◆Voltage gain-Av-利用虚短和虚断 0-yN='N-v0 RI Rf ∴0=(1+ R LVN=VP=Vi ◆Input resistance-R, R=y龙=，DR=0 ◆Output resistance-—R,=O 2.Voltage follower电压跟随器 虚短→y,=ywVp=;→V=V; →A=1 R=∞，R。=0 EWB演示 ◆Voltage gain-Av -利用虚短和虚断 ) RR 1(Av) RR 1(v 1f vi 1f  O  f ON 1 N R vv Rv0    N   vvv iP ◆Input resistance - Ri ii Ri Ri = vi /ii = vP /iP Ri =∞ iP =0 ◆Output resistance—Ro =0 vi - + R2 R1 vN vP - + vo+- Ro 2. Voltage follower 电压跟随器 vi vo - + vN vP 虚短vo =vN =vP =vi vo =vi Av =1 Ri =∞, Ro =0 EWB演示