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 :-

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

Owen bridge disadvantages :-

1.   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 :-

1.  Maxwell's bridge
2.   Hay's bridge
3.  Anderson bridge
4.   Schering bridge

Other topics :-

1.  Hot wire Instruments