一种测量气敏材料电阻的快速响应电路

A Fast Response Resistance Measurement Circuit of the Gas Sensitive Materials

电阻测量是开发电阻型气敏材料的重要环节,测量具有较高灵敏度的气敏材料电阻通常需要很高的测量速度,针对此类需求,通过对传统测量气敏电阻方法的改进,提出了一种可以快速响应同时可观测气敏电阻细节动态过程的设计。本设计通过单片机控制换挡电路,比较待测电阻与分档电阻的分压值,实现对0~200MΩ电阻的测量,并将测量电阻数据经过origin软件修正后传输至MATLAB上位机软件上,实时显示电阻-时间曲线。当电阻小于30MΩ时,测量的电阻值与实际的电阻值最大误差为1.1%,当电阻大于30MΩ时,最大误差为2%,0.2s显示一次数值。电路达到了在测量气敏材料电阻时速度和精度的要求,实时显示的曲线具有直观性与易操作性,在测量工作中大幅度提高了效率。

Resistance measurement is an important part of developing resistive gas sensitive material. The measurement of the resistance of air sensitive material with high sensitivity usually requires high measurement speed. Aiming at this kind of demand, through the improvement of the traditional measurement of the gas sensitive resistance method, a design of the detailed dynamic process of the observed gas-sensitive resistor is proposed. This design controls the shift circuit through a single chip microcomputer to compare dividing voltage value of the resistance and the step resistance, which implement the measurements of 0~200 MΩ resistance. Meanwhile, after corrected by Origin software, the resistance data is transmitted to MATLAB on PC software to display real time resistance-time curve. When the resistance is less than 30 MΩ, the maximum error is 1.1% between the measure resistance and the actual resistance on the contrary, the maximum error is 2%. The data is displayed every 0.2 second. The circuit meets the requirements of speed and accuracy in measuring the resistance of the gas sensitive material. And the curve is also intuitional and operable. The efficiency is greatly improved in such measurement work.