PWMsäätöpiireissä

PWMsäätöpiireissä, or Pulse Width Modulation (PWM) control circuits, are electronic circuits used to control the average power delivered to a load by switching the power supply on and off rapidly. The width of the pulse, which represents the "on" time, is varied while the frequency of the pulses remains constant. This variation in pulse width directly controls the average voltage or current supplied to the load, effectively regulating its behavior.

The core principle of PWM is to modulate the duty cycle, which is the ratio of the pulse's on-time to its total period. A higher duty cycle means the load receives power for a longer duration within each cycle, resulting in a higher average power. Conversely, a lower duty cycle reduces the average power. This on-off switching action, when performed at high frequencies, creates a smooth approximation of a lower average voltage or current that would be difficult to achieve with simple linear regulators, especially for high-power applications.

PWM control circuits are widely employed in various applications. Common uses include motor speed control, where varying the duty cycle adjusts the motor's rotational speed, and dimming LEDs, where precise brightness control is achieved. They are also found in power supplies, audio amplifiers, and heating elements. The advantages of PWM include high efficiency, as the switching components are either fully on or fully off, minimizing power dissipation, and good linearity in controlling the output. Implementing PWM typically involves a microcontroller or a dedicated PWM generator IC, along with power switching elements like transistors (MOSFETs or BJTs) or integrated circuits.