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.
The purpose of this circuit is to power a small fluorescent lamp from from a 12 V battery. The circuit...
This circuit was found in a 1968’s publication and uses germanium transistors. Equivalents can be...
This circuit generates the busy tone of ordinary telephones. The transistors can be the BC548 and...