Pulse Width Modulation (PWM) is a technique used to control the power supplied to a load, such as a motor or LED, by changing the timing of how long it stays on and off. It is a method of controlling the average power delivered to a load without incurring the losses that would result from linear power delivery by resistive means. PWM works by turning the power on and off at a high frequency, and the ratio of on-time to off-time is called the duty cycle. The duty cycle determines the amount of power delivered to the load. PWM is used in many applications, including:

• Motor control: PWM is particularly suited for running inertial loads such as motors, which are not as easily affected by discrete switching. Many modern microcontrollers integrate PWM controllers exposed to external pins as peripheral devices under firmware control by means of internal programming interfaces. These are commonly used for direct current (DC) motor control in robotics, switched-mode power supply regulation, and other applications.

• Fan control: PWM is used to control the speed of fans and pumps in computer cooling systems. PWM fans and pumps use an integrated circuit to control the speed of a fan or pump and, therefore, how much cooling it’s providing to the CPU or GPU. PWM fans and pumps can alter their speed and airflow based on the components temperature.

• Signal modulation: PWM has been used in certain communication systems where its duty cycle has been used to convey information over a communications channel.

• LED dimming: PWM is used to control the brightness of LEDs by adjusting the duty cycle.

Overall, PWM is a versatile and widely used technique for controlling power delivery to a load.