PWM Controller Hacking
Enough people have asked about it so I figured I would write up my PWM controller that I’ve hacked together. Ultimately I’d like to make it ATtiny powered and I might have made a mistake by getting the analog version working - as it works well enough and has removed the pressing need to build the digital version.
I managed to source everything at Radio Shack except the MOSFET. I picked that up at a local, terribly overpriced component supply store. I also purchased the pot there, simply because I liked the physical size of it - RS had a reasonable replacement. In choosing your N-channel MOSFET, make sure you select one that is fully ‘on’ at the level generated by the 555 circuit (not a problem as the signal is around 12V peak-to-peak) and has a very low $$R_{ds(on)}$$. If you are planning to use an ATtiny for the controller (instead of the 555) then you need to select a MOSFET with an appropriately low threshold voltage, such as the STP36NF06L.
