Cooling fans play a crucial role in electronic equipment, servers, industrial equipment and other fields. For different use needs, there are two main types of 3-Pin (3-pin) and 4-Pin (4-pin) fans on the market, and their main difference is the speed regulation mode - 3-pin fan speed regulation by voltage, while 4-pin fan uses PWM (pulse width modulation) speed regulation. So, what are the advantages and disadvantages of these two speed regulation methods? This article will explain it in detail.

Features of 3-pin fan (voltage adjustable speed)

The 3-pin fan, which is more common in traditional cooling solutions, controls the speed of the fan by adjusting the input voltage. Typically, the motherboard or fan controller lowers the voltage to reduce the fan speed, thus reducing noise.

Advantages:

simple structure, low cost, suitable for common heat dissipation requirements.

 is directly compatible with most motherboards without a special PWM controller.

 is suitable for the 2800 RPM exhaust fan, which provides stable heat dissipation under high voltage.

Cons:

 The speed regulation precision is low, can not achieve linear adjustment.

 Low voltage may cause fans to fail to start or stop, which affects heat dissipation.

 The startup voltages of different fans may vary, which may cause compatibility problems.

Features of 4-pin fan (PWM speed regulation)

On the basis of the 3-pin fan, a Pulse Width Modulation (PWM) signal line is added to the 4-pin fan, which adjusts the fan speed by changing the duty cycle of the PWM signal, while the supply voltage of the fan remains constant.

Advantages:

 Precise control of fan speed, wide speed range, more suitable for intelligent temperature control system.

 Since the fan always operates at rated voltage, startup problems that may result from low voltage are avoided.

PWM signal can independently control multiple fans, so that they operate simultaneously, improve heat dissipation efficiency.

 For "double ball bearing exhaust fans", PWM control can effectively reduce fan wear and improve service life.

Cons:

 The price is relatively high, and some old motherboards may not support PWM speed regulation.

 Requires the motherboard or fan controller to support PWM signals, otherwise it will not be able to take advantage of it.

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