Test: AC Bridges to Electrical & Electronics Measurements - Electrical Engineering (EE) MCQ

For 3 kHz frequency headphone (Range - 250 Hz to 4 kHz) and tuned amplifier detector (Range - 10 Hz to 100 kHz) will be used.

The bridge circuit for the given balance condition indicates that of a Maxwell’s inductance capacitance bridge as shown below.

For sliding balance, R₄ and C₄ will be varied since they are not common in the equations of R₁, and L₁.
in order to achieve convergence to balance point, R₄ and C₄ will be varied since they are in the same arm of the bridge.

“Carey Foster slide wire bridge” is a special type of bridge circuit which is used for the measurement of medium resistance by comparing with a standard known resistance. This bridge circuit will give no error due to connecting lead resistances, thermoelectric emfs and contact resistances.

At balance condition,

Separating real and imaginary parts, we have:

The frequency measured by the Wien bridge is: 

Maxwell’s bridge is used to measure Q-factor of medium Q-coils i.e. 1 < Q < 10

Anderson bridge is used for the measurement of low Q -coils i.e. measurement of low inductance.

Hay’s bridge is used for the measurement of inductance of high Q-coils (Q > 10).