Design of high accuracy resistance measuring instrument system
Yechao Bai · Modern Electronics Technique · 2012
In order to realize the precision measuring of resistance,a high accuracy resistance measuring instrument system was designed.This system used MCU as the core of control.Different standard resistance were connected to high accuracy constant voltage resource so as to create a series of high accuracy constant current which operated though the resistance under test.The voltage on the resistance under test measured by four-terminal measuring technique was converted to digital signal by A/D converter so that the value of the resistance could be worked out.This system can change measuring grades and numbers of significant digits automatically with a range about 3m-3MΩ.When the measurement speed is 15 times per-second,it can achieve the accuracy of 0.5%,and maintain the digits of change under 3.