This Power supply sources from 500 to 1,000 mA according the transformar and was found in a publication of the year 1958. The diodes can be now the 1N4004 and the transistor should be mounted on a heatsink.
This circuit uses a FET to drive an LED with constante currente. The current up to 20 mA can be...
The TDA2040 is not a common IC these days, but if you find one you can build this high quality...
This ouput push-pull stage using bipolar transistors was found in a publication of the year 1968....