求出图4－3所示电路从电容端口向左看的等效电阻，进而求出电路的零输入响应uC（t)。已知R1=200Ω，R2=300Ω，C=50μF

A . A B . B C . C D . D

A . 3.523 B . 3.236 C . 4.535 D . 5.253

A .https://assets.asklib.com/psource/2015102715442257377.jpg B .https://assets.asklib.com/psource/2015102715442535355.jpg C .https://assets.asklib.com/psource/2015102715442726007.jpg D .https://assets.asklib.com/psource/2015102715443096508.jpg

如图1．3．16所示电路为晶体管放大器等效电路，电路中各电阻及β均为已知，求电流放大系数Ai(Ai=i2/i1)、电压放大系数Au(Au=u2／uS。 <img src='https://img2.soutiyun.com/ask/uploadfile/5385001-5388000/7e6ad554669d6eb2c2594eab2bfde8ab.jpg' />

练习题4-12图所示电路;(1)试求单口网络N₂的等效电阻;(2)求出当N₂与N₁相连时的端口电压u₂;(3)试用置换定理求电压u_o。 <img src='https://img2.soutiyun.com/ask/2020-08-24/967136830775237.png' />

图示电路中，N为含源线性电阻网络，其端口伏安特性曲线如图(b)所示，其戴维南等效电路参数为()。 A．Uoc=-12V，R0=-3Ω B．Uoc=-12V，R0=3Ω C．Uoc=12V，R0=3Ω D．Uoc=12V，R0=-3Ω <img src='https://img2.soutiyun.com/ask/uploadfile/2766001-2769000/efeb2fb9e7ac950f1ab146ca4df3e402.jpg' />

A．<img src='https://img2.soutiyun.com/shangxueba/ask/18087001-18090000/18087885/2015102715442257377.jpg' /> B．<img src='https://img2.soutiyun.com/shangxueba/ask/18087001-18090000/18087885/2015102715442535355.jpg' /> C．<img src='https://img2.soutiyun.com/shangxueba/ask/18087001-18090000/18087885/2015102715442726007.jpg' /> D．<img src='https://img2.soutiyun.com/shangxueba/ask/18087001-18090000/18087885/2015102715443096508.jpg' />

<img src='https://img2.soutiyun.com/ask/2020-07-06/962894436190544.png' /><img src='https://img2.soutiyun.com/ask/2020-07-06/962894441876869.png' />

<img src='https://img2.soutiyun.com/ask/2019-11-15/942680729450843.png' />

8． 利用两种电源模型的等效变换，求下图所示电路中2Ω电阻的电流I＜sub＞0＜/sub＞ <img src='https://img2.soutiyun.com/ask/5514001-5517000/e3d8e2f6ab0ac066928afcdcc63ffefe.jpg' /> <img src='https://img2.soutiyun.com/ask/5514001-5517000/ab4d139cd0af64a3557e3ace372ce543.jpg' />

对于题1-19图所示电路,(1)当端口电压U_ab=50V时,求输出电压<img src='https://img2.soutiyun.com/ask/2020-10-09/971093340927358.png' /><img src='https://img2.soutiyun.com/ask/2020-10-09/971093352207003.png' />(2)计算端口等效电阻R_ab. <img src='https://img2.soutiyun.com/ask/2020-10-09/971093371271093.png' />

<img src='https://img2.soutiyun.com/shangxueba/ask/50796001-50799000/50796740/967040986097027.png' />

<img src='https://img2.soutiyun.com/ask/2020-09-01/96781572451352.png' />

求题2.25图所示电路中A、B端口的等效电阻。已知R₁=2Ω;R₂=12Ω,R₃=5Ω,R₄=8Ω,R₅=10Ω,R₆=14Ω。 <img src='https://img2.soutiyun.com/ask/2020-10-07/970904454837801.png' />

<img src='https://img2.soutiyun.com/ask/2020-12-25/97778751420716.png' />

<img src='https://img2.soutiyun.com/ask/2020-12-28/978030790456659.png' />

A．4．5A B．6A C．1A D．2A

正弦稳态 电路如图题9-4所示，(1)分别求出4Ω和3Ω电阻的平均功率;(2)试由端口ab的电压相量、电流相量,求出ab右侧单口网络的平均功率。 <img src='https://img2.soutiyun.com/ask/2020-07-24/964436387402091.png' />

<img src='https://img2.soutiyun.com/ask/2020-08-24/967136592941634.png' /><img src='https://img2.soutiyun.com/ask/2020-08-24/967136602053155.png' /><img src='https://img2.soutiyun.com/ask/2020-08-24/967136609348572.png' /><img src='https://img2.soutiyun.com/ask/2020-08-24/967136618306084.png' /> <img src='https://img2.soutiyun.com/ask/2020-08-24/967136626942578.png' />

<img src='https://img2.soutiyun.com/ask/2020-11-17/974477730554804.png' />