I built another lamp controller for my microscopy lights. This is a simple DC dimming circuit designed for 15W tungsten microscopy lights, such as for my LOMO OI-19 (ЛОМО ОИ-19). Though I have a couple other similar lamps from Carl Zeiss Jena and Leitz.
The circuit is powered using an external 7.5V 5A power supply. I calculated the heat sink to heat up 40K in the worst case, assuming around 20C room temperature this is still within the limit of the polystyrol enclosure.
Here shown the circuit diagram for one of the two channels.