课程名称︰电路学
课程性质︰大一必修
课程教师︰吴忠帜
开课学院：电资学院
开课系所︰电机系
考试日期（年月日）︰2019/5/9
考试时限（分钟）：1 hour
试题 :
1. (35%)Please use nodal analysis to determine the output voltage vo(t) shown in Fig.1 with the current source is(t) = 2cos(50t+30) A
https://imgur.com/7j3ZWax.jpg
2. (30%)For the circuit shown in Fig.2, please use superposition to determine:
(a) node voltage VA (20%)
(b) source current Is (5%)
(c) draw the phasor diagram of VA, Is, and Ic (5%)
3. (35%)As shown in Fig.3, the 60Hz voltage source Vs supplies the power to an induction motor load via a transmission line with (1 + j50) Ω. The induction motor is operated at an rms value of 200∠0 Vrms and 40kW with power factor 0.707 lagging.
https://imgur.com/LuxJi0X.jpg
Please determine:
(a) the voltage source Vs at rms value (10%)
(b) the average power supplied by the voltage source (5%)
(c) the efficiency of the system (5%)
(d) the capacitance needed at terminal AB to improve the load power factor to 0.95 lagging (10%)
(e) the values of the source current Is before and after the capacitor is connected (5%)