Wheatstone bridge

Wheatstone bridge circuit diagram. The unknown resistance Rx is to be measured; resistances R1, R2 and R3 are known, where R2 is adjustable. When the measured voltage VG is 0, both legs have equal voltage ratios: R2 / R1 = Rx / R3 and Rx = R3R2 / R1.

A Wheatstone bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component. The primary benefit of the circuit is its ability to provide extremely accurate measurements (in contrast with something like a simple voltage divider). Its operation is similar to the original potentiometer.