I have worked through a question and I am unsure if my answer is correct. It is a series RL circuit with a switch that closes at t=0, supplied by a dc source, which I am trying to derive an expression for the current i, when the switch is closed.
Something like the circuit below:
My answer is: i(t) = V/R e^(t/T)
But does this not represent the discharging current as an exponentional decay rather than a growth? I can show all my workings out if it is not correct.
I thought the current when the switch is pressed should be represented by:
i(t) = V/R ( 1 - e^(t/T) )
The image below shows the only way I know how to derive an equation for the instantaneous current in this circuit: