Question

In the circuit given below, the value of V1 is __________

(a) 32.2 V

(b) -25.23 V

(c) 29.25 V

(d) -29.25 V

I had been asked this question in a job interview.

This intriguing question comes from Advanced Problems Involving Complex Circuit Diagram in portion Network Theory and Complex Circuit Diagram of Network Theory

Answer 1

The correct choice is (b) -25.23 V

The explanation is: \(\frac{V_A}{30} + \frac{V_A-40}{12} + \frac{V_A-V_B}{8}\) = 0

Or, 29 VA – 15 VB = 400

Also, \(\frac{V_B-V_A}{8} + \frac{V_B-120}{8}\) + 6 = 0

Or, VA = 65.23 V, VB = 99.44 V

V1 = 40-65.23 = -25.23 V.