PWM fancontroller

[CrazyNutz]

Great advice! I soldered another 1k resistor parallel to the first one (to get 500 ohm resistance), and the Mosfet is barely getting hot at all, even though I'm currently contolling 2 fans with it .

Another quick question: You said something about putting a diode between the j1-1 and j1-2 terminals. Which direction should the diode be facing?

Also, a friend of mine gave me the advice to play with the capacity of the elco to allow for a better control? Is this true, and if so, would a 47uF elco be a good choice?

Right on, No Problem

Look at the source schem, the diode across the motor terminals, this is the direction it should be placed
http://pcbheaven.com/circuitpages/PW...r_using_a_555/

As for the cap, yes your friend may be right, it would depend on your switching frequency though(and load like fgw said). If the cap value is too high it can regulate the voltage that your fan see's to a higher degree, i.e. you may not be able to have much range in the lower RPM region (you may not even be able to reach low rpm). So yes try it lower. Also If you go too low you may start to hear the PWM switching which will drive you nutz..