This timer was found in English documentation from the 80's. The integrated circuit is common nowadays and the MOSFET admits equivalent according to the controlled load.
This circuit can be connected to the output of alarms or sirens with the 555, CMOS or TTL,...
Found in an American leaflet from the 90s, this circuit uses an AM radio out of station to monitor...
Found in the Encyclopedia of Electronic Circuits Volume 5 of 1995 this circuit has the gain...