Objective : To determine the capacitance of an unknown capacitor.
Fig. 1. Schering Bridge for Capacitance Measurement.
The circuit diagram is shown in Fig.1.
Let, C1=capacitor whose capacitance is to be measured.
r1= a series resistance representing the loss in the capacitor C1.
C2= a standard capacitor.
R3= a non inductive resistance.
C4= a variable capacitor.
R4= a variable non inductive resistance.
Equating the real and imaginary terms in equa. (2), we obtain
Two independent balance equations (3) and (4) are obatined if C4 and R4 are chosen as the variable elements.