0

LED brightness
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

LED brightness

by rmfritz3 on Sat Sep 07, 2019 4:05 pm

I'm looking at the light output of LEDs available from Adafruit, and I can only find numbers in millicandelas, which is light output in a particular direction; are values in lumens available?

rmfritz3
 
Posts: 5
Joined: Wed Mar 14, 2018 5:12 am

Re: LED brightness

by adafruit_support_bill on Sun Sep 08, 2019 7:05 am

Since most of the LEDs in the store are designed for indication or display purposes rather than illumination, there is no manufacturer spec for Lumens.

The conversion to lumens depends on the radiation pattern of the LED. The general formula is 1 lumen = 1 candela per steradian,
If you take a typical clear LED with a 20 degree beam, that translates to 0.095 steradians. So if the led is rated for 1000mcd, (1cd) it will put out 0.095 lumens in that cone.

adafruit_support_bill
 
Posts: 74965
Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.