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 an American publication from 1974. It, at the same time, limits the intensity of...
This two-relay circuit gives drive logic that is clear when analyzing the circuit. In the original...
12 V battery chargers provide higher unregulated voltage. With the regulator shown, obtained from...