Stepper Motor Basics:
The Stepper Motor is the most common motor found on small desktop engraving machines, 3D printing machines, they're very common in Open Source Projects and where often found in the older model Paper Printers.
These Motors are brushless, like Servo Motors, and are synchronous electric motors just like Servos, these motors function by converting an AC Frequency into mechanical shaft rotation. "A synchronous electric motor is an AC motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current"
Warning Never connect a Servo motor or Stepper motor Directly to a Power source, only Power Regulated DC Motors, or, Universal Brushed Motors can be used this way.
Stepper Motor Math:
Every revolution of the stepper motor is divided into a discrete number of steps, common denominations include .09 Deg or 1.8 Deg, however finer resolution motors can be found, and we all know that one revolution is equal to 360 Degrees, so if we have a Stepper with a 1.8-Deg Step angle, 1.8 goes into 360, 200 times, that how many steps for one full revolution or that Motor, another way to check: 1.8 X 200 = 360.
Micro-stepping: A stepper motor can be Micro stepped, meaning they will move increments of a full Step.