用于差动电容传感器的高分辨率电路的研究

本文提出了一种用于差动电容传感器的电路 ,采用弱信号检测技术 ,将被测微小电容变化量转换成直流电压信号 .输出电压与差动电容变化量成线性关系 ,经过单片机处理后能自动补偿偏差电容和电路的漂移 .实验表明 ,最小被测电容变化量可达 8f F,灵敏度可达 3.82× 10 1 1 V/ F.实验结果和理论分析具有良好的一致性

A Study of High Resolution Circuit for D ifferen tial Capac itance Sen sors

A circu it fo r differen t ial capacitance t ran sducers is p ropo sed in th is paper. By u sing a method fo r measu ring w eak signal, it can be u sed fo r detect the low capacitance changes. The ou tpu t dc. vo ltage is a linear funct ion of the capacitance change. The signal that is p rocessed by single2ch ip m icrocompu ter can be u sed fo r compen sate to offset capacitances and drif t s au tomat ically. The experimen t resu lt s show a good co rrespondence w ith the theo ret ical analysis. The reso lu t ion of the measu remen t of capacitance change is show ed to be 8 fF. A sen sit ivity of 3. 82×1011V ?F w as given acco rding to these measu remen t values.