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Our pal Greg from DIY live sent in this article he wrote trying to differentiate the difference between AC and DC motors and generators - "I ran across some cool pages while studying about AC vs. DC motors. I was interested in taking a small DC motor, and connecting a propeller to it. I want to stick the motor on the outside of my car, and generate a small DC voltage to power my toy, ie. an iPod, or my cell phone. I need 5v for the task. The question I have been having is if you take a DC motor, and spin it, will you be producing a DC voltage, or an AC voltage. The answer it seems is that you will produce a DC voltage. It is kind of complicated, but is very interesting. The key to understanding a DC motor vs. an AC motor is to see how they are wired. A DC motor has a commutator." - Link.

Related:

• HOW TO - Simple DC Motor Controller - Link.