This power supply for model railroad was found in a February 1961 Radio Electronics Magazine. The transistor must be mounted on a heatsink and the transformer is a 1,5A secondary winding.
The circuit is from American documentation from the 1980s. Operational ones are not common today,...
This simple continuity tester consists of an oscillator found in the 1983 Electronics Experimenter Special...
This circuit is from a 70s linear integrated manual. The integrated circuit used is uncommon today...