高稳定接触电阻监测电路的分析与研究

Analysis and Study of High Stability Circuits for Monitoring Contact Resistance

本文对一种稳定性较高的接触电阻监测电路的组成、工作过程及各元件的作甩作了详细说明。提出用高精度低漂移集成运算放大器OP-07组成同相放大器,作为监测电路的缓冲放大器;计算了相对误差和输入、输出电阻值。还对Kelvin连接的原理作定性分析。从实验验证运算放大器的偏置电流和失调电流在输入端外接电阻上所产生的电压,是影响测量稳定性的主要因素。适当减小输入端外接电阻可有效抑制输出信号的漂移。

This paper gives a detailed description of the composition and operational process of a high stability circuit for monitoring contact resistance,and of the function of each of its components.It proposes using a noninverting amplifier consisting of a high accuracy and low drift integrated operational amplifier OP.07 as a buffer amplifier in the circuit.The relative error,input and output resistance of the amplifier are calculated,and the principle of ke vin connection is analysed qualitatively.It is verified through experiments that the voltage drop on the connected resistance at both inputs which is caused by the bias and offset currents of the amplifier is the main factor affecting the measuring stability of the circurt,and that a proper decrease in the connected resistance at both inputs can effectively restrain the drift of the amplifier output signal.