Quote Originally Posted by Bill Burk View Post
Check out Post #36 of this thread for a good choice color temperature for meter calibration...

http://www.apug.org/forums/forum37/1...g-match-4.html
Thanks Bill. According to Stephen in that thread the color temperature for the calibration light source changes from 2800K to 4700K in 1960. That's fine. So an LED with white LED would be a good choice. The color temperature has to be significantly off for the meter to read differently. Now I think the LED doesn't change color temperature as you dim it down. How would I dim the LED. There is current control and then pulse modulated technique. Something for me to work on...