The Characteristics and Improvements of Nonlinearity on Capacitive Moisture Sensor

The capacitive rapid moisture tester is a common instrument for rapid in situ moisture testing,since the effects of nonlinearity,the accuracy of capacitive rapid moisture testers is restricted.This paper introduces the principle of the capacitive moisture sensor,discusses the effect of nonlinearity on the sensor,builds the mathematical models for the effect of nonlinearity,and presents hardware improvement methods and a software compensation algorithm of polynomial regression based on least squares.The effectiveness of the proposed models and methods has been proved in theory and in practice.