高精密度、高稳定度的应变计测量差动放大电路

Design of high precision and high stability differential amplifying circuit for a special strain gauge

摘要:

针对微应变片的高精密度、高线性度、高稳定度及较高增益的测量要求，采用仪用放大器AD625为核心器件，通过将精密匹配的电阻对安装于器件的恒温位置的巧妙设计，尽可能地消除电路中存在的共模电压，由于电路布局使匹配电阻的温度变化基本一致，也极大地降低了温度漂移的影响，从而获得了一种适用于微应变计测量的高性能差动放大电路，其增益的线性度达到约0.01%的水平，共模抑止比达到129 dB。

Abstract:

The requirements for micro stress measurement of strain gauge are high precision，high linearity，high stability and high gain. One kind of differential amplifier circuit with excellent performance was designed. Some skillful techniques were adopted to avoid common voltage in the circuit and to reduce the temperature drift. The gain linearity is about 0.01%，and its Common-Mode Rejection Ratio(CMRR) is about 129 dB under work conditions.