Well, I wish I could do a good drawing here... but
If we assume that at 0deg, voltage is zero, then, at 90 degrees, voltage
is max. With a perfect inductor, current lags voltage by 90 degrees, so
current is 0. Current is a sine wave. So.. why isn't di/dt==1 at this point?

Joe McElvenney wrote:
Hi,

John is right, di/dt isn't equal to one here. You are mixing
up seconds and degrees.


Cheers - Joe