A Poor Man’s Resistance Bridge

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A Poor Man’s Resistance Bridge (488.74 KB)

Using only a single DMM, scanner and software, a lab can have their own automated resistance bridge capable of accuracies from sub ppm to a few ppm over its entire range. This paper describes how we created a simple resistance bridge using off the shelf test equipment. Software was created to take dual four-terminal DMM resistance ratio readings and control a scanner to automate the process. Multiple forward and reverse measurements are taken to reduce the effects of thermal EMFs and to provide statistical information.

This “bridge” can be set up to automatically scale up or down over a wide range of resistance values. Results from various 1:1 and 10:1 measurements between 1 ohm and 10 kilohm will be presented.