Owen Bridge

We have Hay's bridge for high Q-factor (Q>10) inductance measurement, Maxwell's bridge for medium Q-factor (1<Q<10) inductance measurement and Anderson's bridge for low inductance (upto millihenry) measurements.

But, won't it be more convenient if we can have a single bridge which can measure value of inductance over a wide range ?

This is exactly what an Owen bridge does – Measure inductance over a wide range.

Owen bridge Circuit

Where,

L₃= unknown self inductance of resistance R₃

C₁ = fixed standard capacitor

R₂ = fixed non-inductive resistance

C₄ = variable standard capacitor

R₄ = variable non-inductive resistance

From the circuit, at balance, the current through D will be zero

∴ V₁= V₄

V₂= V₃

I₂= I₁

I₃= I₄

From V₁= V₄

Owen bridge Phasor diagram

Owen bridge Advantages :-

Frequency does not appear in the final balance equations, hence the bridge is unaffected by the frequency variations and waveform.
Owen's bridge is used to determine inductance over a wide range.
Capacitance can also be measured over a wide range as capacitance comes in final balance equations.

Owen bridge disadvantages :-

The bridge uses variable standard capacitor which is quite expensive and this cost further increases as Q-factor of the coil increases as capacitor required will be larger.

Related bridges :-