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Inductance comparison bridge is used to compute
Unknown inductance and resistance
Unknown resistance
Unknown inductance
Unknown capacitance
Unknown inductance and resistance
Quick Summary: An Inductance Comparison Bridge is a modified Wheatstone bridge circuit used to measure an unknown self-inductance by comparing it with a known standard inductance. Because practical inductors are not ideal and possess inherent winding resistance, the bridge simultaneously determines both the unknown inductance and its associated series resistance.
An Inductance Comparison Bridge is a modified Wheatstone bridge circuit used to measure an unknown self-inductance by comparing it with a known standard inductance. Because practical inductors are not ideal and possess inherent winding resistance, the bridge simultaneously determines both the unknown inductance and its associated series resistance.
LxтАЛ=LsтАЛR3тАЛR2тАЛтАЛ тАФ Balancing equation for inductance
RxтАЛ=RsтАЛR3тАЛR2тАЛтАЛ тАФ Balancing equation for resistance
The bridge operates by balancing four arms: one containing the unknown inductor with its internal resistance, one containing a high-quality standard inductor with an adjustable resistor, and two non-inductive ratio arms. Under null conditions, the bridge is balanced such that the product of impedances of opposite arms is equal (Z1тАЛZ4тАЛ=Z2тАЛZ3тАЛ). Since both arms contain resistance and inductance, balance is achieved by adjusting both a standard variable resistor and the variable standard inductor simultaneously.
The bridge requires a known standard inductor (LsтАЛ) which is often expensive and bulky.
Balance is achieved by adjusting RsтАЛ and LsтАЛ to nullify the detector current.
It is primarily used for the measurement of inductors with medium Q-factors.
Unlike the Maxwell Bridge, it uses a standard inductor rather than a capacitor.
Balance equations are independent of the supply frequency.
Can be used to measure inductors over a wide range of values.
Requires a high-quality standard variable inductor, which is costly.
More complex to construct than capacitance-based bridges like the Maxwell or Hay bridge.
Precision measurement of self-inductance in laboratories.
Standardizing inductors used in calibration circuits.
The bridge is essentially a variation of the Wheatstone bridge where resistances are replaced by complex impedances.
Option D is incorrect because capacitance measurement requires a Schering or Wien bridge, not an inductance comparison bridge.
A is correct тАФ The inductance comparison bridge measures both the unknown inductance and its associated internal series resistance by balancing against a known standard inductor.
Always remember that in AC bridges, the balance condition involves both magnitude and phase, requiring the adjustment of two variables (usually a resistor and an inductor/capacitor) to satisfy both real and imaginary components.