Use Kirchhoff's rules to obtain conditions for the balance condition in a Wheatstone bridge.
Let us consider a Wheatstone bridge arrangement as shown below.
Applying Kirchhoff's loop law to the closed loop ADBA, we get
Here, G is the resistance of the galvanometer.
Applying Kirchhoff's loop law in the closed loop BDCB, we get
When the Wheatstone bridge is balanced, no current flows through the galvanometer, i.e. Ig=0
∴ From (1), we get
Similarly, from (2), we get
From (3) and (4), we get
This is the required balance condition in a Wheatstone bridge arrangement.