输入电阻 R.=47M+200k∥200k=47Mg 输出电阻 r=3kQ g bbc rbi 47M 20kct e Blb 10kg260k 200k 3k2 gm 200kg2=  =  +   =  R k R M k k M oi 3 47 200 // 200 47 输出电阻 输入电阻 g +_ s d b e c +_ 47 M 200 k 200 k gm U gs • 10 k 60k 20 k rbe I b • 100  I b •  3k U o •    • Ui