With this circuit it is possible to obtain a voltage of -5 V from a 5 V source. The circuit is from Radio Electronics from May 1982. The maximum current is around 80 mA.
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...