Electric Circuits and Networks

10.8 UNIT IMPULSE RESPONSE OF SERIES RL CIRCUIT

We look at the response of series RL circuit in Fig. 10.1-1 with v_S(t) = δ(t), the unit impulse voltage. We have discussed the unit impulse function in detail in an earlier chapter. We saw that we can view unit impulse function as a limiting case of a rectangular pulse waveform of amplitude 1/Δt V located between t = 0 and t = Δt as Δt ≥ 0. The pulse always maintains unit area under it by increasing the amplitude as its duration decreases. We use this interpretation of unit impulse function to analyse impulse response of RL circuit first. The circuit is assumed to be initially relaxed.

The applied pulse and circuit current response are shown in Fig. 10.8-1. The response in the interval [0⁺, Δt