Author Topic: Yellow LEDs ?  (Read 1164 times)
wide-lite 1000
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Yellow LEDs ? « on: April 23, 2023, 06:34:42 PM » Author: wide-lite 1000
 With all if the discussions about the purple LEDs lately I figured I mention something I've seen alot lately , lemon yellow LEDs !  My doctor's office has some : https://www.lighting-gallery.net/gallery/displayimage.php?album=5209&pos=20&pid=163547 And last night when I went out for dinner , a significant amount of the 2,700k LEDs in the restuarant were also the same lemon yellow color .  WHY ???  :wndr:
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BT25
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Re: Yellow LEDs ? « Reply #1 on: April 23, 2023, 06:45:56 PM » Author: BT25
This usually happens due to inadequate thermal management, therefore the phosphor coating on the blue LED's degrades quickly.
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wide-lite 1000
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Re: Yellow LEDs ? « Reply #2 on: April 23, 2023, 06:57:02 PM » Author: wide-lite 1000
I'm seeing the yellow ones WAY more than purple and only in 120v commercial settings . THe purple color atleast looks kinda cool , the yellow is just sickening !  :sick:
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BT25
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Re: Yellow LEDs ? « Reply #3 on: April 23, 2023, 07:43:04 PM » Author: BT25
The utility that serves my area has installed 3000K LED cobra's...as they age, they're shifting to around 2500K...they're starting to look like an under driven incandescent. ::)
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wide-lite 1000
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Re: Yellow LEDs ? « Reply #4 on: April 23, 2023, 07:48:23 PM » Author: wide-lite 1000
 That would look better than these things ! They look like  a 5,000k LED behind an yellow lens !
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BT25
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Re: Yellow LEDs ? « Reply #5 on: April 23, 2023, 07:50:23 PM » Author: BT25
Yeah, that would look awful... :sick:
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fluorescent lover 40
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Re: Yellow LEDs ? « Reply #6 on: April 23, 2023, 07:53:12 PM » Author: fluorescent lover 40
So far the only LEDs I've seen turn yellow are the Leotek E-Cobras, Cooper Navions, and Cooper Galleons. I haven't seen a LED lamp do it yet.

I'm not sure on the reason.
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wide-lite 1000
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Re: Yellow LEDs ? « Reply #7 on: April 23, 2023, 07:53:22 PM » Author: wide-lite 1000
Too bad my camera won't show an acurate depiction !
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joseph_125
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Re: Yellow LEDs ? « Reply #8 on: April 23, 2023, 08:27:13 PM » Author: joseph_125
Interesting, I'll have to keep an eye out for this failure mode.
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dor123
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Re: Yellow LEDs ? « Reply #9 on: April 24, 2023, 02:05:08 AM » Author: dor123
I've seen yellowish LED like this brand new:
1. https://www.lighting-gallery.net/gallery/displayimage.php?pos=-182011
2. https://www.lighting-gallery.net/gallery/displayimage.php?pos=-125849
I've also seen yellowish LED because of EOL:
1. https://www.lighting-gallery.net/gallery/displayimage.php?pos=-112463
2. https://www.lighting-gallery.net/gallery/displayimage.php?pos=-222184
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Medved
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Re: Yellow LEDs ? « Reply #10 on: April 24, 2023, 02:22:37 AM » Author: Medved
This usually happens due to inadequate thermal management, therefore the phosphor coating on the blue LED's degrades quickly.

I would not say the phosphor itself, but the material covering it, to me it looks like it had browned out from heat and intensive blue exposure, so starts blocking the direct blue light from the LED die.
In any case it is a questionable design indeed.
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HomeBrewLamps
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SodiumVapor 105843202020668111118 UCpGClK_9OH8N4QkD1fp-jNw majorpayne1226 187567902@N04/
Re: Yellow LEDs ? « Reply #11 on: April 27, 2023, 08:13:09 AM » Author: HomeBrewLamps
Good.

Yellow and purple are way more interesting than bland white. I say let more fail!
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