Objective: To determine the capacitance of an unknown capacitor.

Fig. 1. Wien Series Bridge Circuit .

Let,

*C*_{1}= Capacitor whose capacitance is to be measured,

*R*_{1}= a series resistance representing the loss in the capacitor C_{1},

*C*_{4} = a standard capacitance with series resistance of R_{4},

*R*_{2} and *R*_{3} = non-inductive resistances.

At balance,

Equating the real and imaginary terms, we obtain

Two independent balance equations are obtained if *C*_{4} and *R*_{4} are chosen as the variable elements.

The dissipation factor of capacitance *C*_{1} is defined as,