[mythtv-users] Fancontrol with replaced CPU fan
Simon Hobson
linux at thehobsons.co.uk
Tue Oct 13 06:34:53 UTC 2009
Johnny wrote:
> >> I'd assumed this was the way all fans worked in PCs - they do indeed vary
>>> the voltage to vary fan speed.
>>
>> Oops, should have added "on moderately modern hardware". Old hardware does
>> in fact just supply a fixed 12V and the fan runs at constant speed.
>
>Actually newer hardware can often use pulse-width modulation (PWM).
>Basically, they always apply the full voltage but they cycle it on and
>off at different duty cycles to vary the speed.
OK, I stand corrected - but same thing applies, motherboard varies
the supply and fan doesn't need any smarts. Same fan will work with
fixed or variable supply.
--
Simon Hobson
Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
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