i need to regulate the speed of a noisy kitchen FAN from a microcontroller (arduino board), i have been looking around and checked a lot of websites and schematics, and i think the solution should goes to a TRIAC regulator I think...

The point is that i have no knowledge in power electronics and i don't know witch circuit is going to be good and reliable. I have seen some circuits that use only a TRIAC and others that uses a TRIAC and a DIAC... Why is the difference? and the DIAC function?

Could you provide me with some good schematics or recommendation form my situation?

thanks you very much :)


Word or warning - TRIAC control will generate noise in the windings of the motor (fan) coils. This can be almost as annoying as a fan running fast. The problem is the TRIAC switching on part way though the cycle gives a current surge and the winding will physically move (not damaging) which makes the deep hum.

Also you need to check that you fan is a true AC fan and not what we call in the industry a EC fan. These are supplied by AC mains but have a internal PSU and then drive a DC fan - TRIAC control will not work on these fans.

However AC fans run very quiet if you run them of a step down transform, auto transformer which is good if you want a fixed speed.

I would suggest looking at getting a replacement fan if you want quiet operation. DC fans are easy to speed control with either a PWM input or by voltage regulating them (DO NOT voltage chop a fan - its kills them). Or look of a fan with speed control inputs, two speed AC or EC fan.

Just worth considering as a option from the start that all.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.