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From: Watson 'Atto Parsec' Name
Subject: Re: luxeon star leds
References: <3DDD9A57.58900EFB@RobertsResearchInc.com> <email@example.com> <3DDDB646.96D0D9D2@RobertsResearchInc.com> <3DDE7264.CD48F4F8@RobertsResearchInc.com> <firstname.lastname@example.org> <3DDEB081.884EC92A@RobertsResearchInc.com> <3DE03D65.932BF9BF@RobertsResearchInc.com> <3DE15871.EF8FF9EA@RobertsResearchInc.com> <3DE224D3.81EFBA3C@RobertsResearchInc.com> <3DE4C4C1.50072B92@RobertsResearchInc.com> <3DE50083.6ED3B4DC@RobertsResearchInc.com>
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Date: Wed, 27 Nov 2002 10:46:09 -0800
NNTP-Posting-Date: Wed, 27 Nov 2002 11:44:25 PST
Organization: InReach Internet
In article <3DE50083.6ED3B4DC@RobertsResearchInc.com>,
Vic@RobertsResearchInc.com talked about...
> Watson 'Atto Parsec' Name wrote:
> > If you're serious about all this speculation that has been discussed, I
> > suggest you assemble a Star/O into a working device and use it, and then
> > come back and tell your experiences. I don't think you will then be so
> > critical of the heat problem.
> The Luxeon datasheet clearly shows the negative effects on
> both initial efficacy and lumen depreciation caused by
> operating the junction at any temperature over 25C. Of
> course it is not possible to hold the junction at 25C
> without a refrigerated heatsink, but it could be held to 45C
> if the LED is mounted to a good heatsink in ambient air.
> I based on the data I posted I no longer believe the Luxeon
> will "burn out" if operate only with the MCPBC and no other
> heatsink, but I do believe the data published by Luxeon that
> both efficacy and lumen maintenance will suffer. "Proof" of
> the former can be measured quickly with a good light meter,.
> Proof of the later would take a life test of many hours that
> I am not interested in conducting (unless of course someone
> wishes to support such a study.)
One other point I'd like to make. The standard 5mm T1-3/4 LED runs at 120
mW, with no heatsink at all. The Luxeon 1W star runs at about 8 times
this, yet has many tens, if not hundreds of times the surface area for heat
At one watt, it's really not a problem, especially considering that the LED
has to be mounted to something, and that will probably be by using the
screw slots, which makes the flat aluminum contact some other surface. And
that helps dissipate the heat.
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
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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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