The main advantage of PWM is that power loss in the switching devices is very low. Selecting a switching frequency that is too low for the application causes oscillations in the load. Choosing a switching frequency that is too high for the application results in smooth control of the load, but may cause premature failure of the mechanical control components. For example, switching only has to be done several times a minute in an electric stove 100 or 120 Hz (double of the utility frequency) in a lamp dimmer between a few kilohertz (kHz) and tens of kHz for a motor drive and well into the tens or hundreds of kHz in audio amplifiers and computer power supplies.

The PWM switching frequency can vary greatly depending on load and application. The goal of PWM is to control a load however, the PWM switching frequency must be selected carefully in order to smoothly do so. PWM is particularly suited for running inertial loads such as motors, which are not as easily affected by this discrete switching. Along with maximum power point tracking (MPPT), it is one of the primary methods of reducing the output of solar panels to that which can be utilized by a battery. The longer the switch is on, the higher the total power supplied to the load. The average value of voltage (and current) fed to the load is controlled by switching the supply between 0 and 100% at a rate faster than it takes the load to change significantly.

Pulse-width modulation ( PWM), or pulse-duration modulation ( PDM), is a method of controlling the average power delivered by an electrical signal.

Pulse width modulation