Networks Analysis and Synthesis - Engineering

Q1:

An RC circuit initially at rest has a step signal. The response V(t) across C is V(t) = 1 - e-at, If now there is an initial voltage on C of 2 volts for the same step signal, V(t) is now

A 1 + e -at

B 1 + 2e -at

C 2 - e -at

D 3 - e -at

ANS:A - 1 + e -at

At t = 0+, V0 = 4 volt. at t = ∞ C open Vf = 4 x 2 = 8 volt.