Question

In the circuit given below, Z1 = 10∠-60°, Z2 = 10∠60°, Z3 = 50∠53.13°. The Thevenin impedance as seen from A-B is _____________

(a) 56.5∠45°

(b) 60∠30°

(c) 70∠30°

(d) 34.4∠65°

This question was addressed to me during a job interview.

The origin of the question is Problems Involving Standard Time Functions topic in section Application of the Laplace Transform in Circuit Analysis of Network Theory

Answer 1

The correct answer is (a) 56.5∠45°

For explanation: ZTH = ZA-B = Z1 || Z2 + Z3

= \(\frac{Z_1 × Z_2}{Z_1 + Z_2} + Z_3\)

= \(\frac{10∠-60° × 10∠60°}{10∠-60° + 10∠60°}\) + 50∠53.13°

= 56.66∠45°.