PWM - definition
PWM - definition
PWM (Pulse-Width Modulation) is a technique used in electronic and automation systems for regulating the power delivered to loads, controlling devices, and encoding information in the form of a binary signal with a variable high-state duration. It involves the cyclic generation of a rectangular waveform at a fixed frequency, where the duty cycle—the ratio of the pulse width to the total signal period—is modulated according to the value of the control signal.
By varying the pulse width while maintaining a constant frequency, PWM enables effective control of the average voltage or current supplied to a load. This average value is proportional to the signal’s duty cycle, allowing for precise regulation of device operating parameters with minimal energy loss. As a result, PWM is widely used in powering electric motors, controlling LED brightness, operating solenoid valves, processing analog and digital signals, and in power conversion systems.
Compared to traditional linear control methods, PWM offers high energy efficiency, as switching elements such as transistors operate mainly in full conduction or complete cut-off states, minimizing heat-related power losses. A PWM signal can be generated either by hardware—using dedicated microcontroller modules or timing circuits—or by software, through appropriate control of output pins.
In digital systems, PWM also serves as a control interface, allowing analog information to be transmitted using purely binary logic signals. To retrieve a continuous analog voltage or value, the PWM signal can be passed through a low-pass filter that smooths the pulse waveform. The effectiveness of PWM depends on proper selection of modulation frequency, pulse shape, load parameters, and the quality of the driver circuitry.
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