PWM
From uCtrl.net
Information
Pulse-width modulation of a signal or power source involves the modulation of it's duty cycle. This can be used to either convey information over a communications channel, or control the amount of power sent to a load. The output current stays the same, but the duty cycle is given a rectangular waveform, as shown in the picture. This can be used for controlling LED brightness, motor speeds, etc.
