As it turns out, the ever-useful 555 timer chip does the job admirably. It’s a simple enough circuit, the threshold pin is pulled high so the output goes high, and the PWM drive from an Arduino ...

Well, sort of. It really bugs me that there’s an entire arduino there just for some PWM. I can go buy the components to do 555 timer PWM circuits if all I want is PWM. Then again, if I compare ...