A electric motor that turns a well define amount ( say 7 degrees ), a step, when connected to the right power source. Repeated activation will cause the motor to move any number of steps in either direction desired. Used for carefully controlled motion. Microcontrollers are often used as part of the drive system for a stepper motor.
- Machine tools
Micro controller driving
A servo motor can be any kind of motor that is equipped with a position sensor. The information from that sensor is then used to control the motor. In common "RC" servos the sensor is a potentiometer and all the drive electronics are packaged inside the case with the motor.