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From: "petrus bitbyter"
Subject: Re: Fan controller
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
Date: Sun, 13 Oct 2002 12:55:17 GMT
NNTP-Posting-Date: Sun, 13 Oct 2002 14:55:17 MET DST
Organization: chello broadband
I consider a microcontroller quite a heavy hammer for so small a pin but
that's up to you.
A micro can drive a Mosfet directly. That's where Mosfets are known for:
Very high input impedance. A transistor between them will not do any good.
You have to realise your fans are an inductive load. You will need a
freewheel diode to protect your Mosfet.
"Michael Brown" schreef in bericht
> Hello all,
> I'm in the process of designing a fan controller for my computer, and
> it's going to be situated quite close to my hard-disk, I'm wary about
> relays to do the switching for the fans (as I have done with my other
> control circuits). The load is going to be 12V and not more than 2A, and
> controller is going to be a AT90S8585 microcontroller. After reading up a
> bit, it seems the best way to go is to use a decent MOSFET to do the
> switching, and have another (smaller) transistor between the MOSFET and
> microprocessor to keep the current requirements on the microprocessor
> Is this the right approach and are there any things I should watch out
> Thanks in advance,
> Michael Brown
> My inbox is always open (remove the obvious):
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