课程名称︰电子学一
课程性质︰必修
课程教师︰吴肇欣
开课学院：电资学院
开课系所︰电机系
考试日期（年月日）︰2014/11/13
考试时限（分钟）：110
是否需发放奖励金：是
（如未明确表示，则不予发放）
试题 :
1. Fig.1 shows the circuit model of a voltage amplifier loaded with a resistor
RL and a capacitor CL. The parameters are given as RS = 40 kΩ, Ri = 200kΩ,
AVo = 140, and Ro = 2kΩ.
(1)[7%] Find the minimum RL allowed to maintain a voltage gain no less than
40dB.
(2)[7%] Base on (1), what is the maximum CL allowed to keep a 3-dB frequency
higher than 20 kHz?
(3)[9%] The input voltage form is given by 0.1sin(10^4t) + 0.5sin(10^5t)[V].
With the minimum RL and the maximum CL, find the output voltage Vo.