Pulse-width modulation (PWM) is varying the duty cycle of a rectangle wave, usually with a constant frequency.
*P*ulsed *W*idth *M*odulation is most often used in robotics for motor control applications.
- For a brushed DC motor, the PWM duty cycle controls the speed of the motor.
- For RC servos, the PWM duty cycle controls the servo position.
- Brushless DC motors use multiple PWM waveforms to control each phase of the motor.