Rectified wave problem

[gunayburak]

I use 'ac opto' to get 0xing. vary R3 to change width of the zero areaAttachment 7388

oh, add series resister to opto input !!

Thanks for your replies guys .

To amgen ; Why would we still need the diodes and the cap since the AC opto and a series resistor are sufficient to detect the zero crosses ?
I mean the following link would have sufficied I suppose ?

http://i.stack.imgur.com/sw3mO.png