Okay,
so the thread may be closed nevetheless I still cannot understand:
a) what does the PWM 20...200Hz need for;
b) what is the reason to regulate Voltage on a resistor, especially at 5A current, why not effective power. From other side, P=U<sup>2/R and so when you regulate the power then you regulate the Voltage as well;
c) just switch AC On for 1 hour, then off for second one - it produces 1/2 of average voltage (=

Regards,
Oleg</sup>