摘要
高分子薄膜湿敏电容是目前湿度测量经常使用的传感器,其基本原理是在高分子薄膜的上下表面蒸镀一层微孔电极,构成一平行板电容器。当测量气体的相对湿度发生变化时,高分子薄膜在吸湿或脱湿过程中其介电常数ε变化,使湿敏电容的容量与被测气体的相对湿度近似为正比例变化,再将容量变化转化成频率信号即可测量相对湿度。但是,湿敏电容的灵敏度漂移较大,参数的一致性较差。如果硬件采用差频测量方法,并配合相应的软件进行数据处理,在一定程度可以消除传感器调理电路电源波动、环境温度变化、分布电容对测量精度的影响。
The macromolecule humidity sensing of thin film is a humidity sensing to use at usually. It's postulate is to make a parallel board electric capacity from use smoke plate a flat smallest hole pole on the surface of the macromolecule of thin film. When opposite degree of humidity for the measured gas be changed, the macromolecule of thin film in moisture absorption or moisture doff its mind electricity constant ε changing, this make the capability of the humidity sensing capacitance and the relative humidity of the measured gas changed as well as direct proportion. When we translate the variety of capacitance into frequency signal we can measure relative humidity. Usually the precision of the humidity sensing capacitance changed, parameter's coherence worse. If we adopt difference frequency measure in hardware, at the same time use relevant software do data processing; we can avoid infection for measure precision from sensor mediate circuit power supply wave?the change of condition temperature,the distributing capacitance in degree.
出处
《仪表技术与传感器》
CSCD
北大核心
2003年第8期34-35,共2页
Instrument Technique and Sensor
