用于电容式传感器的差动线性电路

提出了一种差动电容式传感器的前置电路,基于电容/ 电压转换的原理,对微小电容变化量进行测量。电路输出的直流电压与差动电容变化量成线性关系,且能对偏差电容和电路的漂移进行自动补偿。实验表明,被测电容分辨力为8 f F , 灵敏度可达3. 82 ×1011 V/ F。实验结果和理论分析具有良好的一致性。
关键词: 电容式传感器; 小电容测量; 线性电路; 电容/ 电压转换
Abstract : A prepositive circuit for differential capacitance transducers is proposed. It can be used to detect small capacitance changes based on capacitance to voltage conversion. The output dc voltage is a linear with the com2 plementary capacitance change and can be used to compensate for offset capacitance and drifts automatically. The experiment results show a good correspondence with the theoretical analysis. The resolution of the measurement of capacitance change is 8f F ,and sensitivity is 3. 82 ×1011 V/ F.
Key words : capacitive transducer ; low2capacitance measurement ; linear circuit ; capacitance/ voltage conversion