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.
This amplifier for a sinusoidal function generator uses a 741 integrated circuit. The circuit is...
This circuit is from Motorola's Linear Interface ICs of 1993. The circuit can be powered by...
This circuit is from 2005 documentation. It automatically starts an irrigation pump when the...