Hi folks, long time no post. I've been looking around at DIY/home-made fan controllers. They all seem to change the speed of the fan vs. temperature in a linear fashion (when exponential seems more appropriate to me). I assume there is a particular reason for this, I'm just not sure what it is. Possible problems: -how on earth do you do exponentials on a PIC? -the voltage range used to control a fan is too small to necessitate anything other than linear. Thanks for your help! m.