5242并联负反馈时的A 开环源增益:A R r+r 闭环源增益: R R A Rs+Rr Rs+Rr l+ ab 得: 1+A.B 对电压并联负反馈: 1+AB 对电流并联负反馈: +a B5.2.4.2 并联负反馈时的Afs A R R R i x i i i x A i s s d o s d s o s + 开环源增益: = = = 闭环源增益: AB A R R R A R R R i x i i i x A s i f s f s i f s i o s i s o f s + + = + = = = 1 得: A B A A s s fs + = 1 对电压并联负反馈: r g rs rfs A B A A + = 1 is i is ifs A B A A + = 1 对电流并联负反馈: