What is the difference between stepper motors and servo motors?

A servo motor converts an input voltage signal into angular displacement or angular velocity output on the shaft to drive the control object. Changing the control voltage can change the direction and rotational speed of the servo motor. Its main characteristic is that when the signal voltage is zero, there is no self-rotation phenomenon, and the rotational speed decreases uniformly with increasing torque. A stepper motor is an electric motor that converts electrical pulse signals into corresponding angular displacement or linear displacement. For each pulse signal input, the rotor rotates by a certain angle or advances one step. The output angular displacement or linear displacement is proportional to the number of input pulses, and the rotational speed is proportional to the pulse frequency. Therefore, the stepper motor is also called a pulse motor. Thus, by controlling the number of pulses, their frequency, and the phase sequence of the motor windings, the desired rotation angle, speed, and direction can be achieved.