What does PWM stand for and what is its primary function?

Pulse Width Modulation, commonly abbreviated as PWM, is a technique used primarily for controlling power to devices by varying the width of the pulses in a signal while keeping the frequency constant. The fundamental concept behind PWM is that by changing the duration of the "on" time relative to the "off" time within a cycle, the average power delivered to a load can be controlled. This is particularly effective in applications such as motor control, where varying the average voltage across a motor allows for precise speed control.

In contrast, while controlling the frequency of signals is an important aspect of various modulation techniques, it does not encapsulate the primary function of PWM, which is about the modulation of pulse width for effective power management. Similarly, the other options such as "Pulse Wave Modulation" and "Pulsed Wideband Modulation" don’t accurately represent the standard, widely accepted definition of PWM nor its prevalent application areas, particularly in the context of power control in electronic devices.