Question

3,下图所示放大电路中,晶体管的β =50,rbe=1KΩ,UBEQ=0.7V;要求静态时 ICQ=2mA,

Answer 1

(1)

“=1V”应该是 Ueq 吧.

Rc=(Vcc-Ucq)/Icq

=(9-4)/2

=2.5kΩ

Ieq=Icq*(1+β)/β

=2*51/50

=2.04mA

Re=Ueq/Ieq

=1/2.04

=0.490kΩ

=490Ω

Ibq=Icq/β

=2/50

=0.04mA

Rb=(Vcc-Ueq-Ubeq)/Ibq

=(9-1-0.7)/0.04

=182.5kΩ

(2) 略

(3)

Au=-β(Rc//Rl)/rbe

=-βRc/2rbe

=-50*2.5/2*1

=-62.5

Ri=Rb//rbe

=0.995kΩ

≈rbe

Ro=Rc

=2.5kΩ