Using the 723 integrated circuit, this circuit was found in an article on power supplies in the August 1971 Radio Electronics magazine. The transistor may be the BD136 on a heatsink.
This circuit was found in an Experimenters Handbook of the 1990s. The purpose of this circuit is to...
This source, from a 1982 documentation, uses a triac to control the power and voltage applied to...
This circuit was found in the September 1984 issue of Radio Electronics magazine. The circuit has...