stepper motor

Electric motor that can be precisely controlled by signals from a computer. The motor turns through a precise angle each time it receives a signal pulse from the computer. By varying the rate at which signal pulses are produced, the motor can be run at different speeds or be turned through an exact angle and then stopped. Switching circuits can be constructed to allow the computer to reverse the direction of the motor.

By combining two or more motors, complex movement control becomes possible. For example, if stepper motors are used to power the wheels of a small vehicle, a computer can manoeuvre the vehicle in any direction.

Stepper motors are commonly used in small-scale applications where computer-controlled movement is required. They are often used inside dot-matrix and ink-jet printers, to control both the feeding of the paper and the movement of the print head across the page. In larger applications, where greater power is necessary, pneumatic or hydraulic systems are usually preferred.