Reduce Fan Speed With Resistor

The only thing that has to be done is to connect a resistor in series with the power supply of the fan.

Reduce fan speed with resistor.

This voltage drop will be subtracted from the overall voltage on the fan and therefore the voltage across the fan will be reduced. Emmawatsun sep 20 2018 6 48 am in response to rayjai you should put a big size resistor on the 5 volt side. This highlights one potential pitfall of this method you can t safely use 1 4w resistors for this unless you make up the target resistance using several smaller resistors of equal value in series. Quite practical and useful.

Use the 3 pin cable to connect the power supply to your cooling fan it will reduce the speed of the fan and cut the noise output dramatically. Designed with a resistor on the cable. The resistor will cause a voltage drop across its leads. Quite practical and useful.

It uses a resistor to generate voltage drop and thus reduce the speed of a dc motor like the pc fan. In our psc example we would likely have had to slow the fan speed by 7 15 to give us the ability to get much closer to our target of 350 cfm ton. So to achieve a voltage drop of 5v we would need a resistor with value of 42 ohms and capable of dissipating 0 6w of power. Ecm motors typically offer all the same speed adjustments as psc s with the added ability to reduce speed in smaller increments from the low medium low medium high and high settings.

However the motor will draw more current when starting up and as the load increases causing higher voltage drop and reducing speed even more. Use the 3 pin cable to connect the power supply to your cooling fan it will reduce the speed of the fan and cut the noise output dramatically. I have a 5v usb fan and i want to reduce the speed. Among all circuits i have make this is the simplest one.

3 pin male to female.