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,

(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