Hi! On Thu, Feb 4, 2010 at 9:12 PM, Jake Anderson wrote: > Chris McSweeny wrote: >> On Thu, Feb 4, 2010 at 8:21 PM, M. Adam Davis wrote: >> >>> Further, Lumens specifically measures light output *as perceived by >>> the human eye*. =A0By pulsing the LED at higher than rated current, "the >>> human eye" may perceive significantly more light than running the LED >>> at its DC rating. >>> >> Actually no, it doesn't work like that. If you pulse an LED, the >> perceived brightness will be the brightness if it was on the whole >> time multiplied by the duty cycle. There is no magic to pulsing with >> LEDs. >> > http://www.ledsmagazine.com/news/5/5/11 Interesting research, but wrong conclusion :-) , you can download the pape= r at: http://www.jstage.jst.go.jp/article/jlve/32/2/32_161/_article If you see graphs from 7 to 18, the actual perception versus power applied = at the blue and green LEDs are smaller with pulsed light. This is because the LEDs are a lot less efficient at higher currents. Daniel. -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist