输入电阻和输出电阻r b Bi b bl 20k2T10k9 Re 2k 5 6k92 2k $2 ible +(1+B)RI 十 十 bI b2 CbI Rb2 e +(+B)R F=R∥R2M|ce+(1+B)R 已:a9i b rbe i c βi b B C Rb1 E 20kΩ Rc 2kΩ RL 6kΩ Rb2 10kΩ ui Re 2kΩ i 输入电阻ri和输出电阻ro 1 2 // //[ ( ) ] 1 i b b be e r R R r R = + +  1 2 1 2 1 1 1 1 1 [ ( ) ] ( ) ( ) i b be e i i b i b b b b be e u i r R u u i i u R R R R r R   = + + = + + = + + + + i r o r