《电子信息专业英语》PPT课件

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1、UnitTwoAnalogCircuitNewWordsandExpressionsdiode['daiəud]二极管nonlinear[nɔn'liniə]非线性one-way单向的valve[vælv]阀门semiconductor[ˌsemikən'dɔktə]半导体schematic[ski:'mætik]原理图symbol['simbəl]图表arrows箭头battery['bætəri]电源lamp[læmp]灯permit[pə'mit]准许prohibit[prəu'hibit]禁止polarity[pəu'lærəti]极性Conversely相反

2、switch[switʃ]开关oddly['ɔdli]奇怪地invent发明predominantly占主导地位的conventional[kən'venʃənəl]习惯的、传统的notation[nəu'teiʃən]符号、标记metallurgically[ˌmelə'lə:dʒikli]冶金silicon['silikən]硅n-typeN型p-typeP型juxtaposed[ˌdʒʌkstə'pəuzd]紧靠的ohmmeter['əumˌmi:tə]欧姆表qualitatively['kwɔlitətivli]定性地purpose目的expect期望mili

3、tary['militəri]军用civilian[si'viljən]民用peak[pi:k]峰值clamper['klæmpə]钳子rectification整流photic['fəutik]光decoration[ˌdekə'reiʃən]装潢、装饰TextDiodeAdiodeisanonlinearelectricaldeviceallowingcurrenttomovethroughitinonedirectionwithfargreatereasethanintheotherandusuallyactingasaone-wayvalveforcurren

4、t.Themostcommonkindofdiodeinmoderncircuitdesignisthesemiconductordiode,althoughotherdiodetechnologiesexist.SemiconductordiodesaresymbolizedinschematicdiagramssuchasFig.2-1.InFig.2-1,arrowsindicatethedirectionofelectroncurrentflow.Whenplacedinasimplebattery-lampcircuit,thediodewilleither

5、alloworpreventcurrentthroughthelamp,dependingonthepolarityoftheappliedvoltage.(Fig.2-2)(a)Currentflowispermitted;thediodeisforwardbiased.(b)Currentflowisprohibited;thediodeisreversedbiased.Whenthepolarityofthebatteryissuchthatelectronsareallowedtoflowthroughthediode,thediodeissaidtobefo

6、rward-biased.Conversely,whenthebatteryis“backward”andthediodeblockscurrent,thediodeissaidtobereverse-biased.Adiodemaybethoughtofaslikeaswitch:“closed”whenforward-biasedand“open”whenreverse-biased.Oddlyenough,thedirectionofthediodesymbol's“arrowhead”pointsagainstthedirectionofelectronflo

7、w.Thisisbecausethediodesymbolwasinventedbyengineers,whopredominantlyuseconventionalflownotationintheirschematics,showingcurrentasaflowofchargefromthepositive(+)sideofthevoltagesourcetothenegative(-).Thisconventionholdstrueforallsemiconductorsymbolspossessing“arrowheads”.Thearro