This sonic relay or vox was found in a Popular Electronics from the 90's. The power MOSFET can be of any type determining the controlled load.
We found this multiple thermostat circuit in July 1980 Radio Electronics magazine. It uses...
This circuit is from a 1986 Revista Española de Electrónica. It consists of an amplifier with...
Suggested by a 1968 Philips documentation this Eccles Jordan rocker as it was called can operate...