🎯 Why It Matters
Speed control saves energy and reduces noise. A fan running at 50% speed uses only ~12.5% of full-speed power (cube law). PWM allows precise digital control from microcontrollers. 0-10V is simpler for analog PLC systems. TC enables autonomous thermal management without a controller.
📐 How to Read
PWM frequency: typically 25kHz (above audible range). Duty cycle range: 0-100% (some fans need 20-30% minimum to start). 0-10V: linear relationship — 5V = ~50% speed. TC: resistance vs temperature curve specified in datasheet.
📏 Typical Values
Server/IT: PWM (4-wire). Industrial PLC: 0-10V analog. Simple electronics: 2-wire (fixed speed) or 3-wire (tach only). Smart cooling: TC with built-in thermistor.
🔗 Related Parameters
Voltage, Power, Noise, Thermal Management
❓ Frequently Asked Questions
PWM vs 0-10V — which to choose?
PWM for digital/MCU control (precise, efficient, supports tach feedback). 0-10V for analog/PLC systems (simple wiring, no programming needed). PWM is more common in modern designs.
Can I PWM-control a 2-wire fan?
Not recommended. 2-wire fans aren't designed for rapid switching — the internal electronics may malfunction. Use 4-wire PWM fans for proper speed control. 3-wire fans can be voltage-controlled but not PWM-controlled.
What is the minimum speed for a PWM fan?
Most PWM fans can go down to 20-30% duty cycle. Below that, the fan may stall or not start reliably. Check the datasheet for minimum duty cycle specification. Some premium fans support 0% = stop functionality.