19 圖示放大器電路若電流源 I 為 1 mA、RB = 100 kΩ，RC = RL = 2 kΩ，Re = 100 Ω，電晶體電流放大率 β = 100，則電壓增益約為若干？ (A)-100(B)

問題詳情

19 圖示放大器電路若電流源 I 為 1 mA、RB = 100 kΩ，RC = RL = 2 kΩ，Re = 100 Ω，電晶體電流放大率 β = 100，則電壓增益約為若干？

(A)-100
(B)-10
(C)-8
(D)-4

答案：C
難度：適中0.581818
統計：A(15),B(21),C(64),D(5),E(0)

re=VT/IE=25m/1m=25Av=-(Rc//RL)/re+Re=-8

樓上應是Av=-(Rc//RL)/(re+Re)=-8

【劉政文】評論

Av = -gm*Vpi*(Rc//RL) / ( Vpi + gm*Vpi*Re ) =-gm*1k / ( 1 + gm * 100 )gm = Ic / VT = 1m /25m =0.04Av = -0.04k / (1 + 4 ) = -8