Talk:Incandescent light bulb/Archive 1

message: More than half of the introduction for incandescent light bulbs is talking about switching from them to CFLs.  This seems completely bizzare and out-of-place. 69.141.68.106 01:21, 23 May 2007 (UTC)
thread_title:  Off Topic Introduction 

message: ...not spontaneous emitters.  The following: 
"As the electrons that travel through the filament bump into the atoms, some of the electrons in the atom may become excited. This means they temporarily boost its energy level and raise to higher orbit. When they fall back, energy is released as photons, a photon being the particle form of light."
is true, but the vast majority of the light comes from blackbody radiation, which isn't even mentioned.  I guess this is what happens when you copy from howstuffworks.com...
168.230.48.248 03:25, 5 July 2006 (UTC)
replies: text: A tungsten filament isn't exactly a blackbody, either (nothing really is) - the emissivity of tungsten varies according to wavelength and temperature.  Fortuitously the declining emissivity at longer wavelengths means a coiled-coil filament is a better emitter of visible light than it would be had it been a real blackbody. What we need is a cheap way to cross an incandescent light bulb with a frequency-doubling phosphor of some kind, like IR pumped lasers use, to reclaim some of the IR and fold it up to the visible part of the spectrum. --Wtshymanski 18:07, 2 November 2007 (UTC)
thread_title:  Light bulbs are blackbodies... 

message: The article Light bulb says in section History of the light bulb 
: In 1801 Sir Humphry Davy, an English chemist, made platinum strips glow by passing an electric current through them, but the strips oxidized too quickly to make a useful lamp.  
I assume (not much of chemist, i) that oxidation of Pt is unlikely, and that this misinterprets 
Lights by Edward Willett, or something similar, which refers to 
* Davy's "fine platinum wire" and 
* to other incandescants where "the filament burned away very quickly".  
I say "oxidation ... unlikely" in the belief that Davy chose Pt bcz that (and maybe Au) were the only things he could find that didn't oxidize when incandescant (and maybe bcz Au melts a lot earlier).
Here are some #s from WP: 
Parameter ---------- W ----- Pt 
Melting point --- 3695 K  2041.4 K 
Boiling point --- 5828 K  4098 K 
ρ-1 (106/m ohm) -- 18.9 09.66  (or should i be suspicious of the leading zero?)
At. wt. (amu) --- 183.84 195.078 
What i understand to be the main failure mechanism in ductile-tungsten filaments is the positive feedback at the hottest points, of 
* increased thermal migration of W, 
* thinning, 
* increase of resistance-per-unit-length, 
* increased share of delivered power, and 
* increased T, 
culminating in local melting across the whole cross-section, of enuf length that sag (or just instability?) lets the liquid portion flow away from its center. (Haven't noticed if that's in the article; it should be IMO.)
IMO, the presence or absence of air doesn't make a lot of difference in that kind of failure, bcz even if convection is more efficient for the first few inches than radiation alone, incandescence is required, and the operating temperatures are going to be essentially the same.
With Pt in the same geometry such failure just happens sooner; i imagine much sooner: i  base that on the principle that chemical reaction rates go up very rapidly with temperature bcz they are controlled by the population in excess of the activation energy, which increases much faster than mean energy, and on my belief that thermal migration should similarly limited by an activation energy representing a surface atom  breaking all but two (or if not,  all but one) of its bonds, so it can swing to its next position.
The higher conductance of W (which surprises me, but whadda i know) does mean the Pt filament has twice the cross-section area for the same length, voltage and current, but that may not be what determines the geometry: with modern W, it may be economical for  filaments to be made thicker and longer (for ruggedness and reduced thermal-migration failure, but with Pt the cost of filament material has to limit the feasible increase of dimensions.  So i think the lower conductance is completely swamped by the melting point and perhaps dimension issues, and i am convinced the same non-oxidative failure mechanism can explain Davy's results. --Jerzy '03 Dec 15
==== Sublimation ====
:Sublimation is another problem. -- Heron
Thx! On reflection i agree.  I may have been searching for my keys under the street lamp, esp since i despair of having any hope of estimating sublimation rates, either relative between materials or relative to the solid-state thermal surface migration -- other than to note that activation energy for sublimation has to be higher than for surface diffusion.  Maybe i should have taken another thermo course or four.  
I think sublimation can also participate in the feedback loop, but at least initially it promotes a graceful degradation, with the bulb getting cooler (and dimmer) as the filament thins and delivered power drops.
(My first thot on reading the sublimation contrib was "Ah, then the bulb maintains a vapor pressure of the filament material, and makes a difference other than via restricting convection to a remote heat-flow mechanism." No, fool, the bulb just makes it obvious that sublimation is a second thermal-migration mechanism that you didn't even consider: thermal migration via gas phase to the sub-incancesent bulb instead of via solid phase within the filament. 'Scuse me, gotta go off and cry somewhere.) --Jerzy 19:41, 2003 Dec 16 (UTC)
Don't be too hard on yourself, Jerzy.  You were right to dispute the "oxidized" claim (which I just changed).  
Looking into this further, I think sublimation may be a less graceful degradation mechanism than you say, but I'm not sure.  For analytical purposes, I imagined a filament divided into 100 segments in series.  For a 240 V 100 W bulb (common here in Britain), I calculate the filament resistance when hot to be nominally 576 R.  In my scheme that's 100 5.76 R segments in series.  If, due to evaporation, one segment doubles in resistance to 11.52 R, then the total filament resistance will increase by 1% to 581.76 R.  With the same supply voltage, the power will drop by nearly 1% to 99.01 W.  As you said, this will cool the bulb and help to slow down the evaporation.  On the other hand, think what happens to the thinned segment.  The current through the filament has now dropped by 1% (from 0.4167 A to 0.4125 A), but the resistance of the unfortunate segment has doubled, so the power in that one segment has now increased by 96% (from 1 W to 1.9606 W), making it evaporate much faster!  It seems that the increase in local power dissipation will strongly dominate the slight decrease in global power dissipation, causing a runaway failure, but I haven't proved that this is true for all cases.
If you have been, thanks for reading this far! -- Heron
: Absolutely i'm reading you! I think we agree on what you just said; our difference is that i assumed (without justification) that evaporation/sublimation (let's just say erosion, in contrast to the reshaping of the same mass of filiment by thermal migration) was uniform; as you point out, the positive feedback effects apply either way to the extent that either phenomenon is non-uniform.
: Now looking into the justification, i continue to think that the overall trend of the erosion is gradual loss of light output.  However, i agree that erosion can magnify non-uniformities about as effectively as migration.
A big issue i keep coming back to, tho, is that we'd like to find phenomena that work when the non-uniformities are infinitesimal. I think your example points out the fact that power goes up faster than segment resistance, because P = VR2, which enhances the feedback, at least once the uniformities get large.  But what i'm starting to worry about is that unless we're talking about irregularities that are there from the factory machining, they are likely to be swamped by the thermal noise.  IMO there are some things that work against the feedback: i think infinitesimal surface roughnesses are subject to negative feedback: atoms at convex surface points are bound to fewer atoms and therefore (i think) less strongly bound; atoms at concave surface points by the same token more strongly bound.  We therefore expect the background surface diffusion (the component not driven by temp differences) to favor moving atoms from convexities to concavities, and smooth out the surface.  Gets more complicated as we examine more closely, i fear.
It sounds, tho, like you know no more than i abt how hard it is to oxidize Pt at those temps, & i fear our alternate failure mechanism (instead of fairly uniform erosion (or resistance increase, on the assumption that the oxide is non-conducting but non-volatile), by oxidation) is irrelevant - i.e., if there's nothing wrong with the previous editor's oxidation hypothesis!  
What i haven't done is finished searching the web for statements that Davy's Pt failed by oxidation; i've been treating the suspicious text like a smoking gun, but there may be a more credible source out there that says "oxidation" explicitly.
Interesting, nonetheless. [smile] --Jerzy 03:28, 2003 Dec 17 (UTC)
You are right to say that I don't understand the chemistry of what's happening.  I will leave that to someone else.
"The Invention of the Incandescent Lamp" by Globusz Publishing, among other web pages, points out (in somewhat convoluted English) that the temperature at which platinum glows is very close to its melting point, which is what makes it so unreliable.  I think this is the (disappointingly simple) answer. -- Heron
I hope you will not mind if I throw my two cents in.
The failure modes of incandescent lights has interested me too. I think evaporation is an important failure mode, and you can confirm this by noting that high intensity bulbs build up a dark layer on tungsten (or whatever) on the inside of the bulb as they age. The halogen cycle helps slow down this loss. The bulb temperature must be very high though for this trick to work. This is why quartz glass must be used. Halogen lamps intended for projection use are rated for 50 hour life and are specified to operate at about 50C below the melting temperature of tungsten. The melting temperature of tungsten, I believe, is closely related to, and limits, the quoted "color temperature" of tungsten light. I believe that lamp lifetime varies with the sixth power (I forget, but the effect is big) of operating voltage, and I could look up the empirical derating formula if anyone cared.
What I really wanted to offer, though, is another observation. I believe that it is common for lamps to fail at the moment they are turned on. I have noticed that when incandescent lamps are dimmed very low using a phase control dimmer that they emit a noticable sound. I believe that tungsten lamp electrical loads draw a nominal 10x current surge when the load is first turned on, that is, the rule of thumb for sizing switch contacts, etc. is to expect this much surge. I believe this is due to the cold filament having a much lower electrical resistance initially. Careful examination of the phase control circuit waveform shows that there is an enormous, short duration current spike on each half cycle as the partially cooled filament is connected to a relatively high voltage, instead of the normal smooth sinusoidal voltage buildup. I believe that some of the corresponding noise may be from thermal distortion as the filament heats rapidly. However, I suspect, that some of the noise may be due to forces created by the rapidly changing, 10x magnetic field around the (usually) coiled filament, due to the current surge, acting on the conducor. I think this magnetic effect may also account for the tendency of the bulb to fail as it is turned on, by adding one more stress to the cold and weakened metal.
:I added a source which says Davy demonstrated in 1802 that current from the powerful battery at the Royal Institution could make a fine strip of platinum glow, althoug it drew too much current and did not last long enough to be a practical lamp. The cost of a new strip of platinum each time it was lit for a few minutes was another limitation on the practicality. How can the time chart be edited to show this being in 1802? It now looks like it is before that, but I do not see the chart showing up as an editable element of the article. I seem to recall reading somewhere that Volta made a fine wire glow in 1800, but I cannot now find a reference to substantiate that. It appears that every experimenter after 1802 who made a fine platinum wire glow for a while gets credited as "inventor" of the incandescent lamp, when they did not materially improve on Davy's 1802 demonstration. Edison 17:48, 19 April 2007 (UTC)
thread_title:  incandescant platinum 

message: :Sublimation is another problem. -- Heron
Thx! On reflection i agree.  I may have been searching for my keys under the street lamp, esp since i despair of having any hope of estimating sublimation rates, either relative between materials or relative to the solid-state thermal surface migration -- other than to note that activation energy for sublimation has to be higher than for surface diffusion.  Maybe i should have taken another thermo course or four.  
I think sublimation can also participate in the feedback loop, but at least initially it promotes a graceful degradation, with the bulb getting cooler (and dimmer) as the filament thins and delivered power drops.
(My first thot on reading the sublimation contrib was "Ah, then the bulb maintains a vapor pressure of the filament material, and makes a difference other than via restricting convection to a remote heat-flow mechanism." No, fool, the bulb just makes it obvious that sublimation is a second thermal-migration mechanism that you didn't even consider: thermal migration via gas phase to the sub-incancesent bulb instead of via solid phase within the filament. 'Scuse me, gotta go off and cry somewhere.) --Jerzy 19:41, 2003 Dec 16 (UTC)
Don't be too hard on yourself, Jerzy.  You were right to dispute the "oxidized" claim (which I just changed).  
Looking into this further, I think sublimation may be a less graceful degradation mechanism than you say, but I'm not sure.  For analytical purposes, I imagined a filament divided into 100 segments in series.  For a 240 V 100 W bulb (common here in Britain), I calculate the filament resistance when hot to be nominally 576 R.  In my scheme that's 100 5.76 R segments in series.  If, due to evaporation, one segment doubles in resistance to 11.52 R, then the total filament resistance will increase by 1% to 581.76 R.  With the same supply voltage, the power will drop by nearly 1% to 99.01 W.  As you said, this will cool the bulb and help to slow down the evaporation.  On the other hand, think what happens to the thinned segment.  The current through the filament has now dropped by 1% (from 0.4167 A to 0.4125 A), but the resistance of the unfortunate segment has doubled, so the power in that one segment has now increased by 96% (from 1 W to 1.9606 W), making it evaporate much faster!  It seems that the increase in local power dissipation will strongly dominate the slight decrease in global power dissipation, causing a runaway failure, but I haven't proved that this is true for all cases.
If you have been, thanks for reading this far! -- Heron
: Absolutely i'm reading you! I think we agree on what you just said; our difference is that i assumed (without justification) that evaporation/sublimation (let's just say erosion, in contrast to the reshaping of the same mass of filiment by thermal migration) was uniform; as you point out, the positive feedback effects apply either way to the extent that either phenomenon is non-uniform.
: Now looking into the justification, i continue to think that the overall trend of the erosion is gradual loss of light output.  However, i agree that erosion can magnify non-uniformities about as effectively as migration.
A big issue i keep coming back to, tho, is that we'd like to find phenomena that work when the non-uniformities are infinitesimal. I think your example points out the fact that power goes up faster than segment resistance, because P = VR2, which enhances the feedback, at least once the uniformities get large.  But what i'm starting to worry about is that unless we're talking about irregularities that are there from the factory machining, they are likely to be swamped by the thermal noise.  IMO there are some things that work against the feedback: i think infinitesimal surface roughnesses are subject to negative feedback: atoms at convex surface points are bound to fewer atoms and therefore (i think) less strongly bound; atoms at concave surface points by the same token more strongly bound.  We therefore expect the background surface diffusion (the component not driven by temp differences) to favor moving atoms from convexities to concavities, and smooth out the surface.  Gets more complicated as we examine more closely, i fear.
It sounds, tho, like you know no more than i abt how hard it is to oxidize Pt at those temps, & i fear our alternate failure mechanism (instead of fairly uniform erosion (or resistance increase, on the assumption that the oxide is non-conducting but non-volatile), by oxidation) is irrelevant - i.e., if there's nothing wrong with the previous editor's oxidation hypothesis!  
What i haven't done is finished searching the web for statements that Davy's Pt failed by oxidation; i've been treating the suspicious text like a smoking gun, but there may be a more credible source out there that says "oxidation" explicitly.
Interesting, nonetheless. [smile] --Jerzy 03:28, 2003 Dec 17 (UTC)
You are right to say that I don't understand the chemistry of what's happening.  I will leave that to someone else.
"The Invention of the Incandescent Lamp" by Globusz Publishing, among other web pages, points out (in somewhat convoluted English) that the temperature at which platinum glows is very close to its melting point, which is what makes it so unreliable.  I think this is the (disappointingly simple) answer. -- Heron
I hope you will not mind if I throw my two cents in.
The failure modes of incandescent lights has interested me too. I think evaporation is an important failure mode, and you can confirm this by noting that high intensity bulbs build up a dark layer on tungsten (or whatever) on the inside of the bulb as they age. The halogen cycle helps slow down this loss. The bulb temperature must be very high though for this trick to work. This is why quartz glass must be used. Halogen lamps intended for projection use are rated for 50 hour life and are specified to operate at about 50C below the melting temperature of tungsten. The melting temperature of tungsten, I believe, is closely related to, and limits, the quoted "color temperature" of tungsten light. I believe that lamp lifetime varies with the sixth power (I forget, but the effect is big) of operating voltage, and I could look up the empirical derating formula if anyone cared.
What I really wanted to offer, though, is another observation. I believe that it is common for lamps to fail at the moment they are turned on. I have noticed that when incandescent lamps are dimmed very low using a phase control dimmer that they emit a noticable sound. I believe that tungsten lamp electrical loads draw a nominal 10x current surge when the load is first turned on, that is, the rule of thumb for sizing switch contacts, etc. is to expect this much surge. I believe this is due to the cold filament having a much lower electrical resistance initially. Careful examination of the phase control circuit waveform shows that there is an enormous, short duration current spike on each half cycle as the partially cooled filament is connected to a relatively high voltage, instead of the normal smooth sinusoidal voltage buildup. I believe that some of the corresponding noise may be from thermal distortion as the filament heats rapidly. However, I suspect, that some of the noise may be due to forces created by the rapidly changing, 10x magnetic field around the (usually) coiled filament, due to the current surge, acting on the conducor. I think this magnetic effect may also account for the tendency of the bulb to fail as it is turned on, by adding one more stress to the cold and weakened metal.
:I added a source which says Davy demonstrated in 1802 that current from the powerful battery at the Royal Institution could make a fine strip of platinum glow, althoug it drew too much current and did not last long enough to be a practical lamp. The cost of a new strip of platinum each time it was lit for a few minutes was another limitation on the practicality. How can the time chart be edited to show this being in 1802? It now looks like it is before that, but I do not see the chart showing up as an editable element of the article. I seem to recall reading somewhere that Volta made a fine wire glow in 1800, but I cannot now find a reference to substantiate that. It appears that every experimenter after 1802 who made a fine platinum wire glow for a while gets credited as "inventor" of the incandescent lamp, when they did not materially improve on Davy's 1802 demonstration. Edison 17:48, 19 April 2007 (UTC)
thread_title:  Sublimation 

message: :In Australia and South Africa a light bulb is also called a light globe, but this term is not used elsewhere.
Well, my grandmother in Pennsylvania calls them light globes, so the above claim is too strong.  I always figured it was a largely obsolete term from her youth, that has fallen out of favor in the U.S.  Anyone else know of "light globe" being used outside of Australia and S.A.? -- Coneslayer 15:09, 2005 July 28 (UTC)
::I confirm that the phrase is popular though not exclusive one in Australia.  (And someone has nicely put a redirect in place.) Anyone know about new Zealand? 220.240.58.190 04:43, 28 April 2007 (UTC)
thread_title:  "Light Globe" 

message: Maybe someone can offer some insight here. The spectra that I recently uploaded of a (unfiltered, clear) flashlight bulb  appears to have a peak emission of around 630 nm. However this  says the filament should therefore have a temperature of ~4600K which is clearly impossible.... Does the glowing filament deviate from a blackbody that severly as to make an approxamation like this impossible? What happened?--Deglr6328 06:39, 5 September 2005 (UTC)
thread_title:  hmmm 

message: I wondered if the tungsten use was an alloy or pure (mostly) tungsten?  Anyone know?
:I have always believed it was pure tungsten (as you want the highest-possible melting point, and the un-alloyed metal should have that), but I have no reference to back up my assumption, and I wouldn't be too surprised to find that some small amounts of alloying metals were added to improve the drawing characteristics of the pure tungsten wire. Perhaps someone else really does know :-) ?
:Atlant 15:11, 8 September 2005 (UTC)
replies: text: Creep (deformation) says that they use an alloy to reduce creep. njh 03:18, 31 December 2005 (UTC)
thread_title:  Tungsten Alloy? 

message: Efficacy might be a correct term, but to me it seems less specific than energy efficiency, and the linked efficacy article doesn't (currently) seem to or address the idea at all.  On the contrary, it's very weighted towards psychological meanings, with small cameos for medicine and politics.  It isn't anywhere near as helpful as the energy efficiency article was.  The efficacy article could almost be a disambiguation page, or have some redirect text at the top to point people at energy efficiency if they want something about energy.  Anyway, I'm not quite sure what the best approach is here.  I'd quite like to point the links back to energy efficiency, because it seems to be more specific and it is a more widely recognised term, in my opinion.  In the interests of avoiding an edit war, though, does anyone have any strong opinions on this? Izogi 22:24, 9 September 2005 (UTC)
replies: text: Just because people dont understand a correct term is no reason for it to be excluded. There is a link to the term. Maybe the link needs modifying. But please be assured that the term efficacy is the correct one --Light current 07:33, 10 September 2005 (UTC)
replies: text: There does seem to be a difference between luminous efficacy and luminous efficiency.  Try Googling for "luminous efficacy" "luminous efficiency".  See this PDF from IUPAC  for a definition, but this is in the context of the reception, not the emission, of light.  To summarise, efficacy is the lumens/watt column in our table, and efficiency is the "percent" column, which is the ratio of efficacy to the reference efficacy of 680 lm/W.  Here's a tech note (PDF) from Pulnix  that says the same thing in simpler language. --Heron 12:29, 10 September 2005 (UTC)

text: If we said 'the luminous efficacy (sometimes erroneously referred to a luminous efficiency).....' would that satisfy everyone?--Light current 18:27, 10 September 2005 (UTC)
replies: text: That is roughly what I put in the article a few hours ago. --Heron 21:23, 10 September 2005 (UTC)

text: Yes it looks a lot more accurate now!--Light current 21:45, 10 September 2005 (UTC)

text: You're absolutely right.  I'm working on a complete rewrite of that chart.  I have already gathered efficiency data for white LEDs, tungsten incandescents (clear, soft white, long life, "daylight"), thin wall BT15-style halogens, and heavy wall halogens.  I'm working on long tube fluorescents and ballasts.  After that, compact fluorescents, high and low pressure sodium, mecury vapor, and metal halides.  I will take a look at xenon arc lamps, but I suspect they are not really used for large scale illumination.  Every number in my chart has been taken from the technical datasheet of a currently shipping lighting component.  Every lamp type includes specific examples from at least three manufacturers.  For LEDs, I used Cree, Nichia, and LumiLeds.  For incandescents, I used Philips, Osram-Sylvania, and General Electric.  I should finish this up in a week or two.  —Ryanrs 10:54, 16 March 2006 (UTC)

text: Forgot to mention, the new chart will include color temperature and CRI Ra values, when available.  Osram even provides CRI R9 figures for their warm white LEDs, which is nice.  —Ryanrs 10:59, 16 March 2006 (UTC)
thread_title:  Efficacy? 

message: When you go to "Incandescent light bulb" from the Search it gives you this:
The invention of the light bulb is usually attributed to Amanda "Mugsy" Emms, who contributed to its development by producing a practical and viable electric lamp. However her invention was stolen by Thomas Edison who marketed the device successfully. Alexander Nikolayevich Lodygin developed an incandescent light bulb around the same time. Many others also had a hand in the development of a practical device for the production of electrically powered lighting.
But when you go to "Light Bulb" from the search it gives you this:
The invention of the light bulb is usually attributed to Thomas Alva Edison, who contributed to its development by producing a practical and viable electric lamp, and marketed the device successfully. However, it is now believed that Heinrich Göbel built functional bulbs three decades earlier. Alexander Nikolayevich Lodygin developed an incandescent light bulb around the same time. Many others also had a hand in the development of a practical device for the production of electrically powered lighting.
I honestly don't know much about the lightbulb so I'm not going to correct it on a hunch (no matter how big), but I've never heard of the Amanda Emms version of the story. 
Also why is there two different pages that claim to redirect to the same place [Incandescent light bulb]? --Taboo Tongue 20:13, 19 November 2005 (UTC)
thread_title:  Vandalism? "Amanda 'Mugsy' Emms" 

message: It's my understanding that the Woodward and Evans light bulb did in fact work and that Thomas Edison thought that their approach was sufficiently promising to buy rights to their patents.  I am not an expert in the field, however.  My source is .  I would gladly defer to another who is more expert or who can provide a more authoritative source.  On another note, what's the point of emphasizing that Woodward was not a "gentleman" (presumably a noble?) but "merely" a hotel operator.  It may be true, but unless it's relevant to the history of the develpoment of the light bulb, I recommend that that fact be removed.--Nowa 00:15, 21 December 2005 (UTC)
replies: text: Lots of people made wires or other substances glow with electricity,from the invention of the Voltaic pile onward, but those pre-1879 devices simply did not work in terms of operating for more than a few minutes or giving off enough light to replace gas lights, or drawing a small enough current that they could be operated from an electric system. Patenting something or having an idea is not "inventing" it. The Canadian pride sites are not reliable sources. Find a scholarly article in a peer reviewed journal, or a scholarly book from a respectable publisher, not a blog or someone's website. The patent drawing shows a big chunk of carbon, which would not have constituted a "filament". It would have drawn high current. There is no believable claim that thjey demonstrated a light bulb which was bright enough and long lasting enough to be usable, ignoring the requirement for high resistance and a small radiating surface. Nor is there evidence that their work influenced Edison or Swan. Edison 15:12, 20 March 2007 (UTC)
thread_title:  Woodward & Evans 

message: Thomas Edison has been nominated on WP:IDRIVE. Vote for this article and help improve it to featured status. --Fenice 14:02, 26 December 2005 (UTC)
thread_title:  Improvement Drive 

message: There are too many links, especially in the intro paragraphs, and some ("archaically"?) are not really relevant to the context. See Wikipedia's style info on this. I'm taking out links to some plain English words and irrelevent words. Benhoyt 03:10, 6 March 2006 (UTC)
thread_title:  Too many links 

message: I have changed the comparision of electricity cost to reflect more accurately the lumen output of a CFL. 13-15w CFL's output 800-900 lumens. In the range of a 60W lamp. See http://www.energyfederation.org/consumer/default.php/cPath/25_44_785 for an excellent sampling of CFL wattages and lumen outputs. The existing references also support ~14w CFL =~ 60w incandescent.
:Yep, ok.  Looks like the CFL manufacturers are misleading the public (and hurting themselves by giving CFL a repuation for being dim!).  14W would line up with the approx 4* greater luminous efficiency listed. --njh 04:30, 20 March 2006 (UTC)
thread_title:  11W CFL != to 60W incandescent 

message: Now I'm no expert however I've been purchasing light bulbs for a while and I'm pretty sure the expected life time of a CFL one and an incandescent one is roughly the same, this is ofcourse greatly company dependent but if someone with the education could confirm and/or correct this?
:Sorry, but the life of any "general service" fluorescent lamp will greatly exceed the life of a typical "general service" incandescent lamp. In round numbers, a fluorescent lamp lasts 10,000 hours whereas an incandescent lamp lasts 1000 hours.
:One thing to be aware of: Each "start" of a fluorescent lamp reduces its lifetime a little (as it blasts some cathode material off the filaments of the lamp). So if the on-off cycle of a fluorescent lamp is very short, then its life won't approach that average 10K hour number I cited above. On-off cycling also has an effect on incandescent lamps, but it's much less significant, especially for lower-voltage lamps.
:Another thing to be aware of is that by derating the service voltage, incandescent lamps can be made to last much longer than is normal (but their brightness and efficiency goes down as well). In North America, a typical "long life" incandescent lamp is actually a 125V or 130V lamp; when operated on 120V, it can live a very long life. The lifetime of an incandescent lamp is approximately inversely proportional to the sixteenth power of the voltage! See the article for more details.
:Atlant 13:33, 31 March 2006 (UTC)
replies: text: From the first decade of lightbulb manufacturer, makers have known they could trade off efficiency versus lifetime. This they now sell "long life" bulbs with a 130 volt filament rating for use on 120 volt mains. The engineer's rule of thumb is that a 10% voltage variation halves or doubles filament lifetime. A bulb with a 130 volt filament used on 120 will have a warmer color tone (lower filament temperature). Voltage affects lifetime of fluorescent bulbs as well, but I do not know the tradeoff equation. There is a longer empirical equation with several terms, which suggests that a 240 volt bulb powered by 120 volts should last decades, but in practice I have seen such buylbs fail in a few years. I expect that a voltage spike from utility faults or switching or a nearby lightning jolt every couple of years may give the lie to claims of 50,000 hours for LED lights or the very long lifetimes for compact fluorescents, just as they cause the failure of other electroniuc equipment. We should guard against this article becoming a bandwagon for proposals to ban incandescents. Such coverage should not become as long as it presently is, beyond mention in the section on efficiency. The CFL bandwagon should not come to dominate this article, any more than an article about buggies talks about how great cars are. There is a separate article for CFLs. Edison 00:04, 13 March 2007 (UTC)
thread_title:  Lifetime of CFL vs incandescent 

message: What does the following sentence mean?
Bamboo continued to be used until 1893, later enhanced by a cellulose coating, introduced around 1882 and produced until at least 1929.
Bamboo was obviously used without cellulose coating until 1882. From that year, it was coated in cellulose, but what happened between 1893 and 1929, when bamboo use had supposedly ceased, but cellulose coating had not? LX 06:05, 20 April 2006 (UTC)
replies: text: The edit that seems to have injected the confusion is this one by 70.18.119.241, who was only seen for two days in December 2005. —LX 17:24, 29 April 2006 (UTC)

text: Since nobody has come forth with an explanation, I have removed the sentence. Feel free to insert a more coherent sentence in its stead. —LX 05:50, 4 May 2006 (UTC)
thread_title:  Confusion over bamboo and cellulose coating in Edison's design 

message: Could be insert also the contribution to this invention by the italian scientist Alessandro Cruto? HI
--80.104.130.37 10:47, 8 May 2006 (UTC)
thread_title:  Alessandro Cruto? 

message: What is it about a fingerprint that destroys a quartz halogen lamp?  According to http://www.its-90.com/al-sil.html, (last section, "PRECAUTIONS TO PREVENT DEVITRIFICATION OF QUARTZ ENVELOPES"), "Fused quartz is vitreous in nature but, like other glasses, can be stimulated to crystallise (devitrify) by external influences at high temperatures.... Sealed quartz cells can be used for thousands of hours without devitrification if precautions are taken to ensure that the outside surface is scrupulously clean before raising them to temperature. Any surface dirt, a water spot or a single fingerprint is a potential seed for devitrification." 208.42.18.222
:The oils or fats left by the finger cause uneven heating of the surface, which puts it under stress. --Kjetilho 00:25, 1 August 2006 (UTC)
thread_title:  Quartz Halogen Fingerprints 

message: Does the "Operation removes lightbulb from anus" news link (added with this edit: http://en.wikipedia.org/w/index.php?title=Incandescent_light_bulb&diff=61329116&oldid=61100085) have any place in the External Links section in this article? I think not, but I thought I should ask before removing it. It seems the point of the linked story is that the guy somehow ended up with an object in his anus, and the fact that that object was a light bulb isn't terribly significant. I think the link adds no value to this article and therefore should be removed.
Ra* 23:36, 14 August 2006 (UTC)
thread_title:  External Links 

message: I've been trying to find out the difference between CA, C7, and C9 bulbs.  One, or all of them, is the Candlabra kind, but I don't know the difference.  These terms may be used in the U.S. only.
:I don't know about "CA", but C7 and C9 are both standard American designations that follow the usual scheme. "C" means "Candle" (flame) shaped and 7 and 9 are the size in 1/8s of an inch, so a C7 lamp is 7/8 inch in diameter while a C9 lamp is 9/8 inch in diameter.
:C7 lamps used to be the standard size for indoor Christmas lights (with a "candelabra" screw base); nowadays they're mostly used only for nightlights and a few appliance lighting applications.
:C9 lamps used to be the standard for outdoor Christmas lights (with an "intermediate" screw base).
:Atlant 00:37, 21 October 2006 (UTC)
thread_title:  CA, C7, C9? 

message: Do you think that the redirects at the top of the pages are maybe a bit too confusing? You know you can follow 'incandescent light bulb' to 'lamp (electrical component) to 'light fixture', then to 'stage lighting instrument' And these are all quite substantial articles. I think a disambiguation-type page would make things a lot easier to navigate...Theonlyduffman 07:19, 7 November 2006 (UTC)
thread_title:  disambiguation 

message: Jobrien13057 added chlorine to the list of halogens used in tungsten-halogen lamps. I've reverted that out for now, but I'm more than willing to be proven wrong with a citation. Anyone have one?
Atlant 16:52, 14 December 2006 (UTC)
thread_title:  Chlorine used in lamps? 

message: It the beginning of the article, it says:
The current heats the filament to an extremely high temperature (typically 2000 to 6000 K depending on the filament type, shape, and amount of current passed through).
But I'm inclined to doubt this information, as tungsten melts at 3422K, and boils at 5555K, making me think that the filament is never "typically" heated to such a high temperature.
—The preceding unsigned comment was added by 24.147.72.202 (talk • contribs).
:This information was inserted by 18.250.0.177 on 8 November 2006 in an otherwise-valid edit, but I'll bet they acquired some Fahrenheit/Celsius/Kelvin confusion along the way. I understand that tungsten-halogen lamps run about 50C/K below the melting point of tungsten, so feel free to be bold and fix this up!
:Atlant 18:12, 18 December 2006 (UTC)
thread_title:  Molten, boiling filaments? 

message: I forget the names myself, but could someone add that to the history.
—The preceding unsigned comment was added by 70.48.39.164 (talk) 02:53, 4 January 2007 (UTC)
thread_title:  Names of the canadians who sold the patent to edison ? 

message: Many links to www.pegasusassociates.com on other articles were link spam. After removing a link to www.pegasusassociates.com on this article, I wasn't so sure it was link spam, so I reverted my link removal. I'll watch what others do and follow their lead. 24.160.188.24 22:45, 26 January 2007 (UTC)
thread_title:  What are limits of link spam? 

message: I was looking around at other websites (namely http://www.thehistoryof.net/the-history-of-the-light-bulb.html and http://invsee.asu.edu/Modules/lightbulb/meathist.htm) that claim Warren De la Rue enclosed the platinum filament in the year 1820 rather than 1840 as the article says. Is Wiki wrong? Throktar 05:49, 27 February 2007 (UTC)
replies: text: I noticed this same thing, after looking around I found several sites that said this. I am going to change it to 1820 for the time being, if someone finds a very reliable source that says 1840 feel free to change it back. 69.155.37.16 00:48, 28 February 2007 (UTC)
replies: text: Please provide a source which satisfies WP:ATT before claiming 1840 or 1820. Unsourced claims may be removed. The article on de la Rue in Wikipedia is not a reliable source. Harold Evans "They Made America" (Little, Brown and company, New York, 2004) says  (p152)that before Edison's 1879 invention of the evacuated bulb with the carbon filament of high resistance and small radiating surface, which gave off more light than a gas light and lasted long enough to be comercially practical, and drew little enough current to be supplied from a generating station, "The idea of the bulb itself had been around for 50 years; many other inventors had tried to heat filaments to incandescence: Ira Flatow, the science reporter, gave up counting at 23."  But it had not been "invented" 50 times because none of them worked or were practical or useful.  On page 159 Evans says "Nobody in the world in 50 years of experiments had been  able to keep an incandescent light alive for more than a few moments". Swan gave up in 1860 after experimenting for 12 years. If de la Rue or anyone else had invented a lightbulb which gave off a good light in 1840, why would the leading scientists such as Silvanus Thompson call Edison's claim an incandescent lamp could be made to work "sheer nonsense?" Sir William Preece British electrical expert claimed that "A subdivision of the electric light is an ignis fatuus" or "foolish fire. Sawyer predicted ignominious failure and denied that any light buld could be made to give off several candlepower for more than 4 hours. Edison 16:16, 20 March 2007 (UTC)
replies: text: De la Rue is a fairly obscure scientist. I could find nothing specifically about his work in a moderate sized public library, and the encyclopedia articles give no specifics on light bulb work. There are blogs/websites which claim 1840 and some which claim 1820 when he was 5 years old, so these are self-evidently unreliable sources. Looks like this will require a university research library to find 19th century sources. Edison 13:59, 2 April 2007 (UTC)
thread_title:  Warren De la Rue's date is wrong? 

message: The section on the halogen lamp should be its own article. There is already a page with that name created in 2002 as a redirect.
This would trim this lengthy article, improving readability and ease of use. A lot of relevant information from this article could also be transcribed over, creating more relevant article for those looking for information on halogen lamps. 
Ng.j 15:28, 4 March 2007 (UTC)
replies: text: Add  # Support  or  # Oppose  on a new line in the appropriate section followed by a brief explanation, then sign your opinion using ~~~~.  Please remember that this survey is not a vote, and please provide an explanation for your recommendation.
====Survey - in support of the move====
#mild oppose -- There's too much commonality to factor out halogen lamps. -- Atlant 19:56, 2 April 2007 (UTC)

text: Add any additional comments:
Hey - this is my first post, so be gentle on me.  I'm not quite sute how all this works.  All  I wanted to say was that Australia has not banned the incandescent light globe as stated in the introduction to the article. EJH69 07:38, 22 March 2007 (UTC)
thread_title:  Halogen lamp section should be separate article 

message: :Add  # Support  or  # Oppose  on a new line in the appropriate section followed by a brief explanation, then sign your opinion using ~~~~.  Please remember that this survey is not a vote, and please provide an explanation for your recommendation.
====Survey - in support of the move====
#mild oppose -- There's too much commonality to factor out halogen lamps. -- Atlant 19:56, 2 April 2007 (UTC)
thread_title: Survey

message: #mild oppose -- There's too much commonality to factor out halogen lamps. -- Atlant 19:56, 2 April 2007 (UTC)
thread_title: Survey - in support of the move

message: :Add any additional comments:
Hey - this is my first post, so be gentle on me.  I'm not quite sute how all this works.  All  I wanted to say was that Australia has not banned the incandescent light globe as stated in the introduction to the article. EJH69 07:38, 22 March 2007 (UTC)
thread_title: Discussion

message: Someone recently removed the brackets  [ ] from the the convenience links to online sources. The practice I am familiar with is to put the brackets around the html link and then to have text outside the brackets identifying the source. With this, the weblink, which may be quite long, appears in the reference section as a colored number, and the verbal description appears as black text. Is there a convention to just have the weblink and the description of it between the    and    in the inline cite in the text? I reverted to the previous version pending discussion. Edison 23:54, 12 March 2007 (UTC)
thread_title:  References 

message: It is a shame that lighting efficiency is such a complex technical subject!  It seems like the one thing people could most clearly agree on and understand is what percent of the energy supply turns directly into heat, so these numbers should be listed.  But what ordinary folk most want to know is, what percent of the energy supply is emitted in the visible spectrum, from the light fixture as a whole.  The complexities of adjusting that number to compensate for the sensitivity of the eye to various frequencies leads to numbers that should certainly be mentioned, but not as the only or even primary numbers here. (If a black box turns all of the electricity supplied into emitted orange light, to me that is 100% efficient.  If another box turns all of the electricity supplied into emitted purple light, to me that is 100% efficient.  If a scientist considers one to be more "efficient" than the other, because the eye sees purple better or worse than orange, that would be interesting to know, but would not change the fact that each is basically 100% efficient.)-69.87.193.242 15:31, 4 April 2007 (UTC)
thread_title:  Heat vs. efficiency 

message: Incandescent bulbs have a low resistance when cold, about one-tenth of the hot resistance.  So, when they are turned on, they use about ten times as much power for an instant, until the filiment gets hot.-69.87.193.242 15:31, 4 April 2007 (UTC)
thread_title:  Start surge 

message: I know it to be a fact that Germany after 1933 propagated the view that Jews could not be trusted. Are you seriously expecting Wiki to air such view (if Wiki existed in the 1930s)? You must be very naive if you expect citizens to believe what their governments tell them. Why should Wiki act as their mouthpiece? Wiki must stand by verifiable facts and not hide behind government statements or websites. If you must put your own POV, then you have to accept that others have a different viewpoint, and that their views need representation. Peterlewis 19:05, 11 April 2007 (UTC)
replies: text: There is a huge difference between saying "this is a fact because the government says so", and merely reporting "the government says this". This has nothing to do with believing what the government says, or the government being always right. Please check Wikipedia's neutral point of view policy; the way of balancing an article is not to delete the points of view you don't agree with, but to add references to reliable sources that show the opposing viewpoint. However, saying that the government announced that they want to phase out incandescent light bulbs is not even a point of view! It is merely a statement of fact. Saying "light bulbs are evil" would be an example of a point of view. --Itub 07:49, 12 April 2007 (UTC)
replies: text:  I agree with your first point, but if Wiki puts gov views, then it should also put in refs to the problems. It should also point out that govs change their views frequently, and are not necessarily reliable sources, since elections may change policies when different parties take control. Wiki should also point out that statements are frequently made by politicians solely to "fly a kite" without any reference to bodies responsible for consumer safety (for example), or other public bodies. They are simply trying to attract attention to themselves, and to advance their own name. Peterlewis 09:21, 12 April 2007 (UTC)

text: I'm sorry, did you just compare the push to ban lightbulbs to genocide propagation? I think you did. In any case, Wikipedia is supposed to present facts. It should not point out that politicians often make false statements because a) that is unverifiable and b) unrrelated to this particular case. Furthermore, Wikipedia is not an advocate for consumer safety either. It has no duty to act as such. —The preceding unsigned comment was added by 24.89.214.201 (talk) 16:00, 25 April 2007 (UTC)
thread_title:  Government Views 

message: Why is much of the introduction to this page on Incandescent light bulbs talking about CFLs?
I realise they are mentioned in relation to proposed laws in a handful of jurisdictions to ban incandescent lights, but surely there info that is more relevant that should be placed there. Most of the last paragraph sounds to me like little more than an attack piece against those proposed laws than anything relevant to a factual article. Canderra 16:48, 30 April 2007 (UTC)
replies: text: This should be split into another article about the banning of Incandescent lights. I don't see why people looking for information about the efficiency of incandescent lights (40w vs 60w) should have to look so hard to find that information. I was trying to make a decision based on the overall costs to see how much difference it would really make, and it was very hard! Benkenobi18 22:15, 8 November 2007 (UTC)
replies: text: I've created a new article, Incandescent lightbulb bans, which felt like it wanted to be it's own article. All of the information there has been moved, further information on this topic can easily be added without overwhelming the incandescent light bulb article. Benkenobi18 22:58, 8 November 2007 (UTC)
thread_title:  Much of the introduction is about CFLs and an editors dislike for them 

message: "Higher wattage bulbs tend to be more efficient than lower wattage ones. One reason for this is the fact that thicker filaments can be operated at a higher temperature, which is better for radiating visible light.
Another reason is that since higher wattage bulbs would lead you to use fewer bulbs, you buy fewer bulbs and the cost of bulbs becomes less important. To optimize cost effectiveness in this case, the filaments are designed to run hotter to improve energy efficiency to reduce your electricity costs.
Smaller bulbs use less electricity apiece, making the cost of the bulb more important. This is why lower wattage bulbs are often designed to last 1500 to a few thousand hours instead of 750 to 1000 hours. Designing the bulbs to last longer reduces their light output and energy efficiency."
Please add lumens/watts for typical 4W/7W E12 candelabra nightlight bulbs.  Explain why lower wattage bulbs are so much less efficient.  Add good links to collections of real spec sheets...-69.87.204.2 20:42, 15 May 2007 (UTC)
thread_title:  4W/7W E12 candelabra nightlight 

message: There is a lot of content about halogen lamps - looks like it could be spun out to get this article down in size and not so rambling in content. --Wtshymanski 23:37, 18 May 2007 (UTC)
replies: text: Done.  Started, anyway. Some of the "science" of electic lighting could also move out of this article and into electric light. --Wtshymanski 21:56, 28 August 2007 (UTC)
thread_title:  Split off halogen lamp? 

message: Are the output etc statistics given (and that appear on the labels in the stores) for a new bulb, or typical averages over the service life?  Over the service life, how does the output (lumens) and efficiency (lumens per watt) vary, for ordinary 40-100W 120VAC bulbs?  It seems like as the filament evaporates, the bulb would become more like a lower-wattage bulb, and have higher resistance, emit less light, and be less efficient in lm/W -- is this correct?  How large is the typical change?  Where is there more data about this?  Eventually, if we want to compare different lighting technologies fairly, we need to be discussing typical average performance of the life of the device/product/system, not just "maximum when new" claims.-69.87.201.16 11:20, 25 May 2007 (UTC)
thread_title:  output variation over service life 

message: (there are said to be about five billion light bulb sockets in North American households -- if we can pin down and source some such statistic, it should maybe be in the intro)
We need some photos of prism-separation of incandescent light.
These are interesting resources:
*Supplement: Build Yourself a Simple Hand-Held Spectrograph good sample spectra
*SPECTROSCOPY FOR THE SCHOOL build a simple spectroscope from a CD
*Lighting Reference Guide – Understanding the Theory lighting design reference tables
*Craig Johnson's ledmuseum hundreds of detailed spectra, of different kinds of lamps/bulbs -- but the infrared seems to not be fully included, and what about calibration?
-69.87.203.221 02:04, 26 May 2007 (UTC)
thread_title:  Spectra 

message: * General Service (A)
Yellowish-white light emitted in all directions.  Available in either clear or frosted.
Types: General (A), Globe (G), Decorative (D) (flame, teardrop and other shapes)
* Reflector (R) 
Reflective coating inside the bulb directs light forward. Flood types (FL) spread light. Spot types (SP) concentrate the light.  Reflector (R) bulbs put approximately double the amount of light (foot-candles) on the front central area as General Service (A) of same wattage.
* Parabolic Aluminized Reflector (PAR)
Parabolic Aluminized Reflector (PAR) bulbs control light more precisely.  They produce about four times the concentrated light of General Service (A), and are used in recessed and track lighting.  Weatherproof casings are available for outdoor spot and flood fixtures.
120V (PAR) 16, 20, 30 and 38 bulbs: Available in numerous spot and flood beam spreads.  Like all light bulbs, the number represents the diameter of the bulb in 1/8s of an inch. Therefore, a PAR 16 is 2" in diameter, a PAR 20 is 2.5" in diameter, and a PAR 38 is 4.75" in diameter. 
* Multifaceted Reflector (MR)
-- Halogen Bulbs  are available in two distinct voltage types - 120V AC and 12V AC/DC. 12V MR16 and MR11 bulbs are available in multiple color temperatures. 
* High-Intensity Discharge (HID)
Types of Bulbs and Their Usage
* HIR
"HIR" means that the bulb has a special coating that reflects infrared back onto the filament.  Therefore, less heat escapes, so the filament burns hotter and more efficiently.
-69.87.199.232 13:42, 19 June 2007 (UTC)
replies: text: You say "Like all light bulbs, the number represents the diameter of the bulb in 1/8s of an inch" - that may be so in America but is it true in the rest of the world who use the metric system? Jim77742 09:18, 6 September 2007 (UTC)
thread_title:  Bulb shapes, sizes, and terms 

message: I hope nobody objects to the reversion of the following line "During WWII, Hitler liked to burn jews and use their ashes to reduce oil usage." from 209.129.155.253 of the California State University Network. Kesmet 21:33, 20 July 2007 (UTC)
thread_title:  Vandalism 

message: I reverted an edit which removed a reference which stated that Edison's was the first "practical" light bulb. Let's discuss what constitites an incandescent electric light, and what factors make one practical or not. The determination is not really up to an editor; it should be cited to reliable sources who say a bulb was or was not a practical incandescent light. As soon as the battery was invented, around 1800, experimenters noted that electric current of sufficient amperage would make metals such as platinum (favored for its high melting point) and the nonmetal carbon glow brightly. The arc light was demonstrated by Davy before 1810. When the thin carbon rods  of the arc light were touched together to start the arc, they glowed brightly: they became literally incandescent before they were drawn apart and the aarc light was exhibited. If the conductor glowed brightly, it soon burned out, so it was a nice demo for a science class or to show a newspaper reporter, but not yet a practical light. A reporter could be impressed by a wire glowing red, but it would not be a satisfactory or practical light. If there were any oxygen left in the enclosure, it would soon burn out, and in any event the carbon from the heated rod would soon darken the glass. I say "rod" because generally early experimenters gave no thought to the need for a high resistance carbon filament, to allow powering a light from a central generating plant. They just connected a huge and expensive battery to a nearby conductor, made it glow for a few minutes, and voila. No one stood watching the demo 24 hours a day to notice that the glowing conductor only lasted perhaps one evening, like a candle wick made of platinum. Getting a patent on an incandescent electric light in the 1840's or 1850's does not constitute reducing the idea to practice. Swan and Edison in the late 1870's were the first to create incandescent lights that had any degree of practicality, as opposed to replicating the demonstration from the beginning of the 19th century that electric current makes a conductor glow for a while, until you increase the current to get near-white incandescence, soon after which it would burn out. Swan and Edison both have claims to fame in the development, but Edison accomplished a better product sooner, partly because of his greater research budget. See above under "Warren De la Rue's date is wrong?" for more references countering claims that earlier experimenters were the "true inventors." It is hard to document accomplishments of De la Rue because sometimes sources say De la Rive. Both experimented with electricity. Several experimenters were brought forward  in patent litigation of the 1890's to make hard to substantiate claims of prior research (just as happened with the telephone). Edison 22:38, 5 September 2007 (UTC)
thread_title:  Practical light bulb 

message: Whew.  I've tried to remove some of the excess fuzz and lint from the article.  Surprisingly, it only got about 4 kb shorter.  I think it's better organized now  - comments, please? But three hours at a time is about all I can stand. How long before it needs another clean-up? I really think the "ban the bulb" section should be sput out into a separate article if it needs to be represented at all; it's just a list of press releases at this point. We need more content - how about colored lamps? Rough-service bulbs? So-called long-life bulbs? --Wtshymanski 16:31, 20 October 2007 (UTC)
replies: text:  I have added some citations to GE Technical Publication TP-110. The efficiency values now in the table appear wrong, compared with this reference, and the original Web site is no longer available. --Wtshymanski 17:58, 26 October 2007 (UTC)
thread_title:  Sheep shearing 

message: Moved contents to Incandescent lamp, since this is the professional term of art for this type of lamp (and it is consistent with the names of other types of lamps). "Bulb" is a colloquial term, like "globe."  I didn't know what to do about the discussion, so I left it. Agateller 12:10, 1 November 2007 (UTC)
replies: text: Hold on a minute there... cat isn't under felis domesticatus. Let's talk about this before moving the article.  I agree that "incandescent lamp" is the term used by many in the business, but "light bulb" is a very common term and is commonly recognized, at least on the west side of the Atlantic. --Wtshymanski 15:08, 1 November 2007 (UTC)
replies: text:  The Merriam Webster dictionary here in the office says "Light Bulb" and redirects to "N: Incandescent Lamp" but doesn't tag it as colloquial. Strictly speaking, a gas mantle is also an incandescent lamp so we should say "electric incandescent lamp". Googling shows about 5:1 in favor of either "light bulb" or "lightbulb" over "incandescent lamp". Seems they call them "light bulbs" in India and the UK, too, according to Google. "Light globe" gets about a quarter the hits of "incandescent lamp" and not surprisingly many of these are from Australia.    Finally, ask youself - have you ever heard the joke about how many people it takes to change an electric incandescent lamp? --Wtshymanski 17:47, 1 November 2007 (UTC)
thread_title:  Moved text 

message: but modern exit signs must use LEDs)
Fluorescent emergency exit signs are the standard equipment in most of the world.
: Oh really?  Reference?  Not on my rather long-ago trips to Europe. It does say "modern".  --Wtshymanski 16:38, 11 November 2007 (UTC)
replies: text: Well, that's sweet that you're trying to be so careful of the teeming hordes who only get to see light bulbs in the palace of the local dictator, but the United States generates considerably more than 5% of the world's electricity. Got a reference? "Safety codes" are mostly a North American/European concern, anyway. --Wtshymanski 16:38, 11 November 2007 (UTC)
thread_title:  International Wiki 

message: I believe that there should be a link under the title along the lines of "Lightbulb redirects here. For Fluorescent bulb, click here. --HobbesDS (talk) 02:09, 7 January 2009 (UTC)
thread_title:  Link To Other Lightbulb Types