§102共发射极组态 共发射极组态的输入阻抗 扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫扫 BAl H r+re pe re-Bre r+rA c Z,△ ①|a △ (-) A=(+)+ r++2 z(T型)等效电路 Z1=0→20=5+(1+)-≈5+(1+)=b。(>r) retr =0 2m=+F 一般有Z1202i<20 若r>Z2,则ZxZ≈h§10-2 共发射极组态 共发射极组态的输入阻抗 (T型)等效电路 r  b Ib re rc Ib Ic Vbe Vce ZL Zie be b e e b ce e c e c c V rr r I V r rrr I                          V ZI ce L c     be c e ie b e e b ec L V r r Z rr r I rrZ        ZL=0     0 1 1 e c ie b b e ie e c r r Z r r rh r r        ZL= ie b e Z  r r  r r c e   一般有 Zie< Zie < Zie0 若 rc >> ZL , 则 ie ie ie Z  Z  h 0