View Single Post
  #6  
Old March 16th 05, 05:58 PM
kony
external usenet poster
 
Posts: n/a
Default

On Wed, 16 Mar 2005 16:15:30 GMT, "Noozer"
wrote:



Just wondering... When trying to slow a fan in a PC, which is better - using
5v and 12v to get 7v to the fan, or adding a resistor inline?


The resistor, assuming a reliable connection is made
(soldered or good crimp, not just twisted bare wires) and
electrically isolated (like heatshrink or similar, as
electrical tape can degrade and unravel especially in hotter
environments).

In practice, either has worked fine for most people trying
(either). The resistor is certainly a higher level of
control, being able to choose some other voltage... 7V is
too slow for some applications and 5V too low for some fans
to even reliably spin-up. With today's larger 92-120mm fans
becoming more common, in some cases running the fan from 5V
(5V rail & ground) could be a good alternative instead.


I've got a Media PC that's very quiet except for one case fan.


Only issue there is being aware of the resultant temp
changes that come from flow reduction.