Computer fans are controlled primarily through methods managed by the computer's motherboard.
Computer fans are essential for cooling components like the CPU, GPU, and chipset, preventing overheating and ensuring stable performance. The speed of these fans is dynamically controlled based on system temperature and user settings.
According to the provided reference, "There are two main options for adjusting the fan speed via a computer's motherboard:" These methods regulate how much power is delivered to the fan, thus changing its rotation speed (RPM).
Here are the two primary methods:
- Adjusting the Supply Voltage: One method involves regulating the supply voltage (DC, lower voltage = lower speed). Traditional 3-pin fans often use this method. By reducing the voltage supplied to the fan, less power is delivered, causing the fan to spin slower. Conversely, increasing the voltage makes the fan spin faster.
- Controlling via a PWM Signal: The other main method is by controlling the fan via a PWM signal. PWM stands for Pulse Width Modulation. This method is typically used with 4-pin fans. Instead of constantly changing the voltage level, the fan is rapidly switched on and off. The "width" of the "on" pulse determines the effective power delivered. A wider pulse (more "on" time) results in a higher effective voltage and faster speed, while a narrower pulse (less "on" time) results in a lower effective voltage and slower speed. This method offers finer control over fan speed compared to simple voltage adjustment.
In summary, motherboards control fan speed by either directly lowering or raising the DC voltage sent to the fan or by rapidly pulsing the power (PWM), with both techniques effectively adjusting the power delivered to achieve the desired speed.
