Fan regulator
 

Hi! I just completed my recent project, a fan regulator that regulates the speed of the fan depending of the heat that the cpu is producing.

Its just a simple circuit with one p-channel mosfet a ntc and a pot.

Now for the question : is it dangerous for a fan (mine is a taisol) to get less voltage than it requires to start? My fan starts at approx. 4 V but when I start my computer the voltage over the fan is much lower than that. It takes approx. 1 minute before the voltage reaches 4. So it isnt that long time that the fan gets less than 4V.

Besides that flaw my fan reg. works great! Always 44 - 46 C (Full load as idle). And the best thing about it that I can't even hear the cpu fan any more!:)

no there's no problem in doing that.
-Kev