A speed controller is a device or electronic module used to regulate the rotational speed of, for example, a fan. Its main purpose is to allow the user to adjust the performance of the fan to their needs or preferences. The fan speed controller can be built into the fan itself or be a separate device that connects between the power source and the fan. Thanks to this, the user can increase or decrease the fan speed, which affects the intensity of air flow and the level of generated noise.