Color changing LEDs
mister_...@the-newzgroups.com
they were all white (blueish white). Lately I see them where they
change color. Yet, they only have one LED. How can a LED change
color? I thought the color was determined by dopeing it with a metal.
So how can they change? This has me puzzled.
D Yuniskis
How do you *know* it is "one LED"? I suspect it is a "bicolor"
LED (almost a sure bet if it has more than two leads -- still
possible even with just *two*).
You might want to notice the ranges of colors and consider
what color *mixes* could make them (e.g., red + green LEDs in
the same package will yield yellow-ish -- plus variations from
red *to* green depending on the mixing rates)
Phil Allison
<mister_...@the-newzgroups.com>
>I keep seeing these little solar power sidewalk lights. Last year
> they were all white (blueish white). Lately I see them where they
> change color. Yet, they only have one LED. How can a LED change
> color?
** Bi-colour LEDS like this have been around for 30 years.
http://www.effled.com/images/products/bicolor-led/throughhole-led/3mm_Bin_Color_LED_RG.jpg
... Phil
Cydrome Leader
> On Thu, 06 May 2010 01:20:36 -0500,
> mister_...@the-newzgroups.comwrote:
> polarity and you switch on the other LED.
this probably has nothing to do with bicolor LEDs. Who the hell would make
a red/green sidewalk light anyways?
Anyways, white LEDs are sort of like flourescent lights. They junction
makes bright blue light and there is a phosphor that then converts this
into "white". Quite a bit of the blue leaks out.
The quality of white can vary (and does so more with cheap LEDs) in
addition to the phosphor actually aging.
so a visible color change from a cheap white LED isn't all that
surprising.
D Yuniskis
> Meat Plow <mhy...@yahoo.com> wrote:
>> On Thu, 06 May 2010 01:20:36 -0500,
>> mister_...@the-newzgroups.comwrote:
>>
>>> I keep seeing these little solar power sidewalk lights. Last year
>>> they were all white (blueish white). Lately I see them where they
>>> change color. Yet, they only have one LED. How can a LED change
>>> color? I thought the color was determined by dopeing it with a metal.
>>> So how can they change? This has me puzzled.
>> Bi-color LED have two LED inside with a common cathode. Change the
>> polarity and you switch on the other LED.
>
> this probably has nothing to do with bicolor LEDs. Who the hell would make
> a red/green sidewalk light anyways?
http://www.pentairpool.com/pdfs/IntelliBriteLEDLandscapeOM.pdf
Andrew Rossmann
mister_...@the-newzgroups.com says...
It could be the plastic windows on those cheap things turning yellow?
--
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Phil Allison
"Meat Plow"
>
> The OP asked how an LED can change color and I gave an answer. You got a
> problem with that? And most white light LEDs are made from yellow and
> purple junctions and are not in the least like a fucking fluorescent
> light.
** Fraid that is simply not true.
Nearly ALL high intensity / high efficiency white LEDs are made using
phosphors that convert blue or purple light to yellow.
.... Phil
Spamm Trappe
>
> Well then I am uninformed on newer technology ...
Says it all.
Cydrome Leader
> problem with that? And most white light LEDs are made from yellow and
> purple junctions and are not in the least like a fucking fluorescent
> light.
yeah, that's it. taking one color and using it to excite a phosphor to
emit another color is nothing like a flourescent light at all.
you called me, cree and nichia on our conspiracy.
So tell me, what's the forward drop on an LED with "yellow" and "purple"
junctions again, and how are the wired again?
asdf
They could be RGB leds. These devices, now very cheap on ebay, are
externally identical to an ordinary two pin led though they contain three
emitting diodes in the same package plus a small circuit that flashes
each of them independently.
http://www.youtube.com/watch?v=PPtg4mFC_-k
Cydrome Leader
> anything, fuckk off.
Maybe you should take your yellow and purple LEDs and leave if you don't
like it here.
Meat Plow
> Maybe[SLAP]
Maybe you should learn what the words fuck off mean?
Cydrome Leader
why don't you come teach me?
sparky
> Meat Plow <mhyw...@yahoo.com> wrote:
> > On Tue, 11 May 2010 17:07:56 +0000, Cydrome Leader wrote:
>
> >>> On Fri, 07 May 2010 22:47:07 +0000, Cydrome Leader wrote:
>
> >>>>> On Thu, 06 May 2010 15:21:52 +0000, Cydrome Leader wrote:
>
You would have to be retrained every day.
Cydrome Leader
> On May 11, 4:01?pm, Cydrome Leader <prese...@MUNGEpanix.com> wrote:
>> Meat Plow <mhyw...@yahoo.com> wrote:
>> > On Tue, 11 May 2010 17:07:56 +0000, Cydrome Leader wrote:
>>
>> >> Meat Plow <mhyw...@yahoo.com> wrote:
>> >>> On Fri, 07 May 2010 22:47:07 +0000, Cydrome Leader wrote:
>>
>> >>>> Meat Plow <mhyw...@yahoo.com> wrote:
>> >>>>> On Thu, 06 May 2010 15:21:52 +0000, Cydrome Leader wrote:
>>
>> >>>>>> Meat Plow <mhyw...@yahoo.com> wrote:
>> >>>>>>> On Thu, 06 May 2010 01:20:36 -0500,
>> >>>>>>> mister_frien...@the-newzgroups.comwrote:
>>
>> >>>>>>>>they were all white (blueish white). ?Lately I see them where they
>> >>>>>>>>change color. ?Yet, they only have one LED. ?How can a LED change
>> >>>>>>>>color? ?I thought the color was determined by dopeing it with a
>> >>>>>>>>metal. So how can they change? ?This has me puzzled.
you and your boyfriend should be able to handle that.
Meat Plow
> why[SLAP]
looks like I had you read like a dime store novel. Now you're gunna get
all tough guy on me huh? You and a million other fuckstains like you.
heh
Cydrome Leader
Are you sure you can even read a dime store novel? You seem to have having
problems replying to my posts here.
Meat Plow
> Are[SLAP]
As if by MAGIC you prove my point.
heh