When the voltage supplying the circuit falls below the zener value, the LED lights up, and if a low current buzzer is used, it is activated. The circuit is from a 1999 American publication.
This circuit is from the 1977 RCA Linear Integrated Circuits Manual. The circuit has a...
This circuit was found in 1980's Radio Electronics. The circuit produces a 1500 Hz modulate 35 kHz....
The maximum power of the controlled load depends on the triac used. The circuit is from a Radio...