东南大学电子学院《电路基础》期末考试样卷及答案-2023修改整理

千里之行，始于足下让知识带有温度。第第2页/共2页精品文档推荐东南大学电子学院《电路基础》期末考试样卷及答案Solvethefollowingproblems.(100points)

1、(6points)FindUabinthecircuitinFigure1.

Figure1

ab

2、(8points)FinduoandiointhecircuitinFigure2.

uoFigure2

-

3、(6points)InthecircuitofFigure3,readingsofvoltmeter○V1，○V2and○

V3are10V,18Vand6V,respectively.Pleasedeterminatethereadingofthevoltmeter○V

.

a

Figure3

4、(8points)TheresonantortunercircuitofaradioisportrayedinFigure4,whereus1representsabroadcastsignal,giventhatR=10Ω，L=200μH,Us1rms=1.5mV，f1=1008kHz.Ifthecircuitisresonantwithsignalus1,pleasedeterminate:(1)thevalueofC;(2)thequalityfactorQofthecircuit;(3)thecurrentIrms;(4)thevoltageUcrms.

Figure4

u

5、(8points)Abalancedthree-phasecircuitisshowninFigure5.Calculatethephasecurrentsandvoltagesinthedelta-connectedloadZ,ifVUA?∠=?

0220,Z=(24+j15)Ω，ZL=(1+j1)Ω.

Figure5

?

6、(8points)Findthey

parametersforthecircuitinFigure6.

?

?

Figure6

7、(15points)Forthecircuitinfigure7,findthermsvalueofthecurrentiandtheaveragepowerabsorbedbythecircuit,giventhatΩ10=Lω,

Ω51=R,Ω202=R,Ω

20/1=Cω,V)302cos(50cos10080)(?+++=tttusωω.

Figure7

2

us

8、(12points)InthecircuitofFigure8,determinatethevalueofZthatwillabsorbthemaximumpowerandcalculatethevalueofthemaximumpower.

Figure8

V?∠050ω=103?

rms

9、(14points)IftheswitchinFigure9hasbeenclosedforalongtimeandisopenedatt=0,finduc,iL,ukfort≥0.

20Figure9

uc+-

10、(15points)TheswitchinFigure10hasbeeninpositionaforalongtime.Att=0,itmovestopositionb.Findi2(t)fort≥0andsketchit.(Attention:Please

markthekeydatainyourgraph.)

Figure10

10Ω

Solvethefollowingproblems.(100points)

1、(6points)FindUabinthecircuitinFigure1.

Figure1

ab

Solution:

Uab=9V

2、(8points)FinduoandiointhecircuitinFigure2.

uoFigure2

-

Solution:

V4.2=ou,0.256mA

-=oi3、(6points)InthecircuitofFigure3,readingsofvoltmeter○V1，○V2and○

V3are10V,18Vand6V,respectively.Pleasedeterminatethereadingofthevoltmeter○V

.

a

Figure3

Solution:

Thereadingofthevoltmeter○Vis10V.

4、(8points)TheresonantortunercircuitofaradioisportrayedinFigure4,whereus1representsabroadcastsignal,giventhatR=10Ω，L=200μH,Us1rms=1.5mV，f1=1008kHz.Ifthecircuitisresonantwithsignalus1,pleasedeterminate:(1)thevalueofC;(2)thequalityfactorQofthecircuit;(3)thecurrentIrms;(4)thevoltageUcrms.

Figure4

u

Solution:

pF5.12)1(≈C.126)2(≈QμA150)3(=rmsImV190)4(=CrmsU

5、(8points)Abalancedthree-phasecircuitisshowninFigure5.Calculatethephasecurrentsandvoltagesinthedelta-connectedloadZ,ifVUA?∠=?

0220,Z=(24+j15)Ω，ZL=(1+j1)Ω.

Figure5

?

Solution:

A3.69-11.74''?∠=?

BAI,V31.28332''?∠=?

BAU

6、(8points)FindtheyparametersforthecircuitinFigure6.

?

?

Figure6

Solution:

[]Sy???

?

??=0.5

40.022.07、(15points)Forthecircuitinfigure7,findthermsvalueofthecurrentiand

theaveragepowerabsorbedbythecircuit,giventhatΩ10=Lω,

Ω51=R,Ω202=R,Ω20/1=Cω,V

)302cos(50cos10080)(?+++=tttusωω.

Figure7

2

us

Solution:

A17.6357.2714.42.3222222120=++=++=

IIIIrms

P=P0+P1+P2=256+333.28+50=639.28W

8、(12points)InthecircuitofFigure8,determinatethevalueofZthatwill

absorbthemaximumpowerandcalculatethevalueofthemaximumpower.

Figure8

V?∠050ω=103?

rms

Solution:

IfΩ13

5j

ZZeq

+==*

,Zwillabsorbthemaximumaveragepower.Themaximumaveragepoweris,W7.24913

56.1941412max

=?=?=*

eqOCRUP

9、(14points)IftheswitchinFigure9hasbeenclosedforalongtimeandis

openedatt=0,finduc,iL,ukfort≥0.

20Figure9

uc+-

Solution:

0A,5.15.1)5.10(5.14040>-=-+=--teeittL，

0V,60120)12060(12022/20/>-=-+=--teeuttC0,V6030902022/40>+--=-=--teeuiuttCLK

10、(15points)TheswitchinFigure10hasbeeninpositionaforalongtime.At