LED brightness spectrum

Matty1973 · Post by **Matty1973** » Thu Jun 30, 2011 10:54 am

Hey sparkies, most "white" LED's I have been using have a blue tinge to them, are there any that are less bright and have less blue to them?

More like an incandescent light globe colour?

robiwon · Post by **robiwon** » Thu Jun 30, 2011 11:18 am

Search for "warm white" LEDs. They have more of a yellow tinge to them similiar to incandescents.

Matty1973 · Post by **Matty1973** » Thu Jun 30, 2011 7:55 pm

Ok so I searched warm white led via eBay, and found many but with varying mcd from 4000 to 16000, what's the difference?

USS Atlantis · Post by **USS Atlantis** » Thu Jun 30, 2011 8:08 pm

mcd is the amount of light it puts out

1mcd = 1/1000 candala

Candala is the SI unit of luminous intensity - similar to but different than Lumens (the unit you see on light bulbs)

Candala measures intensity from one arc, not all around as Lumens do

Example - a 25w CFL bulb puts out about 1700 Lumens - looked at it from a single direction, that's about 135cd, if all those Lumens were focused into a 20 degree beam, then it would be around 18,000cd

Now LEDs run 50mcd (.05cd) to 18,000mcd (18cd) - doesn't sound like much, but the wavelengths that Whites and Blues operate on are particularly intense to the eye - so no looking directly into them please

DLMatthys · Post by **DLMatthys** » Mon Jul 04, 2011 11:13 am

It means that 16000mcl is 4 times brighter than 4000mcl
It is better to poke around at DigiKey about LEDs rather than on the E-Bays.
You can look on each specific LED spec sheet... Most are PDFs
Those varieties are in the thousands.