polymorph:
Hang on... someone pointed out either here or the Electronics_101 Yahoogroup that the maximum current starting with no charge on the capacitor is actually if you connect right at the zero crossing. I even did an LTSpice simulation, which agreed with him.
It's actually slightly after the zero crossing. (Think about it, how could there be any current if there are no initial voltages in the circuit and the applied voltage is zero?) It's slightly after, and no larger than the peaks during steady-state. See "sine.png", attached.
If powered up at a peak with no charge on the capacitor, the current should be at about 170mA for a very short time.
LTspice begs to differ, see "cosine.png", attached. Not sure where the 170mA is coming from, I might check my component values.
But as I pointed out above, the current peak is actually higher, albeit a bit later, if started at the zero crossing. I can't fire up LTSpice right now.
Try it with the attached model when you can. It's basically just a simple RC circuit, the diodes actually have little effect on overall circuit behavior.
opto.asc (856 Bytes)