The light control module is a bit more complex. Dimming modules are different depending on the load they have to control. The circuit to control inductive loads (many halogen lamps are 12V and use a transformer to get that voltage) is different from an Ohm resistive load (classical bulbs) which is different from neon tubes. What type of load do you wanna control?The circuit for a 12V load is relatively easy. A power MOSFET should do the bulk of the job.
The actual lamp dimming functionality is actually usually some kind of triac or scr, controlledby the potentiometer.In principle you can regulate the lamp with the potentiometer alone, but it wastes a lot ofenergy and you have the problem of waste heat dissipation from the device itself.
What is a 'power mosfet'?