I want to supply DC power to a heating resistor. There will be a thermostat to turn AC wall socket power on or off to the device. But rather than using just that method which might result in significant unwanted temperature swings I am thinking of using something that has a pulsed square wave style output where the pulse width can be adjusted with a knob. That way I get it adjusted to where it delivers just slightly more power than necessary to run at the desired operating output temperature and occasionally the thermostat turns it all off breifly to keep it from getting too hot.
What device am I looking for?