I'm certainly no electrical engineer, and I see how the nice duality was lost in my description. Yes, I was thinking about the ones I'd actually worked with,

I'm certainly no electrical engineer, and I see how the nice duality was lost in my description. Yes, I was thinking about the ones I'd actually worked with, where the resistance was the control knob. I haven't done much electronics since, so my recollection isn't perfect. I have recently been doing some esp-32 control projects where I just used some power supply I bought. I should look into how it works! Edit- I just looked up switching power supplies and remembered that I did actually know about those!