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.
This source, from a 1982 documentation, uses a triac to control the power and voltage applied to...
This circuit was found in Motorola documentation from 1968, using high power transistors and...
This circuit was found in documentation from the 1980s. The circuit uses several components of the...