This charger was found in the February 1978 issue of Radio Electronics magazine. The circuit is for low current, only 150 mA, and has a 12 V transformer in the power 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...