The above circuit combination is called a wheatstone bridge circuit. It is a combination of 4 Resistors connected to a power source in above manner.
Balanced bridge is a condition in which the flow of current in the central galvanometer is ZERO. Such a condition can be achieved by a specific combination of all 4 resistor values.
Calculation of Resistor Values for balanced Wheatstone Bridge
For Balanced whetston bridge, Ig (current throgh Galvanometer ) should be zero.
Applying Loop rule in first loop:
Applying Loop rule in second loop with condition that and :
Finally we arrive at equation :
Thus for a balanced Wheatstone Bridge condtion to be achieved, all four Resistors should be such that