A handy resource for stepper motors
Stepper Motor Hardware Interfacing
http://www.piclist.com/techref/io/steppers.htm
A stepper motor is a kind of electric motor with an internal rotor containing permanent magnets and a set of electro-magnet coils around the rotor which are switched electronically. Stepper motors "cog" to a limited number of positions, but with a microstepping controller, which partially activate adjacent coils so that the rotor rests between positions, stepper motors can rotate more smoothly
Stepper Motor Hardware Interfacing
Estimating Needed Power Standard NEMA Sizes Determining Wiring Connection Options Power Supply Heat
