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Archive 1

Not notable?

Now it seems to be the case that whatever happens outside USA or Canada, is not notable. I suggest that this "english" Wikipedia should be renamed "U.S." Wikipedia. —Preceding unsigned comment added by 84.206.43.2 (talk) 07:02, 5 July 2010 (UTC)

No. The scale of the event is important, not its location. Materialscientist (talk) 07:07, 5 July 2010 (UTC)

Especially if the american part of the world is seen through a magnifying glass? —Preceding unsigned comment added by 84.206.43.2 (talk) 08:05, 6 July 2010 (UTC)

I suggest using the section heading "pioneering uses" for large or innovative projects. This way only very large, very early or very interesting uses will be included as notable, wherever they are located. "Current uses" is not a good heading because being current is not the same as being notable.--Thorseth (talk) 14:22, 6 July 2010 (UTC)

The critical question is, who is going to judge on the notability of an addition to a Wikipedia article. If the power to judge on the Wikipedia contents is limited to only a small group, the whole project may finally collapse. — Preceding unsigned comment added by 84.206.43.2 (talk) 13:57, 24 August 2011 (UTC)

Big Mess

I stumbled on this article the other day, the disclaimers at the top are not joking, it's a pretty big mess. I'm going to do some cleanup. I've fixed some grammar / clarity things. Now it's time to remove all of the information that is elsewhere in wikipedia, we don't need a zillion copies of charts and conversions.

It also needs to be severely updated to reflect the current state of the technology. —Preceding unsigned comment added by 142.166.56.95 (talk) 19:53, 31 July 2008 (UTC)

Thanks for the warning (you don't have to), maybe you can combine the action with the shovel action on the left Light-emitting diode. Cheers Mion (talk) 13:10, 1 August 2008 (UTC)

There is also heavy use of 'current' and 'currently' and references to examples with no indication of time of writing. This is a fast moving area and several comments are already well out of date (15 January 2010) —Preceding unsigned comment added by Nickhoare (talk • contribs) 10:05, 15 January 2010 (UTC)

LED Lamp?

Sorry to split hairs but 'LED Lamp' IMO used to mean the LED itself (as used as a status indicator for example). This Wiki entry refers to LEDs used as compact solid-state light sources - 'luminaires'? Which are usually made up of clusters of individual LED lamps. 81.86.144.210 18:54, 14 June 2007 (UTC)

Within lighting engineering/design, "lamp" is the common term for "bulb" (and "luminaire" or "fixture" is the term for "lamp," as in "table lamp"). The individual LED can be referred to as a "device," which is incorporated in the ANSI/IESNA definition of LED. [1] Rdlpdx (talk) 22:36, 16 October 2009 (UTC)

disputed?

Why the disputed tag? Someone put it in the article, but there is no actual discussion about it. 129.130.48.10 -

Environmental Concerns

Compact fluorescent lamps cannot be thrown away like regular Incandescent light bulbs when they extinguish or break because of the mercury in CFLs. What are the environmental hazards of SSLs? Can they be thrown away? Can they be recycled? If they break (I know they are harder to break), can they be vacuumed up? -57.67.16.50 13:41, 20 April 2007 (UTC)

Well, the BEST way to recycle an SSL would be to salvage the LEDs -- most would still be usable, even if at reduced efficiency/light output (if the SSL has been on tens of thousands of hours) -- and use them for other things (indicators etc rather than primary lighting).-69.87.200.219 00:25, 11 May 2007 (UTC)

Yes - I agree completely. CFLs usually cost a few dollars each, but an LED bulb may cost ten times that amount. When a CFL fails, it is usually the lamp electrodes which can no longer establish current flow, so unless you are looking for a nice high-voltage capacitor (in the ballast), trash or recycle are the only two options. But LED lamps will likely last nearly forever, unless taken out by a voltage surge. In that case the valuable LEDs could be scavenged and re-used in a variety of interesting ways. LEDs only require a few volts, so they are safe to operate with bare leads. Fluorescent lamps require tens to hundreds of volts, along with an annoying ballast impedance and a high-voltage starting circuit - not ideal for the amateur hobbyist. — Preceding unsigned comment added by 129.55.200.20 (talk) 21:05, 24 September 2012 (UTC)

What are actual field experience with the life of the LED bulb? My experience with CFLs was that they didn't last nearly as long as they were theoretically supposed to. Some of my CFLs failed within a few months. I installed 2 LEDs about four months ago (during cool weather) and they are still shining.

Would someone explain the ultraviolet output of LEDs. On Amazon.com one notation on the LED bulb says "not ultraviolet safe for artwork?" Is there a need to be concerned about ultraviolet especially in regard to skin cancer? I am not indicating I know anything about LEDs and ultraviolet, I am just asking. — Preceding unsigned comment added by 173.57.179.159 (talk) 02:26, 24 February 2013 (UTC)

Economics

Projections and future hopes are nice, but the main practical subject here is the economics, and the reader wants details of current economics. There are pictures of LED lamps. How much do they cost? How much light do they put out? Etc. Other WP articles are now saying that LED is now economic, as general incandescent replacement. We need some place, here or somewhere, that goes into the details.-69.87.204.36 13:56, 27 April 2007 (UTC)

Someone redirect LED lamps to LED lamp please

And leave a note on my User talk:Mattjs page telling me how to do it as I come across this problem quite alot at wikipedia. Regards, Mattjs 17:22, 29 April 2007 (UTC)

Available now

There are special 120VAC LED assemblies now generally commercially available, intended for retrofit in incandescent EXIT signs. Search for 'LED "exit sign" retrofit'. Cost is $5-50 for 1-3 watt assemblies in red, green, or white. Socket adapters available.-69.87.203.202 01:33, 12 May 2007 (UTC)

This source sells LED bulbs for $25-75, as floodlights, 2-12 watts, 30-120 LEDs: Note the flim-flam they engage in to rate them, since LEDs are good for directional lighting, not so good for general illumination:

-69.87.201.141 11:54, 12 May 2007 (UTC)

This source has a dozen various LED lamps with standard bases, 1-5W, up to 120 lumens: And very nice detailed spectral graphs: The prices are here, $10-40: -69.87.203.248 02:14, 16 May 2007 (UTC)


This user recently bought 3 bulbs of 0,3 watt for some € 3,50 each. (They give as much light as former 5 watt bulbs). So the price indication in the article ("$15 – $20 each") will have to be adjusted to the nowadays situation. --VKing (talk) 15:12, 8 May 2010 (UTC)

8-watt Lamina LED bulb

Someone was offended by a discussion-page posting, and removed all mention of this recent product introduction. So, if you are interested, you'll have to read the history for 11may07. Then, if you are really interested, you could try to write it in a way that the censor will leave... (Note: what one person may sincerely believe is "blatant spam", another person may sincerely believe is "just trying to contribute useful, relevant info".)-69.87.201.141 11:48, 12 May 2007 (UTC)

Nightlights

120VAC LED nightlights are now generally available cheap. What are typical lumens/watt? How are they wired/designed/built inside -- do they use bulbs in sockets? How does the light output compare to standard 4W/7W incandescent E12 candelabra nightlight bulbs? What is the lumens/watt for those traditional bulbs?-69.87.204.2 20:56, 15 May 2007 (UTC)

Color Spectrum

All the LED and other lighting articles should include a handy reference sidebar along these lines:

  • Color Spectrum
Red 780 - 622 nm
Orange 622 - 597 nm
Yellow 597 - 577 nm
Green 577 - 492 nm
Blue 492 - 455 nm
Violet 455 - 390 nm

-69.87.203.97 13:10, 20 May 2007 (UTC)

Wavelength-nm Color Name

over 1100 Infrared
770-1100 Longwave NIR
770-700 Shortwave NIR
700-640 Red
640-625 Orange-Red
625-615 Orange
615-600 Amber
600-585 Yellow
585-555 Yellow-Green
555-520 Green
520-480 Blue-Green
480-450 Blue
450-430 Indigo
430-395 Violet
395-320 UV-A
320-280 UV-B
280-100 UV-C

Color Temperature Example

2000° Gaslight
2470° 15 watt incandescent bulb
2565° 60 watt incandescent bulb
2665° 100 watt incandescent bulb
2755° 500 watt incandescent bulb
2900° 500 watt Krypton bulb
3100° Projector type filament bulb
3250° Photo Flood
3400° Halogen
3900° Carbon arc
4200° Moonlight
4700° Industrial smog
5100° Hazy weather
5500° Sun 30° above horizon
6100° Sun 50° above horizon
6700° Electronic Flash
7400° Overcast sky
8300° Foggy weather
30,000° Blue sky

Notes on LEDs -69.87.203.97 15:13, 20 May 2007 (UTC)

Radiation angle

full beam width angle or half

"2Ø1/2 Half intensity angle (deg)"

This is a very confusing subject, that needs explanation. It needs typical graph curves. LED etc beam width seems to be usually speced at full beam width, side-to-side, down to half of peak (central) power. But sometimes it is given as +/-, which seems to maybe be the angle from the central axis to one side? Please help!-69.87.203.97 13:25, 20 May 2007 (UTC)

LED sizes

Size Millimeter

T1 3mm
T1 1/2 4.8mm
T1 3/4 5mm
T2 1/2 8mm
T3 1/4 10mm

(is this the main diameter of the body of the LED?)-69.87.204.47 23:18, 21 May 2007 (UTC)

Yes, it's the diameter of the main body of the lamp in eighths of an inch, so a T1 lamp is 1/8 inch = 0.125" = 3.175mm in diameter.
Atlant 15:52, 22 May 2007 (UTC)

We should probably mention, the standard round LED shape has a flared flange at the base, in addition to the above main diameter (right?). The purpose of this is so the LED can be inserted into a round hole, grommet, etc mounting, from the back, and seated against this flared flange.-69.87.202.34 17:39, 22 May 2007 (UTC)

LED Life Expectancy

"LEDs have a MTBF (mean time between failures) usually in the range of 100,000 to over 1,000,000 hours. This is a long time for continuous operation, considering that a year is 8760 or 8784 hours. In practice, the useful measure of LED lifetime is its half-life; an LED is deemed to have reached the end of its life when the light output falls off to half the original.

When current flows through an LED junction the current flow is not uniform, resulting in small temperature differentials within the chip. These temperature differentials exert stress on the lattice, causing minute cracks to occur. These lattice defects accumulate with use, and reduce the photon conversion efficiency of the chip, thus reducing light output. The attrition rate varies from the LED material, temperature, humidity, and the forward current."
[1] Good intro to various LED tech details.

The Piranha/Super-flux data sheets at Jameco, from MCDelectronics, have good life-testing data sets at the end (see MCDL-1870XX (7.62 MM x 7.62 MM PIRANHA 40° - 40mA 664341.pdf), showing 10% intensity loss in first 1,000 hrs, and at least another 10% loss in the next 10,000 hrs. Additional 5% loss at elevated temps. Seems like most current LEDs may be significantly dim after 50-100,000 hrs! -69.87.204.14 15:04, 22 May 2007 (UTC)

I have seen white LEDs that have dimmed significantly after 2 months of use in a lighting application. The appearance of the yellow phosphor is different after use. I have seen no discussion of the impact the use of phosphors in white LEDs on their operational life compared with LEDs that do not have phosphor. Given that white LEDs are being promoted as a long life alternatives, based on figures like those here, I think more information is needed to a true picture of the life of some types of LEDs. -(someone wrote sometime)

Note: one year of continuous use is approx. 9000 hours.

Color Spectra

We need some photos of prism-separation of LED light.
These are interesting resources:

Although the fancy versions of these instruments can cost thousands of dollars, any prism or diffraction grating can manifest these behaviors, and they are all around us, even the surface of a CD. Edmund Scientific offers a variety of Spectrometers and Spectroscopes in their Light Analysis category for $1-50. They also offer info on:

  • Build Your Own Grating Spectroscope
  • How Diffraction Gratings Work

[2] -69.87.199.97 11:43, 26 May 2007 (UTC)

DIY circuits

What are the best sources of detailed reviews of LED devices?
What are the best forums that discuss LEDs in great detail?
What circuits are used in commercial multi-LED lamps?

What are the best circuits for DIY experimentation?
Some resources:

Posted by Matthew Sun, 26 Feb 2006 LED lighting is becoming increasingly popular in ... household lighting. This article intends to be a comprehensive guide to their advantages, powering them, and creating dimming solutions.

* Why use LED lighting?
* Powering your LEDs with a DC source
* Using an AC source to drive LEDs
* Dimming your LEDs (with PWM)
* Purchasing LEDs
basic circuit discussion

By claude, Posted on Sun Jan 28th, 2007 a tutorial to making factory-made-look-a-like LED bulbs. about converting regular GU4(MR11) halogen bulbs to LED bulbs 12V 22-LED very detailed photos good discussion of line-voltage circuits (non-tech)

By commanda, Section Light Posted on Fri Apr 20th, 2007 constant current sources Extended discussion of circuit theory and practice

By clone477 Posted on Wed Oct 5th, 2005 Anyone design 120V AC LED Lighting?? serious theory/discussion/experience

Find out how to make your own LED spotlight bulbs 12VDC 22-LED Aluminum sheet, superglue, hotmelt good assembly photos

-69.87.203.17 00:04, 28 May 2007 (UTC)

-69.87.201.66 13:22, 29 May 2007 (UTC)

OddOne's White LED Information ("OWLI") - info on homebrewing LED projects, LED news...

-69.87.200.80 00:42, 15 June 2007 (UTC)

you need what kaid of lamp —Preceding unsigned comment added by 116.230.203.149 (talk) 15:41, 5 January 2009 (UTC)

Capacitor AC

The simplest way to drive an LED from line-voltage AC is with a large series resistor, which functions as a current source. Very inefficient, due to power loss in the resistor.

We could also drop line voltage to a low voltage to drive an LED with an AC capacitor. We can calculate power in the capacitor by V x A, but the result is not real watts - the answer is ideally all "imaginary" VA? In the real world, how do we calculate power dissipation in real capacitors used thus: how hot they would get, what would be safe design, etc? For example, if two LEDs are anti-parallel, and you want the total average current through the pair to be 20 mA, from a series capacitor, at 120 VAC, what capacitance is needed, what capacitor types would be appropriate, and would power issues in the capacitor be a concern?-69.87.204.197 13:34, 28 May 2007 (UTC)

This is a question about caps rather than LEDs. The answer is there is zero power dissed in the cap, hence it doesnt get warm. However your expensive LEDs wont last long on such a circuit. Tabby (talk) 04:23, 18 January 2008 (UTC)

This is not a theoretical question. This is a practical question, about a real-world LED circuit. "Zero power" in the cap is the theoretical answer. The real world does not work that way. What is the actual power dissipated in the series cap? And why do you think the LED won't last in such a circuit? It should last fine, if it has proper protective circuit design and cooling. -71.174.180.243 (talk) 02:55, 16 June 2009 (UTC)

AC? fastest way to fry an LED is to run reverse current through it. Due to the high forward voltage of LEDs and the low reverse voltage of highly doped semiconductor, there wiil be enough reverse current, 2 LEDs antiparallel, to affect LED life. --Shjacks45 (talk) 02:10, 8 March 2012 (UTC)

multi-chip LEDs

Multi-chip LEDs are common. About four 20 mA chips are often combined in one four-pin so-called piranha or super-flux package. However, these are usually internally wired in parallel, making good current-sharing hard to achieve, and making them hard to drive directly from line voltage. Series-wired packages seem very rare. But the Osram OSTAR line offers up to six chips in series, for a nominal voltage of 20 V. They do seem very expensive and high-powered.[3]

"They comprise six chips, with the option of a matching lens. The 2 cm x 2 cm high-flux LED with lens provides 410 lm at 2700 K, 460 lm at 3000 K and 520 lm at 4200 K, in each case from an operating current of 700 mA. Their power input is 15 W.[4] -69.87.204.119 01:05, 2 June 2007 (UTC)

Reality

When an article starts comparing non-existent devices that are just figments of an excited imagination praying for more funding to todays products, with no allowance for the future improvements in those too, its time for some serious reality checking. This article as it stands needs to come all the way back down to the ground, to fact. Tabby (talk) 11:49, 6 January 2008 (UTC)

Yes, feel free to start. Mion (talk) 12:12, 6 January 2008 (UTC)

Maybe some time I'll have time to tackle the rest. Remaining sections look in need of relatively hard editing. Tabby (talk) 10:31, 11 January 2008 (UTC)

The thermal problem

"It is currently impossible to replace filament lamps with equivalent LED lights due to thermal considerations. To achieve greater success a new type of LEDs will be needed with either much higher temperature tolerance or much higher efficacy."

This is a key point about LEDs, and one of the 2 main reasons why LED lights dont put out as much light as mains filament lamps.

If you're going to remove something, really you need to give a reason, otherwise its just wasting people's time. Tabby (talk) 20:29, 1 February 2008 (UTC)

I know its news until its in production, so maybe under research ? [5]. Cheers Mion (talk) 16:50, 4 February 2008 (UTC)
Unfortunately I dont understand your comment. Tabby (talk) 12:17, 15 February 2008 (UTC)


Mercury

"In addition, mercury is detrimental to health, and should the lamp break, exposure to the substance can be hazardous."

The average human contains a few grams of mercury. Fl light mercury content varies, but is in the milligram range. Perhaps this is why no government anywhere in the world considers it hazardous. Tabby (talk) 12:17, 15 February 2008 (UTC)

i think the mercury part is about CFL's, it doesn't belong on the LED page, and there is a lengty EPA mercury page [6]. Mion (talk) 18:40, 15 February 2008 (UTC)
One of the key advantages to LEDs are that they avoid Mercury pollution on disposal. As this is an important consideration for Government bodies which manage Landfills and Incinerators, and deserves a note here. A mention of RoHS regulations would also be appropriate.
You seem to mistake Acute (short term) toxicity to Chronic (long term exposure to small amounts). Long term exposure to Mercury affects mental functioning in adults ("mad as a hatter") as well as other less recognized symptoms. Mercury is teratogenic (causes birth defects), most teratogens also being carcinogenic. Its affect on the young is much greater than upon adults. By the way, I've never seen "The average human contains a few grams of mercury." in any biology or medical text. I have several silver-mercury fillings however at the ratio of silver to mercury used in dentistry it isn't "a few grams of mercury" and even then it is in metal alloy form. --Shjacks45 (talk) 02:41, 8 March 2012 (UTC)

Hyper-hype

I removed the following table because it is nothing but wild speculation from a body wishing to assure and maximise its funding.

Bear in mind that both LEDs and fl lighting are improving as years go by, and comparing a wildly optimistic, non-existant, impossible hoped for future light source to today's fluorescent products is hard to regard as realistic in any way.

"The following chart, derived from information from Sandia National Laboratories, compares a perfected SSL device (to be released before 2025) with incandescent and fluorescent lights"

Technology Future solid state lighting Fluorescent Incandescent
Luminous efficacy (lm/W) 200 85 16
Lifetime (kh) >100 10 1
Flux (lm/lamp) 1,500 3,400 1,200
Input power (W/lamp) 7.5 20 75
Lumen cost ($/klm) < 2 1.5 0.4
Lamp cost ($/lamp) <3 5 0.5
Color Rendering Index (CRI) >80 82 95

I put it here because this table surely deserves inserting in wikipedia somewhere, not as a reality based comparison of technologies or products, but rather to illustrate how wildly LEDs are currently being hyped, and to illustrate how people are wililng to swallow just about anything if the right person says it. Tabby (talk) 12:53, 15 February 2008 (UTC)

yes agreed on, but it was speculation in 2001, (the date of the table), it sure needs proper updating, before it goes back. Mion (talk) 18:35, 15 February 2008 (UTC)

If you know of a reason why a piece of wild speculation belongs in a wiki article I'd love to hear it. Re updating, nothing significant in it has changed since 2001, its still the same blue sky it was then. Even basic known facts in the table are wrong, let alone the imaginary stuff. Tabby (talk) 18:55, 21 February 2008 (UTC)

CRI why

"The current generation of LEDs, which employs mostly blue LED chip + yellow phosphor, has a CRI around 70, which is much too low for widespread use in indoor lighting. More research & development is needed to improve this."

The solution has been known for over half a century. It is simply a question of cost cutting with uncompetitive products. Tabby (talk) 13:04, 15 February 2008 (UTC)

I don't think "The current generation of LEDs" "has been known for over half a century". Original "white" LEDs were ultraviolet, white was all phosphor. Now we have high efficiency blue and use yellow and red-orange phosphor fill in. Narrow band blue and broadband yellow orange, absorption/emission of phosphor depends on blue power level. Having worked with tunable Organic Laser Dyes, it is difficult to get reasonable fluorescence of green from blue light. Of course you won't get blue-violet from blue. We got coherent beams by frequency doubling Neodymium (IR) (e.g. LiIO3) and can get low brightness white from red that way, at non-commercial efficiencies. LED emitters are more efficient in pulsed mode (same power but lower duty cycle), many LEDs begin to LASE at higher current levels: the emission band becomes narrower and approach coherency. (Unlike gas tubes like fluorescents where higher currents broaden spectral lines.) IEEE article notes that laser display systems (narrow bandwidth beams) require four colors to make visually acceptable white. Wiki Color_model (CIE) notes that the sensitivity curves of human eye photoreceptors (cone cells) overlap and change at different brightness.--Shjacks45 (talk) 09:08, 8 March 2012 (UTC)

Tech comp.

    • It is hoped future SSL developments may add further advantages, such as higher energy efficiency than existing technologies.

Currently, however, there is no SSL on the market that can be offered as a true replacement for incandescent or fluorescent lamps, despite marketing claims. White LEDs produced today are relatively high cost, making them uncompetitive, and practical LED lamps today are not as bright as traditional lighting due to cost and thermal issues.

However LED technological development continues apace, and it is hoped that future developments in LED technologies may address most of these issues.

Based on a study conducted by the Department of Energy (DOE) and the Optoelectronics Industry Development Association (OIDA), it is speculated that by the year 2025, SSL may well be the preferred method of illumination in homes and offices. Study at Cambridge University, England is puts forward 2012 for the take off of widepsread use of LED lighting.

Up to the last sentence was from 2001, the last sentence isn't referenced and is also mentioned in the bbottom of the article. Mion (talk) 19:05, 15 February 2008 (UTC)

":Up to the last sentence was from 2001"

It isnt, its a recent edit, but so what either way? Its either correct or not, and it is correct. Its also germane, as the average reader comes here with the usual LED marketing hype in their minds, and this addresses it, enabling reader understanding.

Do you have any qualifications in this subject? Tabby (talk) 18:59, 21 February 2008 (UTC)

No such thing as Dimmable Flourescent Lamps?

This simply isn't true as I have used a strip lighting unit which was had a remote control dimmer in an office block I was working in 15 years ago. The unit was made by Philips. Can someone get this verified because I am 110% sure I am right 77.100.16.146 (talk) 04:01, 3 February 2009 (UTC)

I don't see the article claiming there are no dimmable fluorescent lamps; there is "Full dimmability – unlike fluorescent lamps...", which is true - dimmable fluorescent lamps cut off completely when dimmed to a certain point, and "Most fluorescent luminaires are not compatible with dimmers", which is also true. —EqualRights (talk) 13:45, 3 February 2009 (UTC)
Leds have a negative resistance power profile (like gas tube florescent) hence use of power wasting resistive ballast (easily dimmed by changing power conduction angle on AC) or use of an electronic current limiting circuit (ballast) using switching power supply technology (also used in some fluorescent ballast)(hard to dim because the circuitry automatically adapts to input power changes). --Shjacks45 (talk) 00:19, 8 March 2012 (UTC)

LED lamp and Light-emitting diode overlap a whole lot

This article and the Light-emitting diode articles overlap a whole lot. My best guess is that this article is supposed to cover replaceable lightbulbs where the light is generated by LEDs rather than incandescence or fluorescence. If that is true, then many of its sections should either be moved to the light-emitting diode article, or just deleted. Examples include:

  • All of the History section, except for the last paragraph on Sentry Equipment Corporation lighting its factory (although that may merit removal for other reasons)
  • All of the "Technology overview" section on how individual LEDs are manufactured so they output different colors (i.e. half of the section)
  • Most of the "Driving LEDs" section, except for the information on powering from the mains (i.e. 3/4 of the section)
  • Most of the "Research and development" section, except for the final paragraph on the new Cambridge University bulb (i.e. about 2/3 of the section)

That would cut this article's size approximately in half.

I'd do this myself, but the surgery would be drastic, and I'd rather get some feedback before I do so. If my assumption about the purpose of this article is incorrect, please let me know exactly what this article is supposed to cover, and why it needs to be separate from the light-emitting diode article. -- Dan Griscom (talk) 22:50, 22 February 2009 (UTC)

Please clean this article up.. started moving some refs inline, then stopped after seeing your comment. gioto (talk) 14:14, 25 February 2009 (UTC)
OK, I've done a broad pruning and rearrangement, cutting about 1/3 of the article. What remains is pretty good, although of uneven quality (e.g. the Comparison to other lighting technologies section is seriously confused). There's a lot of tweaking to be done: tweak away. -- Dan Griscom (talk) 01:50, 28 February 2009 (UTC)

There are 23 different LED-related pages, and I think there should be less than half that many. I've started a discussion on this at Talk:Light-emitting_diode#An_absurd_number_of_articles_involving_light-emitting_diodes; please come and join in. -- Dan Griscom (talk) 03:09, 3 March 2009 (UTC)

Geobulb merge

I've merged in the geobulb article and developed the section on the LED light bulb. This a product of my recent adventures researching the LED bulb replacements. I've decided that at the moment such bulbs are a little too dim and a little too costly for my normal household use. I hope this will change in the next year or two. I will leave it to others to check that the merge is o.k. and to redirect the Geobulb page. Bdushaw (talk) 01:18, 7 February 2010 (UTC)

weirdness in geobulb-section

The geobulb-section claims that:

This lamp was reported to be the most efficient LED light bulb on the market at the time of its introduction. This bulb was never commercially available, however

Which is confusing: How can you be the most efficient on the market, if you're not actually on the market? "not comercially available" means it wasn't actually possible to buy the bulb, right ? How can one claim that a device which one cannot actually buy, is nevertheless "on the market" ? What market would that be, precisely ? --Eivind Kjørstad (talk) 12:44, 11 February 2010 (UTC)

I pasted this in from the geobulb article which has been merged here, together with elements of geobulb from this article (mashed together). I don't know what that means either - I was trying to preserve the intent/content of the article in the transfer. But now we can take a look at meaning and whether things are referenced properly. I hazard to suggest that both of these sentences should just be deleted, unless a reference can be found for them; I've worked on this section to be sure, but I am nervous about deleting such things - happy to go with a consensus. (I could also have just screwed it up...check the geobulb article for the original source) Bdushaw (talk) 13:11, 11 February 2010 (UTC)

LED Tube Light

Now the LED Tube Light is now available cheap from China. The typical lumens/watt is 90-100lumens. For the T8/T10/T12 tube light, the base type is G13, it can directly replace the coventional fluorescnet tubes and without ballast and starter. The brightness of 20W LED Tube is equivalent to 40W fluorescent tubes, it can save energy at least 56%. —Preceding unsigned comment added by Cimoonled (talk • contribs) 07:59, 24 May 2010 (UTC)

Comparison to other lighting technologies

Added to this section can be the fact, that LED is not just essentially more environment friendly (because of it's much lower energy use), but also more nature friendly; for when being used, LED lamps don't get hot, like other kinds of lamps, but stay perfectly cold, so that insects, that are attracted by the light, aren't killed any more by the heat, when touching the glass. --VKing (talk) 03:16, 27 May 2010 (UTC)

Unless you have a reliable source coming to that conclusion, that's synthesis. - SummerPhD (talk) 02:15, 29 May 2010 (UTC)


Sorry, but bugs crash into my computer monitor too, it isn't just incandescentsBolegash (talk) 23:07, 22 December 2011 (UTC)

LED light bulbs

"As of 2010, only a few LED light bulb options are available as replacements for the ordinary household incandescent or compact fluorescent light bulb. One drawback of the existing LED bulbs is that they offer limited brightness, with the brightest bulbs equivalent to a 45-60 W incandescent bulb"

Proposition to replace these sentences by:

"As of 2010, many LED light bulb options are available as replacements for the ordinary household incandescent or compact fluorescent light bulb from 5 up to 40 Watt, only a few for the ones between 40 and 60 Watt and as good as none for the ones above 60 Watt. LED bulbs of among others 0,3 , 0,5 , 1 , 1,2 , 1,6 , 2 , 3 , 4 and 5 Watt are available as equivalents of more traditional ones of 5, 10, 15, 20, 25, 30 and 40 Watt." VKing (talk) 03:17, 10 June 2010 (UTC)

LED lights can blow up

I tried LED 12volt halogen replacement bulbs "MR16", after a few minutes they flickered and one exploded (blowing the face plate of leds off the backing), I tried another one and it exploded too, (a led came flying out of it). The capacitors were melted inside. (16 volt capacitors)

After some mucking around I eventually discovered the voltage coming out of the standard 12volt OSRAM transformers in my ceiling was actually 30volts, presumably due to the lack of 'load'.

So, I had to replace the transformers. Just thought this story would be useful to others and might save some waisted time :-) —Preceding unsigned comment added by 60.234.149.210 (talk) 01:40, 8 November 2010 (UTC)

LED Bulbs in stores

I was walking around Wal-Mart a few days ago, and notice they were selling LED Light bulbs. Sadly, they looked like they could screw into a normal incandescent socket, but there are like 5 or so different types of them: G4X, G5X, G3X, and so forth. None of them showed on the package that they could replace a normal light bulb, nor did that store sell any LED Lamps, and these light bulbs were among the "Normal" portion of their light bulb wall. Tell me, what are these for? 68.190.118.106 (talk) 18:00, 6 January 2011 (UTC)

LED lamp works from AC converted to DC. It must be blinking. Creating battery-like linear DC requires expensive electronics. The article should mention this with details. —Preceding unsigned comment added by 89.133.8.161 (talk) 04:33, 4 February 2011 (UTC)

LED Bulb Efficiency

The section on Household LED Lamps suggests that 7 watt LED bulbs are replacements for 60W incandescent bulbs and that a 13W LED is equivalent to an 100W incandescent. Neither claim is accurate nor consistent with the 59 lumen/watt value also quoted in the article. To produce the 800 - 900 lumen output of an incandescent bulb currently requires at least a 12W LED bulb such as the Philips or Sylvania bulbs which are rated at about 800 lumens.

There is also a statement that LED bulbs are more efficient than CFL bulbs with a citation to a non technical NYT article. This statement in incorrect and inconsistent with both the rest of the article and the Wikipedia article on lighting efficiency.

Bottom line is this section is inaccurate and misleading in it's comparisons of LED, incandescent and CFL lighting.

NCARalph (talk) 17:30, 10 May 2011 (UTC)

The value of 59 lm/W is very outdated. LEDs have become much efficient in the last two years. High-end models reach 150 lm/W. Around 90 lm/W is a typical value for a current non-expensive model. --77.177.166.95 (talk) 23:46, 22 July 2011 (UTC)
The value of 59lm/W ist right, this is for LED-Lamps. The whole System has a lower efficiency in causo to transform loss.
90-150lm/W is the efficiency for modern SMD-LEDs.
http://www.istl.com/system.php
(Angerdan (talk) 15:50, 23 July 2011 (UTC))

OLEDs

This article incorrectly stated that OLEDs are not commercially available. Osram Sylvania introduced commercial OLEDs during the 2010 Light+Building tradeshow in Frankfort, Germany. Acuity introduced OLEDs at Lightfair, Philadelphia in 2011. I altered the article so as not to say that OLEDs are not commercially available. GreenEconomy (talk) 22:39, 28 May 2011 (UTC)

I've used my cell phone as aflashlight, it had OLED screen back in 2006. Cell phones had OLED screens several years before that. --Shjacks45 (talk) 00:23, 8 March 2012 (UTC)

Alternating Current?

I'm trying to figure out, based on this article, if LED replacement bulbs flicker. Right now I can only use incandescent lights because I have seizures from flickering bulbs. CFLs, fluorescents, etc will give me instant and severe seizures and with the incandescent ban, I'm trying to find an alternative. From what I gather, LED bulbs run on 120 volt AC. 120 Hz is still within the range that can give me seizures. Do the internal rectifier circuits prevent them from flickering or what? 209.134.115.5 (talk) 02:57, 11 September 2011 (UTC)

You really should seek medical advice from a medical professional. Electronic ballasts in fluorescent lamps aren't supposed to flicker either. --Wtshymanski (talk) 13:55, 11 September 2011 (UTC)
Household power is usually 60 cycles per second (16.7 millisecond per cycle) with peak power occurring 120 times per second. A large heated filament can take a second or so to cool down and even a small fast response incandescent can take 250 milliseconds, therefore smoothing out the light power peaks. the gas plasma in the center of a long fluorescent can take a half second ( 500 miliseconds) to decay. Phosphorescent phosphors, (like the "glow in the dark paint" that charges in sunlight and then continues to glow for hours) are used in some fluorescents and TV sets helps reduce intensity changes at the expense of rapidity of response (in a darkened room you can see an old black and white TV screen glow for several seconds). NTSC television sets refreshed half the screen every 1/30 seconds, 30 times per second peak intensity. New ATSC TVs usually refresh the entire screen every 1/60 of a second although now newer can refresh every 1/120th and 1/240th of a second. Cold cathode fluorescents (LCD TV backlights) run at 400 to 2000 cycles per second. LED lighting is direct current however the electronic ballast they use to regulate LED current are of the switching power supply type switch at 5000-20000 per second (heavy magnetics parts are smaller at high frequencies). "Compact flourescent" bulbs also often use higher inverter frequencies so as to use smaller components. Many in the rural areas have battery backup in case of power failure and run 12 volt DC lighting as well as AC. (Automotive florescent headlights also run at high frequencies.) --Shjacks45 (talk) 01:56, 8 March 2012 (UTC)
Maybe fluorescent lamps aren't "supposed" to flicker, but a lot of them do, especially when they get old. It can be very annoying. (I do notice that the CF bulbs aren't as prone to this, though; possibly due to the higher frequency switching. They tend to just fail, instead of flickering for a year before they fail.)
However, LED bulbs don't have that particular problem. Geoffrey.landis (talk) 17:15, 2 June 2012 (UTC)

UV concerns.

What about those LED lights that aren't true white, but give off a blueish or violetish hue, should we have a section on health concerns like CFLs? Are they possibly giving off dangerous ammounts of UV?

And what of other things like people sensetive to certain kinds of light? Bolegash (talk) 23:02, 22 December 2011 (UTC)

you seem obsessed by the Fluorescent_lamps_and_health article which basically concludes that all light is bad and that YOU should live in a cave.
If you can see it, it isn't UV. LEDs emit narrow frequency bands, a typical 395nM (edge of UV-A) UV LED emits 390 to 400nM. UV leds are inefficient (see UV_light #ultraviolet_LEDs) and unlikely to generate enough power to hurt you. High power white LEDs use high efficiency blue LED (430-450nM) with yellow phosphor. Re diseases see Pyrimidine_dimersand Ultraviolet, light above 300nM fixes DNA damage and used in Phototherapy. Ordinary glass and most plastics are opaque to UV-B and UV-C which cause damage to DNA and sunburn. If you are afraid of blue sky light perhaps you should stay inside?

--Shjacks45 (talk) 10:32, 8 March 2012 (UTC) 

   480-450 Blue
   450-430 Indigo
   430-395 Violet
   395-320 UV-A
   320-280 UV-B
   280-100 UV-C
Yes, a LED bulb shouldn't be emitting UV-- this would be an efficiency loss. The blueish hue in some LED bulbs is simply visible blue, not UV. There's no reason to make phosphors that emit UV. Geoffrey.landis (talk) 17:06, 2 June 2012 (UTC)

LUMENS PER WATT?

Or lumens per what? There are 2 conflicting charts in the article. One claims 100 lumens per watt (which would mean 10 watts would produce 1000 lumens. Yet the 2nd chart says something quite different. (EnochBethany (talk) 04:57, 23 February 2012 (UTC))

Trippy, man. It's like different kinds of LED bulbs have different efficacies or something...who could have imagined such complexity? I've simplified it as the table was redundant anyway and also uncited ( the Energy Star ref is just giving minimum ratings to qualify for the label.) It is true you can't buy a consumer 1000 lumen LED that screws into an incandescent socket, but surely that's given elsewhere in the article. --Wtshymanski (talk) 14:22, 23 February 2012 (UTC)
100 lumens per watt is pretty much the maximum for what you can buy today. The LED bulb of reference 18 is 900 lumens, 9 watts, so that comes to 100 lumens per watt on a commercially available bulb.
Yes, you can buy 1000 lumen LED bulbs that screw into an incandescent socket-- the EvoLux is a 1000 lumen bulb, for example. There's also a 1100 lumen A-19 from Philips in their “AmbientLED” series. Those aren't 100 Lumens per watt, though (EvoLux is 13 watts. That was pretty good two years ago, but not pushing the efficiency limit today). Geoffrey.landis (talk) 16:53, 2 June 2012 (UTC)

Need a *** REAL *** explanation of LED driving and efficiency

So far, the few 120v LED bulbs I have purchased are rated about the same lumens per watt as CFLs. Operating the bulbs, they are clearly putting out more heat at the base area than the light itself, strongly implying that most of the power is being lost in the conversion from 120vac to the current limited DC used to drive the LEDs themselves. These bulbs are the "rage" now, even selling at huge markups from CFLs. The LED lighting industry is headed for a fallout when people wake up and realize that they save virtually no more power than a CFL over incandescent, despite being dramatically more expensive. To that end, this article needs a *real* explanation of how they are driven from 120vac circuits, instead of a single reference to "they use a rectifier", which is not in fact true -- you also need current limiting. Also, less of a rabid "fan boy" approach is needed. LED lighting has real problems to overcome, and so far their sales are driven on pure hype. — Preceding unsigned comment added by 64.79.114.83 (talk) 03:05, 1 May 2012 (UTC)

The fact that the bulbs you have put out their waste heat at the base, and not at the dome, is not evidence that the energy is lost in the AC/DC conversion; it just shows that for the bulbs you have, the thermal radiator is located at the base. Heat rejection is a big design issue for LED bulbs, and the LED elements themselves are attached to a heat-sink plate that will be attached to a heat rejection system somewhere-- in the base, for the bulbs you have; in fins, on some other bulbs; in grooves in the actual bulb part of the bulb, for the Philips.
LED bulbs have advantages and disadvantages. If I had small children in the house, for example, I think I'd replace every single light in the house with LED bulbs.
I do agree that a good discussion of the drive circuitry for consumer-level LED lamps would be an excellent addition to the article.

"six or more equally-tempered wavelengths"

"equally-tempered" links to the musical concept of equal temperament, which applies to hearing only, not vision — Preceding unsigned comment added by 174.31.242.120 (talk) 19:31, 3 May 2012 (UTC)

Perhaps the editor was using "equally-tempered" as a metaphor? The concept of equal-tempering, which arose first in the context of musical tuning systems, is just that of making equal steps between the fixed points of some scale.
Finding those equal divisions may lead to surprises, since the mathematical midpoint of any two points in a frequency scale is not given by their "average" (arithmetic mean) or half their sum, but rather by their geometric mean, which is the square root of their product. Similarly, to accurately divide the frequency range from Red to Blue into six equal steps requires us to take one-sixth roots (equal to the cube roots of the square roots).
However, in practice, manufacturers will choose LEDs of colours which they can manufacture cost-effectively, and these colours are unlikely to be distributed quite so neatly as this model suggests. A combination of most of the seven colours Newton saw in the rainbow: Red, Orange, Yellow, Green, Blue, Indigo and Violet would certainly approximate a pure white light better than a simple RGB combination. But this would still have a different spectral distribution from that of sunlight, which the most "natural" available lamps, called "Full Spectrum Lighting" or "FSL", are intended to emulate.
It's worth keeping in mind, too, that the visible spectrum doesn't end at blue, but at violet, and any lamp not producing violet cannot properly reproduce the colours we see under direct sunlight, or even under ambient daylight in the shade. Of course, we don't want too much of the potentially harmful far ultraviolet (UV-B and UV-C) rays.
What I find more objectionable is that the entire statement:
It can be expected that the number of colors will be further increased to six or more, equally-tempered wavelengths.
lacks any supporting reference. Is this simply personal opinion, or can we find any evidence to support the assertion?
yoyo (talk) 05:44, 1 January 2013 (UTC)

LED street light

Write about this new application for this technology. http://www.youtube.com/watch?v=G6Y_iwzl6MU&feature=related — Preceding unsigned comment added by 190.239.225.175 (talk) 23:14, 12 June 2012 (UTC)

price

Imho ist should be noted in the "Remaining problems" section, that the price is not high when compared to the life time. Most LED lamps last at least 20.000h-30.000h, a tungsten bulb lasts about 1.000h, so the price per hour life time is in most cases lower than with tungsten bulbs (and you safe a lot of money on electricity). --MrBurns (talk) 08:57, 18 January 2013 (UTC)

Yes, but...there's such a thing as time value of money. A dime off your power bill in 2023 isn't worth a dime to you today, and especially not if you have to take $40 out of the beer and pizza budget to swing that series of tiny savings. --Wtshymanski (talk) 18:57, 18 January 2013 (UTC)
I think that this is a serious problem that needs to be addressed in several ways. In the existing comparison table, it appears that the most important problem is that the total cost does not appear to include the replacement costs for the other lamps over the period of the total cost projection. I also think that the cost of the bulbs should probably reflect the changing prices over time, especially since the LED lamps are likely to become even less expensive. However, that probably isn't nearly as significant as estimating the trends of electric rates. I suggest that the chart should handle electric rates with at least two trend lines: unchanged electric rates and rates rising at historical levels. However I also think there should be two other rates included, probably at least one above and below. I admit that it's hard for me to imagine rates falling compared to rising, but it's even harder to imagine that electric rates will be constant for a ten-year projection. Shanen (talk) 07:12, 3 March 2013 (UTC)

LED lamp shape nicknames

So far I've seen "corncob", "sno-cone" and "alien head" used to describe different LED bulb shapes. If these terms are at all widespread, they might be worth documenting here. --Wtshymanski (talk) 15:39, 19 April 2013 (UTC)

Personal reflections, original research and free writing

There's been an improvement but much of it is unaddressed. Cantaloupe2 (talk) 07:05, 22 August 2013 (UTC)

Since you refuse to have these tags removed[7], you are going to have to elaborate on what it is that you find problematical in the article as it is. By this I mean actual quotes of the text that you feel needs to be improved, and why (preferably with cited sources as to why). It is not possible simply to add banners, without at the same time helping to improve the article, at least by explaining what you mean. --Nigelj (talk) 07:56, 22 August 2013 (UTC)

citation needed

DOE Say "pivotal emerging technology" link is http://www.netl.doe.gov/ssl/

I don't know how to cite stuff, but found above link. Tim S

The above comment is not dated, and so is not being checked by the archive bot as to age so it can ever move to the Talk page archive. Adding this comment so it will eventually get picked up and archived. Cheers. N2e (talk) 03:54, 23 August 2013 (UTC)

New generation white LEDs, more than 110 lm/W commercially available now

It's been quite an interesting year for the white LED industry, with mayor players trying to catch up among them, and significantly improving efficiencies in the meanwhile. There are already available "cool white" parts with efficiencies over 120 lm/W, and several manufacturers with even better chips down the pipeline. See, for example, the following data sheets:

http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

http://www.lumileds.com/pdfs/DS56.pdf

http://www.seoulsemicon.co.kr/_homepage/home_kor/product/spec/W4218X.pdf

All of the above parts are commercially available from many sources, and already integrated into end-user products.

The above comment is not dated, and so is not being checked by the archive bot as to age so it can ever move to the Talk page archive. Adding this comment so it will eventually get picked up and archived. Cheers. N2e (talk) 03:54, 23 August 2013 (UTC)

Efficiency

I think there should be some information on the efficiency of LED lamps. --Mortense (talk) 07:36, 8 May 2014 (UTC)

There is. Searching the article for 'efficien', I just found 24 occurrences of the words efficiency and efficient in the text, excluding the references section. Do you have any WP:RS new sources that have information we don't already cover? Also remember that 'efficiency' is quite hard to define for a light source, given the human eye's response to different wavelengths of light. The easier term to define, which much of the literature prefers, is luminous efficacy. --Nigelj (talk) 09:49, 8 May 2014 (UTC)

Pictures

Meaning no disrespect to the people who go to the trouble of taking and posting pictures, I do have some questions about the usefulness of a couple of them:

File:LED T-bar ceiling light.JPG , caption "Dropped ceiling with LED lamps": There is nothing evident in this photo that indicates LED lamps are being used. I could take a photo of a dropped ceiling with fixtures using 2x2 fluorescent tubes (or incandescent bulbs, or light pipes to a daylit sky) and it would not look any different. In fact, I could such a photo with a similar file name and caption to this one, claiming it to be LEDs, and nobody would be able to prove the lie... except perhaps by spectral analysis of the RGB data in the file. So... what does this photo add to the article?
File:LED-flickering.JPG , caption "Camera of mobile phone can detect flickering of LED light bulb": This photo at least needs the caption to describe exactly how it is detecting or showing flickering, and why the effect (whatever it is) is not some other artifact. Jeh (talk) 15:56, 13 August 2014 (UTC)

LED floodlamp bulb radio frequency interference

FM radio tuner reception degraded badly, hissing noise, when floodlamps turned on. This with new bulbs. Old LED floodlamp no problem. FM antenna located in attic above LED floodlamp bulbs Edvonessen (talk) 09:14, 4 September 2014 (UTC) edvonessen

Lumen Maintenance

Lumen Maintenance discussion should be included for an article talking about LED Lamp Rimsky.cheng (talk) 12:27, 21 September 2014 (UTC)

Technology

I'm missing more information about the electronics inside the lamp (for household application) and how the AC current is converted to a DC supply. Riki (talk) 12:43, 29 September 2014 (UTC)

Incorrect info in article.

Article claims, "A 100 W light bulb for 120 V operation emits about 1,180 lumens, about 11.8 lumens/W; for 230 V bulbs the figures are 1340 lm and 13.4 lm/W." and helpfully provides a reference.

Although the reference does support the claim for 230 volt bulbs, it does not support the claim for the 120 volt. This is not surprising because the quoted figures are wrong. 120 volt 100 watt bulbs have filaments that are four times the cross section area of 230 volt (because they consume four times the current). As such the surface area to volume ratio is lower and this permits the filaments to operate at higher temperatures for the same average life. The official light output of a 120 volt 100 watt lamp is 1700 Lumens (ref [8]) Article adjusted accordingly. DieSwartzPunkt (talk) 16:37, 30 September 2014 (UTC)

Cold temperature operation?

I have found from personal experience that a 60 watt cfl bulb in an outdoor fixture did not last more than 3 months during the winter even though it was turned off in the daytime. A fluorescent fixture in my uninsulated attic would not start in cold weather.1archie99 (talk) 16:12, 22 November 2014 (UTC)

Safety

There have been some reports (link in French) by reputable organizations that LED spotlights might not be safe, especially for children. It would be nice if the article addressed this problem. Joelthelion (talk) 17:45, 19 April 2015 (UTC)

Better lamp

Impressive! This Philips bulb is much better than the one in the table. I was going to add these numbers

2.49 8.5 800 94 2700 80 10,000 5 48 58 63

but the "limit 10 per order" pushes me not to. At the amazon price, though, it still beats the other bulbs by a significant margin. So should we replace the extant Philips bulb, using the Amazon pricing or the special deal at The Home Depot? Calculation for last row (Total cost per 860 lumens over 20 years @ 13 cents/kWh & @ 6 hours/day) : (40*13/11*1.02+4.97*2)*860/800=62.52 (40*13/11*1.02+12*2)*860/800=77.63 --Elvey(t•c) 15:35, 7 May 2015 (UTC)

Wikipedia should not be a parts catalog nor a sales brochure. Although we may list "typical" prices for things it should not be specific to any vendor, "special deal" or not. Jeh (talk) 16:21, 7 May 2015 (UTC)
Agreed; let's update it and go with the typical pricing, thus:
6 8.5 800 94 2700 80 10,000 5 48 72 77
--Elvey(t•c) 04:55, 16 May 2015 (UTC)
I just reverted a change that replaced the typical pricing (which I updated a few days ago) with the special deal pricing - despite the above consensus to use typical pricing (which already makes this product the price leader), and made what seems a wrong replacement of 2 with 5 in terms of unit counts per 20 years.--Elvey(t•c) 21:22, 24 May 2015 (UTC)
FFS! 4 bulbs needed for 20 years @ 6 hours/day, AFAICT. Not 5. WTF? --Elvey(t•c) 06:04, 30 May 2015 (UTC)

Well, with your revert we now have the situation where different bulb types with identical 10,000 hour lives have a different number of bulbs to last 20 years, which is simply wrong! Also pre-revert we had the happy situation that all the long-life bulbs were replaced to give an identical 50,000 hours of life. Please rv your revert to get the table back into this happy situation. Thank. Rwendland (talk) 11:29, 30 May 2015 (UTC)

I think I see where we differ. I did my calculations based on 10,000 hour bulbs lasting 5 years @ 6 hours a day, hence 4 bulbs needed for 20 years @ 6 hours/day, as I said. I'm guessing you're saying 10,000 hour bulbs lasting just UNDER 5 years @ 6 hours a day, hence 5 bulbs needed for 20 years. Is that why we're disagreeing? Indeed, identical 10,000 hour lives have a different number of bulbs to last 20 years is simply wrong. Lifetimes are estimates, and we should be treating them as such, so I'd say it's more likely that 4 bulbs would be needed for 20 years @ 6 hours/day than 5. So I'm going to change the table to be consistent with that.
Also, there were some ">" in the table that were inappropriate; I removed 'em. --Elvey(t•c) 23:21, 3 June 2015 (UTC)
Perhaps it's more appropriate to have non-integers for the average # of bulbs per 20 years. If you agree, feel free to make it so! --Elvey(t•c) 23:31, 3 June 2015 (UTC)
Are we agreed - it's more appropriate to have non-integers for the average # of bulbs per 20 years? Not convinced the bulb just added adds to the article. Thoughts? The chart assumes only 1 will be needed for 20 years, but that's unlikely.--Elvey(t•c) 09:17, 16 June 2015 (UTC)

Table needs updating

The Philips bulb linked now says $8.18 for a 10.W 25,000 hour bulb all different values (except the item number). The Lenovation bulb linked is discontinued by that seller (I think), is 10.5W not 9.4, no mention of life hours and not dimmable. Rmhermen (talk) 11:38, 5 June 2015 (UTC)

Yep, as you say our Philips data does not match the cite. There used to be a 9.4w Lenovation at that cite - impressive low wattage for the lumens, but it does look like it has been discontinued for some more cheaper technology that is no longer so efficient. At one time the 3 LED bulbs we showed in the table represented significantly different levels of LED efficiency/technology, but now they are a commodity we don't see that any more. Should we change to only list one representative LED bulb now, as they are so similar? Rwendland (talk) 20:49, 7 June 2015 (UTC)
I fixed the link to the better Philips bulb in the table- to be to the newer one with better lumens/watt: 8.5w, 800 lumen 10khr bulb. See#Better_lamp and edit history. Doesn't seem like they're so similar to me. --Elvey(t•c) 04:35, 9 June 2015 (UTC)

Elvey what is your concern with the addition to the table?Unconventional2 (talk) 13:30, 16 June 2015 (UTC)

What parts of "Not convinced the bulb just added adds to the article." and "Also 810 is wrong; would be 1200 (last row)" and do you miss or not understand?--Elvey(t•c) 17:43, 16 June 2015 (UTC)
Sorry I didn’t and still don't see where you wrote "Not convinced the bulb just added adds to the article." Thanks for pointing out the 810/1200 error. What would you see as necessary criteria for the inclusion of additional bulb(s) in the table?Unconventional2 (talk) 18:20, 16 June 2015 (UTC)
As the most energy efficient (lumens/watt) standard consumer bulb I have seen, I believe that as a comparison it shows off the difference between the old and new technology’s the best.Unconventional2 (talk) 18:37, 16 June 2015 (UTC)
.Unconventional2:OK, that's a good enough reason for me to drop my objection. (Though I've had to return (feit) LED bulbs because they were less than half as bright as they claimed to be.) Please learn how to indent your replies. See, e.g. Wikipedia:Tutorial/Talk_pages. --Elvey(t•c) 06:48, 17 June 2015 (UTC)
Elvey,Thanks for undoing your change!

Energy price

The price 13 US cent per kWh seems to be too low for an world wide average. Realistic seems to be something between 10 and 30 Euro cent ~ 12 .. 36 US cent.

I recommend to use at least a value of 20 Euro cent for the table as this makes traditional lamps even more inefficient. Schily (talk) 13:53, 16 June 2015 (UTC)

Much as I'd quite like it, if we went for non-US prices we'd have to find a cite for average bulb prices in Europe somehow as well - it would certainly show LED bulbs further cheaper than the others. But I think that would make it too complicated to do and maintain - we already probably spent too much time maintaing this table. For the U.S. the latest EIA residential average price is 12.35 cents/kWh, so our 13 seems OK. Rwendland (talk) 21:49, 16 June 2015 (UTC)
If table computations in Wikipedia support variables, I would recommend to try to support two sets of prices ac 12.something cent in the US is aprox. 10 Euro cent and this is definitely unrealistic for residential electricity prices in Europe even though the industry may pay something between 3 and 5 Euro cent. But the table already shows that the energy price is dominant for the total costs and I would like to be able to show that with higher energy prices, the total cost difference is much bigger and a LED based lamp typically redeems after a single year already. And BTW: you are right, lamp prices for incandescent and halogen lamps are higher in Europe and LED lamp prices are lower. A noname filament LED lamp with 100 lumen/W and 4W is e.g. available for aprox. 8 Euro - for 10-12 Euro, you get a LED with a CRI > 85. Schily (talk) 10:06, 17 June 2015 (UTC)

Osram missing in the table

Why is the largest supplier of light solutions missing in the table? Schily (talk) 10:42, 4 June 2015 (UTC)

They're the biggest when it comes to LED lamps, which are the subject of this article? I'd guess Cree or Philips is. --Elvey(t•c) 02:14, 5 June 2015 (UTC)
I've never seen Cree lamps in a retail store, so Cree seems to be far away from being a market leader. It may be that Cree is a local phenomenon in the US, but Osram acts worldwide and is much larger than Cree. Philips is large but not as large as Osram. From the presence in retail stores, I would guess that Philips is 1/2 to 2/3 of the size of Osram. In case you don't know: Osram is the company that invented the phoshor that made the white LEDs possible. Schily (talk) 09:45, 8 June 2015 (UTC)
The original reason for listing 3 LED bulbs was that there were 3 significantly different grades/specs of LEDs: generic/cheap, quality manufacturer giving better lumens/watt - Philips was the example, leading-tech bulb - expensive but best lumens/watt. Cree was the cheap one at one point so got named instead of "generic". Nowadays the performance of all 3 have become quite similar so we don't see much different in the spec, especially as the 9.4w Lenovation seems discontinued. I wonder if we should change to only list one representative LED bulb now, as they are so similar? Be easier to maintain one, and 3 does not give much extra info now. Rwendland (talk) 19:08, 8 June 2015 (UTC)
The article could be enhanced in general: Why not mention basic development milestones?
  • Telefunken made the first blue LEDs around 1980 (but they have been made from Silicon Carbide and as a result have been very expensive).
  • Nichia made the first cheap blue LEDs around 1994.
  • Fraunhofer IAF (Dr. Jürgen Schneider) made the first white LED using luninescence conversion around 1995.
  • Osram was a pioneer for the phosphor that allowed to make white LEDs for illumination purposes from blue LEDs and there was a long court case on the patents from Nichia and Osram [9] that started in 2001 because Osram did not pay for the Nichia cheap blue LED patent and Nichia did not pay for the Osram phohspor patents. The result of the case was that they both may continue not to pay, because both companies own the fundamemtal ideas that in common allow white LEDs. Schily (talk) 08:59, 9 June 2015 (UTC)
FYI, ideas per se are not patentable. Sounds like content for the article on LEDs, not this one on LED lamps. --Elvey(t•c) 06:56, 17 June 2015 (UTC)
It seems that you did not read the article, otherwise you did know that it was talking about a patent process. Schily (talk) 09:53, 17 June 2015 (UTC)
I was in two hardware stores and a lighting store recently. All three had many Cree lamps. Let's not act based on guesses or anecdotes - yours or mine. --Elvey(t•c) 04:35, 9 June 2015 (UTC)
But why then do you tell me the anecdote that you found cree lamps in a retail store? They are not sold in any retail store I did see for now. Osram however is dominant an omnipresent. Schily (talk) 08:26, 9 June 2015 (UTC)
Doesn't matter if I did or not; we should not act based on guesses or anecdotes - yours or mine. Not true: no Osram LED lamps when I was last at Home Depot. And virtually none (just 1 that's >1 watt) on their site. --Elvey(t•c) 09:17, 16 June 2015 (UTC)
Well it may be that you can find some stores in a specific area on the world where your claim may be right. In general, you rather see Osram than Cree. Schily (talk) 09:57, 16 June 2015 (UTC)
Again, [citation needed].--Elvey(t•c) 06:56, 17 June 2015 (UTC)
Wonderful! So you are willing to give sources on where the lamps in the table are available in retail stores? As this is not the US version of Wikipedia but the international one written in the English language but not assigned to a specific country, I propose to remove entries from the table for products that cannot be bought in a typical retail store in Europe. Schily (talk) 09:58, 18 June 2015 (UTC)

Calculation

As 20 years at 6 hours per day = 43800 hours and as most bulbs don’t last an even multiple of that number I would like to propose that we do a better job of figuring out the last two calculations in the table, by taking the bulb price and mathematically figuring out how much each bulb costs per hour of use and multiplying that by 43800 to arrive at a closer approximation of cost.Unconventional2 (talk) 02:02, 18 June 2015 (UTC)

Updated the “total cost” columns. Using, cost per bulb divided by bulb life times 43800 hours to improve accuracy. Somebody more skilled than I could/should probably update the formula so this doesn’t have to be calculated manually as I did. Also something should be added to the description of the table calculations. I would but am not sure what /how to add it. If/ when I do I will fix that too (if someone else hasn’t already)Unconventional2 (talk) 19:11, 19 June 2015 (UTC)
With this change it is practical to go back to a 10 year comparison period, which is easier for readers to comprehend. We only changed from 10 to 20 years when some LED bulbs had ~20 year lifetimes. We could change to per year, but that would mean adding cents based accuracy, so I don't think this helps comprehension and suggests a spurious level of accuracy. I'll do this unless anyone objects, and also expand the expression so it is easier to maintain. Rwendland (talk) 08:23, 20 June 2015 (UTC)
I have no issue with changing to 10 years. One of the considerations that doesn’t seem to be able to be taken into account on this table is that 20 years from now (even 10 years) electric rates are unlikely to stay at the same as current rates. The longer the time used the more uncertain this gets. Conversely to short a time span doesn’t high-lite the energy savings of LEDs as well. To me 10 years sounds about right but I will defer to others if something better is proposed. Unconventional2 (talk) 23:01, 20 June 2015 (UTC)

Lifespan of halogen bulb

In the comparison table lifespan of incandescent and halogen bulb is listed as the same (1000 hours). However, halogen lamp normally has longer lifespan. True, the value in the table is the same as in the reference and on manufacturer's website [10], but an equivalent bulb from the same manufacturer made for 230 V has a lifespan of 2000 hours [11] (checked for AU, SI and UK). I suggest adding additional column with the 2000 hours lifespan, since an article should not be limited to certain part of the world. Bglazar (talk) 08:43, 4 August 2015 (UTC)

Random numbers

I see that in these edits from a series of IP addresses, various random numbers have added and altered in the table. The data in the table didn't seem be cited to any source or reference beforehand, and certainly isn't now. Therefore it totally fails WP:V, which fundamental to Wikipedia, and can now become a free-for-all repository of any made up rubbish. If I have missed the sourcing reference, please enlighten me and let's make it clearer. If there is none, I suggest we delete the table until sourcing can be found. --Nigelj (talk) 19:14, 25 October 2015 (UTC)

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Out of date?

I'm no expert about LED lights, and only came to the page to find out, but this sentence seems to have some issues:
"The light output of single LED is less than that of incandescent and compact fluorescent lamps; in most applications multiple LEDs are used to form a lamp, although high-power versions (see below) are becoming available."
- On what measure is LED light output less than incandescent? Surely not on power consumption? On bulb availability? On physical size?
- If "multiple LEDs are used to form a lamp" does that mean "mutliple LED bulbs are used to form an LED lamp"? Maybe it goes back to a previous era of LED spotlights? I can't connect it with the bulbs I've just fitted.
- About "high-power versions (see below) are becoming available", when I see below, illustrations are from 2010 and 2012, which makes me think the article may getting significantly out of date?
Tsuchan (talk) 11:31, 10 March 2016 (UTC)

"By what measure..." By light output per device. Lumens.
Forget the word "bulb" for a moment. A 100 watt incandescent light bulb, for example, has a light output of around 1000 lumens. As far as I know there are no individual LED devices with anything close to that much output that are practical for use as incandescent bulb replacements. Plus there are directionality and cooling issues.. Can you give a link to the LED bulbs you're talking about? Jeh (talk) 12:44, 10 March 2016 (UTC)
Yes, it will always be out of date. Badly so until LED technology plateaus. Here is a 100W equivalent LED bulb for standard UK bayonet fittings. Available as of 4th Sep 2016 - don't know how long the link will be good for. Lithopsian (talk) 10:41, 4 September 2016 (UTC)

Table energy cost calculations are wrong

The energy cost calculations in the comparison table seem to be on the basis that electricity is charged at fill price on all reactive power. You might say that is a worst case scenario, but I'm not aware of any supplier that uses that method. In practice, a certain proportion of reactive power is completely ignored (typically between a third and a half) and the rest charged at a rate that allows the supplier to recover the implied excess capacity costs (ie not at the full unit rate). Additionally, this is charged on the overall load from a combination of both low and high power factor devices. Domestic services rarely have any reactive power charges at all, and usually small business users aren't charged either. Large commercial users that have overall low power factor loads can correct their power factors at a much lower cost than would be incurred from the utility company. In summary, nobody is paying double for a device with a power factor of 0.5, nobody is paying even close to that, and most people aren't paying anything extra. The table is wrong. I propose adjusting it to a simple basis of real power used - I can't see any other value that would be meaningful of practical. A note could be added that some users may incur a charge if they use too many low power factor devices. Lithopsian (talk) 10:48, 4 September 2016 (UTC)

So I've commented out the whole lot. Commercially available LED lighting simply doesn't have a power factor of 0.5. There seems to be a sort of "climate-sceptic" movement out there out to demonstrate that LEDs are a waste of time and effort, making claims about low power factors and "real costs". In fact, high power LED lighting typically has power factors anything from 0.85 to near 1.0. Cree claims 0.9 for their A-shape domestic bulbs. Various standards authorities mandate power factors over 0.7 for all except the lowest power lamps. A power factor of 0.5 is the worst case for the crudest possible control circuit. The same basic arguments also apply to CFL lamps. In short, I see nothing to justify either the raw power factors in the table or the numbers derived from them. Feel free to expand or add back properly cited data. Lithopsian (talk) 16:15, 4 September 2016 (UTC)

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Error?

Shouldn't "wearing blue tinted goggles at night to cut out all blueish light" be "wearing orange tinted..." instead? Jlsilva (talk) —Preceding undated comment added 16:22, 17 January 2017 (UTC)

Good catch, blue tint is not going to stop blue light, so I changed it to amber, which is the proper color. --Frmorrison (talk) 18:56, 17 January 2017 (UTC)

LED bulb pricing

The pricing chart for LED bulbs could use updating. I know it is hard to keep up with such a dynamic item when prices are dropping yearly but an accurate comparison would be the ideal goal.2601:647:4401:9A10:D436:B97B:F827:3BAE (talk) 16:39, 11 February 2017 (UTC) John Petro Feb 11, 2017

Power Factor misunderstood

It seems to me that the Power Factor is misunderstood in this article, particularly in the Comparison table. For now I've voided out the Energy cost row of the Comparison table until this is clarified and fixed. My understanding is low Power Factor does not mean you consume free energy requiring PF fudge factors in energy calculations, just that large amounts of low PF consumption is inconvenient/inefficient for the grid and generators. My understanding that the stated Watts on bulbs can be used straight-forwardly per this cited explanation:

A 5W LED lamp with a 0.5 power factor will draw 10 volt-amps (VA) from the grid. It is hugely more energy-efficient than the incandescent lamp, but only converts 50% of its drawn power into work (watts). This does not mean the LED lamp uses 10W of power, since reactive power is returned rather than consumed. However, low power factor increases power transmission losses, voltage dips, distribution costs, and carbon emissions. The grid is forced to supply a higher power level than is required at the load.[12]

(NB Power Factor fudge factors were added an Anon user on 25 October 2015!) Rwendland (talk) 17:21, 23 February 2017 (UTC)

Thank you. The power fudge factors were previously removed by me, but apparently snuck back in by an anonymous user. Nobody pays for twice the energy when the power factor is 0.5. 99% of people, including commercial users, pay nothing extra when power factors of their lighting is below 1. The cost in the table should probably ignore power factor completely. Lithopsian (talk) 17:35, 23 February 2017 (UTC)

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Neutrality issues

I know that only relatively recently have affordable LED lamps become available to replace incandescent and compact fluorescent alternatives, yet this article does seem to be biased against the emerging technology, focusing more on aspects such as power factor and colour rather than the pretty indisputable reduction in power consumed per lumen and time to full illumination. Whilst claims about life of an LED lamp are yet to be proved, it is clear that they consume less energy than equally bright alternatives and this article should reflect this. I'm not an expert on these matters, but to me the whole article seems to be biassed against this technology. I will research and improve, but this is a call to arms for those promoting LEDs as a viable and affordable alternative to more conventional lighting solutions.

I have really only glanced over the article but there is often opposition to new technologies when it so clearly replaces old technologies, the factories of which will need to be closed. They like to drag that out a bit, always happens, from tobacco to lead free petrol. In business circles this is called 'stranded assets' those factories, and nobody is keen on that. I had been looking here for when patents were applied for LED lamps. It's a fairly new development and yet the packages in which they are sold do not contain any patent Nos. Maybe the Chinese who make them did not bother as nobody can supply them at their price? 2001:8003:A921:6300:50AC:46C4:2152:E3A2 (talk) 07:19, 14 August 2017 (UTC)


The article is out of date. It needs to cover the various types of SMD LEDs; 2835, 3030, etc. Each type has a particular use. 2835s and 3030s are used in bright ceiling and flood lights. Other LEDs of lower brightness may be used for subdued and color lighting, and in LED ribbons. 4014 LEDs are the smallest and can make the equivalent of a 75W incandescent but is only 1/3 of the length.14.203.207.166 (talk) 09:15, 10 May 2018 (UTC)

Diolight Forever Bulb

... Someone should add mention of this I imagine. —Hobart (talk) 01:50, 27 July 2018 (UTC)

  1. ^ ANSI/IESNA RP-16-05, Addendum a, "Nomenclature and Definitions for Illuminating Engineering"
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