电子信息专业英语教学课件作者刘睿强unit5.ppt

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1、UnitFiveLesson14TheUseofMultimeterLesson15OscilloscopeLesson16SignalGeneratorLesson14TheUseofMultimeterKeywordsmultimeter万用表physically物理地mode模式probe探测display显示屏upperlight高亮nominal额定的over-range超量程drift漂流下一页返回Lesson14TheUseofMultimeterHowtodetectwhetherthekey“w”andthekey“e”arephysica

2、llyconnectedwithamultimeter(seeFig14-1)Afteradeepconsideration,wewillfindtheproblemisequaltotheproblemofdeterminingcontinuityoftwopointsinPCBwithmultimeter.Inordertoachievethetask,wemaytrythesestepsasfollowing下一页上一页返回Lesson14TheUseofMultimeterGetintothemodeFirststepistogetyourmu

3、ltimeterintothecorrectmode.Lookfortheiconthatlookssortoflikea“soundwave”.Herearetwoexamples.Notethatsometimesthemodeis“dual”(orpossiblymore)usage,asshowninFig14-2下一页上一页返回Lesson14TheUseofMultimeterTouchandgoForamajorityofmultimeters,you’rereadytogo,justtouchthetipsoftheprobestog

4、ethersothattheymakeabeepingsound!HerearesomeexamplescoveringacoupleofdifferentmultimetersExample1:Thismeterisverysimple.Whentheprobesarenottouching,thedisplayshows“1”Whenyoutouchthetipstogether,thedisplaychangestoathreedigitmode(it’sdisplayingresistance,whichwewillcoverlater).It

5、alsoemitsabeep,asshowninFig14-3下一页上一页返回Lesson14TheUseofMultimeterExample2:Thismeterisdualmodebutstillveryeasytouse.Turnthedialtothesymbol.Whentheprobesarenottouchingthedisplayshows“OL”whichstandsforOpenLoop.Whenyoutouchtheprobes,thesoundwaveiconshowsupinthedisplay(upperright)andit

6、alsoshowsanumber.Thenumberisnottheresistance,actuallyit’sthevoltageasshowninFig14-4下一页上一页返回Lesson14TheUseofMultimeterProbingaPCBExample:HereisanexampleoftestingaPCBforcontinuity.Thefirsttestshowsthatthetwopointsarenotconnected;thesecondtestshowsthatthesetwopointsareconnected,ass

7、howninFig14-5下一页上一页返回Lesson14TheUseofMultimeterHowtomeasurethevoltageofdailybatterieswithamultimeter?Voltagetestingisverycommon,you’lluseitalot.Beforeyourtestinacircuit,youmustmakesurethecircuitispowered,andvoltageisalwaysmeasuredbetweentwopoints,inaddition,itisdirectional下一页上一

8、页返回Lesson14TheUseofMultime