The 4 Pin PWM DC Axial Fan is an intelligent adjustable-speed brushless cooling fan with four-pin PWM (Pulse Width Modulation) control function, which is an upgraded version of the traditional 3-pin fan and a core component of high-precision intelligent temperature control heat dissipation systems. On the basis of the 3-pin fan’s power supply, grounding, and speed signal output functions, the 4-pin fan adds an independent PWM speed regulation control pin, realizing active intelligent speed regulation without changing the working voltage. It can accurately adjust the fan’s rotating speed in real time according to the equipment’s internal temperature, achieving the optimal balance between efficient heat dissipation and energy-saving mute operation, which is incomparable to fixed-speed fans and ordinary speed-regulation fans. In terms of functional principle, the PWM speed regulation technology of the 4-pin fan controls the fan’s operating duty cycle through high-frequency pulse signals. The main control board outputs different PWM signal ratios according to the real-time temperature of the equipment. When the equipment temperature is low, the fan automatically reduces the speed to reduce noise and power consumption; when the temperature rises, the fan quickly increases the speed to improve heat dissipation efficiency, realizing full-intelligent adaptive heat dissipation. This speed regulation mode has the advantages of high precision, fast response, and no voltage loss. The fan can maintain stable operation at any speed stage, without jitter or stalling, and the speed regulation range covers 20% to 100% of the rated speed, with extremely high regulation accuracy. In terms of structural and performance advantages, the 4 Pin PWM DC Axial Fan adopts a high-grade brushless DC motor and intelligent drive chip, with more sensitive signal response and stronger operational stability. The optimized mute aerodynamic design effectively reduces wind cutting noise and vibration noise during low-speed operation, realizing ultra-quiet operation in standby and low-load states. The fan has complete size specifications and voltage models, supporting 12V and 24V mainstream voltages, and is suitable for high-end computers, servers, industrial workstations, precision instruments, and high-power industrial equipment. Equipped with high-precision double ball bearings, the service life is up to 60,000 to 80,000 hours, with strong anti-vibration and anti-aging capabilities, adapting to long-term intelligent variable-speed operation. In terms of protection and compatibility, the 4-pin PWM fan is backward compatible with 3-pin fan interfaces. It can be used as a fixed-speed fan when connected to a 3-pin interface, and can exert intelligent speed regulation functions when connected to a 4-pin PWM main control interface, with extremely high compatibility. The built-in multiple safety protection functions such as over-current, over-voltage, locked-rotor, and surge resistance ensure stable and safe operation in complex intelligent control systems. All products comply with international environmental protection and safety certification standards, with low power consumption and high energy efficiency, which can reduce the overall energy consumption of equipment by 20% to 30% compared with fixed-speed fans. In terms of application scenarios, the 4 Pin PWM DC Axial Fan is mainly used in high-end intelligent equipment that requires precise temperature control, low noise, and energy saving, such as gaming computer chassis, server clusters, industrial intelligent control cabinets, medical precision equipment, and new energy intelligent equipment. It solves the problems of excessive noise at fixed high speed and insufficient heat dissipation at fixed low speed of traditional fans, and is the best choice for high-end intelligent thermal management systems.