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Forum I have a 5v usb fan and I want to reduce the speed.

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I have a 5v usb fan and I want to reduce the speed.

rayjai over 12 years ago

I have a 5v usb fan and I want to reduce the speed. how would I do it?

the fans on my laptop cooler is too loud.

thanks

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YT2095 over 12 years ago +1

you could also use a simple 1n4001 diode in series with the positive wire, to drop .7 of a volt for each diode you use, doing it this way still lets you draw exactly the same amount of current (about 500ma…

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0 Former Member over 12 years ago

Simplest thing to do might be to replace the 5V fan with a 12 volt fan that is the same size. The 12 volt fan will run slower from 5V. Just be sure it is not a brushless DC fan.
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0 Former Member over 12 years ago

Simplest thing to do might be to replace the 5V fan with a 12 volt fan that is the same size. The 12 volt fan will run slower from 5V. Just be sure it is not a brushless DC fan.
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0 DavenPaget over 12 years ago in reply to Former Member

That's plain wrong .
A 12v BLDC can work down to 1.5V .

PWM with a TL494 into a N-channel mid power mosfet will do .
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0 Former Member over 12 years ago in reply to DavenPaget

Hi Dave,

You are right. I was thinking of a brushless DC motor that requires 3 phase AC drive (a controller module), not the cheap brushless fans that just provide electronic commutation.
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