answer:Regular lightbulbs have metal (e.g. Tungsten) filaments in them. With a dimmer, you can alter the amount of electricity (trying to keep it simple) going through them. As much electricity goes through the filament, the hotter they get and become bright (give off light). You should be able to do this with a halogen light as well because I think they are filament based. You cant do this with fluorescent lights because they are not filament based. They are gas-based. In other words, there is an inert gas (meaning it cant burn or react) in the tube. At a particular level of electricity, electrons (i.e. electricity) can “jump” from one end of the tube to the other. The “jump” causes the gas to give off light (glow). So, if you want to think of this in simple terms. Think of a filament as a bridge. You could crawl across and still get to the other side. This would be a low level of electricity (using the dimmer) giving off less light. Now, think of the two ends of the fluorescent tube as a trench. You have to run fast and jump over the thing. If you try and crawl, you wont get to the other side and fall in the ditch. This is basically that level of electricity where the light either turns off (electrons cant jump) or on (they can jump). Usually, its not very easy to dim such lights. Very few types are specially made for this type of thing—and they are sometimes noisy. Hope this helps and that it was what you were looking for.