Objective: In this bridge, an inductance is meaured by comparison with a standard variable capacitance. The connection shown in the figure.
L=Unknown Inductance ,
R4=effective resistance of unknown Inductance coil ,
R1,R2,R3= known non inductive resistance,
C1=Standard variable capacitor.
Writing the equation for balance
Equating the real and imaginary parts ,
Two variables R1 and C1 which appear in one of the two balance equations and hence the two equations are independent.
The expression for Q factor