The Wheatstone bridge was first described by British mathematician and scientist Samuel Hunter Christie in 1833. The circuit came to bear the name of Sir Charles Wheatstone, the English physicist who popularized it in the 1840s.
In a typical Wheatstone bridge, four resistors are positioned in a circuit designed in such a way that the current from a battery splits, flows through the sequence of resistors, then recombines into a single conductor.
Three of these resistors have known values, one of which is adjustable. The value of the fourth resistor is not known. By studying and manipulating the paths the current can take through the Wheatstone bridge grid, that fourth unknown resistance can be determined.