Pulse width modulation (PWM) is a technique that is usually combined with a logic-level output. With PWM, a logic-level binary output can turn a device on and off very rapidly with a programmable duty cycle. In other words, the proportions of on and off time can be easily adjusted.
This makes PWM useful for controller devices in a non-binary way. The resolution of PWM ranges from 8 bits (256 levels) to 16 bits (65536 levels).
PWM is a very efficient method to control devices in an “analog” way. This is because the switch is either completely open or closed. A switch that is closed usually dissipates little heat, as compared to a switch that is partially closed. This has to do with power dissipation is the product of voltage-drop and current. A completely closed switch should have very little voltage-drop compared to a partially closed switch.
Applications: