Computer Fans

Types

PWM fans are generally quieter, more durable, and more controllable than DC fans. However, DC fans are cheaper and just as effective

Direct Current (DC) Fan
3-pin Fan

  • are supplied with DC power from a regulated DC supply or motherboard header pins
  • come with 3 pins:
    • supply pin (usually 12 V DC)
    • ground pin
    • signal pin
  • speed of the fan is controlled by voltage from the supply pin
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Pulse Width Modulation (PWM) Fan

  • PWM fans are DC fans with an extra wire
  • PWM fans are 4-pin fans, where the fourth wire sends a PWM signal to the fan motor. The PWM signal is the control input of the PWM fan
  • speed of the fan is controlled by PWM signal pin
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