题图5-8所示电路中的运放工作于线性区，求转移电压比k=u0/ui。

A . 正确 B . 错误

A . A、具有负反馈 B . B、具有正反馈或无反馈 C . C、具有正反馈或负反馈

A . 深度负反馈状态 B . 放大状态 C . 开环或正反馈状态 D . 线性工作状态

A . 正确 B . 错误

A . A、具有负反馈 B . B、具有正反馈 C . C、具有正或负反馈 D . D、无反馈

<img src='https://img2.soutiyun.com/ask/2021-01-03/978524981261597.png' />

<img src='https://img2.soutiyun.com/ask/2021-01-03/978531322948321.png' />

电路如题图12-19所示。已知<img src='https://img2.soutiyun.com/ask/2020-07-07/962980568947105.png' />求u(t)和电源发出的平均功率。 <img src='https://img2.soutiyun.com/ask/2020-07-07/962980580359758.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962980588114202.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962980593054484.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962980598822814.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962980606387247.png' />

若用节点法求题图所示电路中的电流<img src='https://img2.soutiyun.com/latex/latex.action' />和<img src='https://img2.soutiyun.com/latex/latex.action' />，试列出所需的方程。(不必求解) <img src='https://img2.soutiyun.com/ask/5499001-5502000/d6e63fc12e45a789fe69a41d9c5219b0.jpg' />

如题图E3-19所示电路，已知<img src='https://img2.soutiyun.com/ask/2020-11-14/974193896718043.png' />试求电流i。 <img src='https://img2.soutiyun.com/ask/2020-11-14/974193908480716.png' />

<img src='https://img2.soutiyun.com/ask/2020-07-06/962893799329117.png' /><img src='https://img2.soutiyun.com/ask/2020-07-06/962893808339632.png' />

图题2.4.5所示为一增益线性调节运放电路，试推导该电路的电压增益A_P=v₀/(v_i1-v_i2)的表达式。 <img src='https://img2.soutiyun.com/ask/2020-11-16/974407760026192.png' />

题图10-50所示单口网络工作于正弦稳态，已知us(t)=<img src='https://img2.soutiyun.com/ask/2020-07-07/96297017944186.png' />试求单口网络的戴维宁等效电路。 <img src='https://img2.soutiyun.com/ask/2020-07-07/962970193210647.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962970201021094.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962970211392687.png' />

<img src='https://img2.soutiyun.com/ask/2020-09-17/969206067743786.png' /> (1)请为该电路T₁、T₂选择合适的三极管，满足最大管耗、最大集电极电流和最大管压降的要求. (2)若减小负载电阻的阻值，输出级保护电路工作前，负载电阻的最小值是多少？

若题2-1-2图所示电路中电沉源的电流减小一半(即为2A),试根据线性电路的齐次性和可加性求电压U. <img src='https://img2.soutiyun.com/ask/2020-10-09/971097219114177.jpg' />

<img src='https://img2.soutiyun.com/ask/2020-07-07/962965159186717.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962965170045339.png' />

<img src='https://img2.soutiyun.com/ask/2020-07-07/962980707934055.png' /><img src='https://img2.soutiyun.com/ask/2020-07-07/962980722925912.png' />

<img src='https://img2.soutiyun.com/ask/2020-07-06/962894304423007.png' />

单相桥式整流电容滤波电路如题图E9-2所示，变压器:二次电压<img src='https://img2.soutiyun.com/ask/2020-11-14/97419657881545.png' />求 (1)负载电流I₀，每个二极管的平均电流ID，二极管承受的反向峰值电压U_DRM; (2)当DI管发生短路时的负载电流I₀，D4管的电流I_D4; (3)当DI管发生虚焊断路时的负载电流I₀，D4管的电流I_D4。 <img src='https://img2.soutiyun.com/ask/2020-11-14/974196590724131.png' />