Hi, thanks all for your help.
Ron: I think i know how, but what would this acheieve?
The fan is a 12v case fan (computer).
I want to pwm the fan at 18v because it is too much of a wimp for the job at hand
Would what you suggested, make the fan run quicker?
Using a bigger fan would have been the ideal option, but I have allready foolishly spent along time on designing my case in autocad, and now have manufactured it!
Mneary:
Ok thanks, just out of interest, what would be wrong with that
?
Robert-Jan: Im using the full bridge just for board simplicity (im very lazy!), also see above.
I have included a new schem, is this right now?
Many thanks,
chris.