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Discussion Starter #1
I've heard these mentioned but could somebody here tell me a bit more about them. What is the difference between warm ones and regular white? Who makes em? Know any part numbers? Where can I get some?

Thanks in advance.

Regards,
Matt
 

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The 'warm' is the frequency of the light the led emits.

'Standard white' leds have a heavy blue component to them. This most readily shows up in photographs, but is not so easy to spot with our eyes. Human eyes show the brain what's going on, but the brain has it's own narrative going. It sees what should be white and tells you it's white, even if it's not. So, a lot of model pictures with white leds in them look white in person, but the photos posted here they look tinged blue. Any photos of warm white leds look like the white you would expect to see in person. (This is why digital cameras have to be 'white balanced' Film stock is pre-balanced for prevailing conditions the particular stock is expected to be used in.)

As a further example, consider fluorescent lights. They 'look' white when you are in the room with them, but really they are very green. And that is only really obvious when directly compared to another light source, such as a nearby room with incandescent light bulbs -which look very orange. But standing in either room with no other light sources, things look 'white'.

So too, with white leds. Warm whites refer to the spectrum. They tend to be on the 'orange' side compared to standard whites which tend to be on the blue side. I recently came across some 'warm' whites that were actually closer to a cool green.

At $10 shipped for 100 leds of most any color, I get all my leds and resistors off ebay. Usually Asian sellers, but there are some here in the States. Warm whites tend to be closer to .20¢ ea instead of .10¢, but well worth the price! Just search "100 pack leds" and you'll find them easy enough. Go to a place like radioshack and you'll pay many dollars for a single led. Forget that noise!

Actually, for a most excellent primer on light, skim this page over.
http://micro.magnet.fsu.edu/primer/lightandcolor/lightsourcesintro.html


This page gives a nice and easy overview of light sources and even some history and is the source of the image above. In this graphic, you can see the blue spike in the white led that gets lumpy back into the yellow and tails off into red. A warm white led would have a spike in the orange and tail off into the blue.

Also note that smooth bell curve our 'noon sun' has which nearly flatlines across blue to orange. In the evening, the atmosphere weights it orange and the dawn hours, the light weights blue. But noon sun is what we see/interpret as 'true' white. The functional definition of 'true' white is different of course and would be a strictly flat line going across all visible spectra.

If Sol was a blue giant, or any other class of star, our interpreted white would be much different, perhaps close to that curve the tungsten lamp has. If we then visited Earth, our subjective definition of white would be much different than the local primitives have.

What it all comes down to is that light is utterly funky stuff and truly magical in the wonderous sense of the word!
 

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I've heard these mentioned but could somebody here tell me a bit more about them. What is the difference between warm ones and regular white? Who makes em? Know any part numbers? Where can I get some?

Thanks in advance.

Regards,
Matt
If you need warm white leds in 5-3mm size we stock them. Call or drop us a email @ [email protected].

Thanks!
Randy Neubert
www.voodoofx.com
 

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Discussion Starter #5
The 'warm' is the frequency of the light the led emits.

Thanks for the very detailed explanation MMTom. I found a source of warm leds and that helps me move forward with my project.

Also, I work with an electrical engineering consultant who provided the following information about a new type of LED technology. It would enable fine tuning the color spectrum for a given lighting application:

http://spectrum.ieee.org/semiconductors/optoelectronics/quantum-dots-enhance-led-lighting

Regards,
MattL
 

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The 'warm' is the frequency of the light the led emits.

Thanks for the very detailed explanation MMTom. I found a source of warm leds and that helps me move forward with my project.

Also, I work with an electrical engineering consultant who provided the following information about a new type of LED technology. It would enable fine tuning the color spectrum for a given lighting application:

http://spectrum.ieee.org/semiconductors/optoelectronics/quantum-dots-enhance-led-lighting

Regards,
MattL
Hello Matt, Looks like you got it under control. Thanks for the info about the new led tech!
 
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