姓名學(xué)號(hào)學(xué)院姓名學(xué)號(hào)學(xué)院專(zhuān)業(yè)座位號(hào)(密封線內(nèi)不答題)……………………密………………封………線……線………_____________________…華南理工大學(xué)期末考試《電路與電子技術(shù)》（雙語(yǔ)）試卷A考試時(shí)間：120minutes Date：January,15,2013注意事項(xiàng)：1.考前請(qǐng)將密封線內(nèi)填寫(xiě)清楚；2.所有答案請(qǐng)直接答在答題紙上；3．考試形式：閉卷；4.本試卷共11大題，滿分100分， 考試時(shí)間120分鐘。題號(hào)1234567891011總分得分評(píng)卷人1.ConsiderthecircuitshowninFig.1giventhatUS1=6V,US2=10V,R1=4,R2=2,R3=4,R4=1,R5=10.FindthevalueofI1,I2,I3,I4,I5andVAB.（6scores）Fig.1I5=0A 5VAB=0V 62.ConsiderthecircuitshowninFig.2,thetwoidealdiodesareofthesametype,vi=6sinwtV,pleasejudgethestateofD1andD2(onoroff)andplotthewaveformofvoltagevO.（6scores）Fig.21.Whenvi>=3V,D1on,D2off,vo=3V2.Whenvi<=3V,D1off,D2on,vo=3V2.When3<vi<=3V,D1off,D2off,vo=vi3．ConsiderthecircuitshowninFig.3giventhatUS=1V,IS=1A,R1=R2=R3=1.DeterminecurrentI1,I2andvoltageUinsuperposition,whichelementsaresupplyingpower?（8scores）Fig.3ISactsalone：I1'=I2'=0.5IS=0.5A U'=R3IS+R2I2'=1.5V 2U"=R2I2"=0.5V 4so：I1=－I1'+I1"=0I2=I2'+I2"=1A U=U'+U"=2V 電流源IS是電源 8 4．FindtheTheveninequivalentcircuitsforthetwoterminalcircuitshowninFig.4giventhatR1=R2=2k,R3=0.4k.（10scores）Fig.4原電路化為下圖：等效電壓源電路如下圖所示：Fig.56.ConsiderthesinusoidalcircuitshowninFig.6giventhatR=8,XL=6,I1rms=I2rms=0.2A.FindthevalueofIrms,Vrms,thepowerfactorandreactivepowerofthetotalcircuit.（10scores）Fig.67.Abalancedpositivesequencewyethreephasesourcehaslinetolinevoltagesof380Vrms.thissourceisconnectedtoabalancedwyeconnectedloadinFig.7.EachphaseoftheloadisZ=3j4.FindtheinstantaneouscurrentofiaA,ibB,icC,iNn,theapparentpower,averagepowerandthereactivepowerdeliveredtotheload.AssumethatthephaseofVabiszero.（10scores）Fig.7各線電流瞬時(shí)值 8.ConsiderthecircuitshowninFig.8giventhatR1=R2=R3=10kΩ,RF=20kΩ,uI1=1V,uI2=2V,uI3=1V,.FindthevalueofoutputvoltageuO.（10scores）Fig.8利用疊加原理9.TransistorsareoperatingintheactiveregioninFig.9,assumethat:β=50,rπ=1kΩ,determine：（1）plotsmallsignalequivalentcircuit；（2）calculateinputresistorriandoutputresistorro；（3）voltagegainAu.(12scores). Fig.9(1)411.ConsiderthesourcefollowerillustratedinFigure10,determine:(1)plotsmallsignalequivalentcircuit;(2)putethevoltagegain,inputresistance,andoutputresistance.(10scores)fig.10SOLUTION411.ConsiderthecircuitshowninFig.11,writethelog