Xref: utzoo sci.electronics:1801 comp.sys.mac:10465
Path: utzoo!mnetor!uunet!husc6!linus!gatech!amdcad!phil
From: phil@amdcad.AMD.COM (Phil Ngai)
Newsgroups: sci.electronics,comp.sys.mac
Subject: smart fan
Message-ID: <19808@amdcad.AMD.COM>
Date: 5 Jan 88 00:40:52 GMT
Organization: Advanced Micro Devices, Inc., Sunnyvale, Ca.
Lines: 16


I see that Rotron now has a great idea in fans. It's a DC operated fan
with an extra two wires. The resistance you provide between the wires
determines the speed of the fan, with the intention being that you use
a thermistor to regulate the amount of air moved based on the
temperature. The power supply voltage is not a factor (within limits
of course). This is all done with PWM type stuff so that efficiency is
very high. 

I hope Apple takes note of this!

-- 
"how long will the machine be down?"
"as long as you stand there and bother me"

Phil Ngai, {ucbvax,decwrl,allegra}!amdcad!phil or amdcad!phil@decwrl.dec.com