What is a pulse width modulator?

Question

What is a pulse width modulator?

Answer 1

A pulse width modulator may do the things listed in the other answer, but is used for power control more frequently.  One example would be with LED's.  An LED is a current operated device and you can't control the brightness very well with voltage control.  By modulating the width of the DC power it runs on you have a very nice brightness control.  It's also used for DC motor control.  One good example is in model trains.  If you just use voltage control the model engine suddenly jumps ahead when the voltage reaches a certain point.  It's not smooth or realistic looking.  Using PWM allows the model to start slowly and smoothly, just the way a real engine would.  

There are many other uses of course.

Answer 2

Pulse Width Modulation, abbreviated as PWM, is a method of transmitting information on a series of pulses. The data that is being transmitted is encoded on the width of these pulses to control the amount of power being sent to a load. In other words, pulse width modulation is a modulation technique for generating variable width pulses to represent the amplitude of an input analog signal or wave. The popular applications of pulse width modulation are in power delivery, voltage regulation and amplification and audio effects.