Define pulse-width modulation (PWM).

Pulse-width modulation (PWM) is a technique utilized primarily in electronic control systems to manage the amount of power delivered to a device. By varying the duration of the 'on' state in a signal, PWM enables precise control of power delivery with high efficiency. This is essential in applications such as motor speed control, LED dimming, and heating elements, where the ability to adjust power output in a finely-tuned manner is advantageous.

The fundamental concept of PWM involves switching the power to a device on and off at a rapid pace. The proportion of time the signal is 'on' compared to the total cycle time (the 'duty cycle') dictates the effective power being delivered. A higher duty cycle means more power is provided, while a lower duty cycle means less power. This modulation allows for effective control without significant energy loss, which is why it is widely adopted in various electronic applications.