This benchtop power supply with various output voltages from 1.5 to 12 V was found in Radio Electronics magazine from August 1960. The circuit uses power transistors of the time.
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...