4差模电压放大倍数Aa CC R 0 1 R. c2r h9 R R ui? 当u1=-u12(大小相等,极性相反),差模输入信号 设un个,uaV,使u,ua2个。设uC1=uc1-△uc1, uc2=uc2+△uc2。因un=-u2,△uc=△uc2 →u=uC1-uC2=-△ucr△uc2=2△ucr 差模电压放大倍数A=2un 0 u(很大,>1)+UCC RC R1 T2 R B u o R R C 1 T1 R B u i2 u i1 uC1 uC2 4.差模电压放大倍数Ad 当ui1 =- ui2(大小相等,极性相反),差模输入信号 (很大,>1) 设ui1 ,ui2 , 使uC1 ,uC2 。设uC1 =uC1 - uC1 , uC2 =uC2 + uC2 。因ui1 = -ui2,→ uC1 = uC2 → uo= uC1 - uC2=- uC1- uC2 =- 2 uC1 差模电压放大倍数Ad = uo ui1 -ui2 = uo 2ui1