光电探测器微变信号放大电路的设计和分析

Design and Analysis of a Circuit for the Weak Signal from a Photoelectric Detector

针对火灾探测过程中的光电探测器输出的微弱信号设计了一个微变信号提取放大电路。将探测器内阻分解为微变内阻和不变内阻 ,采用两路取样信号方法进行差模放大。经过计算选择了特定的电路参数 ,使得电路输出和探测器微变内阻成正比关系 ,从而实现了微变信号的放大。用斩波方法进行了电路输出性能的实验。

A new circuit has been designed and developed for picking up and amplifying the weak signals of a photoelectric detector in fire detecting system. As the signal cannot pass through capacity, it is necessary to develop a method to separate the weak signal from the DC bias. The basic way is to consider the detector resistance as two parts, one is of micro various, and the other is of changeless. Special circuit parameters are selected by calculation so that the output is proportional to micro various resistance, which means the circuit output is proportional to the weak signal. The circuit parameters and the drift are analyzed in details.