An idea in an earlier blog is to make a pwm interface that can accept 5, 12 and 24V pulse streams. That one uses a bunch of resistors and has three separate inputs. Below that, wise commenter DB ...

…which would take a pulse-width-modulated waveform at any frequency, and produce a signal with exactly the same mark/space ratio, but at a nominated frequency (see ‘Why might this be useful?’ below).

I have spent at least an hour almost every day since the 80’s advancing my knowledge in electronics. Recently I brushed up my knowledge on LED fading secrets and attained something pleasant. Now, I’d ...