Wheat stone (metre) bridge

Wheatstone Meter Bridge. A Wheatstone bridge has four resistors forming the sides of a diamond shape. A battery is connected across one pair of opposite corners, and a galvanometer across the other pair. Wheatstone bridge circuit diagram. The unknown resistance Rx is to be measured; resistances R1, R2 and R3 are known and R2 is adjustable. If the measured voltage VG is 0, then R2/R1 = Rx/R3.