海南大学：《计算机电子电路技术—电路与模拟电子部分》第6章 放大电路分析基础（2/3）

电压放大倍数 B Irbe sri R bI R中R L 20kT10k2 Re 2k 6k2 2k2 Icr=-BlbR Ui=lbre+ler=Ibte+(+ BRI BluR R I6Irbe +(1+B), he +(1+B)R 已:a9

i b rbe i c βi b B C Rb1 E 20kΩ Rc 2kΩ RL 6kΩ Rb2 10kΩ ui Re 2kΩ 电压放大倍数 o u i U A U = o c b U I R I R = − = − L L    i b e b[ (1 ) ] U I r I R I r R = + = + + be e be e  1 1 ( ) [ ( ) ] o b L L u be e i b be e U I R R A r R U I r R       = = − = − + + + +

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:a9

i 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

C b Bi R b2 20k2T10k2 Re 2k 3 2k2 0 +(+B)R i=ic+ir= bi R R R 已:a9

i b rbe i c βi b B C Rb1 E 20kΩ Rc 2kΩ Rb2 10kΩ ui Re 2kΩ i i r o r 0 ( ) 1 i b be e u i r R  = = + + R b c c c u u i ic i i R R = + = + =  o c r R =

存在问题 R B B XBi IR IR F1=Rb∥ R C R Bi R中R he +(1+B)R L Ok 5 T10k 2 Re 2k 2 Tak I 2k2 =R2 F=R∥ Rb,/I+(1+B)R

存在问题 i b rbe i c βi b B C E Rs Rb Ui Rc RL i b rbe i c βi b B C Rb1 E 20kΩ Rc 2kΩ RL 6kΩ Rb2 10kΩ ui Re 2kΩ ( ) 1 L u be e R A r R    = − + + ' L u be R A r = − // i b be be r R r r =  o c r R= o c r R = 1 2 // //[ ( ) ] 1 i b b be e r R R r R = + + 