Of course, I still think their spiky spectrum stinks. This usually translates into a poor CRI (Color Rendering Index) - although lately the CRI's seem to be getting better, but I'm not seeing the correlation to good, even, spread spectrum light like incandescents or tungsten, etc... Stuff with spiky phosphors to achieve a color temperature always look crappy to me. It's not just the color of the light - it's how well it emits all the wavelengths and how smooth that emission is...
Most LED lights make skin color look awful. Have your wife dress in LED lights, and then go outside and see if she still thinks the colors coordinate. It's not your (or her) imagination. There is science in there that explains it.
Um... you're confused... at 2800K, stainless steel is melted (almost at the boiling point of iron, actually). That's pretty hot.
You're thinking of Correlated Color Temperature. When people say that the light is 2800K or 5600K daylight or standard D65 or 6500K daylight, they are saying that the light's color is the same hue as that of an ideal black body radiator at that temperature. The "black body curve" on the standard CIE 1932 color charts that you commonly see is the hue that you get from a black body radiator at those temperatures... not the actual temperature of the light source you're describing.
Your monitor is usually peaked up to something like 9500K by default. That certainly doesn't mean that it's actual temp is 9500K... it would burn through your desk just before it explodes into a gaseous mess at that temp! ;-)
Nah, we are out there. I love dimmers. I use them constantly to adjust ambient light depending on my need or mood.
For this reason I still prefer incandescents and it really bothers me that some nanny-staters can limit my choices. That should bother you all too, much more than poor efficiency.
I've never used dimmers, not even for incandescent lamps (I only use CFLs now). I've never found the dimming function necessary. I should think that 99% of all light fixtures are not connected to dimmers, so this is a niche market.
Just use LED bulbs: 12.5W, lower TCO, 22.8 years, 2700K color temperature, no hazardous disposal, not subject to price hikes from China cornering the rare earth phosphors market, and, oh yeah, dimmable. I really like the DOE prize wining Philips AmbientLED lights at Home Depot or Amazon.
Tom does not mention the 120VAC input to the CFL. Current distortion is around 114% TDD, just a current spike. Power factor is 0.61. I cannot wait until all of Washington DC is on CFLs, electronic ballasts, computer switching power supplys and VFDs.
KNME distributed free cfls at the Magdelena Ridge Observatory, NM on Saturday June 27, 2009.
See practical comparison of cfl and incandescent photographed performance.
I have to note I bought some three way CFL bulbs from GE a few years ago. They must have the stupidest engineers/testers/marketers.
Instead of the normal low/medium/high of an incandescent bulb it goes low/high/medium.
Blog Doing Math in FPGAs Tom Burke 15 comments For a recent project, I explored doing "real" (that is, non-integer) math on a Spartan 3 FPGA. FPGAs, by their nature, do integer math. That is, there's no floating-point ...