Found in a Popular Electronics from the 1990s, this circuit monitors the voltage of a power supply or battery. The trigger voltage is adjusted with a potentiometer.
This circuit was found in a 1992 documentation and has excellent sensitivity, using components that...
This practical idea from a 1992 documentation shows how to count the turns of a winder using a...
In this circuit from the 60s, the power supply is made with 22.5 V, which is the voltage of the...