This circuit is intended for detecting 3 levels power grid voltage, and it can be adapted to operate with the most diverse voltages. The circuit uses neon indicator lamps.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...