The motor controller will be connected to the power supply, which may be battery or mains power. There will also be some circuits that can input or output (digital or analog) signals. The most widely used small motors include DC motors, brushless DC motors and stepper motors. The main difference between stepping motor, DC motor and brushless DC motor is their driving mode.

The motor controller can be operated manually, remotely or automatically. It can only include the functions of starting and stopping the motor, and can also include other complex functions. Motor controllers can be classified according to the type of matching motor, such as driving permanent magnet synchronous motor, servo motor, series or shunt DC motor, or AC motor.