# Stepper Motor Control: Stepper Theory

Introducing the Stepper Motor
The stepper motor is a type of motor that uses the principle of induction to work. Each stepper motor has 2 or more coils surrounding the motor. When electricity flows through a coil a magnetic field is created by the current flow. If the coils are charged in the correct order we can make the motor turn by either pushing or pulling it via magnetism!

Here is an example of a 4 coil (phase) stepper motor in operation:

The red line indicates current flowing through it.

This is only a simple example that shows one coil active at a time. When a coil is active (current flowing through it), a magnetic field is created that pushes the motor a tiny bit. One complete cycle is called a "Step" (every stepper motor will have a unique step size, our 9.2v stepper motor has a 0.9° step size). Our 2 coil (phase) stepper motor operates in a much simpler fashion and doesn't just operate on one coil at a time as seen above.
Another very important thing to notice is that each coil requires 2 connections (electric current flows in & then out). That means if a stepper motor has 4 coils, it will require 8 connections. Since we are using a 2 coil stepper motor for this tutorial we will need 4 connections.

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