Introduction

To determine the self-inductance of an unknown coil.

Theory

This bridge may be used for measurement of an inductance in terms of capacitance. Fig. 1. shows the connections for this bridge, under balance conditions.

Let, L₁= Unknown self Inductance of resistance R₁,

R₂= Variable non-inductive resistance,

R₃= Fixed non-inductive resistance,

C₂= Variable standard capacitor,

C₄= Fixed standard capacitor.

At balance condition,

$$ (R_1 + j \omega L_1) * (\frac{1}{j \omega C_4}) = (R_2 + \frac {1}{j \omega C_2}) * R_3 ........(1) $$

Equating both the real and imaginary parts in eq.(1) and seperating them,

The balance may be obtained by variation of resistance R₂ and capacitor C₂.