In all the texts I read, including online tutorials, "reactance" is defined as the resistance to alternating current and they always base the equation off the assumption that the voltage is continuously changing. The equation is X(L) = 2piFL
But as far as I can tell, this doesn't seem to hold up right when you're talking about a coil's reaction to applied DC where you apply a steady ON voltage and then wait for the current to reach maximum amplitude.
As far as I can tell the inductive resistance to a 50% duty cycle square wave is actually just 2x the circuit's DC resistance if the pulses are timed to exactly 1/4 the inductor's natural frequency. The current will rise and fall steadily at the start and end of every pulse. During the transition period, it will always move from zero Amps to maximum Amps assuming you are always cutting the voltage input right when the maximum current amplitude is reached. So the result is you're getting approximately half the current you'd get if it were just a continuous flow DC circuit.
Can anyone clear this up if I'm missing something here. And if I DO understand it right, then is there some special term for what I'm describing?
Here is a diagram of what I'm talking about:
It appears to me that the average current is just a matter of computing the average amplitude of a parabola, which I don't know how to do. LOL I can go research that, but I'm just trying to see what some of the other folks have to say about this.