估算图3.1（d）～（h）所示各电路在深度负反馈条件下电压放大倍数。<br /> <img src="https://nimg.ppkao.com/2018-09/yuanhao/2018091014442728077.jpg?sign=38451907002bb3bec551f1635705f58a&t=62d1bc3e" />