The continuous working of DC fan in audio amplifier or any other circuit project will reduce its life. Building a simple and automatic DC fan controller will adjust the speed of fan based on the temperature. This will increasing the life span of the cooling fan. So in this article I’m sharing the circuit diagram and working explanation of this automatic fan controller circuit.
P55NF06 Mosfet Pinout
Components Required
| Component | Specification/Value |
|---|---|
| Thermistor | 10K NTC (Marked 103) |
| Resistor | 1 kΩ |
| Capacitor (C1) | 10 µF / 25V (Electrolytic) |
| MOSFET | P55NF06 (or IRFZ44N) |
| DC Fan | 12V DC Fan |
| Power Supply | +12V DC |
Automatic DC Fan Speed Control Circuit
Connections and Working
In this circuit the P55NF06 mosfet is act like the main controller of 12V DC fan. The fan gets the DC input supply based on the temperature. If the temperature is high the mosfet provides high current to the DC fan and the fan rotates faster than usual. when the temperature goes below the speed of fan decreases.
This setup is fully automatic and we don’t adjust the speed of DC fan manually. The 10K thermistor and a 1K resistor is connected to the Gate pin of the mosfet. when the temperature is increases the thermistor resistance getting low and pass through more positive charge to the mosfet gate pin. More positive charge to the Gate pin means more current in Drain. This process in continuous and no need additional circuits or manual actions to adjust the speed of DC fan.
