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ID:9366837
大小:245.00 KB
页数:15页
时间:2018-04-29
《lab 5 pulse width modulation》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、TEXASA&MUNIVERSITYENGR111B:FoundationsofElectrical&ComputerEngineeringLab5:PulseWidthModulationTeamMembers:__________________________________________________SectionNumber:__________TeamNumber:__________ThisLabisduebytheBeginningoftheNextLabSession.WrittenBy:HankWalkerLorneLiechty15WrittenbyTexas
2、A&MUniversityLab5:PulseWidthModulationTimeLimit:1weekOVERVIEWUsingRCcircuitswecannotonlytimeindividualevents,butwecanalsocreaterepeatingtimers.Thisoscillatorytimingisusedinvirtuallyeveryelectronicdeviceavailable.InthislabstudentswillexaminetheuseofadigitallyoscillatingsignaltocontrolDCmotorspeed
3、.Thisapproachcontrastswiththesimpleresistor-basedcurrentlimitingmethodyouusedpreviously.Topicscoveredinthislabincludethefollowingmaterial:-DigitallyOscillatingSignals-PulseWidthModulation-AverageVoltage,Current,andPower-HowaPWMsignalcanbegeneratedusinga555timer-Diodes-PWMSignalControlofDCMotorBA
4、CKGROUNDToassiststudentsincompletingtheexercisesrequiredbythislab,thefollowingbackgroundinformationhasbeenprovided.Itisrecommendedthateachstudentreadallofthefollowinginformationasabeneficialreviewofthetopicsrequired.DIGITALOSCILLATIONSAnoscillatingsignalisonewhichchangesbetweentwolevelsaccording
5、toaregularpatternofintervals.AC(AlternatingCurrent)voltagesareincludedintherealmofoscillatingvoltages,butthetermACisreservedforsignalswhichincludebothpositiveandnegativevoltages.Adigitaloscillationalsoswitchesbetweentwolevelsaccordingtodefinedintervals,andtheidealdigitalsignalexistsonlyatthespec
6、ifiedlevelsanddoesnotexistatthelevelsinbetween.ThesignalsrepresentedinFiguresB1aretwodifferentdigitallyoscillatingsignals.FigureB1:DigitallyOscillatingSignals15WrittenbyTexasA&MUniversityExaminingthesignalsinFigureB1,noticethatthelowerofthetwovoltagesdoesnothavetobesettozerovolts,orground;thelow
7、ervoltageofadigitalsignalisdefinedtobealogicalLOWor0,butthevalueisnotrequiredtobezero.WhenasignalisnotcenteredaroundzerothesignalissaidtohaveaDCoffsetthatraisesorlowersthesignaltoanewcentervoltage.SignalsthatdonothaveDCoffse
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