While looking at some stuff on stepper motors for my courses, I came across a really nice resource on stepper motors. The article outlines some of the rationale for choosing a stepper motor, the physics behind them, with practical examples of how they are used, and what motor parameters to look at when choosing one. It also covers some information about closed-loop control of a stepper motor system. It is quite a good read as a quick guide to how stepper motors work. I found these notes to be very informative, and probably more informative than my class notes (although it doesn’t have as much math as in mine).