Question

The arms of an a.c. Maxwell bridge are arranged as follows: AB is a non inductive resistance of 1,000 Ω in parallel with a capacitor of capacitance 0.5 μF, BC is a non-inductive resistance of 600 Ω CD is an inductive impedance (unknown) and DA is a non inductive resistance of 400 Ω . If balance is obtained under these conditions, find the value of the resistance and the inductance of the branch CD.

Answer 1

The bridge is shown in Fig..

The conditions of balance have already been derived in .

Since R1R3 = R2R4

∴ R3 = R2R4/R1

∴ R3 = (600 x 400)/1000 = 240Ω

Also L3 = CR2R4

= 0.5 x 10-6 x 400 x 600

= 12 x 10-2 = 0.12H