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From: Watson 'Atto Parsec' Name
Subject: Re: luxeon star leds
References: <3DDD9A57.58900EFB@RobertsResearchInc.com> <firstname.lastname@example.org> <3DDDB646.96D0D9D2@RobertsResearchInc.com> <3DDE7264.CD48F4F8@RobertsResearchInc.com>
X-Newsreader: MicroPlanet Gravity v2.60
Date: Sat, 23 Nov 2002 16:05:50 -0800
NNTP-Posting-Date: Sat, 23 Nov 2002 18:09:26 PST
Organization: InReach Internet
In article <3DDE7264.CD48F4F8@RobertsResearchInc.com>,
Vic@RobertsResearchInc.com talked about...
> Lizard Blizzard wrote:
> > Victor Roberts wrote:
> > > John Larkin wrote:
> > >>On Fri, 22 Nov 2002 02:45:37 GMT, Victor Roberts
> > >> wrote:
> > >>>The thermal resistance to
> > >>>"free space" of an unmounted device should therefore be
> > >>>lower than the thermal resistance of a device mounted to a
> > >>>heat sink.
> > >>Then why do people buy heat sinks?
> > >>
> > > Because use of heat sinks will lower the temperature of the
> > > junction. Operating without a heat sink will decrease the
> > > apparent thermal resistance between the junction and the
> > > heat sink mounting plate on the LED because of the other
> > > paths available for power loss. Operating without a heat
> > > sink does not lower the junction temperature, it raises it.
> > What you really meant is that operating without a heatsink decreases the
> > thermal conductance, which is the inverse of thermal resistance.
Looks to me like your statement below contradicts your previous statement,
> No, I mean what I said in my last message. Operating with a
> heat sink _decreases_ the "apparent" thermal resistance
> between the junction of the LED (or any other semiconductor
> device) and the heat sink mounting plate on the LED (or
> other semiconductor) package.
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you put NOSPAM in the
Subject: line. alondra101 hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
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