[Tfug] 90mm fan

[Bexley Hall]

> OK,
>         Thanks guys. I just checked and the old fan
> is clearly 2-wire.
> So, if
> there is any speed variation, the PS must be
> tweaking the voltage.

Fans typically only draw ~80mA.  So, putting
an NTC thermistor in series with the fan (directly)
effectively causes the voltage to the fan to rise
as the temperature does.

However, if that thermistor is in the power supply,
then it is the temperature of the PS that is governing
the fan's speed -- not the temperature of whatever
device(s) it may be cooling, etc.

You can buy two wire (12VDC) fans with a sensor *in*
the fan that will monitor the temperature of the
air passing through the fan itself and adjust it's
speed accordingly (wiring such a fan as an *exhaust*
is obviously what you would want in said case).

> Yeah, I've seen HS kids with their
> souped-up video game boxes.
> That's who buys the LED-studded fans.

... and epileptics (sp?)  :>


 
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