Design about Simple Tester of Low Capacitance Based on MAX038

Simple tester of low capacitance was designed based on MAX038 in this paper. The principle is that external capacitor of MAX038 as test capacitor to provide corresponding frequency signal output, and TM4C123GH6PM was selected to measure frequency by equal precision and calculate test capacitance. In order to improve the accuracy, data were piecewise fitted by the least square method, and comparison tests were between high accuracy capacitance tester and the simple tester to realize auto correction and show measurement results. The tester can detect 10pF~1µF capacitor. Test results show that the tester is running stable, rapid measuring; accuracy is grade 1.