An electromagnetic incremental-motion actuator which converts digital pulse inputs to analog output motion. The device is also termed a step motor. When energized in a programmed manner by a voltage and current input, usually dc, a step motor can index in angular or linear increments. With proper control, the output steps are always equal in number to the input command pulses. Each pulse advances the rotor shaft one step increment and latches it magnetically at the precise point to which it is stepped. Advances in digital computers and particularly microcomputers revolutionized the controls of step motors. These motors are found in many industrial control systems, and large numbers are used in computer peripheral equipment, such as printers, tape drives, capstan drives, and memory-access mechanisms. Step motors are also used in numerical control systems, machine-tool controls, process control, and many systems in the aerospace industry.