This simple continuity tester, whose configuration can be found several times on this site, is powered by only 2 batteries providing the indication on an LED.
This circuit is from an old publication from the 1950s. The circuit uses germanium transistors but can be...
Found in a 1966 Electronics World, this circuit applies to the protection of any analog...
This circuit uses incandescent lamps for the 110V or 220V grid. We found this configuration in a 1989...