UNIPOLAR STEPPER MOTOR CONTROL CIRCUIT. This circuit controls a small, four-phase, five-wire, unipolar stepper motor, commonly designated the KP4M4-001. This type of motor was used in many 5 1/4 floppy disk drives in older computers. Now obsolete, such disk drives are often available on the surplus market for a small fraction of the motors original cost. schematic diagram

UNIPOLAR STEPPER MOTOR CONTROL CIRCUIT. This circuit controls a small, four-phase, five-wire, unipolar stepper motor, commonly designated the KP4M4-001. This type of motor was used in many 5 1/4 floppy disk drives in older computers. Now obsolete, such disk drives are often available on the surplus market for a small fraction of the motors original cost.