题21图所示电路中，uS（t）为单位阶跃函数，R1=R2=2Ω，L=2H。电路的时间常数是（）s。https://assets.asklib.com/psource/2015110209513078451.jpg

A . 2 B . 3 C . 1 D . 0

A .https://assets.asklib.com/psource/2015110209494143366.jpg B .https://assets.asklib.com/psource/2015110209500375015.jpg C .https://assets.asklib.com/psource/2015110209505755318.jpg D .https://assets.asklib.com/psource/2015110209511022670.jpg

A . 0 B . 4 C . 7.5 D . 8

A . R1=2R2 B . R2=2R1 C . R2≥2R1 D . R2≤2R1

<img src='https://img2.soutiyun.com/shangxueba/ask/17862001-17865000/17862233/2015110209254329436.jpg' /> A．<img src='https://img2.soutiyun.com/shangxueba/ask/17862001-17865000/17862233/2015110209260250234.jpg' /> B．<img src='https://img2.soutiyun.com/shangxueba/ask/17862001-17865000/17862233/2015110209262636595.jpg' /> C．<img src='https://img2.soutiyun.com/shangxueba/ask/17862001-17865000/17862233/201511020926411982.jpg' /> D．<img src='https://img2.soutiyun.com/shangxueba/ask/17862001-17865000/17862233/2015110209265736798.jpg' />

如题5-12图所示RLC电路，己知Us(t)=5ω(t)，i(0)=2A, u(0 )=2V。试用S域方法求全响应U(t)。 <img src='https://img2.soutiyun.com/ask/2020-07-10/963223214157704.png' />

电路如图题12-8所示,已知<img src='https://img2.soutiyun.com/ask/2020-07-24/964456047991613.png' />,试分别求出在下列us(t)时的电压u2(t),t≥0 (1)<img src='https://img2.soutiyun.com/ask/2020-07-24/964456140274891.png' />

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

图3-19所示电路中开关S1在t=0时闭合，开关S2在t=1s时闭合，试用阶跃函数表示电流i(t)。 <img src='https://img2.soutiyun.com/ask/uploadfile/5493001-5496000/006c63b713099b96077658762cacfaf9.png' />

电路如图所示，Is=3A，Us=18V，R1=3Ω，R2=6Ω，L=2H，在t＜0时电路已处于稳态。当t=0时开关S闭合，求t≥0时的i_L、u和i(t)。 <img src='https://img2.soutiyun.com/ask/uploadfile/5499001-5502000/c59f97db78e22204b83620ad1e292af9.jpg' />

题7.4图所示为带阻电路，负载端为开路，求其电压比函数<img src='https://img2.soutiyun.com/latex/latex.action' />及其零、极点。 <img src='https://img2.soutiyun.com/ask/5514001-5517000/f6236ac9bcb2541be1e40f07ac074ef5.jpg' />

图所示电路中，U_s=100V，并联谐振回路的谐振频率为10⁶rad/s，Q=100，且谐振时R吸收的功率为最大。试求：

试求题4-27图所示电路在开关闭合后的零状态响应i(t)(图中Us为一直流电压). <img src='https://img2.soutiyun.com/ask/2020-10-09/971121216666759.png' />

在换电路瞬间t=0+时， （1）电感中的电流iL（0+）； （2）电感上的电压uL（0+）。<img src='https://img2.soutiyun.com/shangxueba/ask/18381001-18384000/18383931/2015032014203615061.jpg' />

求题9-17图所示电路的零状态响应i(t).要求对此电路的复频域模型用戴维宁定理求出i(t)的象函数I(s),进而求出i(t). <img src='https://img2.soutiyun.com/ask/2020-10-10/971200769947351.jpg' />

<img src='https://img2.soutiyun.com/shangxueba/ask/17862001-17865000/17862675/2015110209233257635.jpg' /> A．R1=2R2 B． R2=2R1 C． R2≥2R1 D． R2≤2R1

<img src='https://img2.soutiyun.com/shangxueba/ask/17868001-17871000/17868888/2015110209513078451.jpg' /> A．0.25 B． 0.5 C． 2 D． 4

求题4-3-1图所示电路的冲徼响应u_c(t)和i(t),并用阶跃响应的导数对所求结果予以校验. <img src='https://img2.soutiyun.com/ask/2020-10-09/971117740183915.png' />

题1.27图所示电路中,已知U_s1=15V,U_s2=5V,I_s=1A,R=5Ω,求各元件的功率值,并说明各元件是吸收功串还是供出功串。 <img src='https://img2.soutiyun.com/ask/2020-10-06/970864751182512.png' />

练习题6-5图所示RL电路，已知u_s(t)=12e(t)V试求阶跃响应i_L、u₁和u。 <img src='https://img2.soutiyun.com/ask/2020-08-25/967204134099058.png' />

题7-2图所示各电路中开关S在t=0时动作，试求各电路在t=0，时刻的电压电流。已知题7-2图(d)中的<img src='https://img2.soutiyun.com/ask/2020-08-24/96707702037258.png' />。 <img src='https://img2.soutiyun.com/ask/2020-08-24/96707704860863.png' />

试写出题3-4-2图所示图形的时间函数表达式f(t). <img src='https://img2.soutiyun.com/ask/2020-10-09/971112116188241.png' /><img src='https://img2.soutiyun.com/ask/2020-10-09/971112124441713.png' /> <img src='https://img2.soutiyun.com/ask/2020-10-09/971112136616409.png' />