This high sensitivity circuit was found in the July 1992 Radio Electronics magazine. The circuit drives a buzzer, but a relay can be used to activate an external load.
This circuit is the transmitter for the previous project and also for what will come next. It is a...
This circuit was suggested by General Electric in 1969 documentation. It provides a maximum output of...
Found in an English documentation, this circuit provides a 50 Hz signal according to the local...