Pondering bulb bans, and shop lighting...

[LCHIEN]

Enough! Electro-optical engineer chimes in.

Enough of you guys arguing back and forth.

Here's what Wikipedia says about Halogen lamps:

A halogen lamp, also known as a tungsten halogen, quartz-halogen or quartz iodine lamp, is an incandescent lamp that has a small amount of a halogen such as iodine or bromine added. The combination of the halogen gas and the tungsten filament produces a halogen cycle chemical reaction which redeposits evaporated tungsten back onto the filament, increasing its life and maintaining the clarity of the envelope. Because of this, a halogen lamp can be operated at a higher temperature than a standard gas-filled lamp of similar power and operating life, producing light of a higher luminous efficacy and color temperature. The small size of halogen lamps permits their use in compact optical systems for projectors and illumination.

Tungsten-halogen lamps (a tungsten incandescent bulb with some halogen gases in the envelope) are more efficient than plain tungsten incandescents, producing more luminescent output for the same watts because the filaments run hotter they output more visible light. The halogen gas allows them to run hotter without decreasing the life or increasing the watts.

To my knowledge altho some may be working on it there's no breakthrough in more efficient incandescents without halogen. Halogen increases the efficiency by about 28% (e.g. a 72W halogen produces light equivalent to an old 100W bulb.

Classic bulb Manufacturers are able to produce halogens with pretty much the same production lines, most of the process is the same except some halogen is introduced instead of a complete vacuum. Thus the big name makers are probably still GE, Phillips and Sylvania.

Halogens are still relatively cheap compared to LEDs when comparing purchase price. But for applications like... accent lighting with a dimmer lamp (where its on for long times but at low levels extending the life and using lower power), or closets, pantries and powder rooms (on infrequently for short periods of time) the halogens make a lot of sense. Even compared to CFLs which may take 30-seconds or a minute to reach brightness, they are not good for closets and pantries, Halogens can be effective with a little lower price, instant on and limited on time making energy use less important.

Halogens are incandescents. Halogens are legal to manufacture and sell. Halogens will be around until LEDs are cheap enough to complete for all applications.

Incandescents don't fllicker at 60 or 120 Hz. The reason is that the light output is created by the hot filament radiating. WHile the current in the filament goes to zero twice per cycle, the temperature of the filament would have to go to room temperature twice per cycle to make the output cycle at that rate. The filament has enough thermal mass that it won't cool down in 8 milliseconds to where its light output varies. Anyone who says they flicker visibly at 60Hz or 120Hz is dreaming.

Now your old flourescent tubes visibly flicker, that's because the ballasts operate from magnetic transformers that operate at line frequencies. THe bulbs emit based upon electric field and since the electric field goes from a zero ti a maximum to zero twice per cycle the light output is in and off at the same rate. The newer fuorescent fictures with electronic ballasts operate at much higher frequencies using electronic oscillators that are much faster than AC frequecies. Magnetics are more efficient, smaller and lighter at higher frequencies so the cost of the elecrtonics is offset. This the CFLs and new fixtures won't visibly flicker.

An incandescent bulb is an interesting electronic circuit element. It has non linear characteristics being that the resistance is near zero when cold but fairly large when hot with a steep R vs V characteristic. THis feature caused Bill Hewlett and Bob Packard to use it as an amplitude feedback control element in the first HP instrument they manufactured, a signal generator.

Incubators, IR heaters, etc use them for their heat output which they are quite efficient, making about 99 watts of heat for every electrical watt put in.

So there are uses for specialty incandescents.

Finally there's a disagreement over "banned" which is mostly a disagreement of terminology.
One of you is saying that the incandescents are banned by law and the other is saying that incandescents are not banned but can't be made and the other is saying that is the same thing and so on. The facts are:
Incandescents are not banned by name or technology. e.g. the law does not say you can't make incandescents nor does it say you can't make bulbs with an evacuated bulb and a glowing tungsten filament.
The law bans the sale of light bulb technology which does not meet certain efficiency standards (in lumens per watt) and such standards were deliberately set to make old-type incandescents not pass but CFLs and the coming LED technology pass.
This effectively bans incandescents, unless they have a breakthrough which improves the technology. So incandescents are not banned by name, only by the performance they have (or don't have). Halogen incandescents are an example of technology improvement which allows the continued manufacture of incandescents. I imagine halogen technology was known before the law and it was lobbied to set the efficiency standard so that they could squeak through.

[gerti]

Halogens are still relatively cheap compared to LEDs when comparing purchase price. But for applications like... accent lighting with a dimmer lamp (where its on for long times but at low levels extending the life and using lower power), or closets, pantries and powder rooms (on infrequently for short periods of time) the halogens make a lot of sense.

Actually running halogens at low levels is bad for them. For the halogen cycle to work the glass temperature needs to stay very high. At lower temperatures the tungsten that boils of the filament will deposit on the glass. That diminishes the light output (glass turns black) and weakens the filament. That process is somewhat reversible when the bulb runs at full power again.

Another issue is that 120V halogen bulbs are fairly sensitive to vibrations.

12V halogens can't be dimmed easily because they usually use a transformer, and transformers are inductive loads which don't work with most common dimmers.

And lastly because of the high temperatures involved with halogens there may be limits to where they can be installed (proximity to flammable materials etc).

[LCHIEN]

Actually running halogens at low levels is bad for them. For the halogen cycle to work the glass temperature needs to stay very high. At lower temperatures the tungsten that boils of the filament will deposit on the glass. That diminishes the light output (glass turns black) and weakens the filament. That process is somewhat reversible when the bulb runs at full power again.

Another issue is that 120V halogen bulbs are fairly sensitive to vibrations.

12V halogens can't be dimmed easily because they usually use a transformer, and transformers are inductive loads which don't work with most common dimmers.

And lastly because of the high temperatures involved with halogens there may be limits to where they can be installed (proximity to flammable materials etc).

I hadn't considered that the halogen cycle would not be complete and would start darkening the bulb. However incandescent filament life is greatly (reverse exponentially) extended by lower voltage operation the filament life is probably a tradeoff. and comments like the following (and like you said) seem to indicate that use at full brightness will restore them, so I don't think I'm hurting anything too badly operating them dimmed some of the time.

researching, I found stuff like this that makes sense:
The description is mostly right. The bulbs don't fail because the envelope darkens, that's just the side effect. The bulb fails because the boiled off pieces of the tungsten are not redeposited on the filament. You gotta pretty severely dim the things to disrupt the halogen cycle, but if you leave things "moody" for a long time it can happen.
It is correct, that if you don't let things go too far, getting the bulb hot enough again will recover it.

[woodturner]

You click a link to a products page and there are no incandescents there, just LED, CFL, Halogen and fluorescent.

It appears we are using conflicting terminology. LCHIEN's post clarifies I think, and it appears that what I am calling incandescents are what you are calling halogens. To be clear, though, the "incandescent halogen" bulbs are much different than the original and older style halogen bulbs. Technically, by that definition, true incandescents have not been made for some time - most manufacturers have not been making vacuum-only bulbs for some time, due to constraints and efficiencies of the manufacturing process.

Regardless, there seems to be little value in debating the issue, so let's just agree to disagree.

As far as some people being able to see the modulation of the LED lamp I don't understand why a standard incandescent doesn't bother them. It turns off 120 times per second.

LCHIEN already responded to this question (both he and I are electrical engineers), but to further clarify or simplify the explanation:

An LED turns off almost instantly - cut the power and it goes dark immediately, which apparently can cause visible flashing for some people.

An incandescent or other heated filament type of bulb does not go dark immediately, and the inductance of the filament also reduces the rate at which current flow can change. As a result, when power is cut to the filament it starts to dim, but has barely dimmed before the next pulse. As a result, no flashing happens and the very slight dimming is apparently not an issue for those with the medical issues.

Another way of thinking about it is that the heated filament bulbs average (technically integrate) the light output, while LEDs rely on the human eye to do the averaging. If the eye does not average properly, one would see the flashes on LED lamps.

Banned vs restricted sales? i'm not sure i understand the difference.

Banned is generally considered to be a government mandate restricting manufacturing or sale. For example, DDT is banned - it's not legal to buy it or use it. The Apple II computer is "restricted sales" - the market eliminated desire for the product, so is no longer made due to low market demand, but the government never said "you can't make or sell them".

Or at least that's how I view the differences.

[woodturner]

THis feature caused Bill Hewlett and Bob Packard to use it as an amplitude feedback control element in the first HP instrument they manufactured, a signal generator.

Ah yes, the HP200A precision Wien bridge oscillator. It was actually the Wien bridge oscillator I had in mind when I made my comments about applications for incandescent bulbs. Meacham is credited with the idea of using an incandescent bulb in an oscillator circuit, but Hewlett figured out how to stabilize the amplitude and reduce distortion.

We have different ways of doing that now, of course, but in it's day, the Wien bridge oscillator was a significant advancement.

[LCHIEN]

Ah yes, the HP200A precision Wien bridge oscillator. It was actually the Wien bridge oscillator I had in mind when I made my comments about applications for incandescent bulbs. Meacham is credited with the idea of using an incandescent bulb in an oscillator circuit, but Hewlett figured out how to stabilize the amplitude and reduce distortion.

We have different ways of doing that now, of course, but in it's day, the Wien bridge oscillator was a significant advancement.

WT, I have a HP200CD in the garage, do you believe that? Do you know what the suffixes mean? I need to clean the sawdust off it, The leather handle on top is long gone. I think it worked when I last had it on in about 1979... The tubes may still work.

Answering my own question from Wikipedia:
Through the 1940s and into the 1950s, the subsequent versions of the 200A covered different and wider frequency ranges. The latest version was the 200CD; it covered from the subaudio 5 Hz to the low end of the AM radio band at 600 kilohertz. The 200CD became a ubiquitous audio generator in engineering laboratories worldwide from the 1950s to the 1990s.[7][8]

BTW it was their first product, they named it the 200 because they didn't want it to appear to be their first product.

[woodturner]

Answering my own question from Wikipedia

I did not know offhand what the suffixes mean, and was still searching when you edited.

I did find the HP museum page http://www.hp.com/hpinfo/abouthp/his...005/index.html
which suggests the CD was a replacement that combined the C and D frequency ranges.

They also show the original 200A
http://www.hp.com/hpinfo/abouthp/his...002/index.html

[LCHIEN]

here's what mine looks like from the hp webpages you linked. Its from circa 1952. Theirs is missing the leather handle too! I know it was leather because there were still a few scraps hanging on when I got mine.

[leehljp]

Here's a link to the quick and dirty Cost of Ownership spreadsheet used above.

http://tinyurl.com/Lamp-Compare

This comparison may be accurate as to cost of bulbs and energy use by the bulbs, but the real TCO is not necessarily or nowhere near accurately displayed. The real TCO is location dependent in context of user preferences . . . meaning:

Incandescent bulbs produce heat, considerable heat in warmer climates; The cost of running the air conditioner to keep the room temp at 78° in south Texas will be considerable less if using CFLs and LEDs than with incandescents. The AC cooling of the heat produced by incandescents is considerable.

When I changed from incandescent bulbs to CFLs in our house in Japan (2004) and our house in the USA (2005), I started saving over $100 a month every month from May through September. The CFLs did use less electricity for sure, but the biggest savings were noticed in summer when the AC was running and LOML liked 78° as max on the thermostat for the day and 70° at night.

TCO to me takes into account the energy saved or used by the AC to keep the temperature reasonable. IF the heat were not produced, it certainly would not have the need for the extra AC use. Conversely, the heat generated by incandescents in winter might be a "gain" if the heating unit/method were less efficient than the heat produced by the bulbs.

[LCHIEN]

This comparison may be accurate as to cost of bulbs and energy use by the bulbs, but the real TCO is not necessarily or nowhere near accurately displayed. The real TCO is location dependent in context of user preferences . . . meaning:

Incandescent bulbs produce heat, considerable heat in warmer climates; The cost of running the air conditioner to keep the room temp at 78° in south Texas will be considerable less if using CFLs and LEDs than with incandescents. The AC cooling of the heat produced by incandescents is considerable.

When I changed from incandescent bulbs to CFLs in our house in Japan (2004) and our house in the USA (2005), I started saving over $100 a month every month from May through September. The CFLs did use less electricity for sure, but the biggest savings were noticed in summer when the AC was running and LOML liked 78° as max on the thermostat for the day and 70° at night.

TCO to me takes into account the energy saved or used by the AC to keep the temperature reasonable. IF the heat were not produced, it certainly would not have the need for the extra AC use. Conversely, the heat generated by incandescents in winter might be a "gain" if the heating unit/method were less efficient than the heat produced by the bulbs.

good point, a room full of incandescents will be quite a bit warmer than a room with fewer, more efficient lights making the cost of cooling an additional cost of incandescents.

Likewise as you say in colder climes the incandescents might help heat the home some... of course most lights being near the ceiling won't be very efficient at heating the room, since heat rises, unless more air circulation was provided. Still, the incandescents we know produce about 1% light energy and 99% heat energy from the electrical energy used.

[gerti]

Still, the incandescents we know produce about 1% light energy and 99% heat energy from the electrical energy used.

I don't think that makes them 99% efficient furnaces though... ;-)

[LCHIEN]

for those of you not understanding why incandescents are so bad...
Incandescents' principle of operation is based on black body radiation. Physics say that a hot body will radiate energy at a broad spectrum of wavelengths of a hot object (in this case the filament). When you first heat an object it emits at infrared wavelengths and continuing to heat it, becomes what we call red-hot at some point - where it begins to emit in the red-end edge of the visible spectrum. When you continue to heat it it becomes hotter, eventually whiite-hot as they say as its main emissions go shorter in wavelengths the main spectrum increases into the visible. This is the principle of black body radiation.
The following shows the emission spectrum of an incandescent filament. You can see while it gives off light in the visible band, the majority of its energy goes off to longer wavelengths which we know as infrared and is not seen but felt as heat.




The next chart shows what happens when you increase the temperature of the hot object (measured in degrees K)
As you heat it further the main lobe of the spectrum moves out of the infrared and more to the visible spectrum which is why Tungsten hALOGEN iNCANDESCENTS are more efficient in visible lumens per watt.




Finally here's a composite spectrum of mutliple lighting sources:
Red is classic incandescent, yellow is tungsten Halogens, green is CFL and blue is LED. The CFL and LED spectrums do not use black body radiation but electrically stimulated emitters whose primary emissions are dependent upon the exact fluorescing compounds and additives of the bulb so they will appear different for various manufacturers which is one reason for all the confusion - they are not as alike as incandescent bulbs were and some people are more critical of the spectrum. Anyway you can see the most efficient sources emit majority of their spectrum in the visible spectrum.



I hope this was informative.

[gerti]

I hope this was informative.

Sure was, thanks!

[LCHIEN]

I don't think that makes them 99% efficient furnaces though... ;-)

they are not because the furnace is direct conversion of fuel into heat less the inefficiency of combustion (e.g. 100% of the potential chemical energy is never achieved - maybe 90%? guessing).
if we tried to duplicate heating with incandescent bulbs or simply resistors that don't have 1% optical output then we burn fuel at the electrical power plant, yielding 90% efficiency in making heat then 90% in steam heat to turning mechacnical turbines, the generators, electricity then we have 95% of that in transmission losses (IR drop, capacitive and inductive leakage etc) and the we have making maybe 80% efficiency from the fuel to bulb... not as good as burning fuel directly. Its the multiple conversions that are not 100% that rob you.
That's why gas or fuel oil central heat in cold climates is way better than electric heat which you may sometimes find in more tropical climes that don't see many cold days. Electric heat has cheap initial costs since Heating strips are cheaper than furnaces esp. when you don't have to plumb the house for gas. But the initial savings wears off in operating costs when its cold a lot.