Question

Find the current through 3Ω resistor in the circuit shown below using Millman’s Theorem.

(a) 4

(b) 3

(c) 2

(d) 1

This question was addressed to me during an interview for a job.

My query is from Millman’s Theorem topic in division Useful Theorems in Circuit Analysis of Network Theory

Answer 1

Right answer is (b) 3

Easy explanation: V^‘=((V1G1+V2G2))/(G1+G2)=(10(1/2)+20(1/5))/(1/2+1/5)=12.86V. R’=1/((G1+G2))=1/(1/2+1/5)=1.43Ω. Current through 3Ω resistor=I=12.86/(3+1.43)=2.9A≅3A.