电路问题,试求题2-15图a,b的输入电阻Ri

2025-04-16 13:14:41
推荐回答(1个)
回答1:

a、用外加电压法,i=-(us/R2+us/R1+阝*us/R1),故,Req=us/i=…
b、用外加电压法,us=u1,i=i1+i2=(us-uu1)/R1+us/R3,故,Req=us/i=…