Pulse Width Modulation (PWM) is a technique used to control the amount of power delivered to electrical devices. It works by varying the width of the pulses in a signal while keeping the frequency constant. A wider pulse means more power, while a narrower pulse means less power. This method is commonly used in applications like motor speed control and dimming lights. PWM is efficient because it minimizes energy loss compared to other methods of power control. By rapidly switching the power on and off, it allows devices to operate effectively without generating excessive heat. This makes PWM a popular choice in modern electronics.