非平行板电容传感器的微小电容检测电路设计

Design of Small Capacitance Detection Circuit for Non-parallel Plate Capacitive Sensor

为了满足对室内浅层埋线探测的需求,利用电容传感器的边缘效应,设计了非平行板电容传感器的微小电容检测电路。使用multisim软件对交流电桥和差分运放电路进行仿真;实验验证电路功能,并采用MATLAB软件拟合实验数据。实验表明,在频率为10 kHz的正弦波作用下,该电路的电容检测灵敏度可达0.1 V/pF,满足浅层埋线探测系统的灵敏度要求。

In order to meet the needs of indoor shallow buried line detection,the micro-capacitance detection circuit of non-parallel plate capacitive sensor was designed by using the edge effect of capacitive sensor.The alternating current bridge and differential operating amplifier circuit were simulated using multisim software.The circuit function was verified experimentally and the experimental data was fitted using MATLAB software.Experiments show that the capacitance detection sensitivity of the circuit can reach 0.1 V/pF with 10 kHz sine wave,which satisfies the sensitivity requirements of the shallow buried detection system.