For TT and those interested in alternate energy, a link you may not know.

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**I've read four paragraphs, so far and found these two gems:
"...that in the near future, white LED lighting applications will be powerful and cheap enough to replace incandescent lighting for everyday use in our homes, in street lights, outdoor signs, and offices."
How far away is this "near future"? 5 years, 10 years, 100 years. Talk about bullshit.
"When designed properly, an LED circuit will approach 80% efficiency, which means 80% of the electrical energy is converted to light energy."
Where are these 80% efficient LEDs?
The guy who wrote this nonsense has no clue.
--
Trevor Wilson
www.rageaudio.com.au
Reply to
Trevor Wilson
and the datasheet supports your statement. The InGaN super white lamp datasheet
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gives:
theta = 15 degrees so w = 0.214 Steradians
I = 10Cd
Phi = I*w = 2.14 lm
at 555nm, 1W = 685lm, so 685lm/W (relative luminosity curve, Optics 10th ed., Freeman, p.330)
luckily they spec wavelength as x,y coordinates in a color space, and I'm too lazy to figure out the relvant wavelength(s), but an optimistic answer is to pick 555nm, relative luminosity plummets on eother side of this.
2.14lm/685lm/W = 3.13mW @ Vf = 3.3V, If = 20mA.
Hang on a minute, thats Pin = 66mW, but we get 3.13mW of visible light.
n = 3.13mW/66mW = 4.7%
pigs arse thats 80% efficient.
I'm picking I'd need to look at the spectral output, and integrate over that spectrum to get the true optical output power, but there aint no way its gonna go up by a factor of 20.
and the 100,000 hours is equally laughable. Arrhenius gets in the way, and buggers LEDs at high currents/temperatures. Anyone who has ever designed an optocouple circuit into a long-life application will know how much LEDs degrade over time, and that high lifetime only occurs at low temperatures and low If.
Cheers Terry
Reply to
Terry Given
powerful and cheap enough to replace incandescent lighting for everyday use in our homes, in street lights, outdoor signs, and offices."
Talk about bullshit.
which means 80% of the electrical energy is converted to light energy."
and the datasheet supports your statement. The InGaN super white lamp datasheet
formatting link

gives:
theta = 15 degrees so w = 0.214 Steradians
I = 10Cd
Phi = I*w = 2.14 lm
at 555nm, 1W = 685lm, so 685lm/W (relative luminosity curve, Optics 10th ed., Freeman, p.330)
luckily they spec wavelength as x,y coordinates in a color space, and I'm too lazy to figure out the relvant wavelength(s), but an optimistic answer is to pick 555nm, relative luminosity plummets on eother side of this.
2.14lm/685lm/W = 3.13mW @ Vf = 3.3V, If = 20mA.
Hang on a minute, thats Pin = 66mW, but we get 3.13mW of visible light.
n = 3.13mW/66mW = 4.7%
pigs arse thats 80% efficient.
I'm picking I'd need to look at the spectral output, and integrate over that spectrum to get the true optical output power, but there aint no way its gonna go up by a factor of 20.
and the 100,000 hours is equally laughable. Arrhenius gets in the way, and buggers LEDs at high currents/temperatures. Anyone who has ever designed an optocouple circuit into a long-life application will know how much LEDs degrade over time, and that high lifetime only occurs at low temperatures and low If.
Cheers Terry
Hi, is there a chart that shown power eff% for white light, for all the common forms of lighting? also how do you work this out for sodium vapour types, where the spectra is "monochromatic" orange, and not green?
Reply to
Ed /:-}
Hi Ed,
see if you can dig up a copy of this:
Lamps and Lighting, 2nd ed. SI Units The Staff of Thorn Lighting ed. S.T. Henderson, A.M. Marsden pub. Edward Arnold ISBN 0-7131-3267-1
Cheers Terry
Reply to
Terry Given
?????????!!!
Huh? Why pick on me?
TT
Reply to
TT
Sorry, I thought you were talking about installing a solar electrical system recently. I guess I have become mixed up as to who started the post.
Reply to
APR
That's OK :-)
BTW in my share portfolio I do actually have a Solar Energy Co
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so I am actually trying to do my bit for the planet already.
So if anyone is actually going to do this
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there are already products out there.
Cheers TT
electrical system
the post.
Reply to
TT
Yeah, but unfortunately the grid-feed inverters are ridiculously expensive, the solar cells are still ridiculously expensive, and to claim any government eco re-bate scheme you have to have some "accredited" solar dude install it all for you. Sucks big time. I have AGL "Green Power" instead, doesn't cost any extra, and it's 100% renewable power (including solar).
National Solar House Day is on 11th Sep:
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Well worth visiting.
Dave :)
Reply to
David L. Jones

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