What is the purpose of pulse-width modulation (PWM) in electrical control systems?

The purpose of pulse-width modulation (PWM) in electrical control systems is to control the amount of power delivered to a device by varying the duty cycle of a digital signal. PWM is a technique used to generate an analog signal from a digital source. Instead of continuously varying the voltage or current, PWM rapidly switches a signal between on and off states. The duty cycle is the percentage of time that the signal is in the on state. A higher duty cycle means the signal is on for a longer period, delivering more power to the device. A lower duty cycle means the signal is on for a shorter period, delivering less power. The frequency of the PWM signal (the rate at which it switches on and off) is typically much higher than the response time of the device being controlled, so the device effectively sees an average voltage or current proportional to the duty cycle. PWM is widely used to control the speed of motors, the brightness of lights, the position of valves, and other analog devices. It offers several advantages over traditional analog control methods, including higher efficiency, greater linearity, and better noise immunity. For example, PWM can be used to control the speed of a cooling fan in an engine. By varying the duty cycle of the PWM signal sent to the fan motor, the fan speed can be precisely controlled to maintain the engine temperature within a desired range. A higher duty cycle increases the fan speed, while a lower duty cycle reduces it.