yes that is true. the transformer output voltage is rectified using 1N4007
bridge. then given to optocoupler ic 4n35 using 220K ohm resistor.. then
the output of 4n35 is given to pwm controller ic sg3524.
If the circuit is:
220VDC ----- [R] ----- [opto] ---- GND
then be aware that you're only getting about 1 mA to the opto. If you want
to use that to regulate it, I'd do something to reduce the amount of
influence the opto characteristics have on the quality of the feedback.
How about just a voltage divider? 220K with, say 5K in series will give
you about 5V for about 220V in. Buffer that, and then drive your opto.
But, since it's already an inverter, why do you need the isolation in
the first place? Or is it a second level of isolation?
What is it you're trying to accomplish?
Cheers!
Rich
