[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
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