform,sothatthemotorstartsnormally.VI.ConclusionThisarticlesummarizesthedesignschemeforthepressurecontrolofionnitridingbasedontheL298Nchip.Ithasbeenprovedthattheuseofthiscontrollertocontrolthegasflowcanreduceproductioncosts,increasethesystemcostperformance,andimprovethecontroldynamicperformanceandstabilityoftheentiresystemcontrol.FAQWhatisl298n?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.Whatistheuseofl298n?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.Howdoesl298ncontrolDCmotorspeed?1.IfyousendaHIGHsignaltotheenable1pin,motorAisreadytobecontrolledandatthemaximumspeed;2.IfyousendaLOWsignaltotheenable1pin,motorAturnsoff;3.IfyousendaPWMsignal,youcancontrolthespeedofthemotor.Themotorspeedisproportionaltothedutycycle.Whatisl298nmotordrivermodule?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.Howdoesl298nmotordriverwork?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.Howdoiuseal298motordriverwithArduino?Startbyconnectingpowersupplytothemotors.InourexperimentweareusingDCGearboxMotors(alsoknownasTTmotors)thatareusuallyfoundintwo-wheel-driverobots.Theyareratedfor3to12V.So,wewillconnectexternal12VpowersupplytotheVCCterminal.WhatisthefunctionofHbridge?AnH-bridgeisanelectroniccircuitthatswitchesthepolarityofavoltageappliedtoaload.ThesecircuitsareoftenusedinroboticsandotherapplicationstoallowDCmotorstorunforwardsorbackwards.Whatisthedifferencebetweenl293dandl298n?L293isquadruplehalf-HdriverwhileL298isdualfull-Hdriver,i.e,inL293allfourinput-outputlinesareindependentwhileinL298,ahalfHdrivercannotbeusedindependently,onlyfullHdriverhastobeused....Hence,heatsinkisprovidedinL298.

LM5020

I.IntroductionDCmotorsarewidelyusedinvariousfieldsduetotheirgoodspeedregulationperformance,largestartingtorqueandstrongoverloadcapacity.Inrecentyears,thestructureandcontrolmethodsofDCmotorshaveundergonegreatchanges.Withcomputersenteringthecontrolfieldandthecontinuousemergenceofnewpowerelectronicpowercomponents,PWM(pulsewidthmodulation)speedregulationhasbecomeanewwayofDCmotorspeedregulation.Andwiththeadvantagesofhighswitchingfrequency,stablelow-speedoperation,excellentdynamicperformance,andhighefficiency,itiswidelyusedinDCmotorspeedregulation.Therefore,thispaperproposesthedesignofaDCmotorPWMcontrolsystembasedon80C196KCandL298N.CatalogI.IntroductionII.PrincipleofPWMSpeedControlSystemIII.ControlSystemHardwareDesign3.1IntroductiontoPowerIntegratedCircuitL298N3.2DCMotorControlSystemHardwareCircuit3.3Anti-interferenceandElectromagneticCompatibilityDesignIV.ControlSystemSoftwareRealizationV.ConclusionFAQOrdering&QuantityII.PrincipleofPWMSpeedControlSystemPWM,orpulsewidthmodulation,referstotheuseoftheswitchingcharacteristicsofhigh-powertransistorstomodulateafixedvoltageDCpowersupply,whichisturnedonandoffatafixedfrequency,andthelengthoftheonandofftimeinacycleischangedasneeded.BychangingthedutycycleofthevoltageonthearmatureoftheDCservomotor,theaveragevoltageischangedtocontrolthespeedofthemotor.Therefore,itisoftencalledaswitchdrivedevice.TheschematicdiagramofPWMcontrolisshowninFigure1.Figure1PWMcontrolschematicdiagramThereareusuallytwowaystochangethedutycycle:PWMandPFM(pulsefrequencymodulation).PWMisbychangingthewidthoftheon-pulse,whichiscommonlyreferredtoasthefixedfrequencywidthmodulationmethod.PFMmeansthattheon-pulsewidthisconstantandthedutycycleischangedbychangingtheswitchingfrequency.Becausewhenitencountersmechanicalresonanceataparticularfrequency,itoftenresultsinsystemvibrationandhowling.Therefore,inthecontrolofDCmotors,thePWMcontrolmethodismainlyused.III.ControlSystemHardwareDesignTheDCmotorspeedcontrolsystembasedon80C196KCandL298Niscomposedofthesmallestsingle-chipmicrocomputersystem,R/Dconverter,PWMpoweramplifiercircuit,A/DandD/Aconversioncircuit,andreceivingcommandinterfacecircuit.Theminimumsystemofthesingle-chipmicrocomputeradoptsthe16-bitsingle-chip80C196KCexternalexpansioninterfacecircuit,whichismainlyusedtorealizethefunctionsofdataacquisitionandPWMsignalgeneration.TheblockdiagramofthespeedcontrolsystemisshowninFigure2.Figure2BlockdiagramofPWMspeedcontrolsystem3.1IntroductiontoPowerIntegratedCircuitL298NInordertoimprovesystemefficiencyandreducepowerconsumption,thepoweramplifierdrivecircuitadoptstheintegratedcircuitL298NbasedonthebipolarH-bridgepulsewidthmodulationmethod.L298Nisahigh-performancepulse-widthmodulationpoweramplifierproducedbySGS,whichhasthecharacteristicsofsmallsizeandstrongdrivingability.ItcontainstwoH-bridgehigh-voltageandhigh-currentbridgedrivers,whichcanrealizethefull-bridgedriveofthemotorwithasinglechip,whichcandrivemotorsbelow46Vand2A.TheinternalstructureofL298NisshownasinFigure3.Figure3L298Ninternalstructureblockdiagram3.2DCMotorControlSystemHardwareCircuitL298NcandrivetwoDCmotors,becausethespeedcontrolsystemisasingle-axisstructure,inordertomakefulluseoftheloadcapacityofthepoweramplifiercircuit,sothatthesystemstartsatthemaximumaccelerationandbrakesatthemaximumacceleration,inthedesign,theinputterminalandtheoutputterminalareconnectedinparalleltocontroltheDCmotor.Thesingle-chip80C196KCgivesaPWMsignalaccordingtothecalculationresultsofthepositionloopandthespeedloop.ThePWMsignalisdirectlyoutputtotheIN1(IN3)terminal,andthePWMsignalisinvertedandoutputtoIN2(IN4)through7406.WhenthedutycycleofthePWManalogsignalis50%,thepositiveandnegativevoltagesatbothendsofthemotorareappliedforthesametime.Themotorisinastateoftremoratthisposition,thatis,inthepowerlubricationstate.Whenthedutycycleisgreaterthan50%,thesignalvoltageOUTAisgreaterthanOUTB,andthemotorrotatesforward,otherwisereverse.Therefore,theoutputpolarityofeachlinkmustbestraightenedouttoformnegativefeedbackandcompleteclosed-loopcontrol.RelyingonchangingthePWMdutycycletocontrolthemotorspeedcanalsochangethemotorrotationdirection,thecontrolmethodissimpleandreliable.Inaddition,becausethemotorisofelectriccoiltype,reverseelectromotiveforcewillbeformedwhenthemotorhasanemergencystopandsuddencommutation.ToensurethenormaloperationoftheL298Ndrivechip,twopairsofcontinuationsareaddedbetweentheoutputterminalsOUTA,OUTBandtheDCmotor.TheflowdiodeshuntsthecurrenttothepositiveorgroundterminalofthepowersupplytopreventbackelectromotiveforcefromdamagingtheL298N.3.3Anti-interferenceandElectromagneticCompatibilityDesignWhenthemotorisdriven,therapidon-offofthepowermainswitchingelementleadstoalargerateofchangeofpowercurrentandvoltage,whichnotonlyaffectsthedrivecircuitbutalsoentersthecontrolcircuitthroughthepowersupplyandground.Inaddition,whenthemotorstartsandbrakes,thetransientvoltageisgeneratedatthesuddenchangeoftheload,itsamplitudewillbehigherthanthepowersupplyvoltage,andtheleadingedgeissteep,thefrequencybandisverywide,anditentersthecontrolcircuitthroughtheDCpowersupply.Therefore,anti-interferenceandelectromagneticcompatibilitydesignisalsoveryimportant.Thesystemhasadoptedmeasuressuchascurrentsmoothing,deburringandshielding.Currentsmoothing:BecausetheinstantaneousenergyofthePWMswitchisrelativelylarge,theRCfilterisusedattheoutputofthePWMpoweramplifiertofilter.Byselectingtheappropriateresistanceandcapacitancevalues,high-frequencyharmonicsareeffectivelysuppressedandthepeakvoltageofthePWMpoweramplifierisabsorbed.Therebyreducingtheinterference;Deburring:Thesystemincreasesthefiltercapacitoronthepowersupplyside,andusesonelargeandonesmallcapacitorinparallel.Thelargecapacitorisresponsibleforthedecoupling,filtering,andsmoothingoflow-frequencyalternatingsignals,andthesmallcapacitoreliminatesmid-andhigh-frequencyparasiticscouplinginthecircuitnetwork,whicheffectivelyreducesspikesandburrs;Shielding:Themotordrivecableadoptsdouble-shieldedcables,andthewiringshouldbeseparatedfromothercablesasmuchaspossible.Figure4DrivehardwarecircuitdiagramIV.ControlsystemsoftwarerealizationThecontrolsystemadoptsthespeed-positionclosed-loopcombinationmethod,takingthepositioncontrolmethodasanexampletointroducetherealizationmethodofthesoftware.ThepositioncontrolisbasedontheclassicPIcontrolalgorithm,andtheproportionalandintegralparametersaresimplifieddesign,andthesegmentedPIcontrolisintroduced.,Thatis,thecalculatederrorisdividedintosections,anddifferentproportionalandintegralparametersparticipateintheadjustmentwithintheerrorrangeofeachsection,whichensuresthesmootherandmorestableoperationofthesystem.ThederivationandsimplificationprocessofPIformulaisasfollows:ThespecificsoftwareimplementationflowchartisshowninFigure5.Thatis,afterreceivingagivenanglecommand,firstcalculatethedifferencebetweenthesampledpositioninformationandthegivenangle,andthendividethedifferenceintonequalparts,andeachsegmentcorrespondstoasetofparametersKp1andki1participateinmediationcontrol,calculatetheoutputofPIcontrolandthenconvertitintothecorrespondingPWMnumericaloutput.Figure5ThespecificsoftwareimplementationflowchartV.ConclusionThisarticlesumsupthedesignschemeoftheDCmotorPWMcontrolsystembasedon80C196KCandL298N.Thesingle-chipmicrocomputergeneratesPWMsignaltothepowerintegratedcircuitL298N.TheclassicPIsegmentcontrolisusedtocontrolthemotor.Ithasthecharacteristicsofsimplecircuitandconvenientcontrol.Theoperatingtestresultsshowthatthesystemworksstablyandreliably,meetstherequirementsofthespeedregulationfunction,andhasbeensuccessfullyappliedtomanyairborneproducts.FAQWhatisl298n?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.Whatistheuseofl298n?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.Howdoesl298ncontrolDCmotorspeed?1.IfyousendaHIGHsignaltotheenable1pin,motorAisreadytobecontrolledandatthemaximumspeed;2.IfyousendaLOWsignaltotheenable1pin,motorAturnsoff;3.IfyousendaPWMsignal,youcancontrolthespeedofthemotor.Themotorspeedisproportionaltothedutycycle.Whatisl298nmotordrivermodule?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.Howdoesl298nmotordriverwork?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.Howdoiuseal298motordriverwithArduino?Startbyconnectingpowersupplytothemotors.InourexperimentweareusingDCGearboxMotors(alsoknownasTTmotors)thatareusuallyfoundintwo-wheel-driverobots.Theyareratedfor3to12V.So,wewillconnectexternal12VpowersupplytotheVCCterminal.WhatisthefunctionofHbridge?AnH-bridgeisanelectroniccircuitthatswitchesthepolarityofavoltageappliedtoaload.ThesecircuitsareoftenusedinroboticsandotherapplicationstoallowDCmotorstorunforwardsorbackwards.Whatisthedifferencebetweenl293dandl298n?L293isquadruplehalf-HdriverwhileL298isdualfull-Hdriver,i.e,inL293allfourinput-outputlinesareindependentwhileinL298,ahalfHdrivercannotbeusedindependently,onlyfullHdriverhastobeused....Hence,heatsinkisprovidedinL298.

IDescriptionDS18B20isawidelyuseddigitaltemperaturesensor,anditsoutputisadigitalsignal.DS18B20hasthecharacteristicsofsmallsize,lowhardwareoverhead,stronganti-interferenceabilityandhighprecision.TheDS18B20digitaltemperaturesensoriseasytowireandcanbeusedinmanyoccasionsafterbeingpackaged.Suchaspipe,thread,magnetadsorption,stainlesssteelpackageandsoon.ThisArduinoforbeginnerstutorialwillteachyouhowtoreadtheDS18B201-wiretemperaturesensor.CatalogIDescriptionIIIntroductiontoDS18B202.1DS18B20BasicInformation2.2DS18B20Features2.3DS18B20StructureIIIIntroductiontoComponents3.1Memory3.264-bitLithographyROM3.3ConnectionofExternalPowerSupply3.4ConfigurationRegister3.5TemperatureReadingIVDS18B20WorkingPrincipleVConclusionFAQOrdering&QuantityIIIntroductiontoDS18B202.1DS18B20BasicInformationDS18B20isanimprovedintelligenttemperaturesensornewlylaunchedbyAmericanDALLASSemiconductorafterDS1820.Comparedwiththetraditionalthermistor,DS18B20candirectlyreadthemeasuredtemperatureandcanrealizethe9-12-digitdigitalvaluereadingmodethroughsimpleprogrammingaccordingtoactualrequirements.Itcanalsocomplete9-bitand12-bitdigitalquantitiesin93.75msand750ms,respectively.Moreover,theinformationreadfromtheDS18B20ortheinformationwrittenintotheDS18B20onlyneedsoneportline(single-wireinterface)toreadandwrite,andthetemperatureconversionpowercomesfromthedatabus.ThebusitselfcanalsosupplypowertotheconnectedDS18B20withouttheneedforanadditionalpowersupply.Therefore,theuseofDS18B20canmakethesystemstructuresimplerandmorereliable.DS18B20hasgreatlyimprovedcomparedwithDS1820intermsoftemperaturemeasurementaccuracy,conversiontime,transmissiondistance,andresolution.Itbringsmoreconvenientuseandmoresatisfyingeffectstousers.2.2DS18B20FeaturesUnique1-WireInterfaceRequiresOnlyOnePortPinforCommunicationReduceComponentCountwithIntegratedTemperatureSensorandEEPROMMeasuresTemperaturesfrom-55Cto+125C(-67Fto+257F)0.5CAccuracyfrom-10Cto+85CProgrammableResolutionfrom9Bitsto12BitsNoExternalComponentsRequiredParasiticPowerModeRequiresOnly2PinsforOperation(DQandGND)SimplifiesDistributedTemperature-SensingApplicationswithMultidropCapabilityEachDeviceHasaUnique64-BitSerialCodeStoredinOn-BoardROMFlexibleUser-DefinableNonvolatile(NV)AlarmSettingswithAlarmSearchCommandIdentifiesDeviceswithTemperaturesOutsideProgrammedLimitsAvailablein8-PinSO(150mils),8-PinSOP,and3-PinTO-92Packages2.3DS18B20StructureTheexternalstructureofDS18B20isshowninthefigure1.Amongthem:VDDisthepowerinputterminal;DQisthedigitalsignalinput/outputterminal;GNDisthepowerground.Figure1.DS18B20ExternalStructureTheinternalstructureofDS18B20mainlyincludes4parts:64-bitlithographyROM;Temperaturesensor;Non-volatiletemperaturealarmtriggersTHandTL;Configurationregister.Figure2.DS18B20ExternalStructureInthe64-bitROM,themanufacturerhasa64-bitserialnumberburnedbythemanufacturerbeforetheproductleavesthefactory.TheserialnumbercanberegardedastheaddressserialcodeofDS18B20,usedtodistinguisheachDS18B20.Soastobetterrealizethemulti-pointmeasurementoffieldtemperature.IIIIntroductiontoComponents3.1MemoryThememoryofDS18B20includeshigh-speedscratchpadRAMandelectricallyerasableRAM.TheelectricallyerasableRAMalsoincludestemperaturetriggersTHandTL,andaconfigurationregister.Thememorycancompletelydeterminethecommunicationoftheone-lineport,andthenumberiswrittenintotheregisterwiththecommandofwritingtheregister.Thenyoucanusethereadregistercommandtoconfirmthesenumbers.Afterconfirmation,youcanusethecopyregistercommandtotransferthesenumberstotheelectricallyerasableRAM.Whenthenumberintheregisterismodified,thisprocesscanensuretheintegrityofthenumber.ThescratchpadRAMiscomposedof8bytesofmemory.Theninthbytecanbereadwiththereadregistercommand.Thisbyteistocheckthepreviouseightbytes.3.264-bitLithographyROMFor64-bitlithographyROM:Thefirst8bitsaretheowncodeofDS18B20Thenext48bitsareconsecutivedigitalcodesThelast8bitsaretheCRCcheckofthefirst56bits.The64-bitlithographyROMalsoincludes5ROMfunctioncommands:readROM,matchROM,skipROM,searchROMandalarmsearch.3.3ConnectionofExternalPowerSupplyDS18B20canuseexternalpowerVDDorinternalparasiticpower.WhentheVDDportisconnectedtoavoltageof3.0V-5.5V,anexternalpowersupplyisused.AninternalparasiticpowersupplyisusedwhentheVDDportisgrounded.Inaddition,whetheritisaninternalparasiticpowersupplyoranexternalpowersupply,theI/Oportlineshouldbeconnectedtoapull-upresistorofabout5K.3.4ConfigurationRegisterTheconfigurationregisteristoconfiguredifferentdigitstodeterminethetemperatureanddigitalconversion.ItcanbeknownthatR1andR0arethedeterminingbitsoftemperature.DifferentcombinationsofR1andR0canbeconfiguredas9-digit,10-digit,11-digit,and12-digittemperaturedisplay.Inthisway,theconversiontimecorrespondingtodifferenttemperatureconversionpositionscanbeknown.Theresolutionsofthefourconfigurationsare0.5C,0.25C,0.125Cand0.0625C,respectively,andareconfiguredto12bitsatthefactory.3.5TemperatureReadingDS18B20isconfiguredas12bitsatthefactory,and16bitsarereadwhenreadingtemperature.Thefirst5bitsaresignbits.Whenthefirst5digitsare1,thetemperaturereadisanegativenumber;whenthecurrent5digitsare0,thetemperaturereadisapositivenumber.Themethodofreadingwhenthetemperatureispositiveis:justconvertthehexadecimalnumbertodecimal.Whenthetemperatureisnegative,thereadingmethodis:invertthehexadecimalnumber,thenadd1onthisbasis,andthenconverttodecimal.Example:0550H=+85degrees,FC90H=-55degrees.IVDS18B20WorkingPrincipleThereadandwritesequenceandtemperaturemeasurementprincipleofDS18B20arethesameasDS1820.Onlythenumberofdigitsofthetemperaturevalueobtainedvarieswiththeresolution.Andthedelaytimeduringtemperatureconversionisreducedfrom2sto750ms.ThetemperaturemeasurementprincipleofDS18B20isshowninFigure3.Figure3.DS18B20TemperatureMeasurementPrincipleDiagramTheoscillationfrequencyofthecrystaloscillatorwithlowtemperaturecoefficientinthepictureislittleaffectedbytemperature.Itisusedtogenerateafixedfrequencypulsesignalandsendittothesubtractioncounter1.Thehightemperaturecoefficientcrystaloscillatorchangesitsoscillationfrequencysignificantlywithtemperaturechanges.Atthesametime,thegeneratedsignalisusedasthepulseinputofthesubtractioncounter2.Thefigurealsoimpliesacountinggate.Whenthecountinggateisopened,DS18B20countstheclockpulsesgeneratedbythelowtemperaturecoefficientoscillatortocompletethetemperaturemeasurement.Theopeningtimeofthecountinggateisdeterminedbythehightemperaturecoefficientoscillator.Beforeeachmeasurement,firstputthebasecorrespondingto-55℃intothesubtractioncounter1andthetemperatureregisterrespectively.Thesubtractioncounter1andthetemperatureregisterarepresettoabasevaluecorrespondingto-55℃.Thesubtractioncounter1subtractsthepulsesignalgeneratedbythelowtemperaturecoefficientcrystaloscillator.Whenthepresetvalueofthesubtractioncounter1isreducedto0,thevalueofthetemperatureregisterwillincreaseby1,thepresetofthesubtractioncounter1willbereloaded,andthesubtractioncounter1willrestartcountingthepulsesignalsgeneratedbythelowtemperaturecoefficientcrystaloscillator.Thisloopuntilthesubtractioncounter2countsto0,stoptheaccumulationofthetemperatureregistervalue.Thevalueinthetemperatureregisteristhemeasuredtemperatureatthistime.Figure4.DS18B20Theslopeaccumulatorisusedtocompensateandcorrectthenonlinearityinthetemperaturemeasurementprocess,anditsoutputisusedtocorrectthepresetvalueofthesubtractioncounter.Aslongasthecountinggateisnotclosed,repeattheaboveprocessuntilthetemperatureregistervaluereachesthemeasuredtemperaturevalue.ThisisthetemperaturemeasurementprincipleofDS18B20.Inaddition,becausetheDS18B20single-wirecommunicationfunctioniscompletedintimesharing,ithasastrictconceptoftimeslots.Therefore,thereadandwritetimingisveryimportant.VariousoperationsofthesystemtoDS18B20mustbecarriedoutaccordingtotheagreement.Theoperatingprotocolis:initializeDS18B20(sendresetpulse)sendROMfunctioncommandsendmemoryoperationcommandprocessdata.ThetimingdiagramofvariousoperationsisthesameasthatofDS1820.VConclusionInconclusion,thisblogsummarizesthefollowing3aspectsofDS1820:Features,structureandworkingprinciple.DS1820mainlychangesitsappearanceaccordingtodifferentapplications.ThepackagedDS18B20canbeusedinvariousnon-limitingtemperatureapplications.Includingcabletrenchtemperaturemeasurement,blastfurnacewatercirculationtemperaturemeasurement,boilertemperaturemeasurement,machineroomtemperaturemeasurement,agriculturalgreenhousetemperaturemeasurement,cleanroomtemperaturemeasurement,ammunitionstoragetemperaturemeasurement,etc.Inaddition,DS1820isabrasion-resistantandimpact-resistant,smallinsize,easytouse,anddiverseinpackaging,suitablefordigitaltemperaturemeasurementandcontrolofvariousnarrowspaceequipment.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)?DescriptionTheCD405xBanalogmultiplexersanddemultiplexersaredigitally-controlledanalogswitcheshavinglowONimpedanceandverylowOFFleakagecurrent.ThesemultiplexercircuitsdissipateextremelylowquiescentpoweroverthefullVDDVSSandVDDVEEsupplyvoltageranges,independentofthelogicstateofthecontrolsignals.TheCD4051Bisasingle8-Channelmultiplexerhavingthreebinarycontrolinputs,A,B,andC,andaninhibitinput.Thethreebinarysignalsselect1of8channelstobeturnedon,andconnectoneofthe8inputstotheoutput.CatalogDescriptionPinoutConfigurationandFunctionCD4051BlockDiagramDocumentsandMediaFeaturesApplicationCD4051TypicalApplicationCircuitsOrdering&QuantityPinoutConfigurationandFunctionCD4051BlockDiagramThelogicdiagramofCD4051iscomposedofthreeparts:logiclevelconversioncircuit,8select1decodingcircuitand8CMOSswitchunits.A,BandCare3-bitbinaryaddressinputterminals,and8combinationsof3-bitbinarycanbeusedforselection8channels;INHistheaddressinputprohibitionterminal,whenitishigh,theaddressinputterminalisinvalid,thatis,nochannelisstrobed.TheinputlevelsofA,B,CandINHarecompatiblewithTTL.CD4051has8input\outputterminals,1output/inputterminal,digitalcircuitpowersupply+Eand-E1,analogcircuitpowersupply+Eand-E2.ThemainfunctionofthelogiclevelconversioncircuitistoinputtheaddressA,B,CandaddressinputinhibitterminalINHinputTTLlogiclevelisconvertedintoCMOSlevel,sothattheswitchunitcanbecontrolledbyTTLlevel.Themainfunctionofthe8-to-1addressdecodingcircuitistoconverttheaddressinputsignalfromthelogiclevelconversioncircuitintothecorrespondingswitchunitstrobesignalandturnonthecorrespondingswitchunit.DocumentsandMediaDatasheetCD405xBCMOSSingle8-ChannelAnalogMultiplexer/DemultiplexerwithLogic-LevelConversiondatasheet(Rev.I)FeaturesWideRangeofDigitalandAnalogSignalLevelsDigital:3Vto20VAnalog:20VP-PLowONResistance,125Ω(Typical)Over15VP-PSignalInputRangeforVDDVEE=18VHighOFFResistance,ChannelLeakageof100pA(Typical)atVDDVEE=18VLogic-LevelConversionforDigitalAddressingSignalsof3Vto20V(VDDVSS=3Vto20V)toSwitchAnalogSignalsto20VP-P(VDDVEE=20V)MatchedSwitchCharacteristics,rON=5Ω(Typical)forVDDVEE=15VVeryLowQuiescentPowerDissipationUnderAllDigital-ControlInputandSupplyConditions,0.2W(Typical)atVDDVSS=VDDVEE=10VBinaryAddressDecodingonChip5V,10V,and15VParametricRatings100%TestedforQuiescentCurrentat20VMaximumInputCurrentof1Aat18VOverFullPackageTemperatureRange,100nAat18Vand25CBreak-Before-MakeSwitchingEliminatesChannelOverlapApplicationAnalogandDigitalMultiplexingandDemultiplexingA/DandD/AConversionSignalGatingFactoryAutomationTelevisionsAppliancesConsumerAudioProgrammableLogicCircuitsSensorsCD4051TypicalApplicationCircuits1.CD4051,CH3130multi-channeldemodulatorcircuitdiagramThiscircuitismainlycomposedof8-channelanalogswitchCD4051andvoltagefollowerCH3130,etc.TheinputsignaloftheprohibitionterminalINHofanalogswitchCD4051isusedtocontrolthegatingofvoltagefollowerCH3130,therebyperformdemodulationtomultipleanalogsignals.2.CD4051constructs32-channelcircuitBecausetheCD4051hasonlyeightinputports,fourCD4051sareneededtobuilda32-waymultiplexer,labeledINH1,INH2,INH3,andINH4.The32-waymultiplexershouldhave5controlports,ofwhichthefirstthreearetheinputportsofCD4051andthelasttwoarecontrolports.(BecauseCD4051hasthreeinputports),labelthemasD1,D2,D3,D4,D5(0000011111,00000channel0,11111channel31).Thebasicideaistorealizethechoiceof32channelports(0-7,8-15,16-23,24-31)byselecting4CD4051s.IfyouchoosethethirdCD4051,youcanchoose16-23(10000-10111)channelport.However,theselectionofCD4051isachievedbycontrollingtheINHlevelofeachCD4051.Forexample,ifyouwanttoturnonthethirdCD4051,makeitsINHhigh(atthistimeD5=1,D4=0,thenINH3=D5!D4).Therefore,thechoiceofINHisachievedbycontrollingthelogicalrelationshipbetweenD5andD4.WhereINH1=!D5!D4;INH2=!D5D4;INH3=D5!D4;INH4=D5D4.

DescriptionLM317isaadjustable3-terminalpositive-voltageregulator,thisbolgcoversLM317regulatoralternative,datasheet,applications,featuresandotherinformationonhowtouseandwheretousethisdevice.ABasicIntroductiontoLM317VoltageRegulatorCatalogDescriptionLM317PinoutLM317FeaturesLM317ApplicationsLM317CircuitLM317ParametersLM317CADModelLM317AdvantageLM317ElectricalCharacteristicsLM317PackageLM317AlternativesLM317EquivalentsWheretouseLM317HowtouseLM317LM317ManufacturerComponentDatasheetFAQOrdering&QuantityLM317PinoutPinNumberPinNameDescription1AdjustThispinsadjuststheoutputvoltage2OutputVoltage(Vout)Theregulatedoutputvoltagesetbytheadjustpincanbeobtainedfromthispin3InputVoltage(Vin)TheinputvoltagewhichhastoberegulatedisgiventothispinLM317FeaturesOutputvoltagerangeadjustablefrom1.25Vto37VOutputcurrentgreaterthan1.5AInternalshort-circuitcurrentlimitingThermaloverloadprotectionOutputsafe-areacompensationLM317ApplicationsATCAsolutionsDLP:3Dbiometrics,hyperspectralimaging,opticalnetworking,andspectroscopyDVRandDVSDesktopPCsDigitalsignageandstillcamerasECGelectrocardiogramsEVHEVchargers:levels1,2,and3ElectronicshelflabelsEnergyharvestingEthernetswitchesFemtobasestationsFingerprintandirisbiometricsHVAC:heating,ventilating,andairconditioningHigh-speeddataacquisitionandgenerationHydraulicvalvesIPphones:wiredandwirelessIntelligentoccupancysensingMotorcontrols:brushedDC,brushlessDC,lowvoltage,permanentmagnet,andsteppermotorsPoint-to-pointmicrowavebackhaulsPowerbanksolutionsPowerlinecommunicationmodemsPoweroverethernet(PoE)PowerqualitymetersPowersubstationcontrolsPrivatebranchexchanges(PBX)ProgrammablelogiccontrollersRFIDreadersRefrigeratorsSignalorwaveformgeneratorsSoftware-definedradios(SDR)Washingmachines:high-endandlow-endX-rays:baggagescanners,medical,anddentalLM317CircuitLM317ParametersOutputoptionsAdjustableOutputIout(Max)(A)1.5Vin(Max)(V)40Vin(Min)(V)3Vout(Max)(V)37Vout(Min)(V)1.25Noise(uVrms)38Iq(Typ)(mA)5ThermalresistanceJA(C/W)24Approx.price(US$)1ku|0.14Loadcapacitance(Min)(F)0RatingCatalogRegulatedoutputs(#)1FeaturesAccuracy(%)5PSRR@100KHz(dB)38Dropoutvoltage(Vdo)(Typ)(mV)2000Operatingtemperaturerange(C)0to125IhsManufacturerTEXASINSTRUMENTSINCBrandNameTexasInstrumentsLM317CADModelPackagePinsDownloadDDPAK/TO-263(KTT)3ViewoptionsSOT-223(DCY)4ViewoptionsTO-220(KCS)3ViewoptionsTO-220(KCT)3ViewoptionsLM317ElectricalCharacteristicsOverrecommendedrangesofoperatingvitualjunctiontemperature(unlessotherwisenoted)LM317PackageDDPAK/TO-263(KTT)SOT-223(DCY)TO-220(KCS)TO-220(KCT)LM317AlternativesSharethesamefunctionalityandpinoutbutisnotanequivalenttothecompareddevice:LM7805,LM7806,LM7809,LM7812,LM7905,LM7912,LM117V33,XC6206P332MR.LM317EquivalentsLT1086,LM1117(SMD),PB137,LM337(NegativeVariableVoltageregulator)WheretouseLM317WhenitcomestovariablevoltageregulationrequirementsLM317wouldmostlikelybethefirstchoice.Apartfromusingitasavariablevoltageregulator,itcanalsobeusedasafixedvoltageregulator,currentlimiter,Batterycharger,ACvoltageregulatorandevenasanadjustablecurrentregulator.OnenotabledrawbackofthisICisthatithasavoltagedropofabout2.5acrossitduringregulation,soifyoulookingtoavoidthatproblemlookintotheotherequivalentICsgivenabove.So,ifyouarelookingforavariablevoltageregulatortodelivercurrentupto1.5AthenthisregulatorICmightbetherightchoiceforyourapplication.HowtouseLM317LM317isa3-terminalregulatorICanditisverysimpletouse.Ithasmanyapplicationcircuitsinitsdatasheet,butthisICisknownforbeingusedasavariablevoltageregulator.So,letslookintohowtousethisICasavariablevoltageregulator.AssaidearliertheIChas3pins,inwhichtheinputvoltageissuppliedtopin3(VIN)thenusingapairofresistors(potentialdivider)wesetavoltageatpin1(Adjust)whichwilldecidetheoutputvoltageoftheICthatisgivenoutatpin2(VOUT).Nowtomakeitactasavariablevoltageregulatorwehavetosetvariablevoltagesatpin1whichcanbedonebyusingapotentiometerinthepotentialdivider.Thebelowcircuitisdesignedtotake12V(youcansupplyupto24V)asinputandregulateitfrom1.25Vto10V.TheResistorR1(1K)andthepotentiometer(10k)togethercreatesapotentialdifferenceatadjustpinwhichregulatestheoutputpinaccordingly.TheformulaetocalculatetheOutputvoltagebasedonthevalueofresistorsisVOUT=1.25(1+(R2/R1))Now,letsverifythisformulafortheabovecircuit.ThevalueofR1is1000ohmsandthevalueofR2(potentiometer)is5000becauseitisa10kpotentiometerplacedat50%(50/100of1000is5000).Vout=1.25(1+(5000/1000))=1.256=7.5VAndthesimulationshows7.7Vwhichisprettymuchclose.Youcanvarytheoutputvoltagebysimplyvaryingthepotentiometer.Inourcircuit,amotorisconnectedasaloadwhichconsumesaround650mAyoucanconnectanyloadupto1.5A.Thesameformulaecanalsobeusedtocalculatethevalueofresistorforyourequiredoutputvoltage.Oneeasywaytodothisistousethisonlinecalculatortorandomlysubstitutethevalueofresistorsyouhaveandcheckwhichoutputvoltageyouwillget.LM317ManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.ComponentDatasheetLM317DatasheetFAQWhatislm317usedfor?TheLM317servesawidevarietyofapplicationsincludinglocal,oncardregulation.Thisdevicecanalsobeusedtomakeaprogrammableoutputregulator,orbyconnectingafixedresistorbetweentheadjustmentandoutput,theLM317canbeusedasaprecisioncurrentregulator.Whatisthemaximuminputvoltageoflm317?TheLM317isanadjustablevoltagelinearregulatorthatcanoutput1.2537Vatupto1.5Acurrentwithaninputvoltagerangeof340V.Whatisthedifferencebetweenlm317andlm317t?Member.Thereisnofunctionaldifferenceastheyareoneinthesame.TheTattheendjustindicatesthatitsinaTO-220package.Theyusuallytagonextrathingsafterthepartnametoreferencethingslikepackage,temprange,etc.Islm317atransistor?TheLM317isanadjustablethree-terminalpositive-voltageregulatorcapableofsupplyingmorethan1.5Aoveranoutput-voltagerangeof1.25Vto32V....Byusingaheat-sinkedpasstransistorsuchasa2N3055(Q1)wecanproduceseveralampsofcurrentfarabovethe1.5ampsoftheLM317.Howdoesanlm317work?Thecircuitconsistsofalow-sideresistorandhigh-sideresistorconnectedinseriesformingaresistivevoltagedividerwhichisapassivelinearcircuitusedtoproduceanoutputvoltagewhichisafractionofitsinputvoltage.WhatisIClm317?TheLM317deviceisanadjustablethree-terminalpositive-voltageregulatorcapableofsupplyingmorethan1.5Aoveranoutput-voltagerangeof1.25Vto37V.Itrequiresonlytwoexternalresistorstosettheoutputvoltage.Thedevicefeaturesatypicallineregulationof0.01%andtypicalloadregulationof0.1%.HowdoIknowifmylm317isworking?Testinglm317t.Ifyoulooktotheic,thelegstowardsyou,therightoneistheinputpin.youmustseeadifferenceofminimum1.2Vbetweenthetwopins,otherwisetheICisfaulty.furthermore,thefirsttestistoseeifyouhaveinputvoltage!Whatistheworkingpricipleoflm317?LM317worksonaverysimpleprinciple.Itisavariablevoltageregulatori.e.supportsdifferentoutputvoltagelevelsforaconstantappliedinputvoltagesupply.HowtomakeasimplevoltageregulatorcircuitusingLM317?DescriptionLM339(Quaddifferentialcomparator)consistoffourindependentvoltagecomparators.Itisacommonintegratedcircuitandismainlyusedinhigh-voltagedigitallogicgatecircuits.UsingLM339caneasilyformvariousvoltagecomparatorcircuitsandoscillatorcircuits.CatalogDescriptionComponentDatasheetLM339PinoutBasicParametersFeaturesApplicationPinFunctionListCircuitDiagramPackageElectricalCharacteristicsInstructionsProductManufacturerFAQOrdering&QuantityComponentDatasheetComparatorDatasheetLM339DatasheetLM339PinoutLM339PinoutBasicParametersParameternameSymbolNumericalvalueunitsupplyvoltageVCC18or36VDifferentialmodeinputvoltageVID36VCommonmodeinputvoltageVI-0.3~VCCVPowerdissipationPd570mWWorkingenvironmenttemperatureTopr0to+70℃StoragetemperatureTstg-65to150℃FeaturesLowvoltageoffset,generally2mVThecommon-modevoltagerangeisverylarge,from0vtothepowersupplyvoltageminus1.5vTheinternalresistancelimittothesignalsourceisverywideSingleSupplyOperation:2-36VDualSupplyOperation:1V-18VThepotentialofoutputcanbeselectedflexiblyandconvenientlyLM339issimilartooperationalamplifierwithnon-adjustablegain.Eachcomparatorhastwoinputsandoneoutput.Oneofthetwoinputterminalsiscalledthenon-invertinginputterminal,whichisrepresentedby+,andtheotheriscalledtheinvertinginputterminal,whichisrepresentedby-.Whencomparingtwovoltages,addafixedvoltageasareferencevoltageatanyinputterminal,andaddasignalvoltagetobecomparedattheotherterminal.Whenthevoltageatthe+terminalishigherthanthe-terminal,theoutputtubewillcutoff.Whenthevoltageofthe-terminalishigherthanthe+terminal,theoutputtubeissaturated.Thevoltagedifferencebetweenthetwoinputterminalsisgreaterthan10mV,whichcanensurethattheoutputcanbereliablyswitchedfromonestatetoanotherstate.Therefore,itisidealtousetheLM339inweaksignaloccasions.TheoutputterminalofLM339isequivalenttoacrystaltransistorthatisnotconnectedtothecollectorresistor.Whenusing,theoutputterminaltothepositivepowersupplygenerallyneedstobeconnectedtoaresistor(calledpull-upresistor).Choosingpull-upresistorswithdifferentresistancevalueswillaffectthevalueofthehighpotentialattheoutput.Becausewhentheoutputtransistorisoff,itscollectorvoltagebasicallydependsonthevalueofthepull-upresistorandtheload.Inaddition,theoutputofeachcomparatorisallowedtobeconnectedtogether.ApplicationIndustrialAutomotiveInfotainmentandClustersBodyControlModulePowerSupervisionOscillatorsPeakDetectorsLogicVoltageTranslationPinFunctionListPinNumberPinfunctionSymbolPinNumberPinfunctionSymbol1Output2OUT28Invertinginput31N-(3)2Output1OUT19Forwardinput31N+(3)3PowerSupplyVCC+10Invertinginput41N-(4)4Invertinginput11N-(1)11Forwardinput41N+(4)5Positiveinput11N+(1)12PowerSupplyVcc6Invertinginput21N-(2)13Output4OUT47Forwardinput2OUT2(2)14Output3OUT3CircuitDiagramLM339CircuitDiagramPackageLM339PackageElectricalCharacteristicsVCC=5.0V,Tamb=25℃,unlessotherwisestatedParameternameSymbolTestconditionsMinimumTypicalMaximumunitInputoffsetvoltageVIOVCM=0toVCC-1.5VO(P)=1.4V,Rs=0-1.05.0mVInputoffsetcurrentIIO--550nAInputbiascurrentIb--65250nACommonmodeinputvoltageVIC-0-VCC-1.5VQuiescentCurrentICCVCC=+5V,noload-1.12.0mAVCC=+30V,noload-1.32.5mAVoltagegainAVVCC=15V,RL>15k-200-V/mVSinkcurrentIsinkVi(-)>1V,Vi(+)=0V,Vo(p)<1.5V616-mAOutputleakagecurrentIOLEVi(-)=0V,Vi(+)=1V,VO=5V-0.1-nAInstructionsTheLM339seriesarehighgain,widebandwidthdeviceswhich,likemostcomparators,caneasilyoscillateiftheoutputleadisinadvertentlyallowedtocapacitivelycoupletotheinputsviastraycapacitance.Thisshowsuponlyduringtheoutputvoltagetransitionintervalsasthecomparatorchangesstates.Powersupplybypassingisnotrequiredtosolvethisproblem.StandardPCboardlayoutishelpfulasitreducesstrayinput-outputcoupling.Reducingthisinputresistorsto10kreducesthefeedbacksignallevelsandfinally,addingevenasmallamount(1to10mv)ofpositivefeedback(hysteresis)causessucharapidtransitionthatoscillationsduetostrayfeedbackarenotpossible.SimplysocketingtheICandattachingresistorstothepinswillcauseinput-outputoscillationsduringthesmalltransitionintervalsunlesshysteresisisused.Iftheinputsignalisapulsewaveform,withrelativelyfastriseandfalltimes,hysteresisisnotrequired.Allpinsofanyunusedcomparatorsshouldbetiedtothenegativesupply.ThebiasnetworkofLM339establishesadraincurrentwhichisindependentofthemagnitudeofthepowersupplyvoltageovertherangeoffrom2Vto30V.Itisusuallyunnecessarytouseabypasscapacitoracrossthepowersupplyline.ThedifferentialinputvoltagemaybelargerthanV+withoutdamagingthedevice.Protectionshouldbeprovidedtopreventtheinputvoltagesfromgoingnegativemorethan-0.3VDC(at25℃).Aninputclampdiodecanbeusedasshownintheapplicationssection.TheoutputoftheLM339istheuncommittedcollectorofagrounded-emitterNPNoutputtransistor.ManycollectorscanbetiedtogethertoprovideanoutputORingfunction.Anoutputpull-upresistorcanbeconnectedtoanyavailablepowersupplyvoltagewithinthepermittedsupplyvoltagerangeandthereisnorestrictiononthisvoltageduetothemagnitudeofthevoltagewhichisappliedtotheV+terminaloftheLM1339package.TheoutputcanalsobeusedasasimpleSPSTswitchtoground(whenapull-upresistorisnotused).Theamountofcurrentwhichtheoutputdevicecansinkislimitedbythedriveavailable(whichisindependentofV+)andtheofthisdevice.Whenthemaximumcurrentlimitisreached(approximately16mA),theoutputtransistorwillcomeoutofsaturationandtheoutputvoltagewillriseveryrapidly.Theoutputsaturationvoltageislimitedbytheapproximately60RSAToftheoutputtransistor.Thelowoffsetvoltageoftheoutputtransistor(1mV)allowstheoutputtoclampessentiallytogroundlevelforsmallloadcurrents.ProductManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.FAQWhatisLM339?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.

DescriptionThe74HC595isanhighspeedCMOS8-BITSHIFTREGISTERS/OUTPUTLATCHES(3-STATE)fabricatedwithsilicongateC2MOStechnology.Thisdevicecontainsan8-bitserial-in,parallel-outshiftregisterthatfeedsan8-bitD-typestorageregister.Thestorageregisterhas83-STATEoutputs.Separateclocksareprovidedforboththeshiftregisterandthestorageregister.Theshiftregisterhasadirect-overridingclear,serialinput,andserialoutput(standard)pinsforcascading.Boththeshiftregisterandstorageregisterusepositive-edgetriggeredclocks.Ifbothclocksareconnectedtogether,theshiftregisterstatewillalwaysbeoneclockpulseaheadofthestorageregister.Allinputsareequippedwithprotectioncircuitsagainststaticdischargeandtransientexcessvoltage.TheShiftRegister:Explained[74HC595]CatalogDescriptionFeaturesApplicationPinoutLogicDiagramParametersComponentDatasheetPackageProductManufacturerFAQOrdering&QuantityFeaturesLowquiescentcurrent:80AmaximumLowinputcurrent:1Amaximum8-bitserial-in,parallel-outshiftregisterwithstorageWideoperatingvoltagerange:2V~6VShiftregisterhasdirectclearGuaranteedshiftfrequency:DCto30MHzPackage:SOP16ApplicationSerial-to-paralleldataconversionRemotecontrolholdingregisterPinoutPinNo.SymbolNameandFunction1,2,3,4,5,6,7,15QAtoQHDataoutput8GNDGround(0V)9QHSerialdataoutput10SCLRShiftregisterclearinput11SCKShiftregisterclockinput12RCKStorageregisterclockinput13GOutputenableinput14SISerialdatainput16VCCPositivesupplyvoltageLogicDiagramParametersBrandNameDiodesLow-powerconsumptionWhenTA=25℃,Icc=4A(MAX)LowquiescentcurrentMaximum80ALowinputcurrentMaximum1AWideoperatingvoltagerange2V-6VPackageDIP16/SOP16ComponentDatasheetDatasheet74HC595DatasheetPackageProductManufacturerDiodesIncorporatedisaleadingglobalmanufacturerandsupplierofhigh-qualityapplicationspecificstandardproductswithinthebroaddiscrete,logic,analog,andmixed-signalsemiconductormarkets.DiodescorporateheadquartersandAmericassalesofficearelocatedinPlano,Texas,andMilpitas,California.Diodesservetheconsumerelectronics,computing,communications,industrial,andautomotivemarkets.Diodesproductsincludediodes,rectifiers,transistors,MOSFETs,protectiondevices,function-specificarrays,singlegatelogic,amplifiersandcomparators,Hall-effectandtemperaturesensors,powermanagementdevices,includingLEDdrivers,AC-DCconvertersandcontrollers,DC-DCswitchingandlinearvoltageregulators,andvoltagereferencesalongwithspecialfunctiondevices,suchasUSBpowerswitches,loadswitches,voltagesupervisors,andmotorcontrollers.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.DescriptionTheMMBT3904LT1GisaNPNsiliconBipolarTransistor,designedforuseinlinear,lowerpowersurfacemountandswitchingapplications.MMBT3904LT1GHowdoesatransistorwork?CatalogMMBT3904LT1GDescriptionMMBT3904LT1GPinoutMMBT3904LT1GFeaturesMMBT3904LT1GMarkingDiagramMMBT3904LT1GCADModelsMMBT3904LT1GFunctionalEquivalentsMMBT3904LT1GPackageOutlinesMMBT3904LT1GPopularitybyRegionMMBT3904LT1GMarketingPriceAnalysisMMBT3904LT1GManufacturerComponentDatasheetFAQOrdering&QuantityMMBT3904LT1GPinoutMMBT3904LT1GFeaturesTheseDevicesarePbFree,HalogenFree/BFRFreeandareRoHSCompliantSPrefixforAutomotiveandOtherApplicationsRequiringUniqueSiteandControlChangeRequirements;AECQ101QualifiedandPPAPCapableMMBT3904LT1GMarkingDiagramMMBT3904LT1GCADModelsPartSymbolFootprint3DModelMMBT3904LT1GFunctionalEquivalentsMMBT3904LT1GPackageOutlinesMMBT3904LT1GPopularitybyRegionMMBT3904LT1GMarketingPriceAnalysisMMBT3904LT1GManufacturerONSemiconductor(Nasdaq:ON)isdrivingenergyefficientinnovations,empoweringcustomerstoreduceglobalenergyuse.Thecompanyoffersacomprehensiveportfolioofenergyefficientpowerandsignalmanagement,logic,discreteandcustomsolutionstohelpdesignengineerssolvetheiruniquedesignchallengesinautomotive,communications,computing,consumer,industrial,LEDlighting,medical,military/aerospaceandpowersupplyapplications.ONSemiconductoroperatesaresponsive,reliable,world-classsupplychainandqualityprogram,andanetworkofmanufacturingfacilities,salesofficesanddesigncentersinkeymarketsthroughoutNorthAmerica,Europe,andtheAsiaPacificregions.ComponentDatasheetMMBT3904LT1GDatasheetFAQWhatisMMBT3904LT1G?TheMMBT3904LT1GisaNPNsiliconBipolarTransistor,designedforuseinlinear,lowerpowersurfacemountandswitchingapplications.Whatisatransistor?Atransistorisasemiconductordeviceusedtoamplifyorswitchelectronicsignalsandelectricalpower.Itiscomposedofsemiconductormaterialusuallywithatleastthreeterminalsforconnectiontoanexternalcircuit.WhatisPNPtransistor?APNPtransistorisabipolarjunctiontransistorconstructedbysandwichinganN-typesemiconductorbetweentwoP-typesemiconductors.APNPtransistorhasthreeterminalsaCollector(C),Emitter(E)andBase(B).ThePNPtransistorbehavesliketwoPNjunctionsdiodesconnectedbacktoback.Whatdoesatransistordo?Atransistor,alsoknownasaBJT(BipolarJunctionTransistor),isacurrentdrivensemiconductordevicewhichcanbeusedtocontroltheflowofelectriccurrentinwhichasmallamountofcurrentintheBaseleadcontrolsalargercurrentbetweentheCollectorandEmitter.Howmanytypesoftransistorarethere?Transistorsarebasicallyclassifiedintotwotypes;theyareBipolarJunctionTransistors(BJT)andFieldEffectTransistors(FET).TheBJTsareagainclassifiedintoNPNandPNPtransistors.TheFETtransistorsareclassifiedintoJFETandMOSFET.Whatistransistordiagram?DiagramAshowsanNPNtransistorwhichisoftenusedasatypeofswitch.Asmallcurrentorvoltageatthebaseallowsalargervoltagetoflowthroughtheothertwoleads(fromthecollectortotheemitter).ThecircuitshownindiagramBisbasedonanNPNtransistor.Whentheswitchispressedacurrentpassesthroughtheresistorintothebaseofthetransistor.Thetransistorthenallowscurrenttoflowfromthe+9voltstothe0vs,andthelampcomeson.Thetransistorhastoreceiveavoltageatitsbaseanduntilthishappensthelampdoesnotlight.Whatarethetwomainappilcationsoftransistor?Transistorsarecommonlyusedindigitalcircuitsaselectronicswitcheswhichcanbeeitherinanonoroffstate,bothforhigh-powerapplicationssuchasswitched-modepowersuppliesandforlow-powerapplicationssuchaslogicgates.