The purpose of this circuit is to reduce the ripple of a power supply. The circuit is from a Radio Electronics from March 1985. The transistor must have a capacitance according to the source.
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...