Networks Analysis and Synthesis - Engineering

Q1:

In the circuit shown, the steady state is reached with S open S is closed at t = 0, the current I in the 1 Ω resistor connected is to be determined at t = 0+ is given by

A 1

B 2

C 3

D 4/3

ANS:A - 1

If steady is reached L will be short circuited the current in 1 Ω resistor I = 4/2 2A. It will act as current source in parallel with inductor. Now apply superposition theorem consider 4 volt source, current source will be open and inductor also open. Current in R' = 1 Ω resistor = 2A. When current source consider, voltage source will be short circuited and current due to inductor is 1A in opposite direction. Total current 2 - 1 = 1 A.