Tkool Electronics

IIntroductionHere,youcanlearnabouttheAD620instrumentamplifiercircuit.Besides,youcanalsobrowseAD620mainfeatures,workingprinciples,andapplications.Thisbloggenerallydiscussesthefollowing3basicquestions:1.Whatisaninstrumentationamplifier;2.Howdoesitwork;3.Howandwheretouse.Figure1.AD620CatalogIIntroductionIIDescriptionIIIAD620TechnicalIndicatorsIVAD620WorkingPrincipleVAD620ApplicationVIConclusionFAQOrdering&QuantityIIDescriptionOperationalamplifiershaveevolvedoverthedecadesandasaresult,thereisawidevarietyofthem.Theycanbeeasilycategorizedaccordingtotheirapplicationrequirements.Themaincategoriesincludegeneral-purpose,low-voltage,low-power,high-speed,andhigh-precisiontypes.Inrecentyears,applicationssuchasconsumerelectronics,communication,andnetworkinghavebeendevelopingcontinuously.Andtheseconstantlydevelopingindustriesalsoputforwardnewtechnicalrequirementsforop-ampproducts.AD620instrumentamplifieristheproductofADcompany.Duetoitssupertechnology,AD620hasthefollowingcharacteristics:1.3mAMaximumWorkingCurrent5VInputOffsetVoltage1V/℃InputOffsetDriftMaximum93dBCommonModeRejectionRatioAdjustableGainRangeEasytoAdjustandLowNoise.AndwhycanAD620becomeanindustry-standardhigh-performance,low-costinstrumentationamplifier?ThatsbecausethecoreofAD620isathree-stageop-ampcircuit,whichhasahighcommon-moderejectionratio,goodtemperaturestability,wideamplificationband,andlownoise.Andithasthecharacteristicsofhighaccuracy,easyuse,andlownoise.sothisisalsothereasonwhyAD620canbesopopular.IIIAD620TechnicalIndicatorsThemaintechnicalindicatorsofAD620areasfollows:Bandwidth800MHzOutputpower2.4mWPowergain120dBWorkingvoltage15VStaticpowerconsumption0.48mWInoltage60VConversionrate1.2V/SPackageformDIP8Operatingtemperaturerange-55℃~+125℃IVAD620WorkingPrincipleThefunctionalstructureoftheAD620amplifierisshowninFig.2.Figure2.AD620FunctionalBlockDiagramDoyouknowwhatthecharacteristicsofthisamplifierare?Theansweris:differentialinput,asingle-endedoutput.ThevoltagegaincanbedeterminedbyaresistorRG.Thegainsareadjustable,whichsolvestheproblemofconnectingthesubsequentloadtotheground.Besides,A1andA2formadifferentialinputandadifferentialoutputwithin-phasehighinputimpedanceandundertakeallgainamplificationtasks.Becausethecircuitstructureissymmetrical,whichmeanswhenthegainchanges,theinputimpedancedoesnotchange.ThefeedbackresistanceRl=R2=24.7k.Thecommon-modegain,offset,drift,andothererrorsoftheamplifiersA1andA2aremutuallycompensated.ThegainofthelatterstageA3is1,whichhasahighercommon-moderejectionratioandanti-interferenceability.AD620isamonolithicintegratedamplifier.Anditisdevelopedonthebasisoftheimprovementofthetraditionalthree-opamplifiercombination.AsshowninFigure2,theinputtransistorsQ1andQ2providetheonlybipolardifferentialinput.Duetotheinternalultra-processing,itsinputoffsetcurrentis10timeslowerthanthegeneralcase.ThroughthefeedbackoftheQ1-A1-R1loopandtheQ2-A2-R2loop,theintegratedpolecurrentofQ1andQ2iskeptconstant.SotheinputvoltageisequivalenttothetwoendsoftheexternalresistorRG.ThedifferentialamplificationfactorfrominputtoA1/A2outputisG=(R1+R2)/RG+1.TheunitygainsubtractorcomposedofA3eliminatesanycommon-modecomponents.Thereby,itproducesasingle-channeloutputrelatedtothepotentialoftheREFpin.Figure3.AD620SowhataboutRG?ThevalueofRGalsodeterminesthetransconductanceofthepreviousstageop-amp.WhenRGdecreases,themagnificationincreases.WhenRGdecreases,thetransconductancetotheinputtransistorgraduallyincreases.Thishasthefollowingtwoobviousadvantages:First,theincreaseintheamplificationfactorincreasestheopen-loopgain.Therebyreducingthegain-bandwidthproductandincreasingthefrequencyresponse;Second,itismainlydeterminedbytheinputtransistorcollectorcurrentandbaseresistance.ByaccuratelycorrectingthevalueoftheinternalgainresistorsR1andR2to24.7k,wecanmaketheoperationalamplifiergain(derivedbycalculation)accuratelydeterminedbyRG:G=49.4k/RG+1orRG=49.4k/(G-1)Figure4.AD620CircuitStructureDiagramRGistheexternalgainadjustment.Tomeettherequiredamplificationfactor,wecanconnectthishigh-precisionresistancebetweenpin1and8.ByusingtheamplifierAD620,thegainerrorcanbelessthan0.01%,andthenon-linearityislessthan0.002%.Fromtheapplicationpointofview,AD620isparticularlysuitableforapplications.Suchassensorinterface,ECGmonitor,precisionvoltagecurrentconversionandotherapplications.Ifweanalyzethecircuittechnologyperformance,wewilladeeperunderstandingofAD620.Thatis,AD620isactuallyalow-power,high-precisioninstrument,broadbandintegratedoperationalamplifier.VAD620ApplicationInstrumentationamplifiersaresometimesmisunderstoodbypeople.Here,weneedtopointout2ideas:First,notallamplifiersusedforinstrumentationareinstrumentationamplifiers;Second,allinstrumentationamplifiersarebynomeansonlyusedforinstrumentation.Instrumentationamplifiersareusedinmanyfields.Frommotorcontroltodataacquisitionandautomotivesystems.Instrumentationamplifierisaclosed-loopgainunit.Andwithdifferentialinputandsingle-endedoutputrelativetothereferenceend.Inmostcases,theimpedanceofthetwoinputendsoftheinstrumentationamplifierisbalanced.Theresistanceisveryhigh,anditstypicalvalueis109.Theinputbiascurrentisalsoverylow,typically1nAto50nA.Liketheoperationalamplifier,itsoutputimpedanceisverylow,usuallyonlyafewmilliohmsinthelowfrequencyrange.Theclosed-loopgainofanoperationalamplifierisdeterminedbytheexternalresistance.Theexternalresistanceisconnectedbetweenitsinvertinginputandoutput.Therearedifferencesbetweentheinstrumentamplifierandtheamplifier.Theinstrumentamplifierusesaninternalfeedbackresistornetwork,whichisisolatedfromitssignalinput.Toapplyinputsignalstothetwodifferentialinputterminalsoftheinstrumentationamplifier.Thegaincaneitherbepresetinternallyorsetbytheuser.Throughapinconnectedtoaninternalorexternalgainresistor,whichisalsoisolatedfromthesignalinputterminal.Figure5showsablockdiagramofadifferentialamplifier.Figure5.DifferentialAmplifierICThistypeofICisaspecial-purposeinstrumentationamplifier.Anditwhichusuallyconsistsofasubtractoramplifierfollowedbyanoutputbuffer(perhapsone-stagegain).ThefourresistorsusedforthesubtractorareusuallyinsidetheIC,sotheycanbepreciselymatchedtoachieveahigherCMR.Manydifferentialamplifiersaresuitableforapplications.Wherethecommon-modevoltageandsignalvoltagemayeasilyexceedthesupplyvoltage.Thesedifferentialamplifiersusuallyusehigh-valueinputresistorstoattenuatethesignal.Generallyspeaking,instrumentationamplifiersanddifferentialamplifiersareusedinthefollowingranges:DataAcquisitionThemainpurposeoftheinstrumentationamplifieristoamplifytheweaksignaloutputbythesensorinanoisyenvironment.Amplificationofsignalsfrompressuresensorsortemperaturesensorsiscommon.Commonbridgeapplicationsincludestrainforceandweightmeasurement.MedicalInstrumentsInstrumentationamplifiersarewidelyusedinmedicalequipment.Suchaselectrocardiographsandelectroencephalographs,bloodpressuremonitors,anddefibrillators.Thedifferentialamplifierofmonitoringandcontrolelectronicscanbeusedtomonitorthevoltageandcurrentinthesystemandtriggerthealarmsystemwhenthenormalvalueisexceeded.Becausedifferentialamplifiershavetheabilitytosuppresshighcommon-modevoltages,theyareoftenusedinsuchapplications.Figure6.ElectrocardiographSoftwareProgrammableApplicationsToallowsoftwaretocontrolthehardwaresystem,wecanturntoinstrumentationamplifiers.Instrumentationamplifierscanbeusedonchipswithsoftwareprogrammableresistors.AudioApplicationsBecauseinstrumentationamplifiershavehighCMR,theyareusedforaudio(e.g.microphonepreamplifiers)toextractweaksignalsinnoisyenvironments.Also,itcanbeusedtominimizetheoffsetcausedbygroundloopsVoltageandnoise.High-speedSignalConditioningDuetotheincreasedspeedandaccuracyrequirementsoftodaysvideodataacquisitionsystems,thedemandforbroadbandinstrumentationamplifiersisincreasing.EspeciallyinthefieldofCCDimagingequipmentthatrequiresoffsetcorrectionandinputbuffering.Inthisfield,doublecorrectionsamplingtechnologyisusuallyusedtocorrecttheCCDimage.Generallyusetwosample-and-holdamplifierstomonitortheimageandreferencelevel,andsendthesignalvoltagetoaninstrumentationamplifiertoprovideaDCcorrectionoutput.Figure7.CCDCameraVideoApplicationsHigh-speedinstrumentationamplifiersareusedinmanyvideoandcableradiofrequency(RF)systemstoamplifyorprocesshigh-frequencysignals.PowerControlApplicationsInstrumentationamplifierscanalsomonitorthemotor(monitoringandcontrollingthemotorsspeed,torque,etc.)bymeasuringthemotorsvoltage,currentandthephaserelationshipofthethree-phaseACmotor.Thedifferentialamplifierisusedwhentheinputsignalvoltageexceedsthepowersupplyvoltage.VIConcusionGenerallyspeaking,high-speedoperationalamplifiersaremainlyusedincommunicationequipment,videosystems,andtestandmeasurementinstruments.Advancedapplicationsintestandmeasurement,communications,medical,imagingandotherfieldsarethemaindrivingforcestoimproveamplifierperformance;DSLandconsumervideoapplicationsareitslargestmarkets.FAQWhatisAD620?AD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyrequiresanexternalresistortosetthegain.Thegainrangeis1to10,000.CanIchangeAD620toAD623whenmakingMCUproducts?BothAD620andAD623aresingleinstrumentationamplifiers,andthepinarrangementisexactlythesame.Themaindifferenceis:AD620mustusepositiveandnegativepowersupplies,AD623canbeapositiveandnegativepowersupplyorasinglepowersupply.IftheoriginalboardisAD620,youcanreplaceitwith623;iftheoriginalboardisAD623,youmaynotbeabletoreplaceitwith620(itdependsonwhetherthepowersupplyoftheoriginalboardcircuitisdualpowersupplyorsinglepowersupply).AfterreplacingAD620andAD623insingle-chipproducts,theprogramcanworknormallywithoutmodification.WhatisthedifferencebetweenAD620BRandAD620AN?Theirpackagesaredifferent.WhatistheoutputresistanceofAD620?Howtoadjustit?AD620isakindoflowpowerconsumptioninstrumentamplifier,itsoutputresistanceisabout10K,thisistheinherentcharacteristicofthischip,generallyitisdifficulttoadjust.Ifyouhaverequirementsforoutputresistance,youcangenerallyuseanexternalcircuittosolveit.IsAD620apositivephaseamplificationorareversephaseamplification?AD620isaninstrumentamplifier,theoutputvoltageis[(Vin+)-(Vin-)]*gain.Ifthedesiredsignalis(Vin+)-(Vin-),thegainispositive,whichisequivalenttopositiveamplification.Conversely,ifthedesiredsignalis(Vin-)-(Vin+),thegainisequivalenttonegative,whichisequivalenttoreverseamplification.Whatisaninstrumentationamplifier?Instrumentationamplifier,animprovementofthedifferentialamplifier,hasaninputbuffer,doesnotrequireinputimpedancematching,sothattheamplifierissuitableformeasurementandelectronicinstruments

593D107X9010D2TE3-VISHAY

IIntroductionHere,youcanlearnabouttheAD620instrumentamplifiercircuit.Besides,youcanalsobrowseAD620mainfeatures,workingprinciples,andapplications.Thisbloggenerallydiscussesthefollowing3basicquestions:1.Whatisaninstrumentationamplifier;2.Howdoesitwork;3.Howandwheretouse.Figure1.AD620CatalogIIntroductionIIDescriptionIIIAD620TechnicalIndicatorsIVAD620WorkingPrincipleVAD620ApplicationVIConclusionFAQOrdering&QuantityIIDescriptionOperationalamplifiershaveevolvedoverthedecadesandasaresult,thereisawidevarietyofthem.Theycanbeeasilycategorizedaccordingtotheirapplicationrequirements.Themaincategoriesincludegeneral-purpose,low-voltage,low-power,high-speed,andhigh-precisiontypes.Inrecentyears,applicationssuchasconsumerelectronics,communication,andnetworkinghavebeendevelopingcontinuously.Andtheseconstantlydevelopingindustriesalsoputforwardnewtechnicalrequirementsforop-ampproducts.AD620instrumentamplifieristheproductofADcompany.Duetoitssupertechnology,AD620hasthefollowingcharacteristics:1.3mAMaximumWorkingCurrent5VInputOffsetVoltage1V/℃InputOffsetDriftMaximum93dBCommonModeRejectionRatioAdjustableGainRangeEasytoAdjustandLowNoise.AndwhycanAD620becomeanindustry-standardhigh-performance,low-costinstrumentationamplifier?ThatsbecausethecoreofAD620isathree-stageop-ampcircuit,whichhasahighcommon-moderejectionratio,goodtemperaturestability,wideamplificationband,andlownoise.Andithasthecharacteristicsofhighaccuracy,easyuse,andlownoise.sothisisalsothereasonwhyAD620canbesopopular.IIIAD620TechnicalIndicatorsThemaintechnicalindicatorsofAD620areasfollows:Bandwidth800MHzOutputpower2.4mWPowergain120dBWorkingvoltage15VStaticpowerconsumption0.48mWInoltage60VConversionrate1.2V/SPackageformDIP8Operatingtemperaturerange-55℃~+125℃IVAD620WorkingPrincipleThefunctionalstructureoftheAD620amplifierisshowninFig.2.Figure2.AD620FunctionalBlockDiagramDoyouknowwhatthecharacteristicsofthisamplifierare?Theansweris:differentialinput,asingle-endedoutput.ThevoltagegaincanbedeterminedbyaresistorRG.Thegainsareadjustable,whichsolvestheproblemofconnectingthesubsequentloadtotheground.Besides,A1andA2formadifferentialinputandadifferentialoutputwithin-phasehighinputimpedanceandundertakeallgainamplificationtasks.Becausethecircuitstructureissymmetrical,whichmeanswhenthegainchanges,theinputimpedancedoesnotchange.ThefeedbackresistanceRl=R2=24.7k.Thecommon-modegain,offset,drift,andothererrorsoftheamplifiersA1andA2aremutuallycompensated.ThegainofthelatterstageA3is1,whichhasahighercommon-moderejectionratioandanti-interferenceability.AD620isamonolithicintegratedamplifier.Anditisdevelopedonthebasisoftheimprovementofthetraditionalthree-opamplifiercombination.AsshowninFigure2,theinputtransistorsQ1andQ2providetheonlybipolardifferentialinput.Duetotheinternalultra-processing,itsinputoffsetcurrentis10timeslowerthanthegeneralcase.ThroughthefeedbackoftheQ1-A1-R1loopandtheQ2-A2-R2loop,theintegratedpolecurrentofQ1andQ2iskeptconstant.SotheinputvoltageisequivalenttothetwoendsoftheexternalresistorRG.ThedifferentialamplificationfactorfrominputtoA1/A2outputisG=(R1+R2)/RG+1.TheunitygainsubtractorcomposedofA3eliminatesanycommon-modecomponents.Thereby,itproducesasingle-channeloutputrelatedtothepotentialoftheREFpin.Figure3.AD620SowhataboutRG?ThevalueofRGalsodeterminesthetransconductanceofthepreviousstageop-amp.WhenRGdecreases,themagnificationincreases.WhenRGdecreases,thetransconductancetotheinputtransistorgraduallyincreases.Thishasthefollowingtwoobviousadvantages:First,theincreaseintheamplificationfactorincreasestheopen-loopgain.Therebyreducingthegain-bandwidthproductandincreasingthefrequencyresponse;Second,itismainlydeterminedbytheinputtransistorcollectorcurrentandbaseresistance.ByaccuratelycorrectingthevalueoftheinternalgainresistorsR1andR2to24.7k,wecanmaketheoperationalamplifiergain(derivedbycalculation)accuratelydeterminedbyRG:G=49.4k/RG+1orRG=49.4k/(G-1)Figure4.AD620CircuitStructureDiagramRGistheexternalgainadjustment.Tomeettherequiredamplificationfactor,wecanconnectthishigh-precisionresistancebetweenpin1and8.ByusingtheamplifierAD620,thegainerrorcanbelessthan0.01%,andthenon-linearityislessthan0.002%.Fromtheapplicationpointofview,AD620isparticularlysuitableforapplications.Suchassensorinterface,ECGmonitor,precisionvoltagecurrentconversionandotherapplications.Ifweanalyzethecircuittechnologyperformance,wewilladeeperunderstandingofAD620.Thatis,AD620isactuallyalow-power,high-precisioninstrument,broadbandintegratedoperationalamplifier.VAD620ApplicationInstrumentationamplifiersaresometimesmisunderstoodbypeople.Here,weneedtopointout2ideas:First,notallamplifiersusedforinstrumentationareinstrumentationamplifiers;Second,allinstrumentationamplifiersarebynomeansonlyusedforinstrumentation.Instrumentationamplifiersareusedinmanyfields.Frommotorcontroltodataacquisitionandautomotivesystems.Instrumentationamplifierisaclosed-loopgainunit.Andwithdifferentialinputandsingle-endedoutputrelativetothereferenceend.Inmostcases,theimpedanceofthetwoinputendsoftheinstrumentationamplifierisbalanced.Theresistanceisveryhigh,anditstypicalvalueis109.Theinputbiascurrentisalsoverylow,typically1nAto50nA.Liketheoperationalamplifier,itsoutputimpedanceisverylow,usuallyonlyafewmilliohmsinthelowfrequencyrange.Theclosed-loopgainofanoperationalamplifierisdeterminedbytheexternalresistance.Theexternalresistanceisconnectedbetweenitsinvertinginputandoutput.Therearedifferencesbetweentheinstrumentamplifierandtheamplifier.Theinstrumentamplifierusesaninternalfeedbackresistornetwork,whichisisolatedfromitssignalinput.Toapplyinputsignalstothetwodifferentialinputterminalsoftheinstrumentationamplifier.Thegaincaneitherbepresetinternallyorsetbytheuser.Throughapinconnectedtoaninternalorexternalgainresistor,whichisalsoisolatedfromthesignalinputterminal.Figure5showsablockdiagramofadifferentialamplifier.Figure5.DifferentialAmplifierICThistypeofICisaspecial-purposeinstrumentationamplifier.Anditwhichusuallyconsistsofasubtractoramplifierfollowedbyanoutputbuffer(perhapsone-stagegain).ThefourresistorsusedforthesubtractorareusuallyinsidetheIC,sotheycanbepreciselymatchedtoachieveahigherCMR.Manydifferentialamplifiersaresuitableforapplications.Wherethecommon-modevoltageandsignalvoltagemayeasilyexceedthesupplyvoltage.Thesedifferentialamplifiersusuallyusehigh-valueinputresistorstoattenuatethesignal.Generallyspeaking,instrumentationamplifiersanddifferentialamplifiersareusedinthefollowingranges:DataAcquisitionThemainpurposeoftheinstrumentationamplifieristoamplifytheweaksignaloutputbythesensorinanoisyenvironment.Amplificationofsignalsfrompressuresensorsortemperaturesensorsiscommon.Commonbridgeapplicationsincludestrainforceandweightmeasurement.MedicalInstrumentsInstrumentationamplifiersarewidelyusedinmedicalequipment.Suchaselectrocardiographsandelectroencephalographs,bloodpressuremonitors,anddefibrillators.Thedifferentialamplifierofmonitoringandcontrolelectronicscanbeusedtomonitorthevoltageandcurrentinthesystemandtriggerthealarmsystemwhenthenormalvalueisexceeded.Becausedifferentialamplifiershavetheabilitytosuppresshighcommon-modevoltages,theyareoftenusedinsuchapplications.Figure6.ElectrocardiographSoftwareProgrammableApplicationsToallowsoftwaretocontrolthehardwaresystem,wecanturntoinstrumentationamplifiers.Instrumentationamplifierscanbeusedonchipswithsoftwareprogrammableresistors.AudioApplicationsBecauseinstrumentationamplifiershavehighCMR,theyareusedforaudio(e.g.microphonepreamplifiers)toextractweaksignalsinnoisyenvironments.Also,itcanbeusedtominimizetheoffsetcausedbygroundloopsVoltageandnoise.High-speedSignalConditioningDuetotheincreasedspeedandaccuracyrequirementsoftodaysvideodataacquisitionsystems,thedemandforbroadbandinstrumentationamplifiersisincreasing.EspeciallyinthefieldofCCDimagingequipmentthatrequiresoffsetcorrectionandinputbuffering.Inthisfield,doublecorrectionsamplingtechnologyisusuallyusedtocorrecttheCCDimage.Generallyusetwosample-and-holdamplifierstomonitortheimageandreferencelevel,andsendthesignalvoltagetoaninstrumentationamplifiertoprovideaDCcorrectionoutput.Figure7.CCDCameraVideoApplicationsHigh-speedinstrumentationamplifiersareusedinmanyvideoandcableradiofrequency(RF)systemstoamplifyorprocesshigh-frequencysignals.PowerControlApplicationsInstrumentationamplifierscanalsomonitorthemotor(monitoringandcontrollingthemotorsspeed,torque,etc.)bymeasuringthemotorsvoltage,currentandthephaserelationshipofthethree-phaseACmotor.Thedifferentialamplifierisusedwhentheinputsignalvoltageexceedsthepowersupplyvoltage.VIConcusionGenerallyspeaking,high-speedoperationalamplifiersaremainlyusedincommunicationequipment,videosystems,andtestandmeasurementinstruments.Advancedapplicationsintestandmeasurement,communications,medical,imagingandotherfieldsarethemaindrivingforcestoimproveamplifierperformance;DSLandconsumervideoapplicationsareitslargestmarkets.FAQWhatisAD620?AD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyrequiresanexternalresistortosetthegain.Thegainrangeis1to10,000.CanIchangeAD620toAD623whenmakingMCUproducts?BothAD620andAD623aresingleinstrumentationamplifiers,andthepinarrangementisexactlythesame.Themaindifferenceis:AD620mustusepositiveandnegativepowersupplies,AD623canbeapositiveandnegativepowersupplyorasinglepowersupply.IftheoriginalboardisAD620,youcanreplaceitwith623;iftheoriginalboardisAD623,youmaynotbeabletoreplaceitwith620(itdependsonwhetherthepowersupplyoftheoriginalboardcircuitisdualpowersupplyorsinglepowersupply).AfterreplacingAD620andAD623insingle-chipproducts,theprogramcanworknormallywithoutmodification.WhatisthedifferencebetweenAD620BRandAD620AN?Theirpackagesaredifferent.WhatistheoutputresistanceofAD620?Howtoadjustit?AD620isakindoflowpowerconsumptioninstrumentamplifier,itsoutputresistanceisabout10K,thisistheinherentcharacteristicofthischip,generallyitisdifficulttoadjust.Ifyouhaverequirementsforoutputresistance,youcangenerallyuseanexternalcircuittosolveit.IsAD620apositivephaseamplificationorareversephaseamplification?AD620isaninstrumentamplifier,theoutputvoltageis[(Vin+)-(Vin-)]*gain.Ifthedesiredsignalis(Vin+)-(Vin-),thegainispositive,whichisequivalenttopositiveamplification.Conversely,ifthedesiredsignalis(Vin-)-(Vin+),thegainisequivalenttonegative,whichisequivalenttoreverseamplification.Whatisaninstrumentationamplifier?Instrumentationamplifier,animprovementofthedifferentialamplifier,hasaninputbuffer,doesnotrequireinputimpedancematching,sothattheamplifierissuitableformeasurementandelectronicinstruments

IDescriptionThisblogintroducesasimplemethodtodrivesteppermotorsusingL297andL298chips.Thesteppingmotordrivesystemdesignedbythismethodhasthefollowingcharacteristics:simplehardwarestructure,easysoftwareprogrammingandlowprice.IDescriptionIIIntroductionIIIL297andL298Hardwarecircuit3.1L297Overview3.2L298Overview3.3L297andL298CircuitIVSoftwaredesignFAQOrdering&QuantityIIIntroductionSteppermotorisoneofthecommonlyusedembeddedmotioncontrolequipmentinindustrialcontrol.Thisisbecausesteppermotorscanmoveatdiscretesteps,provideaccurateangularpositioninformation,andareeasiertocontrol.WiththeuseofL297andL298chipstogether,arelativelylowpricecanbeusedtoformasteppermotordrivecircuitwithgoodperformance.StandardsteppermotordriverusingL297andL298ICIIIL297andL298Hardwarecircuit3.1L297OverviewL297isasteppermotorcontroller.Itissuitableforthecontrolofbipolartwo-phasesteppermotorsorunipolarfour-phasesteppermotors.Therearethreedrivemodes:half-step,full-step,andwave.Theon-chipPWMchoppercircuitallowsswitchingcontrolofthewindingcurrent.Anotablefeatureofl297isthatonlyclock,direction,andmodeinputsignalsarerequired.Thephaserequiredbythesteppingmotorisgeneratedinsidethecircuit,whichgreatlyreducestheburdenontheCPU.L297hasthefollowingcharacteristics:Normal/wavedriveHalf/fullstepmodesClockwise/anticlockwisedirectionSwitchmodeloadcurrentregulationProgrammableloadcurrentFewexternalcomponentsResetinputhomeoutputEnableinput3.2L298OverviewL298isahigh-voltageandhigh-currentdualfull-bridgedriverwithtwoH-bridges.ItacceptsstandardTTLlogiclevelsignalsandcandrivesteppermotorswithavoltageof46Vand2.5Aperphaseorbelow.Eachbridgehasanenableinput,whichallowsorprohibitsthedevicetoworkwithoutbeingaffectedbytheinputsignal.Theemittersofthetwolow-endtransistorsofeachbridgeareconnectedtogetherandledoutforexternaldetectionresistance.Itsetsanadditionalpowerinputterminaltomakethelogicpartworkatlowvoltage.Figure1.L298internallogicdiagram(halfofthediagram)L298hasthefollowingcharacteristics:Operatingsupplyvoltageupto46vTotalDCcurrentupto4A25wratedpower2enablecontrolterminalstoenableordevicewithoutinputtingsignals.Abletodriveatwo-phasesteppermotor,four-phasesteppermotorortwoDCmotorsBuilt-instabilivolttube78M05canbeusedtoobtain5vfrompowersupply.(Mustbeusedwithanexternal5vlogicsupplywhendrivevoltageisgreaterthan12vtoprotectthechip)LowsaturationvoltageOvertemperatureprotectionLogical0inputvoltageupto1.5V(highnoiseimmunity)Operatingtemperature:-23Cto130CStorageTemperature:-40Cto150C3.3L297andL298CircuitL297andL298canbeusedtomakeatwo-phasebipolarsteppermotordrivecircuit.Itisdrivenbyaconstantcurrentmode,andthepeakcurrentofeachphasecanreach2A.L297isasteppermotorcontrollerthatisusedtogeneratetwo-phasebipolar.Drivesignal(A,B,C,D)andmotorcurrentsettings.L298isusedtodrivethepoweroutputofthesteppermotor.Itisdrivenbyadoublefullbridgemode.Duetothebipolardrive,themotorcoilisfullyutilizedtoenableintothemotorcanachievethebestdrive.WhentwopiecesofL297areusedtodrivethetwowindingsofasteppingmotorthroughL298,andtheVrefcorrespondingtoeachwindingischangedthroughtwoD/Aconverters,asteppingmotorsubdivisiondrivingcircuitisformed.TheprincipleofL297+L298drivewiringisshowninFigure2.PortsP0~P4arerespectivelyconnectedtothecorrespondingcontrolterminalsofL297.Then,throughthereasonablearrangementofthesoftware,thepurposeofcontrollingthemotortorotateintheexpecteddirectionisachieved.Figure2.ElectricalschematicdiagramInaddition,theterminal1ofL297isthesynchronousterminal,whichcanbeconnectedtotheterminal1ofanothergroupofL297andL298drivecircuits.Inthisway,thetwosetsofdriverscanbesynchronizedtoachievetheeffectofdrivingmultiplemotorsatthesametime.IVSoftwaredesignUseClanguagetowriteprogramcode:P0_0=1;//CWP0_1~1;//HALFP0_3=1;//ENABLEP0_2=1;//RESETP0_7=1;//CLOCKTMODone0X01;//TlTH0=(a4000/256);TL0=one(4000%256);TR0=1;for(;;){TH0=one(4000/256);TL0=one(4000%256);do{}while(!TF0);P0_7=!P0_7;//CLOCKTF0=0;}Thespeedofthemotorspeedcanbecontrolledbythetimer.Figure3.WaveformdiagramgeneratedbyL297AccordingtothewaveformgeneratedbyL297,infact,whentheCPUportresourcesarenottight,theCPUcanbeusedtosimulateoutput.Theabovehardwarecircuitsandsoftwareprogramshavebeentestedandarecompletelypractical.FAQWhatisl298n?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.WhatisL297?TheL297integratesallthecontrolcircuitryrequiredtocontrolbipolarandunipolarsteppermotors.UsedwithadualbridgedriversuchastheL298Nformsacompletemicroprocessor-to-bipolarsteppermotorinterface.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.Whatistheuseofl298n?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.I.IntroductiontoGalvanometerThegalvanometerisanimportanttestinginstrument.Itisahigh-sensitivitymechanicalindicatingmeterfordetectingweakelectricity.Itisusedasazero-pointinginstrumentinbridgesandpotentiometers.Itcanalsobeusedtomeasureweakcurrents,voltagesandcharges..Accordingtotheinputmode,itcanbedividedintovoltagetypeandcurrenttype.Generally,voltagetypeismorecommonlyused.Fromthepaneldisplaymodeofthegalvanometer,itcanbedividedintothreetypes:pointertype,digitaltype,andmixedtype.Figure1ThegalvanometerThepointergalvanometercanconvenientlyobservethecontinuouslychangingcurrent,andintuitivelyjudgethedirectionofthecurrentfromthedeflectiondirection,soithasitsuniqueadvantagesinthebridgeexperiment.Thepointergalvanometerscurrentlyusedinphysicalexperimentshavethefollowingshortcomings:(1)Use9Vlaminatedbatterywithsmallcapacity,shortbatterylifeandhighcost;(2)ItsinternalamplifyingcircuitadoptsOP07orICL7650design,withoutpowermanagementcapability,itiseasytocausethebatterytobeconsumedunnecessarily;(3)Duetotheuseofmanydiscretecomponents,theamplifierispronetodriftandunstable.Thispaperusesagalvanometerdesignedbasedonthethree-op-amphighcommon-moderejectionratioandhighstabilityinstrumentationamplifierAD620andMicrochips6-pinMCUPIC10F206tosolvetheaboveproblems.CatalogI.IntroductiontoGalvanometerII.HardwareSystemDesign2.1HardwareSystemBlockDiagram2.2InstrumentationAmplifierAD6202.3MicrocontrollerPIC10F2062.4AmplifyingCircuitofGalvanometer2.5PowerMonitoringandPowerManagementCircuitofGalvanometerIII.SoftwareSystemIV.ConclusionFAQOrdering&QuantityII.HardwareSystemDesign2.1HardwareSystemBlockDiagramTheblockdiagramofthehardwaresystemisshowninFigure2.TheDCvoltagesignalfirstpassesthroughananti-radiofrequencyinterferencelow-passfiltercircuit,weakenstheinterferencesignal,andthensendsittotheinstrumentationamplifierAD620fordifferentialamplification,andthendrivesthepointermetertodisplay.The6-pinmicrocontrollerPIC10F206isresponsibleforthepowermonitoringandpowermanagementofthegalvanometer.Thewholegalvanometeronlyuses3VDCpowersupplyconnectedinserieswithtwoAAbatteries.Figure2Thehardwaresystemblockdiagramofthegalvanomete2.2InstrumentationAmplifierAD620AD620isalow-costandhigh-precisioninstrumentationamplifierlaunchedbytheAmericanADIcompany.Ithasthecharacteristicsofhighaccuracy,lowoffsetvoltage(maximum50uV)andlowoffsetdrift(maximum0.6uV℃/),anditsmaximumoperatingcurrentisonly1.3mA,onlyanexternalresistorisneededtosetthegain,andthegainrangeis1to10000.Inaddition,AD620adopts8-pinSOICandDIPpackage,thesizeissmallerthanthediscretecircuitdesign,andthepowerconsumptionislower,soitissuitableforbattery-poweredinstrumentapplications.Figure3AD620BecauseitsinputstageusesSuperetaprocessing,itcanachievealowinputbiascurrentofupto1.0nA.AD620hasalowinputvoltagenoiseof9nV/Hzat1kHz,apeak-to-peaknoiseof0.28Vinthefrequencybandfrom0.1Hzto10Hz,andaninputcurrentnoiseof0.1pA/Hz,soitcanbeusedasapreamplifierwell.Atthesametime,the0.01%settlingtimeofAD620is15s,whichisverysuitableformultiplexingapplications;andthecostisverylow,enoughtorealizethedesignofaninstrumentationamplifierperchannel.2.3MicrocontrollerPIC10F206PIC10F206isalow-cost,6-pin8-bitflashmicrocontrollerintroducedbytheUSMicrochipcompanythatusesRISCarchitecture.PIC10F206has512wordsofFLASH,24bytesofSRAM,watchdogtimer(WDT),power-onresetcircuit(POR)anddeviceresettimer(DRT)and4MHzinternaloscillator,thuseliminatingtheneedforexternalresetcircuitandthecrystaloscillator,reducessystemcostandpowerconsumption,andenhancessystemreliability.Italsohasawideoperatingvoltagerange(20Vto5.5V).Theabovecharacteristicsmakeitsuitableforapplicationsinprice-sensitiveandbattery-poweredareas.Figure4PIC10F2062.4AmplifyingCircuitofGalvanometerTheamplifyingcircuitofgalvanometertakestheinstrumentamplifierAD620asthecoreelement,asshowninFigure5.ThedifferentialsignaloutputbytheDCbridgeisinputfromthesocketJ1,passesthroughtheanti-radiofrequencyinterferencelow-passfiltercircuit[2]formedbyR1,R2,C1,C2,C3,andreachestheinstrumentationamplifierAD620afterweakeningtheinterferencesignal.D1,D2andR1,R2togetherformtheinputprotectioncircuitofthegalvanometer,whichcanwithstandinputvoltagesoftensofvolts.R3,R4providealoopfortheinputbiascurrentofAD620[1]toensurethatitcanworkstablyandreliably.TheresistanceR0andpotentiometerRP1betweenpin1andpin8ofAD620aregainadjustmentresistors,denotedasRG.R0isconnectedinserieswithRP1tolimittheupperlimitofthemagnificationto495times.ThepotentiometerRP2andR5,R6formthezeroadjustmentcircuitofthegalvanometertogether,realizezeroadjustmentbychangingthevoltageoftheREFpinofAD620.R7andC7formtheoutputlow-passfilterofAD620.R7,D3,D4constitutetheprotectioncircuitofthepointermeterhead.Figure5TheamplifyingcircuitofgalvanometerThemaximumsensitivityofagalvanometerisusually10uV/degreeto15uV/degree,whichcanwellmeettherequirementsoftheexperiment.TheinternalresistanceRgofthegalvanometermeterheadis4.7k,thegainadjustmentresistanceRG=R0+RP1,takeR0=100,R7=1k,whenRP1is0,theamplificationfactorofAD620isTakingintoaccountthepartialpressureofR7andtheinternalresistanceRgofthemeter,themagnificationofthegalvanometerisThecurrentsensitivityofthemeterheadis1Aminute/degree,sothevoltagesensitivityofthemeterheadis4700Vminute/degree.ThesensitivityofthegalvanometerisS=4700/G=115V/divisionMeettherequirementsofphysicalexperiments.2.5PowerMonitoringandPowerManagementCircuitofGalvanometerFigure6isthepowermonitoringandpowermanagementcircuitofthegalvanometer.TheGP2pinofthemicrocontrollerPIC10F206isconnectedwiththeP-channelMOSFETtubeQ1,thepurposeistocontrolwhethertosupplypowertotheamplifyingcircuitofthegalvanometer.WhenGP2outputislowlevel,Q1isturnedon,andthesystemsuppliespowertotheamplifiercircuit.TheroleofICL7660inpowerconversionhereistoconvert+VSto-VS.R8,R9andtheanalogcomparatorinsidePIC10F206togetherformthepowersupplyvoltagemonitoringcircuit.ThenegativeinputterminalCINoftheanalogcomparatorisconnectedtotheinternalreferencevoltageofthesingle-chipmicrocomputer(thenominalvalueofthevoltageis06V),andthepositiveinputterminalCIN+isconnectedwiththepartialpressureofR8andR9.BecausethelowestoperatingvoltageofAD620is23V,fromaconservativepointofview,thelowerlimitoftheoperatingvoltageissetto2.5V.Whenthepositivepowersupplyvoltageislessthan2.5V,thevoltageofCIN+islessthan0.6V,andthecomparatoroutputisreversed.Afterthemirocontrollerdetectsthisevent,theGP2outputshighlevel,turnsoffthepowersupplyoftheamplifiercircuit,andthenexecutestheSLEEPinstructiontomakethemicrocontrollerentersleepstatus.Figure6PowermonitoringandpowermanagementcircuitofgalvanometerInordertosavepowerconsumption,whentheworkingvoltageisnormal,thegalvanometershouldenterthesleepstate(iesoftshutdown)afterworkingforaperiodoftime,anditcanbeawakenedatanytimewhenitneedstowork.ButtonS1issetforthisfunction.Theworkingtimeofthegalvanometerispresetto15minutes.Whentheworkingtimeisup,theGP2ofthesingle-chipmicrocomputeroutputsahighlevel,shutsoffthepowersupplyoftheamplifyingcircuit,andthenexecutestheSLEEPinstructiontomakethemicrocontrollerenterssleepstate.Inthesleepstate,ifS1ispressed,thepinlevelofGP3willchange.Thiseventwillresetthemicrocontroller(note:PIC10F206hasnoconventionalinterruptfunction)andwakeupthemicrocontroller.Inthesleepstate,thecurrentconsumptionofthegalvanometerislessthan0.1A,whichisverypower-saving,sothereisnoneedtoworryaboutforgettingtoturnoffthepowersupplyofthegalvanometerandconsumingthebattery.III.SoftwareSystemWhenthegalvanometerispoweredon,themicrocontrollerfirstperformssysteminitialization,thensuppliespowertoICL7660andAD620,andthenturnsontheanalogcomparatortocheckwhetherthesupplyvoltageisappropriate.Ifthevoltageisappropriate,continuetosupplypowertotheamplifiercircuit,andthenexecutea15-minutecountdown.IfS1ispressedduringthisperiod,thetimingtimeisresetto15minutes.Whenthe15-minutecountdownisup,thesingle-chipmicrocomputerturnsoffthepowersupplyoftheamplifiercircuit,andthenentersthesleepstate(ie,softshutdown).TheflowchartoftheprocedureisshownasinFig.7.Figure7FlowchartoftheprocedureIV.ConclusionThisarticlediscussesthegalvanometerbasedoninstrumentationamplifierAD620andmicrocontrollerPIC10F206,whichhasstableperformanceandlowpowerconsumption.Thecurrentisabout4mAduringnormaloperation,andthecurrentconsumedinsleepmodeislessthan0.1uA,whichisverysuitableforbatterypowersupply.TheuseoftwoAAbatteriesforpowersupplysavesbatterycost.Thesoftshutdownfunctioncaneffectivelypreventbatteryconsumptioncausedbyforgettingtoturnoffthepower.FAQWhatisAD620?AD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyrequiresanexternalresistortosetthegain.Thegainrangeis1to10,000.CanIchangeAD620toAD623whenmakingMCUproducts?BothAD620andAD623aresingleinstrumentationamplifiers,andthepinarrangementisexactlythesame.Themaindifferenceis:AD620mustusepositiveandnegativepowersupplies,AD623canbeapositiveandnegativepowersupplyorasinglepowersupply.IftheoriginalboardisAD620,youcanreplaceitwith623;iftheoriginalboardisAD623,youmaynotbeabletoreplaceitwith620(itdependsonwhetherthepowersupplyoftheoriginalboardcircuitisdualpowersupplyorsinglepowersupply).AfterreplacingAD620andAD623insingle-chipproducts,theprogramcanworknormallywithoutmodification.WhatisthedifferencebetweenAD620BRandAD620AN?Theirpackagesaredifferent.WhatistheoutputresistanceofAD620?Howtoadjustit?AD620isakindoflowpowerconsumptioninstrumentamplifier,itsoutputresistanceisabout10K,thisistheinherentcharacteristicofthischip,generallyitisdifficulttoadjust.Ifyouhaverequirementsforoutputresistance,youcangenerallyuseanexternalcircuittosolveit.IsAD620apositivephaseamplificationorareversephaseamplification?AD620isaninstrumentamplifier,theoutputvoltageis[(Vin+)-(Vin-)]*gain.Ifthedesiredsignalis(Vin+)-(Vin-),thegainispositive,whichisequivalenttopositiveamplification.Conversely,ifthedesiredsignalis(Vin-)-(Vin+),thegainisequivalenttonegative,whichisequivalenttoreverseamplification.Whatisaninstrumentationamplifier?Instrumentationamplifier,animprovementofthedifferentialamplifier,hasaninputbuffer,doesnotrequireinputimpedancematching,sothattheamplifierissuitableformeasurementandelectronicinstruments

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IDescriptionTheperformanceandstructureofthesteppermotordriverchipL297/L298areanalyzed.Atthesametime,combinedwiththeAT89C52single-chipmicrocomputer,asimplemethodofdrivingasteppermotorisintroduced.Thisbloggivesthecontrolschematicdiagram.Theactualmeasurementshowsthatthesteppingmotordrivesystemdesignedbythismethodhasthecharacteristicsofsimplehardwarestructure,easysoftwareprogrammingandlowprice.CatalogIDescriptionIIIntroductionIIIWorkingprincipleVIHardwareVSoftwareCompositionVIConclusionOrdering&QuantityIIIntroductionWhatisasteppingmotor?Asteppingmotorisaprecisionactuatorthatconvertselectricalpulsesignalsintoangulardisplacementorlineardisplacement.Thesteppingmotorhasthecharacteristicsofconvenientcontrolandsmallsize.Therefore,itiswidelyusedinnumericalcontrolsystems,automaticproductionlines,automaticinstruments,plotters,andcomputerperipherals.L297andL298caneasilyformasteppingmotordriver,andcombinedwithAT89C52single-chipmicrocomputerforcontrol.Thatis,itispossibletoformasteppermotordrivecircuitwithgoodperformanceatarelativelycheapprice.IIIWorkingprincipleSinceasteppermotorisanactuatorthatconvertselectricalpulsesignalsintolinearorangulardisplacement,itcannotbedirectlyconnectedtoACandDCpowersupplies.Instead,aspecialdevice,asteppingmotor,mustbeusedtocontrolthedriver.AtypicalsteppingmotorcontrolsystemisshowninFigure1.Thecontrollercansendoutpulsesignalswhosepulsefrequencycanbecontinuouslychangedfromafewhertztotensofkilohertz.Itprovidesapulsetrainfortheringdistributor.Themainfunctionoftheringdistributoristodistributethepulsesequencefromthecontrollinkaccordingtoacertainrule.Thenitisamplifiedbythepoweramplifierandaddedtotheinputterminalsofthesteppingmotordrivepowersupplytodrivetherotationofthesteppingmotor.Therearetwomaincategoriesofringdistributors:Oneistousecomputersoftwaredesignmethodstoachievethefunctionsrequiredbytheringdivider,usuallycalledasoftringdivider.Theotherisaringdistributorcomposedofhardware.Usuallycalledahardringdistributor.Thepoweramplifiermainlyamplifiesthesmalleroutputsignaloftheringdistributortoachievethepurposeofdrivingthesteppermotor.Figure1.TypicalsteppermotorcontrolblockdiagramVIHardwarehesteppermotorcontrolledintheblogisafour-phaseunipolar35BY48HJ120decelerationsteppermotor.TheblockdiagramofthesteppermotorcontroldriverdesignedinthisblogisshowninFigure2.ItconsistsofAT89C52single-chipmicrocomputer,optocoupler,integratedchipsL297andL298.Figure2.BlockdiagramofsteppermotorcontroldriverThesteppermotorintroducedintheblogisafour-phaseunipolar35BY48HJ120decelerationsteppermotor.TheblockdiagramofthesteppermotorcontroldriverdesignedinthisarticleisshowninFigure2.ItiscomposedofAT89C52single-chipmicrocomputer,photoelectriccoupler,integratedchipsL297andL298.AT89C52isalow-voltage,high-performance8-bitCMOSmicrocontrollerfromATMELintheUnitedStates.Thechiphasabuilt-in8Kbytesofre-erasableFlashmemory,256bytesofRAM,three16-bittimers,andaprogrammableserialUARTchannel.Therefore,itissufficienttocompletethesimplecontrolofthesteppermotor.L297isasteppingmotorcontroller(includingringdistributor).L298isadoubleHbridgedriver.Theinterfaceofthemicroprocessortothedouble-bridgesteppingmotorcomposedofthemisshowninFigure3.Theadvantageofthiscombinationisthatitrequiresfewcomponents.Asaresult,theassemblycostislow,thereliabilityishigh,andthespaceissmall.Andthroughsoftwaredevelopment,theburdenofmicrocomputerscanbesimplifiedandreduced.Inaddition,L297andL298areindependentchips,sotheapplicationisveryflexible.TheL297chipisahardwareloopintegratedchipthatcangeneratefour-phasedrivesignalsforcomputer-controlledtwo-phasebipolarorfour-phaseunipolarsteppermotors.TheheartoftheL297isasetofdecodersthatcangeneratevariousrequiredphasesequences.Thispartiscontrolledbytwoinputmodes,directioncontrol(CW/CCW)andHALF/FULL,andsteppingclockCLOCK.Itadvancesthedecoderfromonesteptoanother.Thedecoderhasfouroutputpointsconnectedtotheoutputlogicsectiontoprovidethephasesequencerequiredbythesuppressionandchoppingfunctions.Therefore,L297cangeneratethree-phasesequencesignals,correspondingtothreedifferentworkingmodes:thehalf-stepmode(HALFSTEP).Basicstep(FULLSTEP,fullstep)one-phaseexcitationmethod.Basicsteptwo-phaseexcitationmethod.Insidethepulse,thedistributorisa3bitreversiblecounter,plussomecombinationallogictogenerate8stepsofGraycodetimingsignalpercycle.Thisisthetimingsignalofthehalf-stepworkingmode.Atthistime,theHALF/FULLsignalishigh.IfHALF/FULLissettoalowlevel,thebasicstepworkingmodeisobtained,thatis,thedoublefour-beatfull-stepworkingmode.Figure3.L297PictureAnotherimportantcomponentofL297isthetwoPWMchopperstocontrolthephasewindingcurrentstoachieveconstantcurrentchoppingcontroltoobtaingoodtorque-frequencycharacteristics.Eachchopperconsistsofacomparator,anRSflip-flopandanexternalsamplingresistor.Acommonoscillatorisalsoprovidedtoprovidetriggerpulsesignalstothetwochoppers.InFigure5,thefrequencyfisdeterminedbytheexternal16-pinRCnetwork.WhenR10k,f=1/0.69RC.Whentheclockoscillatorpulsesetsthetriggerto1,themotorwindingphasecurrentrises.WhenthevoltageonRsofthesamplingresistorrisestothereferencevoltageUref,thecomparatorflipstoresettheflip-flop,thepowertransistoristurnedoff,andthecurrentdrops,waitingforthearrivalofthenextoscillationpulse.Inthisway,theoutputofthetriggerisaconstantfrequencyPWMsignal,whichmodulatestheoutputsignalofL297,andthepeakvalueofthewindingphasecurrentisdeterminedbyUref.TheinputoftheCONTROLterminalofL297determinesthatthechopperactsonthephaselinesA,B,C,DorthesuppressionlinesINH1andINH2.WhenCONTROLishigh,ithascontroleffectonA,B,C,D;Whenitislowlevel,itcontrolsINH1andINH2,sothatthesteeringandtorqueofthemotorcanbecontrolled.TheL298chipisahigh-voltage,high-currentdualfull-bridgedriver.L298isdesignedtoacceptstandardTTLlogiclevelsignalsanddriveinductiveloads.Forexample,relays,cylindricalcoils,DCmotorsandsteppingmotors.Ithastwosuppressinputstomakethedeviceimmunetotheinputsignal.Theemittersofthetriodesofeachbridgeareconnectedtogether,andthecorrespondingexternalterminalscanbeusedtoconnectperipheralsensingresistors.Anotherinputpowersupplycanbeinstalledtoenablethelogictoworkunderlowvoltage.TheL298chipisanintegratedchipinamulti-wattin-linepackagewith15leads.Figure4.L298PictureInFigure5,AT89C52isconnectedtothemicrocomputerthroughtheserialportafterMAX232levelconversion,andacceptsinstructionsfromthehostcomputer.Thensendclocksignal,positiveandnegativesignal,resetsignalandenablecontrolsignaltoL297.Inthecircuit,resistorsR13andR15areusedtoadjustthereferencevoltageofthechoppercircuit.Thisvoltagewillbecomparedwiththemagnitudeofthepotentialfedbackthroughthepins13,14todeterminewhethertoperformchoppingcontrol.Inordertoachievethepurposeofcontrollingthepeakvalueofthemotorwindingcurrentandprotectingthesteppermotor.BecauseL297hasachoppingconstantcurrentcircuitinside,thepeakvalueofthewindingphasecurrentisdeterminedbyUref.WhentwopiecesofL297areusedtodrivethetwowindingsofthesteppingmotorthroughL298,andtheUrefofeachphasewindingischangedthroughtwoD/Aconverters,thesteppingmotorsubdivisiondrivingcircuitisformed.Inaddition,inordertoeffectivelysuppresselectromagneticinterferenceandimprovethereliabilityofthesystem,anisolationcircuitcomposedoftwo16-pinphotoelectriccouplingdevicesTLP521-4isusedinthesingle-chipandsteppingmotordrivecircuit.AsshowninFigure5.Figure5.SchematicdiagramofsteppermotorcontroldriverItsfunctionistocutoffthedirectelectricalconnectionbetweenthemicrocontrollerandthesteppingmotordrivecircuit.Inthisway,theseparateconnectionofthesingle-chipmicrocomputerandthedrivingcircuitsystemgroundisrealized,andtheinterferencesignalgeneratedbythedrivingcircuitworkingunderthehigh-currentinductiveloadandtheinterferencesignalgeneratedbythesuddenchangeofthegridloadisseriallyconnectedtothesingle-chipmicrocomputerthroughtheline,whichaffectsthenormaloperationofthesingle-chipmicrocomputer.VSoftwareCompositionInthiscircuit,setP1.0portasthemotorstartbutton.P1.1,P1.2,P1.3arespeedselectionbuttons,thespeedisfromlowtohigh.P1.4isthemotorstopbutton.Themaximumspeedofthethreespeedsis500pps,1000pps,and2000pps.RXD,TXDhavebeenconnectedtotheserialportbyMAX232levelconversion.Inaddition,thestartandstopfrequencyofasteppermotorislow,generallybetween100-250Hz.Themaximumoperatingfrequencyisrequiredtobehigher,usually1-3kHz.Inordertoensurethatitwillnotlosestepduringthewholeprocessofstarting,runningandstopping,butalsocanreachthetargetpositionaccuratelyassoonaspossible,therunningspeedmusthaveanacceleration-constantspeed-decelerationprocess.Here,thecommonlyuseddiscretemethodisusedtoapproximatetheidealtrapezoidalaccelerationanddecreasecurve,asshowninFigure5.Thatis,thetimerinterruptmodeisusedtocontinuouslychangethesizeofthetimerloadvalue.Inthisexample,fortheconvenienceofcalculation,theloadingvaluerequiredforthespeedofeachdiscretepointisconvertedintotherequiredtimingtimebytheformulaandsolidifiedintheROMofthesystem.Here,TH0=(65536-time)/256,TL0=(65536-time)%256isusedtocalculatetheloadingvalue,andtimerepresentsthetimingtimerequiredforeachstep.Thesystemusesthelook-uptablemethodtofindoutthetimerequiredduringoperation,therebygreatlyreducingthetimeoccupiedbytheCPUandimprovingthecorrespondingspeedofthesystem.Therefore,theprogramismainlycomposedofcontrolmainprogram,accelerationanddecelerationsubroutine,andthemainprogramblockdiagramisshowninFigure6.Figure6.MainblockdiagramVIConclusionTheinnovationofthisblogistoproposetheapplicationofsingle-chipmicrocomputerandL297,L298integratedcircuitstoformasteppermotorcontroldriver.Ithastheadvantagesoffewercomponents,highreliability,lessspace,andlowassemblycost.IDescriptionDoyouknowtheDCregulatedpowersupply?DCregulatedpowersupplyiswidelyusedinindustrialproductionanddailylife,anditsdesignoccupiesaveryimportantpositioninpowersupplytechnology.Therefore,basedontheanalysisoftheproblemsofthetraditionalDCstabilizedpowersupply,themethodandcalculationofeachpartofthe5V,1ADCstabilizedpowersupplybasedonL7805CTaredescribed.Besides,itcanalsoprovidea5VDCpowersupplyforcounters,decoders,anddigitaltubestorealizeadditionandsubtractioncounting.ThesystemcircuitbasedonL7805CTintroducedinthisblogissimple,stable,easytocontrol,cost-effective,andisofhighuse-value.CatalogIDescriptionIIIntroductionIIIDesignrequirementsforDCstabilizedpowersupplyIVHardwareunitcircuitdesign4.1Overallstructureofthepowersupply4.2ComponentselectionVApplicationVIConclusionFAQOrdering&QuantityIIIntroductionWiththecontinuousdevelopmentofelectronictechnology,thedesignrequirementsofelectronicequipmentforpowersupplyaregettinghigherandhigher,fromtraditionalrequirementstohigh-quality,high-efficiency,andhigh-stabilitytomeettheneedsofobjects.ThenormaloperationofelectronicdevicesrequiresDCpower.DCpowersourcesincludesolarbatteries,accumulators,anddrybatteries.Butdoyouknowwhichoneisthemostcost-effective?Ofcourse,themostcost-effectivemethodistoconverttheACpowerprovidedbythegridintotherequiredDCpower.Mostelectronicequipmentusesthismode,andthethree-terminalregulatoristhemostwidelyused.AlthoughpeopleusemanytypesofDCstabilizedpowersupplieswithdifferentfunctions,theprinciplesaresimilar.ThevoltageregulatorchipusedinthesystemintroducedinthisblogisL7805CT.L7805CThastheadvantagesofsmallsize,simpleexternalwiring,stableoperationandstrongapplicability.Itcanmeetpeoplesrequirementsinlife,study,andwork.IIIDesignrequirementsforDCstabilizedpowersupplyThedesignrequirementsoftheDCregulatedsingle-channelpowersupplybasedonL7805CTareasfollows:InputACvoltage220V;OutputDCvoltage+5V;OutputDCcurrent1A;Theoutputrippleofthecircuitislessthan50mV;Theequivalentinternalresistanceislessthan0.15;Ripplecoefficientislessthan0.002%;Voltageadjustmentrate0.001%;Voltagestabilizationcoefficient0.005%.IVHardwareunitcircuitdesign4.1OverallstructureofthepowersupplyThisdesignfocusesontheknowledgeandskillsinvolvedinthemainlinksoftheDCpowersupply,andcompletesthecircuitdesignandproductionof220VACinputand5V,1ADCoutput.TheDCpowersupplyisusuallycomposedoffourlinks:PowerTransformers;Rectifiercircuit;Filtercircuit;Regulatorcircuit.AsshowninFigure1.Figure1.BlockdiagramofDCpowersupply4.1.1PowertransformerThepowertransformerconvertsthehigh-voltageACmainspowerintotheappropriatevoltageACandsendsittothesingle-phasebridgerectifiercircuit.Whenchoosingapowertransformermodel,theparametersweneedtoconsiderarecapacityandoutputvoltage.4.1.2RectifiercircuitTherectifiercircuitusestheunidirectionalconductivityofthediodetocompletetherectification.Commonlyusedrectifiercircuitsareasfollows:single-phasehalf-waverectifiercircuit,single-phasefull-waverectifiercircuitandsingle-phasebridgerectifiercircuit.Throughcomparativeresearch,inordertoovercometheshortcomingsofhalf-waverectification,theL7805CT-basedsystemusesasingle-phasebridgerectifiercircuit.Itconsistsof4diodesVD1~VD4connectedintheformofabridge.Whetheritisapositivehalf-cycleoranegativehalf-cycle,thedirectionofthecurrentflowingtotheloadRListhesame.BothtransformtheACvoltageoutputbythesecondarywindingofthepowertransformerintoapulsatingDCvoltage.Thereversevoltagethateachdevicebearsisthepeakvalueofthepowersupplyvoltage,andsymmetricalcurrentflowsthroughthepositiveandnegativehalfcyclesofthetransformer,theutilizationrateishigherthanthatofthefull-waverectifiercircuit,andthecurrentrippleisreduced.Therefore,thereisnounidirectionalmagnetization.4.1.3FiltercircuitTherectifieddirectcurrentcontainsarelativelylargealternatingcurrentcomponent,andthepulsationcoefficientisrelativelylarge,soitcannotbedirectlyusedasthepowersupplyforelectroniccircuits.FiltercircuitsarecommonlyusedtoremoveorreducetheACcomponentintheoutputvoltage,sothatpureACpowerisusedonthedevice.Thisdesignusestheenergystoragecharacteristicsofcapacitorsandinductorstosetappropriateparameters.Whenthecircuitvoltagerises,theenergystorageelementstoresenergy.Whenthevoltagedrops,theenergystorageelementreleasesenergy,soastoachievethepurposeofreducingpulsation.Thecapacityofthecapacitorisrelatedtothedischargetime.Tomakethefilteringeffectbetter,acapacitorwithalargercapacitycanbeusedasthefiltercapacitor.ThefiltercapacitorisgenerallyselectedasRLC(3~5)T/2.4.1.4VoltagestabilizingcircuitTheDCvoltageobtainedaftertheACpowerisrectifiedandfilteredoftenfluctuateswiththefluctuationofthegridvoltage,temperaturechanges,andloadresistancechanges.Then,thequalityofpowersupplywillbereduced,affectingtheoperationoftheequipment.Therefore,avoltagestabilizingcircuitneedstobeaddedbetweenthefiltercircuitandtheloadlinktoachievethepurposeofstabilizingpowersupply.ThechipL7805CThasthecharacteristicsofgoodvoltageregulationperformance,highreliability,easyinstallationandlowcost.Therefore,thelinearstabilizedpowersupplyreplacesthediscretestabilizedcircuitandiswidelyused.Inordertoreducetheinterferenceandmakethevoltagestabilizingcircuitworknormally,theinputvoltageshouldbeatleast2.5~3Vhigherthantheoutputvoltage.4.2Componentselection4.2.1SelectionofpowertransformerConsideringthediodeforwardvoltagedrop,wireresistance,andpowergridfluctuations,theoutputvoltageUIofthethree-terminalintegratedregulatorshouldmeet:Where:Uomaxisthemaximumoutputofregulatedpowersupply;(UI-UO)ministheminimumvoltagedifferencebetweentheinputandoutputoftheintegratedregulator;UIisthechangeoftheinputvoltagecausedbythefluctuationofthepowergrid(generallytakenas10%ofthesumofUO,(UI-UO)min,andUIP).Fortheintegratedthree-terminalregulator,when(UI-UO)min=2~10V,ithasbettervoltageregulationcharacteristics.WhenU1=10VWhenU2=9VInasingle-phasebridgerectifiercircuit,therelationshipbetweenthetransformersecondarywindingcurrentI2andthecapacitorfilteroutputcurrentIIis:Insummary,chooseatransformerwithacapacityof15VAand9V.4.2.2SelectionofrectifierdiodeBecause,thecurrentflowingthrougheachrectifierdiodeinthebridgecircuitis:Themaximumreversepeakvoltageofeachrectifierdiodeis:Insummary,selectthetransistorIN4001,itsparametersare:ID=1A,URM=50V.4.2.3SelectionoffiltercapacitorAlthoughthecurrentpassingthroughthediodeisapulsatingcurrent,becausethecapacitorChasanenergystorageanddischargefunction,thisreducesthedegreeofvoltagepulsationacrosstheloadRLandincreasestheaveragevalue.TheaveragevalueandsmoothnessoftheDCvoltageontheloadarerelatedtothedischargetimeconstant=RLC.ThelargerthevalueofCorRL,theslowerthedischargeofC.ThelargertheoutputDCvoltagevalue,thebetterthefilteringeffect;otherwise,theworse.Generallytake:TheACpowersupplyinsomeAsiancountriesisa50Hzsinewave,with50identicalwaveformspersecond.Afterfull-waverectification,boththepositiveandnegativehalfwavesbecomepulsatingdirectcurrentinthesamedirection.Atthistime,thereare100identicalwaveformspersecond,thatis,f=100Hz.Sothefiltercapacitorcapacityis:amongthem,TheoutputDCvoltageofthecapacitorfiltercircuitisestimatedas:Insummary,twoelectrolyticcapacitorsof2200Fand50Vcanbeused,andtheyareconnectedinparallel.Inordertofilterouttheinterferenceofhigh-frequencysignalsandimprovethedynamiccharacteristicsofthepowersupply,a105pF,50Vhigh-frequencyceramiccapacitorisconnectedinparallelatbothendsofthefiltercapacitor.4.2.4Howtochooseathree-terminalintegratedvoltageregulatorTheconditionthatthepowerconsumptionofthethree-terminalintegratedvoltageregulatormustmeetisgreaterthan5Wandtheoutputvoltageis5V.ThisdesignchoosesL7805CT,theoutputvoltageis4.8~5.2V,thequiescentcurrentis4.2~8mA,andthemaximumoutputcurrentcanbe1.5A,whichmeetsthedesignrequirements.Consideringthelargeoutputcurrent,aheatsinkneedstobeadded.VApplicationAdoptthedesignbasedonL7805CTtoprovide5VDCpowersupplyforcounter,decoderanddigitaltube.Usethebuttontogenerateasingleclock,realizethecountofmodulo10throughthestandardcountercircuit,andgeneratethecorrespondingcode.Thevalueisoutputtotheintegrateddecodingcircuitthroughthedecodertodisplaythenumbers0-9.UsetheDPsectionoftheintegrateddecodingcircuitasapower-onindication.Thecounterhasaresetbutton,andtheintegrateddecodingcircuitadoptsacommoncathodestructuretorealizeadditionandsubtractioncounting.asshowninfigure2.Figure2.L7805CircuitVIConclusionThe5V,1ADCpowersupplydesignbasedontheL7805CTdescribedinthisblogcanprovide5VDCpowersupplyforcounters,decoders,anddigitaltubestoachieveadditionandsubtractioncounting.ThedesigncircuitoftheL7805CTissimple,withfewcomponents,lowpowerconsumptionandstable.Therefore,itcanbeextendedtootherobjectapplicationsasaDCstabilizedpowersupplytoprovideelectricalenergy.FAQWhatisl7805?AvoltageregulatorICmaintainstheoutputvoltageataconstantvalue.7805IC,amemberof78xxseriesoffixedlinearvoltageregulatorsusedtomaintainsuchfluctuations,isapopularvoltageregulatorintegratedcircuit(IC)....7805ICprovides+5voltsregulatedpowersupplywithprovisionstoaddaheatsink.WhatistheworkingprincipleofIC7805?AvoltageregulatorICmaintainstheoutputvoltageataconstantvalue.7805IC,amemberof78xxseriesoffixedlinearvoltageregulatorsusedtomaintainsuchfluctuations,isapopularvoltageregulatorintegratedcircuit(IC).Thexxin78xxindicatestheoutputvoltageitprovides.HowdoItesta7805withamultimeter?TurnontheDCpowersupplyandadjusttheoutputvoltageofabout8Vorslightlylarger.Oralternativelyyoucanuseabattery9V-12Vasvoltagesource.Lookatthevoltmeterpanelwhenyousetthevoltage.PrepareaDCvoltmeterreadingsonvoltagerange50VtomeasuretheoutputvoltageoftheIC7805.Howdoes7805regulatevoltage?For7805IC,itis+5VDCregulatedpowersupply.ThisregulatorICalsoaddsaprovisionforaheatsink.Theinputvoltagetothisvoltageregulatorcanbeupto35V,andthisICcangiveaconstant5Vforanyvalueofinputlessthanorequalto35Vwhichisthethresholdlimit.I.74HC164Introduction74HC164adoptsDIP-14,SO-14,SSOP-14andTSSOP-14packagepinconfiguration.ItiscomplementarytoMOS8-bitserialinputandparalleloutputunidirectionalshiftregister,thelogicsymbolisshowninthefigure1.Thepowersupplyvoltageis2~6V.Inthefigure1,AandBaretheserialcodeinputterminals;CLRistheclearinputterminal;CLKistheclockpulseinputterminal.Withthearrivaloftherisingedgeoftheclockpulse,thestateofphaseA,phaseBandthesubsequentphaseshiftsfromQAtoQHinturn.CatalogI.74HC164IntroductionII.74HC164LogicSymbolIII.CircuitDesignIV.HowtoCheckandRepairtheCircuitFAQOrdering&QuantityII.74HC164LogicSymbolFigure174HC164LogicSymbolIII.CircuitDesignFigure2isaninstrumentcircuitcomposedofserialinputandparalleloutputdigitalintegratedcircuits.T2-T5,C5andresistancetogetherformaturnsignalflashingoscillationcircuit.WhentheDR(connectedtotheturnswitch)inJ8isdisconnected,thiscircuitwillnotworkandtheturnsignalwillnotflash;whenDRison,theoscillationcircuitstarttowork,theturnsignalstartstoflash.Figure2MetercircuitdiagramDRisathree-positionswitch,onepoleisconnectedtotheleftturnsignal,onepoleisconnectedtotherightturnsignal,onepoleissuspendedintheair,andtheotherendofthepolehitstheground.Theswitch-offcircuitiscomposedofTl,DLRllandR12.Aswitch-typeHallelementisinstalledinthefrontandrearbrakesoftheelectricbicycle.Whentheswitchisswitched,theHallelementoutputsalowpotential,thatis,theBRKterminalintheplugJ2isgrounded,Tlisturnedon,andthereisavoltageofnearly5VonthecollectorofTl.ThisvoltageissenttothecontrollerthroughtheBRKterminalinJ2,andthepowersupplycircuitofthemotoristurnedoff.Themotorstopsworkingandactsasabrake.Onthecontrary,whenthebrakeisnotpinched,theHallelementoutputsahighpotential,Tliscutoff,andthemotorrunsnormally.Because74HC164isan8-bitserialinputandparalleloutputshiftregister,itformsamovementmodeandbatterypowerdisplaycircuitwithlight-emittingdiodes.74HC164soutputpin13,pin11,andD5-D7formthesideofthesportsmodedisplaycircuit,andpins6and10andD8-D12formthebatterypowerdisplaycircuit.Thedisplaysignalfromthecontrollerissenttotheserialinputterminals1and2ofthe74HC164throughtheDATAterminalintheJ2,andthenshiftedbytheinternalcircuit,thedrivingsignalisoutputfromtherelevantoutputterminaltolightupthecorrespondinglight-emittingdiode,soastocompletethecontrolofthedisplaycircuit.IV.HowtoCheckandRepairtheCircuitThiscircuitisrelativelysimpleandeasytorepair.Themainbasisforrepairingistojudgethequalityof74HC164.First,checkwhetherthe+5Vvoltageisnormal,andthencheckwhetherthevoltageatpin③ofthe74HC164sclocksignalinputiscloseto+5V.Ifitislowerthan+5V,andafterdisconnectingR73,theCLKterminalvoltageofJ2isnormal,andthe74HC164isdamaged.IfthevoltageoftheCLKportisabnormal,thefaultisinthecontroller.Next,measurewhetherthevoltageoftheserialinputterminals①and②changesduringthetransitionofthemotionmode.Ifnot,thefaultisinthecontroller;ifthereis,the74HC164isdamaged.Fromtheactualrepairsituation,mostofthe74HC164failuresarecausedbydamagetotheinternalcircuitofthe⑩pin(powersupplyterminal).Inaddition,whenpurchasing74HC164,youcanfirstmeasuretheresistanceofthe⑩pin.Theresistancevalueshouldbeabout4kDinthepositivetestandinfiniteinthereversetest.FAQHowdoesthe74HC164transmitdatainthemicrocontrollercircuit?Onepinofthesingle-chipmicrocomputerislikeafaucet,andthedataissentonebyone,thatis,likethewaterfromthefaucet,drippingdropbydrop.The74H164islikeasmallbowlreceivingwater.Itisjustfullafterreceiving8dropsofwater.Atthistime,itissenttothedigitaltube.Thesingle-chipmicrocomputermustsendan8-bit(ormore)data,ifitissentatthesametime,itisaparalleltransmission,ifitisabitbybit,itisaserialtransmission.Thedataofthesingle-chipmicrocomputerissenttothe74HC164bitbybit,whichisserial,andthe74HC164sendsthedatatothedigitaltubeatonce,whichisparallel.So74HC164playsarolefromserialtransmissiontoparalleltransmission.Whatisthedifferencebetween74HC164Dand74HC164NMCU?TheDin74HC164Drepresentsachippackage.TheNin74HC164Nmeansdualin-lineplasticpackaging.Whatisthedifferencebetween74HC164and74LS164,cantheybeusedtogether?74ls164isaTTLcircuit,thepowersupplyvoltageis5V,thehigh-leveloutputcurrentIohis-0.4MA,andthelow-leveloutputcurrentis8MA.74HC164isaCMOScircuit,thepowersupplyvoltageis2V~6V,theoutputdrivecurrentcanreachplusorminus20MA.Ifthepowersupplyvoltageyouuseis5Vandtheoutputdrivecurrentissuitablefor74ls164,theycanbeusedtogether.Whatdevicescan74hc164bereplacedwith?74HC164isaCMOSdevicewithapowersupplyvoltageof2V-6V.Itcanbedirectlyreplacedby74HCT164,40H164.Ifthepowersupplyvoltageis5Vandtheoutputdrivecurrentissmall,itcanalsobereplacedby74164,74LS164,74F164,74ALS164.Whichof74LS164and74HC164hashigherdrivingcapability?74LS164isaTTLdevicewithahigh-leveldrivingcapabilityofabout0.4mAandalow-leveldrivingcapabilityofabout8mA.74HC164isaCMOSdevice,withhigh-levelandlow-leveldrivecapabilityupto20mA.TheabovedatacomesfromDATASHEET.Butgenerallyspeaking,thehigh-leveloutputcapabilityofmanyCMOSdevicesisweak,smallerthanTTL,andthelow-leveldrivecapabilityisstronger.Can74hc164nbeusedtodrivethedigitaltube?Ofcourse,youcanusethe164chiptodrivethenixietube,whichismostlyusedinsituationswheretheIOportresourcesaretightandthedisplaydatarefreshofthenixietubeisslow.Whendesigningthecircuit,multiple164chipsareusedincascade,nomatterhowmanydigitaltubesaredriven,only2IOportsofthesingle-chipmicrocomputerareoccupied.ItcanbesaidthatitisthemostIOport-savingdrivingmethod,anditisstilldrivenstatically,withoutstrobeandbrightnessLowphenomenon.Thedisadvantageisthatmultiple164sareusedincascadeconnection,whichwillcausethesingle-chipmicrocomputertosendalargeamountofdisplaydata(1bytepernixietube)atonetimewhenrefreshingthedisplaydata.Duringthisprocess,thenixietubewillbeallon,althoughthedataissentTheprocessdurationisveryshort,butitstillaffectsthedisplayeffect.Itisrecommendedtoturnoffthedigitaltubewhenrefreshingthedata.

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I.DescriptionAutomaticgaintechnology(AGC)iswidelyusedinthefieldofindustrialautomationclosed-loopcontrol.Inindustrialcontrol,time-varyinggainamplifiersareoftenneededtomeetproductionneeds,ormadeithasacertainregularitytoensurethestabilityofthecontroloutputamplitude,therebyreducingtheinterferenceoftheinputinterferencenoisesignal.Forthesystemtoadjustquikly,thispaperdesignsanAGCcontrollerbasedonthecombinationofAGCchipAD603andswitchingpowersupplychipMC34063,cleverlyusingMC34063sstablereferencevoltageanddynamicvoltageadjustmentoutputtoaccessAD603gaincontrolterminaltocontroltheamplificationgain,thereforeachievethegoalofconstantsystemoutputamplitude.AD603CatalogI.DescriptionII.WorkingPrincipleoftheSystemIII.AD603IV.MC34063V.SystemHardwareCircuitDiagram5.1InputBufferAttenuationCircuit5.2AD603AutomaticGainAmplifier5.3OutputAmplitudeDetector5.4MC34063FeedbackCircuitVI.SystemOperationResultsVII.ConclusionFAQOrdering&QuantityII.WorkingPrincipleoftheSystemThesystemusesAD603asthecorecontroldevice,supplementedbytheswitchingpowersupplychipMC34063tocollecttheoutputofthecontroller,theoutputvoltageistransferredtothevoltagecontrolterminalofAD603throughMC34063tochangetheamplificationgain.ThesystemworkingprincipleblockdiagramisshownasinFig.1.Figure1SystemBlockdiagramInthisclosed-loopcontrolsystem,theMC34063circuitisusedasitsfeedbacklinktodynamicallycollecttheamplitudeoftheoutputsignalofthesystem,andcontroltheamplificationgainofAD603byadjustingthedutycycleoutputvoltageoftheinternalsignal.Thefeedbacklinkinthefigurecanbereplacedwithamicroprocessor.ThemicroprocessorcollectstheoutputvoltageamplitudethroughA/D,transfersittothemicroprocessorchipforsignalprocessing,andthenfeedsbacktotheinputoftheentiresystemthroughD/Aoutputcontrolvoltage.However,thismethodistoocomplicated,becausetheriseandfallofthedigitalchiptakealongtimetosetup,whichaffectstheresponsespeedoftheentiresystem,andrequiresrelativelyhighsignalprocessingalgorithms.Theswitchingpowersupplychipwidelyusedinpowersupplytechnologyisdynamicallyadjustedtoimproveitsoperatingspeed.Inaddition,itsdevelopmentcostislow,whichisconducivetothepromotionoftheindustrialcontrolfield.III.AD603AD603isachipwithprogrammablegain,lownoise,ithas3workingmodes,correspondingtodifferentgainranges.Inordertomakethecontrolmoreextensive,themaximumbandwidthmodeisselectedas90MHz.Thegainisexpressedindecibels,theamplificationgainiscontrolledbythecontrolvoltagetoalinearrelationshipof25mV/dB,andtheslewrateis275V/s.Thegaincontrolvoltageneedstobeinputduringnormaloperation.Thegainformulais:Intheformula:Gisthegain,dB;G0isthestartingpointofthegain,andthesizeofG0isdeterminedbythepinconnection.Thecircuitdesignedinthispapershort-circuitsVOUTandFDBK,G0=10dBisthewidebandmode(90MHzwideband),thegainrangeGofAD603is-11.09~+31.05dB,andVGisinthelinearrangewhentherangeis-500~500mV.ThegaincontrolvoltageVGiscontrolledbytheMC34063output.AD603inputsignalamplitudeUINP1.4V,theactualindustrialcontrolfieldofteninputplusinterferencesumisgreaterthan1.4V,ifthissignalisdirectlyaddedtothesystem,thedistortionislargeandlong-timeworkwilldamagetheAD603,soyoumustaddaninputbufferandattenuationcircuit.IV.MC34063MC34063isamonolithicbipolarintegratedcircuitusedinthefieldofDC-DCconvertercontrol.Itischeapandwidelyusedinthefieldofswitchingpowersupplies.Itcanuseaminimumofexternalcomponentstoachieveswitchingboostandbuck.Itsoperatingfrequencyis0.1-100kHz.ThetraditionalAGCcontrollerconstitutesaclosed-loopcontrolsystem,whichgenerallyneedstoperformA/Dsamplingontheoutputofthesystem,andthentransferthedatatothesingle-chiporcomputerforalgorithmdataprocessing,andjudgetheexecutionsignalD/Aoutputtomaketheactuatorexecute.Inthisfeedbackprocess,sampling,algorithmprocessingandexecutionobviouslyconsumetoomuchtime,andforsomecomplexcontrolsignals,algorithmdataprocessingrequirementsarehigh,andspecialDSPchipsarerequired,whichiscostly.Therefore,theuseofasingleanalogelectroniccircuittoachieveaclosed-loopcontrolsystemhashigherefficiencyandlowercost.InspiredbytheworkingmodeoftheMC34063step-downcircuit,itisanewdesignideatorealizethechangeoftheAD603gaincontrolvoltagebyusingthecharacteristicsoftheMC34063todynamicallyadjusttheoutputvoltage.Theexperimentalverificationisfeasibleanditissimplerandfasterthantheprogramcontrolmethod.Figure2showstheMC34063step-downcircuit.Figure2MC34063step-downcircuitAsshowninFigure2,theinputis+12V,theoutputis+5V,thereferencevoltageofpin5togroundis+1.25V,theresistanceofpin5togroundisR1=1.2k,andtheoutputandpin5areconnectedtoR2=3.6k,Accordingtotheresistancedividerratio,theoutputisclampedat+5V,thusachievingaregulatedoutput.AppliedinthefieldofAGCcontrol,youcanconnecttheoutputofMC34063tothecontrollergaincontrolterminal,andtheinputtotheoutputterminalofthecontroller.Accordingtoitsworkingprinciple,MC34063collectstheoutputoftheAGCcontrollerandtransmitsittopin5.ItsinternaldynamicallyadjuststhePWMdutycycle,dynamicallychangestheAD603gaincontrolvoltage,andcanavoidtheinterferenceofthesystem,andrealizethefunctionsimilartothePIDalgorithm.Itreplacesthealgorithmicdataprocessingmechanism,whichissimpleandeffective,andhascertainreferencesignificancetothefieldofindustrialautomationcontrol.V.SystemHardwareCircuitDiagramFigure3isthesystemhardwarecircuitdiagram.Thesystemismainlydividedintoinputbufferattenuationcircuit,AD603automaticgainamplifier,outputamplitudedetectorandMC34063feedbackcircuit.Figure3SystemHardwarecircuitdiagram5.1InputBufferAttenuationCircuitBecausetheAD603inputsignalamplitudeVINPislessthanorequalto1.4V,fourdiodeclampsareused.Accordingtotheunidirectionalconductivityofthediodeandtheforwardconductionvoltagedropofsilicon,theinputcharacteristicsarelimitedtomeettherequirementsofAD603.Theinputvoltagerequirements,thefollowerplaystheroleofisolatingthechip.AsshowninFigure3,part①.5.2AD603AutomaticGainAmplifierThe3pinofAD603isthesignalinputterminal,the2and4pinsareconnectedtothegroundwithR4=0,R5=0resistancetomakeitworkmorestable.The5and7pinsareconnectedtotheoutput,whichisthesystemoutputoftheAGCcontroller.Pin1isthegaincontrolvoltageVGterminal,thiscontrolvoltageisconnectedtotheoutputterminalofMC34063,MC34063generatesthecorrespondinggaincontrolvoltageVGaccordingtotheoutputofthesystem.5.3OutputAmplitudeDetectorInthefieldofindustrialcontrol,thesignalisonlyintheformofDC,andtheACsignalalsooccupiesacertainproportion.ForthecontroloftheDCsignal,thesystemoutputcanbedirectlytransmittedtotheMC34063forprocessing,buttheamplitudeoftheACsignalmustbedetected,sothedesignisshowninFigure3inpart③.Commonamplitudedetectors,suchasdioderectifierbridges,areonlysuitableforsituationswheretheinputvoltageisfargreaterthanthediodeconductionvoltagedrop.InAGCcontrol,thesignalinthesystemisoftenlowvoltage,soitcannotbeused,soitisverynecessarytodesignanamplitudedetectorthatcanavoiddiodeconductionvoltagedrop.AfterRCcharging,theDCvoltagevaluewithacertainrelationshipisobtained.InFigure3,thevoltageattheintermediatenodeofR13andR14isUf,andtheexpressionis:Intheformula,UINPistheinputamplitude,V.5.4MC34063FeedbackCircuitTheintermediatenodevoltageUfofR13andR14isproperlycalculatedbyasame-invertingamplifierandanadder,andthenconnectedtopin5ofMC34063.Atthistime,itisclampedat5V,andUf=1Vwhenreversed,thentheAGCcontrollersystemcanbedynamicallymaintainedstabilityofoutputvoltageamplitude.Whenthesysteminputisunstableorthereisnoiseinterference,MC34063dynamicallychangestheoutputvoltagevalueaccordingtotheamplitudedetectionresult,soastoachievethepurposeofchangingthegaincontrolvoltageVG.AsshowninthelowerpartofFigure3,theoutputvoltageofpin2ischargedanddischargedthroughswitchingandspecificSchottkydiodes,andtheattenuatedpartialvoltageistransmittedtopin1ofAD603,whichrealizestheautomaticadjustmentoftheamplificationgainandsuccessfullyrealizestheswitchingpowersupplytechnologyapplicationinthefieldofautomaticcontrolgain.VI.SystemOperationResultsTheexperimentalsettingisthatifthesysteminputsaDCsignal,theoutputwillbeaconstant+1VDC;ifanACsignalisinput,theoutputwillbeanACsignalwithaconstantamplitudeof+1V.Intheexperiment,twoinputmethodsweretestedandverified,andbothmetthedesignrequirements.Table1ispartoftheexperimentaldataoftheinputDCsignal.Intheexperiment,theinputoftheAGCcontrollerisconnectedtothevoltageregulatorsource,andtheinputvoltageiscontinuouslyadjusted.Table2ispartoftheexperimentaldataoftheinputACsignal.Intheexperiment,theAGCcontrollerinputisconnectedtotheUTG9002Csignalgenerator,theamplitudeoftheinputsinewaveiscontinuouslyadjusted,andtheoutputisconnectedtotheoscilloscopetoobservethewaveform.Observationfoundthatnomattertheinputamplitudebecomeslargerorsmaller,theoscilloscopewaveformisbasicallyunchanged.ReadtheoscilloscopewaveformamplitudeandfillinTable2.VII.ConclusionThisarticlesummarizesthedesignoftheAGCcontrollerbasedonAD603andMC34063.ExperimentshaveverifiedthattheAGCcontrolleriseffectiveandmeetsthedesignrequirements.Anewapplicationofswitchingpowersupplychipsinthecontrolfieldisproposed.BecausetheinternalPWMdutycycleisfaster,itcanreplacethetraditionalprogrammableAGCcontroller.Amongthem,MC34063canalsobereplacedbyotherswitchingpowersupplychips.Ithastheadvantagesofuniversalapplicability,simpledesign,lowcost,andithasimportantpracticalvalue.FAQWhatisAD603?AD603isalow-noise,voltage-controlledamplifierforradiofrequency(RF)andintermediatefrequency(IF)automaticgaincontrol(AGC)systems.Itprovidesprecisepin-selectablegain,withagainrangeof-11dBto+31dBat90MHzbandwidth,andagainrangeof+9dBto+51dBat9MHzbandwidth.Anyintermediategainrangecanbeobtainedwithanexternalresistor.Thenoisespectraldensityreferredtotheinputisonly1.3nV/Hz,andthepowerconsumptionis125mWwhenusingtherecommended5Vpowersupply.WhataretheproblemsthatneedtobepaidattentiontowhenusingAD603?Thevoltagecannotbetoohigh.Generally,thevoltageisplusorminus5V,andthemaximumvoltagecannotexceedplusorminus7.5V.Theoutputvoltagecannotexceed2V.Howtosolvetheself-oscillationproblemofAD603?Forhigh-frequencyoperationalamplifiers,thefollowingpointsarethebasicwaystosolveself-excitation.Thepowersupplyisstableandnoripple.Theelectricalconnectionwiresareasshortaspossible.Thead603circuitshouldbefarawayfromthepowercircuit,especiallyawayfromthetransformer.Thepowertransformerandthecircuitboardofad603shouldbeshieldedwithametalboxandgroundedifpossible.Onepointisveryimportant.Foropamps,toolargemagnificationcaneasilycauseself-excitation,soreducethemagnificationasmuchaspossibleandminimizethenumberofmagnificationlevels(generallynotgreaterthan4).Reverseamplificationcansuppressself-excitationinmulti-stageamplification.Ifyouwanttoconnecttothepoweramplifierandthenamplify,itisbesttousetwopowersupplies,andthecircuitshouldbeconnectedtothesameground.WhatisthedifferencebetweenAD603AQandAD603AR?Theirdifferencesareinmodel,Temperature,Package.AD603AQ-40Cto+85C8-LeadCERDIPAD603AR-40Cto+85C8-LeadSOIC_NAfterinputtinganACsignalandbeingamplifiedbyAD603,whydoestheoutputcontainaDCsignal?HowtoeliminatetheDCsignal?WhentheDCblockingcapacitorisnotused,thebiasvoltageoftheinputcircuitneedstobeadjustedforcompensation.IftheDCvoltageoftheACsignalisnotfixed,onlyaDCblockingcapacitorcanbeused,ortheaveragevaluecanbeusedtoeliminateitaftersamplingthenumber.I.IntroductionForlargesystemssuchasmissileweaponsandequipment,theirperformanceisoftenaffectedbytheexternalenvironmentandtheirownoperatingconditions.Amongthem,theinfluenceoftemperatureoftenplaysaveryimportantrole.Therefore,temperaturedetectionandcontrolhasalwaysbeenthefocusofmanyresearchers.However,sometemperaturemeasurementandcontroldeviceshavelowaccuracyandinaccuratetemperaturecontrol,andsomenewinstrumentsareexpensiveanddifficulttopromote.Itshouldbeparticularlypointedoutthatthetemperaturemeasurementandcontrolsystemdevelopedinthepastisusuallyanindependentsystem,onethingforoneuse,itisdifficulttobeadoptedbyothersystems,andthereareproblemssuchasmaintenancedifficultiesandinconvenience.Tothisend,theauthordevelopedahigh-precisiontemperaturemeasurementandcontroldevicesuitableforresearchanddevelopmentunderlaboratoryconditionsbasedonthecurrentlypopularmodulardesignprinciple.ThedeviceusesanewintegratedtemperaturesensorAD590asthetemperaturemeasurementelement,andprovidestwocontrolunitsforexperimentalcomparison.Bymeasuringandcontrollingthetemperatureinthethermostat,satisfactoryresultshavebeenobtained.CatalogI.IntroductionII.WorkingPrincipleIII.IntegratedTemperatureSensorAD590IV.TemperatureMeasuringBridgeV.PIDRegulatorVI.ProgramDesignVII.ExperimentalAnalysisandConclusionFAQOrdering&QuantityII.WorkingPrincipleFigure1istheelectricalschematicdiagramoftheWCZ-98temperaturemeasurementandcontroldevice.Itsworkingprincipleis:thetemperaturesignaltakenbythetemperaturemeasuringbridgewithAD590asabridgearmisdifferentiallyamplifiedandbufferedandthensentallthewaytothedigitaldisplayfordigitaltemperaturedisplay,andtheotheriscomparedwiththesetvalue.ThecompareddifferenceiscontrolledbyswitchKandcanchoosetosendtotwo-wayadjustmentcontroller.Onerouteiscomposedofacomparisonamplifierandarelay,whichcanbeusedasanadjustmentcontrollertoformanindependenttemperaturemeasurementandcontrolequipmentwithoutconnectingtoacomputer;theotherrouteisaPIDregulator(composedofA/D,D/AandComputercompositionofPIDadjustmentsoftware)andSCRcomposition.Thesignalfromtheregulatingcontrollerrealizestemperaturecontrolthroughthetemperaturecontrolactuator.Figure1ElectricalschematicdiagramoftemperaturemeasurementandcontroldeviceIII.IntegratedTemperatureSensorAD590AD590isadedicatedintegratedtemperaturesensorproducedbyAmericanADcompany,whichbelongstothecurrentoutputtype.Figure2showsthecurrent-voltagecharacteristiccurveofAD590atthreedifferenttemperatures.Inacertaintemperaturerange,itisequivalenttoahighresistancecurrentsource,anditscurrenttemperaturesensitivityislA/K.Itisnotsusceptibletointerferencefromcontactresistance,leadresistance,voltagenoise,etc.Inaddition,italsohasthecharacteristicsofsmallsize,hightemperaturemeasurementaccuracy,goodlinearityandstronginterchangeability.Itisverysuitableforlong-distancemeasurementandcontrol.Itisalsosuitableforthecharacteristicsofmodularandsplitstructurerequiredbythisarticle.Themaintechnicalindicatorsare:Temperaturemeasurementrange:hCurrentoutput(calibrationfactor):lA/K;Powersupplyvoltage:DC4-30V;Linearity:lessthan0.5℃inthefullscalerange;Repeatability:0.1℃;Outputimpedance:about10MQLong-termdrift:0.1℃/monthFigure2I-VcurveofAD590ThecurrentIrflowingthroughtheAD590isasingle-valuedfunctionoftheabsolutetemperatureofitsenvironment,andthemicroampereofIrisequaltotheabsolutetemperatureT,namely:Ir=T10-6A=TA(1)IV.TemperatureMeasuringBridgeFigure3istheschematicdiagramofthetemperaturemeasurementbridge.ThevoltageformedonthecurrentIiR2andRw2flowingthroughtheAD590is:Ul=Ii(R2+Rw2)(2)Figure3SchematicdiagramoftemperaturemeasuringbridgeByadjustingRw2tomake(R2+Rw2)equalto10K,substitutingformula(1)intoformula(2),wecanget:U1=Ii(R2+Rw2)=T10-2V(3)U2=2.732VbyadjustingRwl.Thentheoutputofthebridgeis:UAB=U1﹣U2=T10-2﹣2.732=(T﹣273.2)10-2V(4)BecauseTistheabsoluteambienttemperaturemeasuredbyAD590,aftersubtracting273.2fromit,theCelsiustemperaturetcanbeobtained,namely:UAB=t10-2V(5)Atthispoint,thetemperaturemeasuringbridgeconvertstheambienttemperatureintoavoltagevaluethatisproportionaltothetemperatureinCelsius.V.PIDRegulatorOneoftheadjustmentcontrollersofthetemperaturemeasurementandcontroldeviceusesaPIDregulator(proportionalintegralderivativeregulator),whichcandeterminethesizeofthecontrolquantityaccordingtotheproportionalvalue,integralvalue,andderivativevalueofthedifferencebetweenthetemperaturesetvalueandtheactualvalue.Thetemperaturemeasurementandcontroldeviceadoptstheoutputfeedbacktypecontrol.Extractingthispartfromthegeneralprinciplediagram,youcangetthePIDcontrolprinciplediagramasshowninFigure4.Inthefigure,UdandUarethesetvalueandactualvalueofthethermostatrespectively,theerrore=Ud﹣KT,Kisthemagnificationofthemeasuringtransducer,andYistheadjustmentvalueofthePIDoutput.Figure4PIDcontrolprinciplediagramThesimulationexpressionofPIDalgorithmis:Intheformula,Y(t):regulatoroutputvalue;E(t):inputdeviation;KP:regulatorproportionalcoefficient;Tl,TD:verseunitintegral,derivativetimeAfterdiscretizingequation(6),thePIDincrementalcontrolequationisobtained:Intheformula,theintegralcoefficientKl=KPT/T1,thedifferentialcoefficientKD=KPTD/r,andTisthesamplingperiod.thenapply(7)toZ-transform,andget:Intheexperiment,theauthorusedastepsignaltoroughlymeasuretheresponseintheopen-loopstate.Fromthestepresponsecurve,itisknownthatthethermostatisafirst-orderinertialinkplusapuretimedelaylink,namely:Thelagtimerofthesystemisdeterminedtobeapproximately20seconds,andthetargettimeconstantTPisapproximately50seconds.Selectthecontroldegreetobe1.5,accordingtothestepresponsecurvetuningparametermethod(refertoliterature[1]),obtain:T=0.34z=6.8sKr=0.85Tr,/r=2.125T1=1.62r=32.4sTD=0.65r=13sSubstitutingtheabovevalueforequation(9),wecanobtain:Q0=6.41Q1=-5.96Q2=4.06TheequationofPIDregulatoris:VI.ProgramDesignThePIDcontrolprogramflowoftheWCZ-98temperaturemeasurementandcontroldeviceisshowninFigure5.ThebasicideaisthesameasthegeneralPIDcontrolflow.Itsnoneedtorepeathere.Figure5PIDcontrolprogramflowchartVII.ExperimentalAnalysisandConclusionPutthetemperaturemeasurementandcontroldeviceintoathermostatwithanexternaldimensionof248208262(mm).Thethermostatuses50mmthickpolystyreneastheheatinsulationmaterialandwaterasthemedium.Theheatingdeviceiscomposedof2SRS3-220/0.5heatingtubesandauxiliarypartstopreventleakage.Thetemperaturecanbepresetoutsidethethermostatandthereisaswitchtoselectthetypeofcontroller.Throughexperiments,comparingthecontroleffectsofthetwoadjustmentcontrolmethods,wefoundthatthetemperatureoftheadjustmentcontrollercomposedofacomparisonamplifierandarelayisnotstableduringthetemperaturecontrolprocessandalwaysfluctuateswithinacertainerrorrange.ThetemperaturecontrolperformanceoftheregulatingcontrollercomposedofPIDregulatorandthyristorisverygood.Takingtemperaturecontrolof60Casanexample,thetemperaturechangecurveobtainedbytheexperimentisshowninFigure6.Figure6PIDtemperaturecontrolexperimentresultcurveItcanbeseenthattheuseofanalogcircuitsforadjustmentandcontrolisbeneficialtomakethemeasurementandcontroldeviceanindependentinstrument(noneedtoconnecttoacomputer),anditstemperaturemeasurementandcontrolaccuracycanmeetthegeneralrequirements;andthroughPIDcontrol,itsprecisionoftemperaturemeasurementandcontrolisveryhigh.Itisusedinconjunctionwiththethermostatandtheself-developedSYZJX-2experimentaladapterbox.TheanaloginputboardPCL-818LandtheanalogoutputboardPCL-726areconnectedtothecomputertoachievehigh-precisiontemperaturecontrol.FAQWhatisAD590?AD590isatemperaturesensor,thecurrentoutputsensitivityis1A/℃,thestandardoutputvalueis298.2Aat25℃,andtheworkingvoltagerangeis4~30V.WhatarethecharacteristicsofAD590temperaturesensor?Singlefunction(onlytemperaturemeasurement),smalltemperaturemeasurementerror,lowprice,fastresponsespeed,longtransmissiondistance,smallsize,micropowerconsumption,etc.Itissuitableforremotetemperaturemeasurementandtemperaturecontrolwithoutnon-linearcalibration.Theperipheralcircuitissimple.HowtodetectthequalityofAD590?AD590hasacurrentof273mAat0.Because2113isaWensensitiveresistor5261,itmeansthatitisgreatlyaffectedbythesurroundingtemperature4102.Itisverydifficulttomeasurewithoutrelyingon1653othertools.Giveyousomesuggestions.Whentheambienttemperaturerisesbyonedegree,thecurrentofAD590increasesby1uA.WhatyouhavetodoistoworkwithAD590simultaneouslywiththehelpofahigh-precisiontemperaturetestinstrument.AfterAD590series10Kresistance,measureitsvoltage,thatistosay,itshouldbe2.73Vat0,and2.98Vatroomtemperature25.Forhigheraccuracy,itisrecommendedthatyouusetheelectronicbuildingblocksoftwareArdunioformeasurement,andputthecorrespondingdataintoMATLABforlinearregression.Thebetterthelinearity,themorestablethemeasurement.AD590isnotahigh-precisiontemperaturetestingdevice.Ifhigh-precisiontestingisrequired,othercomponentsarerecommended.WhatisthedifferencebetweenAD590andPT100?AD590isacurrent-typetemperaturesensor.Itconvertstemperaturechangesintocurrentconversion.Thesimplestprocessingistopassaresistor(10K)aftertheoutputtoconvertthecurrentintoavoltage,andthenthroughthedetectionvoltage,thecurrentatthistimecanbededuced.Usetherelationshipbetweencurrentandtemperatureinthesensordatatocalculatethecurrenttemperature.PT100isaresistancetypetemperaturesensor,whichconvertstemperaturechangesintoresistancechanges.ThesimplestprocessistoplacePt100inabridge,usethevoltagedifferenceatthemidpointofthebridgearm,anduseadifferentialamplifiercircuit(instrumentamplifiercircuit)Amplifythevoltage,usetheamplifiergainandbridgestructuredata,andusethedetectedvoltagetoinverselycalculatethecurrentresistancevalue,andusetherelationshipbetweenresistanceandtemperatureinthePT100datasheettocalculatethecurrenttemperature.IsAD590athermocoupleorathermalresistance?Itisneitherathermocouplenorathermalresistance.Themainprincipleistodetectthetemperatureaccordingtothetemperaturechange,theoutputcurrentchange,andthecurrentsize.

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IDescriptionThisblogintroducestheworkingprincipleoftheL298-baseddirectPWMspeedcontrolsystem.Atthesametime,thesoftwareandhardwarecomponentsofthesystemarealsogiven.TherunningtestinthelatterpartoftheblogshowsthatthisL298-baseddirectPWMspeedcontrolsystemworksstablyandreliably.Moreover,thespeedregulationrequirementsofDCmotorscanbemet.L298MotorControlArduinoTutorialCatalogIDescriptionIIIntroductionIIIWorkingPrincipleofDCHouseholdWMSpeedControlSystemIVIntroductiontoL298VSoftwareImplementationofPWMSpeedRegulationVIConclusionFAQOrdering&QuantityIIIntroductionForalongtime,becauseDCmotorshavethefollowingcharacteristics:Goodlinearspeedregulationcharacteristics;Simplecontrolfunction;HigherefficiencyExcellentdynamiccharacteristics.Therefore,theDCmotoriswidelyusedinspeedcontrol.Especiallywiththedevelopmentofcomputersinthefieldofhumancontrolandthedevelopmentofhighswitchingfrequency,fullycontrolledsecond-generationpowersemiconductordevices(GTR,GTO,MOSinkstoneT,IGBT,etc.),thepulsewidthmodulation(PWM)DCspeedcontrolsystemisinItismoreandmorecommonlyusedinspeedcontrol.IIIWorkingPrincipleofDCHouseholdWMSpeedControlSystemThePWMspeedcontroldeviceusestheswitchingcharacteristicsofhigh-powertransistorstomodulateafixed-voltageDCpowersupply,andswitchesonandoffatafixedfrequency.Then,changethelengthoftheonandofftimeinacycleasneeded.BychangingthedutycycleofthevoltageonthearmatureoftheDCservomotor,theaveragevoltagecanbechangedtocontrolthemotorspeed.Therefore,thisdeviceisalsocalledaswitchdrivedevice.Figure1.PWMcontroldiagramTheschematicdiagramofPWMcontrolisshowninFigure1.ThecontrollableswitchSisrepeatedlyturnedonandoffatcertaintimeintervals.WhenSisconnected,thepowersupplyUsisappliedtobothendsofthemotorthroughtheswitchS,thepowersupplyprovidesenergytothemotor,andthemotorstoresenergy.WhentheswitchSisoff,thepowersupplyUsisinterruptedtoprovideelectricalenergytothemotor.ButtheenergystoredinthearmatureinductanceduringtheswitchSison.Atthistime,themotorcurrentcontinuestoflowthroughthefreewheelingdiodeVD.ThevoltagewaveformobtainedatbothendsofthemotorisshowninFigure2,andtheaveragevoltageUavcanbeexpressedbythefollowingformula:Whereton:Thetimewhentheswitchisturnedoneachtime;T:Shorttimeperiodwhentheswitchison;:Dutycycle.Itcanbeseenfromtheaboveformulathatchangingtheratiooftheswitch-ontimetontotheswitchingperiodT,thatis,changingthedutycycleofthepulse.Theaveragevoltageacrossthemotoralsochangesaccordingly.Thus,themotorspeediscontrolled.Figure2.PWMcontrolwaveformTherearetwomodulationmethodsforchangingthedutycycle:Oneisthattheswitchingperiodisconstant,andthedutycycleischangedbychangingtheon-pulsewidth.Thatispulsewidthmodulation.Anotherwayistohaveaconstantturn-onpulsewidthandchangethedutycyclebychangingtheswitchingfrequency(f=1/T).Thatispulsefrequencymodulation.SincePFMcontrolreliesonthepulsefrequencytochangethedutycycle,whenitencountersamechanicalresonanceataparticularfrequency,itoftenresultsinsystemvibrationandaudiowhistling.ThisseriousshortcomingmakesPFMcontrolunsuitableinservosystems.Atpresent,thecontrolofDCmotorsismainlybasedontheapplicationofPWMcontrol.IVIntroductiontoL298L298isadualH-bridgehigh-voltagehigh-currentpowerintegratedcircuit,whichdirectlyusesITLlogiclevelcontrol.Itcanbeusedtodriveinductiveloadssuchasrelays,coils,DCmotors,andsteppingmotors.Itsdrivingvoltagecanreach46V,andthetotalDCcurrentcanreach4A.TherearetwoidenticalPWMpoweramplifiercircuitsinside.TheinternalstructureofL298isshowninFigure3.Figure3.HardwarecompositiondiagramofPWMspeedcontrollerAccordingtotheinputandoutputrelationshipofL298,theenablecontrolterminalEnAisconnectedtotheP1.0portoftheAT89C52.ForthePWMsignal,theinputterminalIn2islowlevel,themotorrotatesforward;theinputterminalIn2isthePWMsignal,inputterminalIn1isrecordedaslowlevel,themotorreverses).Whenitislowlevel,the4transistorsonthedrivebridgeareallcutoff,sothatthearmaturecurrentoftherunningmotorisreversedandthemotorstopsfreely.ThespeedofthemotorisrealizedbyadjustingthedutyratioofthePWMsignalbythesingle-chipmicrocomputer.VSoftwareImplementationofPWMSpeedRegulationIntermsofprogramdesign,thegenerationofthePWMpulsesignaloftheMCUcanusethefollowingtwomethods:softwaredelayandtimerdelay.Althoughsoftwaredelayiseasiertoimplement,intheory,itoccupiestoomuchsystemresourcesandisinconvenienttouse.ThePWMspeedcontrollerusesthetimer0interruptmodetogeneratePWMpulse,andthePWMcontrolsubroutineistheinterruptserviceroutineoftimer0.Atthesametime,italsogeneratesasamplingperiod,thatis,theAnzhaosamplingperiodstartsA/Dconversion.ItsprogramflowchartisshownasinFig.4.Figure4.ProgramflowchartVIConclusionBasedontheL298DCmotorPWMspeedregulator,the1/0portoftheA8T9C52microcontrolleroutputsthePWMsignal,anddirectlyusestheTTLleveltocontrolthedrivechipL298toadjustthemotorspeed.Itissimpleandconvenienttocontrol.Andtheexperimentshowsthatthesystemworksstablyandreliably,satisfiesthefunctionalrequirementsofspeedregulation,andhasgreattheoreticalandpracticalvalue.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.

IIntroductionTheLM311devicesaresinglehigh-speedvoltagecomparators.Thedevicesaredesignedtooperatefromawiderangeofpowersupplyvoltages,including15-Vsuppliesforoperationalamplifiersand5-Vsuppliesforlogicsystems.TheoutputlevelsarecompatiblewithmostTTLandMOScircuits.Thesecomparatorsarecapableofdrivinglampsorrelaysandswitchingvoltagesupto50Vat50mA.Allinputsandoutputscanbeisolatedfromsystemground.Theoutputscandriveloadsreferencedtoground,VCC+orVCC.Offsetbalancingandstrobecapabilitiesareavailable,andtheoutputscanbewire-ORconnected.Ifthestrobeislow,theoutputisintheoffstate,regardlessofthedifferentialinput.CatalogIIntroductionIIPrecautionsofLM3112.1ChooseComponentsReasonably2.2IncreaseAmplitudeofInputSignal2.3AddFilteringAppliancestoOutputofComparator2.4AdoptLaggingTechnologyFAQOrdering&QuantityIIPrecautionsofLM311LM311isacommonlyusedlinearcomparator,whichiswidelyusedincomparisonandshapingcircuits,andasisshowninFigure1.Figure1.LM311CircuitDiagramHowever,LM311oftenhasunexpectedproblemsintheapplication,thatis,theoutputpulsesignalisnotasidealastheoreticalanalysis.Instead,high-frequencyoscillationoccursnearthefrontandbackedgesoftheoutputpulse,asshowninFigures2and3.Figure2.HighFrequencyOscillationbeforeOutputPulseFigure3.HighFrequencyOscillationafterOutputPulseWhentheinputsignalViamplitudeoftheLM311issmallerandthefrequencyislower,thehigh-frequencyoscillationismoreserious.Thiskindofwaveformcontaininghigh-frequencyoscillationcannotbeuseddirectly.Itwillcausemisoperationtosubsequentcircuits,suchasfrequencymeasurement.Therefore,thissituationmustbepaidattentionto,andtrytoavoidoreliminatehigh-frequencyoscillation.Thefollowingwillgiveabriefanalysisofthecausesofoscillations,andatthesametimeputforwardseveralmethodstoeffectivelyavoideliminatingoscillationsonthebasisofexperiments.Figure4.LM311Whenahigh-speedcomparatorisusedforhigh-speedinputsignalsandlowsourceimpedanceinputsignals,thenormaloutputresponseshouldbefastandstable.However,whentheinputsignalisaslowlyvaryingsignalorahigh-impedancesignalsource(1.0K-10K),thecomparatormayoscillatesuddenlyatthecomparisonthresholdpoint,whichiscausedbythehighgainandwidebandofthecomparator,andthepresenceofinterferenceisalsooneofthedirectcausesofthisoscillation.Inapplication,toavoidthiskindofoscillationandinstability,carefulconsiderationshouldbemadeinadvanceandoverallarrangementsshouldbemade.Thefollowingwillproposeseveraleffectivemethodstoavoidandovercomeoscillations:2.1ChooseComponentsReasonablyReasonablyarrangingtheoccurrenceofstructuraloscillationshasalottodowithstructuralarrangements.Theoutputsignalshouldbefarawayfromtheinputterminalpin,andshouldalsobefarawayfromthetwobalancedterminalpins,becausethefeedbacksignalsensingortouchinganypinmayalmostcauseoscillation.Ifthecomparatorusesaresistorattheinput,itspositionandresistanceareworthconsidering.Theresistanceshouldbeplacednearthetubebase,andthegeneralresistancevalueshouldbelessthan10K(orevenless),pleaserefertothecorrespondingmanualwhenusing.Positiveandnegativepowersupplyshouldadd0.1filtercapacitortofilterouttheinterferenceofthepowersupply,andputthecapacitornearthepin.Thetwobalancedendsshouldbeproperlyhandled.Whennotinuse,theycanbeshortedtogether.Forspecificuse,youcanalsorefertotherelevantmanual.2.2IncreaseAmplitudeofInputSignalThemagnitudeoftheinputsignalamplitudeisdirectlyrelatedtotheoscillation.Experimentsshowthatthesmallerthesignalamplitude,thelowerthefrequency,thegreaterthepossibilityofoscillation.Thefollowingwillmakeasimpleanalysisoftheaboveconclusions.Ifthereisazero-crossingcomparator,theinputsignalisVi=V0sin0t.Theslopeofthesignalatt=0is:Theamountofvoltagechangein△ttimeis:△Vi=K△t=V0sin0t,whichshowsthat△ViisproportionaltoV0,0,thatis,thegreatertheamplitudeoftheinputsignal,thehigherthefrequencyofthesignal.Theninthe△ttime,thelongertheamplitudechangeofVis,whendvi/dtislargeenough,theinputsignalwillquicklycrossthecomparisonthreshold,soastoachievethepurposeofeliminatingoscillation.Becausetheinputvoltagerangeofthecomparatorisgenerallyrelativelywide(forexample:thevoltageinputrangeoftheLM311is30V),thismethodisthemostsimpleandfeasible.Theexperimentprovesthataslongastheamplitudeoftheinputsignalisgreaterthan0.7V,thisdesigncanworkreliablyintherangeof10Hz~60KHz,continuetoincreasethevoltageamplitude,theworkingrangecanbeextendedtothelowfrequencyend.2.3AddFilteringAppliancestoOutputofComparatorPullingaresistorattheoutputofthecomparatorandconnectingacapacitorwithanappropriatecapacityhasasignificanteffectonfilteringandreducingoscillation.Thecapacityofthecapacitorshouldbedeterminedonthebasisoftheexperiment.Thecapacityofthecapacitorshouldnotbetoolarge,otherwisetheleadingedgeoftheoutputpulsewillbedeteriorated.Itwasfoundintheexperimentthatthisnegativeeffectisparticularlyseriousathigherfrequencies,andevenmakethepulseamplitudesmaller,sothatthecounterofthesubsequentstagecannotwork,thesituationisshowninFigure5.Figure5.PulseAmplitudeatHigherFrequenciesTherefore,thismethodhascertainlimitationsintheapplication,andthereasonablechoiceofcapacitanceisthekeytoapplyingthismethod.Ofcourse,thedeterioratedfrontcanberestoredbythe74LS14withashapingeffect.Thenegativeeffectofthismethodistoshifttheoriginalpulsefrontbackward.Inthisdesign,capacitanceC=0.01istaken.Withintherangerequiredbythesystem,thevalueofthepull-upresistorthatthecircuitcanworkreliablycannotbetoolarge.Inthisdesign,R=510.2.4AdoptLaggingTechnologyInthecomparisoncircuit,whentheinputsignalreachesthecomparisonlevel,thecomparatorshouldbereversedimmediately,butifthemeasuredsignalissuperimposedwithacertainamountofinterference,thecomparatormayoscillatenearthecomparisonlevel,asshowninthefollowingfigure(Figure6-7).Figure6.OutputofaCommonZero-crossingComparatorFigure7.OutputwithLagTechnologyTheeffectivemethodtoovercometheoscillationofthecomparatoristousethelagtechnology,thatis,addasmallamountofpositivefeedbacktoitsnon-invertingend.Thecomparisonlevelofthelagcomparatorisnolongerasinglelevel,buthastwopowerlevelsneartheoriginalcomparisonlevel.Ingeneral,forthecircuitinfigure8,theuppercomparisonlevelisrepresentedbyV+H,andthelowercomparisonlevelisrepresentedbyV+L.Figure8.CircuitwithTwoLevelsThehysteresisvoltagecanbeadjustedbyR1andR2.Aslongas△Visselectedproperly,theoscillationphenomenonofthecomparisoncircuitcanbeeliminated.Therefore,theanti-interferenceabilityisgreatlyimproved,butthepresenceofthelaglevel△Vwillmakethedetectionsensitivityworse.Therefore,△Vshouldnotbetoolarge,usuallyR1R2.FortheLM311comparator,adding3mvofhysteresiswilleliminatetheoscillationinthecircuit.Therefore,wemustconsidercarefullyandtreatseparatelywhenusingLM311.Onlyinthiswaycanwebehandywhenusingit.FAQHowtouseLM311?LM311isasingle-channelcomparator.Whenusingit,connectthereferencevoltageandthecomparedsignalvoltagetoitsnon-invertingandinvertinginputterminals(pin2andpin3),anditsoutputistheresultofthecomparison.Ifyouwantthefowardoutputresult,pin7isconnectedtothepositivepowersupplyandpin1istheoutput.Iftheresultistobeoutputinreverse,pin1isgroundedandpin7istheopencollectoroutput.lm311andlm393arebothvoltagecomparators,sowhatisthedifferencebetweenthem?LM311issinglevoltagecomparaotor,LM393isdualvoltagecopatpr.LM311hasaloadcurrentofupto50MAandavoltageof40V.Itcandriverelayswithaminimumpowersupplyvoltageof5V.TheLM393loadcurrentis16MA,andtheminimumvoltageis2Vforasinglepowersupply.WhatsthedifferencebetweenLM311andLM111?Theirfunctionsarethesame,andthe1XXseriescanbeusedinharsherenvironments.The3XXseriescanonlybeusedinacommercialenvironment,typicallytheapplicabletemperaturerangeofthedevice.Thepriceof1xxismuchmoreexpensivethan3xx.Whatdoesthe5and6-pinbalancestrobesofLM311mean?Thefunctionofbalancingthemirrorcurrentofthereversecircuitisrealizedbyconnectingapotentiometerinthemiddle.Inadditiontothebalancefunction,the6pinalsohasastrobefunction,andthe6pincanbegroundedthroughthetransistordrivecircuitforstrobeoutput.Whatisthedifferencebetweenlm311voltagecomparatordualpowersupplyandsinglepowersupply?Thecomparatorsareallopen-collectoroutputs,withoutloadresistance,theycannotoutputvoltagesignals.Dualpowersuppliescandetectsignalslowerthan0,andsinglepowersuppliescanonlydetectsignalshigherthan0.Canthelm311comparatorbepoweredbyapositiveandnegativefive-voltdualpowersupply?Ofcourse,LM311canbepoweredby5Vdualpowersupply.Itsrequirementforworkingpowersupplyisthatthevoltagedifferencebetweenthepositiveandnegativepowersupply(orsinglepowersupplyvoltage)isatleast3.5Vandthemaximumis30V,aslongasitiswithinthisrange.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.DescriptionBC327isageneralpurposePNPtransistor,todaywewilldiscussaboutitspinoutconfiguration,equivalent,uses,packagedimensionsandmanyotherdetails.BC327UsingTransistorsBC327BC337toMakeaMiniPowerfulAudioAmplifierCatalogueDescriptionBC327IntroductionBC327PinConfigurationBC327MarkingDiagramBC327TechnicalSpecificationsBC327CADModelsBC327ApplicationsBC327PackageDimensionsBC327FunctionalEquivalentsBC327PopularitybyRegionWhereandHowtoUseBC327HowtoGetLongTermPerformancefromBC327BC327ManufacturerComponentDatasheetOrdering&QuantityBC327IntroductionBC327isageneralpurposePNPBJPtransistorthatcanbeusedforswitchingandamplificationpurposesinelectroniccircuits.Thetransistorfeatures800mAcollectorcurrenthenceitcanbeusedtodrivevarietyofloadsinanelectronicapplication.Themaxcollector-emittervoltageis-45Vthereforeitcaneasilyhandleloadvoltageunder45V.Apartfromthattransistoralsofeatures625mWcollectordissipationandDCcurrentgainofmaximum630thereforeitcanalsobeusedasanaudioamplifierorforanytypeofsignalamplification.BC327manufacturedindifferenthFEclassificationthatcanbedifferentiatewiththecodenumberwrittenafterthetransistornumber.Ifyoufindcode-16afterthetransistornumberthenthehFEwillbe100~250,ifthecodeis-25thenthehFEwillbe160~400andifthecodeis-40thenthehFEwillbe250~630.BC327PinConfigurationPinNumberPinNameDescription1CollectorCurrentflowsinthroughcollector,normallyconnectedtoload2BaseControlsthebiasingoftransistor,UsedtoturnONorOFFthetransistor3EmitterCurrentDrainsoutthroughemitter,normallyconnectedtogroundBC327MarkingDiagramBC327TechnicalSpecificationsPackageType:TO-92TransistorType:PNPMaxCollectorCurrent(IC):-800mAMaxCollector-EmitterVoltage(VCE):-45VMaxCollector-BaseVoltage(VCB):-50VMaxEmitter-BaseVoltage(VBE):-5VMaxCollectorDissipation(Pc):625MilliwattMaxTransitionFrequency(fT):100MHzMinimumMaximumDCCurrentGain(hFE):100to630MaxStorageOperatingtemperatureShouldbe:-55to+150CentigradeBC327CADModelsBC327PartSymbolBC327FootprintBC327ApplicationsOutputofMicrocontrollerstoDriveLoadsAnyTypeofSignalAmplificationAudioamplifierAudioAmpStagesDriveLoadsUnder800mABC327PackageDimensionsBC327FunctionalEquivalentsBC327PopularitybyRegionWhereandHowtoUseBC327LikeotheressentialgeneralpurposetransistorstheBC327isalsoamustofhavetransistorinyourlabbecauseitcanbeusedinwidevarietyofapplications.Itcanbeusedasaswitchtodriveloadsupto800mAwhichincludeshighpowerrelays,highpowertransistors,highpowerLEDs,ICsandotherpartsofacircuit.With-5Vemitter-basevoltagethistransistorcanalsobeusedastheoutputofmicrocontrollerstodriveloadofupto800mAwhichcaneasilydrivemotors,modules,sensorsetc.HowtoGetLongTermPerformancefromBC327Togetlongtermgoodperformancewiththistransistorinyourelectronicapplicationsitisrecommendedtonotdriveloadmorethan0.8Aor800mA,donotdriveloadormorethan-45V,alwaysuseasuitablebaseresistorwiththetransistor.Donotstoreoroperatethistransistorintemperaturebelow-55centigradeandabove+150centigradeandalwayscheckpinconfigurationbeforeplacinginthecircuit.BC327ManufacturerONSemiconductor(Nasdaq:ON)isdrivingenergyefficientinnovations,empoweringcustomerstoreduceglobalenergyuse.Thecompanyoffersacomprehensiveportfolioofenergyefficientpowerandsignalmanagement,logic,discreteandcustomsolutionstohelpdesignengineerssolvetheiruniquedesignchallengesinautomotive,communications,computing,consumer,industrial,LEDlighting,medical,military/aerospaceandpowersupplyapplications.ONSemiconductoroperatesaresponsive,reliable,world-classsupplychainandqualityprogram,andanetworkofmanufacturingfacilities,salesofficesanddesigncentersinkeymarketsthroughoutNorthAmerica,Europe,andtheAsiaPacificregions.ComponentDatasheetBC327Datasheet

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