一、引言直接耦合的直流放大器(以下简称直流放大器)的灵敏度通常受其初始工作点漂移的限制。它的输出信号常用有用信号和漂移信号之和表示,与输入有关的这个值确定了放大器的最大灵敏度。晶体管放大器的零电平或初始工作点的漂移基本上是由于半导体结的变化以及随之而生的晶体管元件参数的变化引起的。小电流信号的放大常是科 I. Introduction Direct coupled DC amplifier (hereinafter referred to as DC amplifier) ​​sensitivity is usually limited by the initial operating point drift. Its output signal is commonly used as the sum of the useful signal and the drift signal. This value, which is related to the input, determines the maximum sensitivity of the amplifier. The zero-level or initial operating point drift of a transistor amplifier is essentially due to changes in the semiconductor junction and consequent changes in the parameters of the transistor elements. Small current signal amplification is often Section