Pulse Width Modulation (PWM)
Definition - What does Pulse Width Modulation (PWM) mean?
Techopedia explains Pulse Width Modulation (PWM)
A very powerful benefit of PWM is that power loss is very minimal. Compared to regulating power levels using an analog potentiometer to limit the power output by essentially choking the electrical pathway, thereby resulting in power loss as heat, PWM actually turns off the power output rather than limits it. Applications range from controlling DC motors and light dimming to heating elements.