An old abandoned requirement has re-surfaced...
If I wanted to use some series LEDs, illuminated by more LEDs to generate a small amount of isolated power - say to turn on a MOSFET not particularly quickly, say 10V at a few uA - what would be the best type?[I can't use the packaged photovoltaic isolators/drivers, I need a bit more distance.]
I have read that you should use the same colour for drive and sense, which sounds reasonable. I imagine that higher Vf LEDs produce more V, but I'd need a few in series anyway so that doesn't really matter.
I tried a white power LED (just because I had one lying about) and illuminating it with another gave me about 2V on my DMM, short circuit current too small to measure without fiddling about. Yes, I know the yellow phosphor just gets in the way and wastes power, but it's a start.
I'll need to do some experimenting, but I'd like to narrow things down a bit first. I think the packaged photovoltaic isolators use IR LEDs, a guess based on their Vf - would blue LEDs be better? In any event, being able to see it working would be advantageous in this application.