Electric Circuits and Networks, Ist Edition by Pearson

The current in an inductor is related to the voltage across it through the relation

This shows that, with a voltage of 1 V at t  0

+

across it, the current in the inductor

cannot remain at its current value of zero forever. The current has to grow since its derivative

is positive, and hence, it starts growing at the rate of 1/L A/s initially. This in turn implies

that the slope of current versus time curve at t  0

+

will be 1/L A/s.

However, as the current in the inductor grows under the compulsion of the voltage

appearing across it, the resistor starts absorbing voltage. This results in a decrease in the induc-

tor voltage since v

R

and v

L

will add up ...