On Sat, Jul 5, 2014 at 12:18 AM, Bob Blick wrote: > My refrigerator has been set to 4F (freezer) and 38F (refrigerator) > since it was new, about 5 years ago. Last night I changed the > refrigerator to 40 and immediately noticed that one segment of the > display was considerably brighter than the others. That segment was one > that hadn't been lit for 5 years. > Bob, we irradiating plants in microwaves using anechoic chambers. Since are closed chambers, the light comes from LED spots (27 warm SMD warm LEDs at 3000K, 4W/12V per spot). Experiments took from one week to couple of months. (One type of experiment with coloured LEDs is here: http://www.itim-cj.ro/~vasile/T1_SurducanV.pdf)= .. I'm measuring the light intensity using a professional luxmeter. Usually in the first week, the light intensity is decreasing with 200 to 400lux from an initial value of 3000lux measured at 30cm distance to the spot. So, I think your blue LED behaviour is absolutely normal after 5 years. Vasile --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .