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R.Lewis
Guest
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 Posted:
Wed Jan 19, 2005 12:16 am Post subject:
Luxeon emitters |
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Once upon a time the heatsinking 'slug' on the Luxeon emitters was not
electrically isolated from somewhere/something dark and secret within its
'innards and the datasheet/appnotes informed of this fact - detailing that
the slugs must be electrically isolated from each other .
Recently I have noticed that the slugs appear to be electrically isolated
from the anode and cathode connections although I can find no Lumileds
reference to this fact.
Anyone know anything about this?
Regards.
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Leon Sorokin
Guest
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| Posted:
Wed Jan 19, 2005 4:12 am Post subject:
Re: Luxeon emitters |
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i pulled an blue High Dome emitter off the star base just yesterday. I did a
continuity test and it seems to be isolated from both. i havent cleaned the
slug yet from the epoxy that held it on though. but i'm pretty confident of
the fact.
Leon
"R.Lewis" <h.lewis@connect-2.co.uk> wrote in message
news:3551u7F4j9l0gU1@individual.net...
| Quote: | Once upon a time the heatsinking 'slug' on the Luxeon emitters was not
electrically isolated from somewhere/something dark and secret within its
'innards and the datasheet/appnotes informed of this fact - detailing that
the slugs must be electrically isolated from each other .
Recently I have noticed that the slugs appear to be electrically isolated
from the anode and cathode connections although I can find no Lumileds
reference to this fact.
Anyone know anything about this?
Regards.
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Don Klipstein
Guest
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| Posted:
Thu Jan 20, 2005 11:55 pm Post subject:
Re: Luxeon emitters |
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In article <3551u7F4j9l0gU1@individual.net>, R.Lewis wrote:
| Quote: | Once upon a time the heatsinking 'slug' on the Luxeon emitters was not
electrically isolated from somewhere/something dark and secret within its
'innards and the datasheet/appnotes informed of this fact - detailing that
the slugs must be electrically isolated from each other .
Recently I have noticed that the slugs appear to be electrically isolated
from the anode and cathode connections although I can find no Lumileds
reference to this fact.
Anyone know anything about this?
|
I have noticed that some Luxeons have isolated heatsinking and some do
not. If the datasheet does not say anything in this area about a
particular part number, assume that the manufacturer reserves the right to
change that characteristic of that part number and be prepared for the
worst.
- Don Klipstein (don@misty.com)
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Zak
Guest
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| Posted:
Fri Jan 21, 2005 1:58 pm Post subject:
Re: Luxeon emitters |
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Don Klipstein wrote:
| Quote: | I have noticed that some Luxeons have isolated heatsinking and some do
not. If the datasheet does not say anything in this area about a
particular part number, assume that the manufacturer reserves the right to
change that characteristic of that part number and be prepared for the
worst.
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There may be different production lines or an old batch may appear on
the market, indeed.
Thomas |
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Ian Stirling
Guest
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| Posted:
Fri Jan 21, 2005 5:08 pm Post subject:
Re: Luxeon emitters |
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In sci.engr.lighting R.Lewis <h.lewis@connect-2.co.uk> wrote:
| Quote: | Once upon a time the heatsinking 'slug' on the Luxeon emitters was not
electrically isolated from somewhere/something dark and secret within its
'innards and the datasheet/appnotes informed of this fact - detailing that
the slugs must be electrically isolated from each other .
Recently I have noticed that the slugs appear to be electrically isolated
from the anode and cathode connections although I can find no Lumileds
reference to this fact.
Anyone know anything about this?
|
Posted this before, it does not seem to havge appeared.
The LED chip is glued onto the copper slug.
If they change from conductive-non-conductive glue, or the chip sits slightly
skew, with one corner touching the mount through the glue, it could be
conductive. |
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LEDlights
Guest
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| Posted:
Wed Feb 09, 2005 10:07 pm Post subject:
Re: Luxeon emitters |
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The slug is electrically connected to the substrate comprising 2
inverse series zener diodes, this explains why you cannot measure with
an ohm meter. See the Lumileds document RD25.pdf
http://www.lumileds.com/pdfs/RD25.PDF
Each zener may be in the range of 5v - 10v so it will not usually show
a problem in low voltage applications.
Pat |
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