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.
The output current of this circuit reaches 12 mA. The zener diode determines the output voltage. The...
Found in Maxim's documentation from the 90's, this circuit uses an integrated from the time...
Found in a 1980s documentation, this circuit makes use of components from that time. Modern...