华南理工大学-《电路与电子技术》（双语）试卷2013（1）B.docVIP

诚信应考,考试作弊将带来严重后果！ 华南理工大学期末考试 《电路与电子技术》（双语）试卷B 考试时间：120 minutes Date：January, 15, 2013 注意事项：1. 考前请将密封线内填写清楚； 2. 所有答案请直接答在答题纸上； 3．考试形式：闭卷； 4. 本试卷共 11 大题，满分100分， 考试时间120分钟。 题 号 1 2 3 4 5 6 7 8 9 10 11 总分 得 分 评卷人 6 8 8 10 10 10 10 10 10 10 8 1. consider the circuit shown in Fig.1, find current I1, I2 and I3 in KCL.（6 scores） Fig.1 I1=1－3=－2A 2 I3=－=－1A 4 I2=－I3－1=1－1=0 6 2. Consider the circuit shown in Fig.2, assuming that the diodes are ideal. Find the value of I1 and I2. （8 scores） Fig.2 由导通，截止 得＝0，＝mA＝5mA 3．Consider the circuit shown in Fig.3 given that US=9V，IS=3A，R1=3(，R2=6(. Determine current I1，I2 in superposition, which elements are supplying power? （8 scores） Fig.3 IS单独作用时： I2=1A 2 US单独作用时： 4 叠加得：I1=I1+I1=3A I2=I2－I2=0 US是电源 4.Consider the circuit shown in Fig.4 given that US1=10V，US2=20V，R1=R2=R3=R4=R5=2(. Determine current I in thevenin theorem. （10 scores） Fig.4 4 R0=R1//R2+R4//R5=2( 7 10 5.As shown in following circuit Fig.5, R1=60(, R2=120(, R3=40(, L=4H, ，. the switch S has been open for a long time，and then closed at t=0please find the after S is closed. (10 scores) Fig.5 2 (叠加原理) 4 6 10 6.Consider the sinusoidal circuit shown in Fig.6 given that: ，R1=R2=1(，L=0.1mH，C=100(F. Determine: i(t), the power factor and average power of the total circuit. （10 scores） Fig.6 3 5 6 Power factor: 8 Average power: kW 10 7.In the balanced three-phase system with a 380V line voltage of fig. 7 given Z=24+18j(. Find the line current of IaA, IaB，IaC, and plot phasor diagram. Assume that the phase of Vab is zero (10 scores) 设： 2 4 6 因为：负载为三相对称负载 所以： 8 相量图 8. Consider the circuit shown in Fig. given that: R1=R2=R3 RF1=RF2=RF3，find the relationship between uoand uI.（scores 10） 由 得 故 9.Transistors are operating in the active region in Fig.9，assume thatβ=40，rπ=1kΩ，determine：（1）plot small signal equivalent circuit；（）calculate input