just drive your optics hard enough, you'll see back-EMF
/s
Re:Audio Optocouplers
by fuzzfactor on Sunday September 25, 2022 @12:36AM
(#32968977)
I've driven non-photo resistors to the point you could see the glowing in time to the music ;-)
And smell the smoke.
Now with a 1500W space heater as a dummy load on a 1000W amp, you hear a little music come out of the heating elements without any speakers.
So at the same time, magnetically coupled.
Naturally subject to forces including back-EMF which are not shared by optics.