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 part of an oscilloscope project with the PC. Its purpose is to record a peak in a...
This circuit was obtained in the SGS manual of linear integrated circuits of 1982. The transistor can be...
To operate with high input voltages using a 3-terminal voltage regulator such as the LM340-15, we...