A four-wire fan is a type of cooling fan, commonly used in computers and other electronic devices, that uses four wires for power, ground, speed sensing, and speed control. This allows for more precise fan speed management and monitoring compared to two- or three-wire fans.
Here's a breakdown of what each wire typically does:
- Power (+12V or +5V): Provides the necessary voltage to power the fan motor.
- Ground (GND): Completes the electrical circuit.
- Speed Sense (Tachometer): Outputs a signal indicating the fan's rotational speed (RPM - Revolutions Per Minute). This allows the system to monitor if the fan is functioning correctly and at the desired speed.
- Speed Control (PWM): Receives a PWM (Pulse Width Modulation) signal from the system, which controls the fan's speed. By varying the duty cycle of the PWM signal, the fan's speed can be precisely adjusted.
Benefits of Using Four-Wire Fans:
- Precise Speed Control: PWM control allows for fine-grained adjustment of the fan speed, optimizing cooling performance while minimizing noise.
- Fan Speed Monitoring: The tachometer signal allows the system to monitor the fan's speed and detect failures or slowdowns. This is crucial for ensuring proper cooling and preventing overheating.
- Automatic Speed Adjustment: Systems can dynamically adjust the fan speed based on temperature sensors, providing efficient cooling only when needed. This reduces noise and power consumption.
- Improved Reliability: Active monitoring can alert users to potential fan failures before they lead to system instability or damage.
Example Use Cases:
- Desktop Computer CPUs: Keeping the CPU cool is critical for performance and longevity. Four-wire fans are commonly used on CPU coolers to provide efficient and quiet cooling.
- Computer Enclosures (Case Fans): Maintaining airflow within the computer case helps to dissipate heat generated by various components.
- Graphics Cards (GPUs): High-performance GPUs generate significant heat, and four-wire fans are often used on GPU coolers for effective cooling.
- Server Equipment: Servers require robust cooling solutions to ensure stable operation in demanding environments. Four-wire fans are commonly used in server cooling systems.
- Power Supplies: Some power supplies also use four-wire fans for temperature-controlled cooling.
Comparison with Two-Wire and Three-Wire Fans:
| Feature | Two-Wire Fan | Three-Wire Fan | Four-Wire Fan |
|---|---|---|---|
| Power | Yes | Yes | Yes |
| Ground | Yes | Yes | Yes |
| Speed Sense | No | Yes | Yes |
| Speed Control | No | Voltage Control | PWM Control |
| Control Granularity | Limited | Moderate | High |
