2输入电阻 R=Ih Rs d 风风“ (1+B)lb1+ RR R 共基极电路的小倍号等效等效电路 R wWR∥-b8n≈.be 1+B1+B 3输出电阻 1313 2 输入电阻  +  = − + − = −  = = (1 ) 1 be b b be e i i e b r I I r I V R r      +   + = = = 1 1 // // be be e eb e i i i r r R r R I V R   3 输出电阻 Ro  Rc !