I found the concept easy to understand. Basically, the motor gets full power for amount of time per cycle, and the inertia and momentum of the motor will make the motor keep spinning until the next chunk of full power is applied (like, nano-seconds after). That's how I visualized it, although I'm not sure how much help that is to anyone else, seeing as Joe defined it pretty well too. I guess my description is the "Super-Layman's-Terms"
