Hi All,

Friend is building a kit car and has asked me to design a switched (3 or 4 position) speed controller for the interior heater fans (current between 6 to 10 amps total). I did suggest growing a beard and wearing a bobble hat like all the other kit car owners I have seen. But he wasn't to keen on that!

I plan to use a 12f683 PWM output to drive some power Fets.
Are there any do's and don'ts in driving and protecting the Fets?

Also would I need to filter the 12v supply to prevent switching spikes going back into the cars supply?
Any recommendation on what Fets to use? I imagine a low switch on volt drop is important to minimise heat generation?

Any suggestions welcome,

Thanks,
Bob