题图7-7所示电路处于直流稳态。试选择电阻R的电阻值，使得电容和电感储存的能量相同。

A . R，0，0 B . 0，0，∞ C . R，∞，0 D . R，0，∞

A . 由小变大 B . 由大变小 C . 基本不变 D . 无法判断

A . 1 B . 2 C . 3 D . 4

A . A．480A B . B．440A C . C．5～7倍的额定电流 D . D．80A

A . 正确 B . 错误

若题图所示电路中二端口网络的A参数已知，则11&39;端口的输入电阻Z_in=______。 <img src='https://img2.soutiyun.com/ask/5499001-5502000/7cc3154445ed13f2c39a3500448c50d8.jpg' />

<img src='https://img2.soutiyun.com/ask/2020-11-15/974324820322645.png' />

A．大于0．7 kΩ B．小于0．7 kΩ C．大于2 kΩ D．小于2 kΩ

<img src='https://img2.soutiyun.com/ask/2020-10-21/972145930727238.jpg' />

试写出题图12-4(a)、(b)所示双口网络的转移电流比，并用计算机程序画出电阻R=1kΩ和电容C=1μF时电路的幅频特性曲线。 <img src='https://img2.soutiyun.com/ask/2020-07-07/962979932609709.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962979942033248.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962979947940586.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962979953660913.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962979959421242.png' />

<img src='https://img2.soutiyun.com/ask/uploadfile/5364001-5367000/2968ad2b913847aaeafa85b7fd6637c5.jpg' />

题图8-10所示电路中，开关闭合已经很久，t=0时断开开关，试求t>0的电阻电流i(t)。 <img src='https://img2.soutiyun.com/ask/2020-07-07/962962316576129.png' />

<img src='https://img2.soutiyun.com/ask/2020-07-07/962978361111824.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962978376321694.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962978383913128.png' />

题图11-5所示电路中，已知<img src='https://img2.soutiyun.com/ask/2020-07-07/962977146182334.png' />试求20Ω电阻吸收的平均功率。 <img src='https://img2.soutiyun.com/ask/2020-07-07/962977155298856.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962977161434207.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962977167285541.png' />

电路如题图8-26所示，开关转换前电路已经稳定，t=0时开关转换，试求t≥0时的电容电压uc(t)和电阻电流i(t)。 <img src='https://img2.soutiyun.com/ask/2020-07-07/962962907971955.png' />

是 否

题图11-8a电路中，非线性电阻的特性如题图11-8b所示，可近似表示为i=0.01u^2，求其上的u、i。 <img src='https://img2.soutiyun.com/ask/2020-04-30/957112622558393.png' />

<img src='https://img2.soutiyun.com/ask/2020-09-17/969206993890759.png' />

题图11-29所示电路中，<img src='https://img2.soutiyun.com/ask/2020-07-07/962978637698644.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962978650466374.png' />试求每个电阻电流的瞬时值表达式i2(t)、i4(t)，电阻电流的有效值以及电阻吸收的平均功率。 <img src='https://img2.soutiyun.com/ask/2020-07-07/962978663428116.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962978671296566.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962978677442917.png' />

<img src='https://img2.soutiyun.com/ask/2020-06-28/962206848685618.png' />