How to Make a Simple Temperature Control Fan Speed

About: I love diy, electronic, fix something broken.

Intro: How to Make a Simple Temperature Control Fan Speed

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Step 1: Electronic Parts You Need

1 x 10K thermistor

1x IRF540n or n channel MOSFET

1 x 50 kilo-ohms potentiometer

1 x 2.2 uf 16 volts at least capacitor

Step 2: Connect All Parts As the Image Above

This circuit uses a thermistor as a sensor, the thermistor resistance decrease when a temperature increase.

When the temperature increases the thermistor resistance decrease until the voltage set point that adjusts by potentiometer higher than Vgs threshold, MOSFET change to ON state and make a 12 volts fan start and rotating speed faster when a temperature hotter.

The capacitor that parallels with a thermistor help fan starts instantly at lowest speed when power on, The 12 volts DC fan make noise and not rotating without the capacitor(maybe a cheap Chinese power supply cause it).

I set the threshold point at 25 C, The fan start at lowest speed @ 25 C and rotating fastest @ around 38 C (I touch it and wait few munites to see the result)

Enjoy DIY!!!!

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4 Discussions


Question 4 weeks ago on Step 2

Would it work with 5v? If not, what part should I change?

1 answer

Question 7 months ago

This is interesting project. I would like to try it. How do you set the threshold?

1 answer
Easy and work projectsum4all

Answer 7 months ago

I set the threshold by set air conditioner to the temp I want it to start (25c in the video) It's will rotating at slowest rpm @ 25 c