BS: Replacements for incandescent lights

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,The black belt caterpillar wrestler
Date: 10 Jan 08 - 07:46 AM

The BBC web site science page had a recent article about dramatically improving the light output of LEDs recently but I couldn't find it when I searched for it.
Something to do with microscopic holes in the surface. Is this a surface area thing?

Subject: RE: BS: Replacements for incandescent lights
From: The Fooles Troupe
Date: 09 Jan 08 - 07:54 AM

... and he was using the electricity meter as a fan...

Subject: RE: BS: Replacements for incandescent lights
From: Jack Campin
Date: 09 Jan 08 - 07:24 AM

We had an unpleasant experience lightbulb shopping recently. We often visit Turkey, where daylight-balance CF lights have been omnipresent for years - they give a very good light, more natural than incandescents and vastly better than fluorescent tubes. So when we found a UK supplier who was offering daylight balance CF lights, we ordered enough of them for the whole house from a UK mail-order supplier (Coopers of Stortford) assuming we'd get something similar.

BAD mistake. What we got were Chinese-made things (Memolux) whose spectrum is nothing like the Turkish ones - they have a hideous green tinge. Every room that has them as the main light source looks like the set for a horror movie.

We were in Istanbul over the holidays and bought a new high-power CF spiral for the place that makes the biggest difference, but looks like we'll have to write off 100 quids' worth of the Chinese bulbs and go back to Turkey to get a rucksackful of replacements. I really can't live with the spectrum of any CFs you can buy in the UK.

The most natural fluorescent light I've ever seen was in a friend's attic marijuana farm 30 years ago. With a mix of standard, Gro-Lux and daylight-balance tubes totalling about a kilowatt in a small room lined with reflective foil, you could lie back among the waving fronds and think you were on a Caribbean beach.

Subject: RE: BS: Replacements for incandescent lights
From: The Fooles Troupe
Date: 09 Jan 08 - 12:03 AM

"At our house we have a chandelier, with many "flame-shaped" clear bulbs. I don't know the wattage, but low. How are the authorities contemplating that we handle that? Throw out the beautiful pro-rata chandelier?"

They haven't got 'flame shaped' ones yet, but you can get very small 'teardrop' shaped CFL ones - they are of course, about 5 times the cost of 'basic' CFLs. I remember (late 70s, early 80s) there used to be small 'neon flicker' flame shaped lamps, very low wattage comparatively.


"Christmas-tree strings also are designed for incandescent bulbs. Again, throw them away?"

You can now get 'led' Christmas-tree strings, but you will need to replace the whole set, of course.


"We tried a few of those spiral bulbs. They give a very unpleasant, harsh light. "

The very cheap Chinese earlier ones were like that, but the quality is improving.

Subject: RE: BS: Replacements for incandescent lights
From: Little Hawk
Date: 08 Jan 08 - 12:57 PM

We tried a few of those spiral bulbs. They give a very unpleasant, harsh light. I took them out and replaced them with the old-style bulbs. I will not be pleased if the old style incandescent bulbs disappear from the stores, and I will regard it as one more undemocratic ploy by Big Brother, in cahoots with some corporations that stand to profit from the situation.

Subject: RE: BS: Replacements for incandescent lights
From: Uncle_DaveO
Date: 08 Jan 08 - 12:33 PM

We do use a number of the spiral CFL bulbs, where possible. BUT!. . .

At our house we have a chandelier, with many "flame-shaped" clear bulbs. I don't know the wattage, but low. How are the authorities contemplating that we handle that? Throw out the beautiful chandelier?

We also have some high-intensity reading/floor lamps, which I think use filament/incandescent lamps. Are we to throw those fixtures away?

Throughout the house we have built-in enclosed ceiling fixtures. The CFL lamps I've seen come with the injunction not to use them in enclosed fixtures.

Christmas-tree strings also are designed for incandescent bulbs. Again, throw them away?

Dave Oesterreich

Subject: RE: BS: Replacements for incandescent lights
From: Donuel
Date: 07 Jan 08 - 12:44 PM

I think Halogen bulbs will be around a long time.
I like the bluish incandesent bulbs and did not think they might go extinct any time soon.

While you're at it stock up on Northern Lights and Maui Wowee.





don't forget to invite me to dispose of them.

Subject: RE: BS: Replacements for incandescent lights
From: John on the Sunset Coast
Date: 07 Jan 08 - 10:43 AM

My wife is an artist. Other than sunlight, she has found natural spectrum incandescent lighting to offer the most accurate color spectrum when working. I am a stamp collector (yeah, there are still a few of us) and most other lighting does not allow for accurate coloration when trying to identify older stamps. We also have solar tubes in her 'studio' which provide wonderful lighting on sunny days, but not so much on cloudy days or at night. Also, solar tubes allow heat into the room which necessitates the use of air conditioning during the summer, beyond what we might normally use, altho' we do cover them when not needed.
It is my plan to stock up on light bulbs against the day when they are no longer available, use them as long as possible, and damn the nanny state.

Subject: RE: BS: Replacements for incandescent lights
From: Donuel
Date: 07 Jan 08 - 09:41 AM

The best light bulb used by the US government is the micro voltage sulpher bulb. In the base a micro voltage microwave generator stimulates sulpher molecules in the bulb to produce a virtual heat free light that is powerful and 99.5% the spectrum of natural sunshine. They use these bulbs in the museums on the Washington Mall such as the Air and Space Museum.



These bulbs were invented in Germantown MD 12 years ago but it is my suspicion that they may have been bought out by Phillips Corp.

Indoor growers would love to get ahold of these bulbs. The DEA would hate for this to happen since infra red cameras would be useless in dectecting large indoor growing facilities that used this bulb.

So we are left with the highly toxic Mercury flourescent bulbs partly for the same reason that we have Flouride in the water.

It is CHEAPER to incorporate highly toxic substances in a new product or process than it is to safely dispose of highly toxic materials.

Subject: RE: BS: Replacements for incandescent lights
From: maeve
Date: 07 Jan 08 - 08:34 AM

GUEST,The Black Belt Caterpillar Wrestler, here's your link.

http://news.bbc.co.uk/1/hi/uk/7172662.stm

The article THHCW noted refers to the mercury contained in the new low-energy bulbs; thus the problem disposing of them. There are additional links on the site in regard to migraines and skin reactions to these lights.

Subject: RE: BS: Replacements for incandescent lights
From: The Fooles Troupe
Date: 07 Jan 08 - 08:24 AM

With regard to LED lamps as replacements in parkers, etc, but they are labelled here "only for off-road or show use - not for on road use"...

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,The Black Belt Caterpillar Wrestler
Date: 07 Jan 08 - 07:43 AM

http://news.bbc.co.uk/1/hi/uk/7172662.stm

They are back in the news, this time with concerns about how to dispose of broken ones.

Subject: RE: BS: Replacements for incandescent lights
From: folk1e
Date: 11 Oct 07 - 05:26 PM

I use a LED head torch for work and although the light is "cooler" than my Ever Ready 6v Torch it has been running of the same set of 4 AA batteries for well over a year now.

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,redhorse at work
Date: 11 Oct 07 - 08:34 AM

The "super" headlamp bulbs are high intensity discharge bubs. They are about 3.5 times as efficient as halogen: in rough terms they are 35W instead of 55W (less fuel, less emissions), and put out twice as much light energy (lumens). In a headlamp that is designed for them, low beam light above the horizontal is no more than on halogens, the extra light goes on big increases in beam width and a significant increase straight ahead.

The big problem comes when people try to replace halogen bulbs with HID in existing headlamps: the lamps aren't designed to control the light from an HID bulb, so it goes all over the place. These replacement bulbs are actually illegal on the road, but they're sold "for off-road use". Yeah right.

If you want LED headlamps you'll have to buy a Lexus Hybrid (LED low beam, halogen high beam) or wait for the option on Audi R8 next year.

nick

Subject: RE: BS: Replacements for incandescent lights
From: folk1e
Date: 11 Oct 07 - 07:03 AM

Well Donuel .....
IF it is the type I am thinking of you need a co-axial wire to run from the control unit to the lamp as the frequency is quite high!
That is enough to stop most domestic use all on its own.
High pressure sodium lamps give a far better output than halogens ie Sodium 70W = >500W Halogen
Of course there is a cost element involved

Subject: RE: BS: Replacements for incandescent lights
From: Donuel
Date: 10 Oct 07 - 12:46 PM

LED's are great but for

THE BEST DAMN LIGHT BULB IN THE WORLD
that immitates natural sunlight the best - and is used in the Smithsonian Air and Space Museum-

is mercury free and uses a tiny microwave base that stimulates Sodium atoms in the bulb.

It procuces 99% sunshine with so little heat you can touch it while on.

It was invented down the road in Gaithersburg 10 years ago.

Why it is not used domestically is both strange and silly.

Its use for indoor agriculture is second to none.

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,The black belt caterpillar wrestler
Date: 10 Oct 07 - 11:55 AM

Is it the "super" headlights that change colour as the approaching vehicle goes over an uneven surface?

If so how come they don't fall foul of the regulation that a vehicle must not show a flashing blue light unless it is an emergency service vehicle responding to an emergency? Several times recently I've been about to pull over because of a flashing blue light behind me only to realise it is a deffective headlight with a prismatic effect!

Subject: RE: BS: Replacements for incandescent lights
From: JohnInKansas
Date: 09 Oct 07 - 04:43 PM

In the US, according to my observations, the new "super" headlights have appeared on only a few cars, so they're not really too common on the roads I drive. Properly aimed they're distinctive due to their color, but I don't generally find them bothersome when met on the road.

The new bulbs, however, are available as replacements for older halogen lamps, and do show up on the road, nearly always misaligned so that one or the other of the headlights is aimed directly into your face on "low beam" (dimmed) and shoots off into the sky when switched to the high beam.

People rely on the lamp housing remaining at or going back into exactly the original alignment when a new lamp is installed, and this almost never happens. With careful lamp replacement, the misalignment likely will be small, but a "sloppy" replacement can produce a really annoying (to others) setup.

The number of people who think they can just slip a new lamp in vastly exceeds the number who have even a foggy notion that the lamp alignment can be adjusted, and the number who might have some idea how to do it is infinitesimal. Even "professional" service shops commonly replace headlamps without bothering to verify or adjust the aiming after the new bulb is in. (And often the one that burned out was already mis-aimed.)

Although the brighter new bulbs make a misaligned oncoming headlight somewhat more effective in rendering you totally blind, even the old ones often suffer from the same problems of bad alignment.

Vehicle manufacturers perhaps contribute to the number of mis-aimed headlights by insisting that the aiming requires a "special tool" that's somewhat expensive. It's quicker and easier using the tool, and shops that don't have the one for your make/model may decline to attempt an alignment, based on manufacturers "specification" that the tool must be used. Older methods that don't rely on the tool(s) may be slightly less precise, but would certainly be sufficient to eliminate the worst offenders if used more widely - and more intelligently.

John

Subject: RE: BS: Replacements for incandescent lights
From: Greg B
Date: 09 Oct 07 - 01:37 PM

Brightness standards for car headlamps have increased considerably---
even more so in Europe and the UK than in the US. For good reason--- the
old ones were fairly feeble.

In addition, 'projector beam' headlamps can be even brighter than
halogen sealed beams or reflector lamps.

Subject: RE: BS: Replacements for incandescent lights
From: Mr Red
Date: 09 Oct 07 - 01:31 PM

Grab
I take your point re car headlamps - but I heard it more recently than 30 years ago.
BUT how come the current batch of car headlamps blind you when the older style don't? It isn't just the spectrum.

Someone reported using LED stage lights and commented on the coolness (Celsius)

Subject: RE: BS: Replacements for incandescent lights
From: Grab
Date: 08 Oct 07 - 08:47 PM

Thanks folk1e. Something else to save my pennies for, then. :-)

Subject: RE: BS: Replacements for incandescent lights
From: folk1e
Date: 08 Oct 07 - 07:50 PM

They used LED stage lamps at Fylde folk festival a couple of years ago. The concensus was that they performed very well in all colours, including white! The very low life of mobile stage lights would pay for the LED's quite quickly!

Subject: RE: BS: Replacements for incandescent lights
From: JohnInKansas
Date: 08 Oct 07 - 02:06 PM

A somewhat simplified outline of halogen lamps:

In a normal old-fashioned incandescent lamp, some of the tungsten evaporates from the filament and most of it condenses on the inside of the glass. This condensed tungsten is one of the reasons that an old lamp begins to look gray (grey for the Brits) toward the end of its life. The same gray spot often shows up at the ends of fluorescent tubes as they age. A simple incandescent must be operated at a filament temperature that minimizes the rate of evaporation of the filament. The gas, typically Argon, used to fill the bulb helps some in keeping evaporated tungsten close to the filament where some of it may be re-absorbed, but can't do a really effective job at preventing some escape of the filament metal.

By adding a halogen to the gas, the evaporated tungsten combines chemically with the halide to form a tungsten-halide compound that remains volatile (evaporates from the high silica glass if it's hot enough). Most of the evaporated tungsten combines within the gas; but even metallic tungsten that makes it to the glass will be "scrubbed" off the glass by combining with the halide, and the tungsten halide will then "evaporate" back into the gas.

When the tungsten halide in the gas contacts the filament, at filament temperature the compound dissociates and deposits the tungsten back on the filament, freeing the halide to combine with more free metallic tungsten in the gas, and to go back and scrub more of the tungsten off the glass.

Since the same current goes through all of the filament, in a normal bulb any thin spot gets hotter than the rest of the filament, so it continues to get thinner, at an accelerating rate, and eventually the filament fails when the "hot spot" burns away (or actually melts and the filament falls apart).

To some extent, the hottest part of the filament gets the fastest return of tungsten from the tungsten halide in the halogen bulb, so the "hot spots" get "healed" by getting more tungsten re-plated back onto them, maintaining an evenly distributed temperature over the length of the filament – and hence an evenly distributed resistance along the length of the filament. This allows the filament to operate at temperatures much closer to the melting point of the filament.

The high temperature of the glass envelope is necessary for the operation of the tungsten to tungsten halide and back to tungsten cycle, since the tungsten halide will not evaporate from a too-cool glass surface. While a "dimmer" can be used with a halide bulb, dimming enough to cool the glass below the point where the tungsten halide is rapidly evaporated can cause the bulb to fail quite quickly. Halide lamps are commonly used with "two position" dimmers that allow a high/low selection, and are sometimes found with continuous "fader" type dimmers, but bulb life is often somewhat shorter when used in either of these kinds of fixtures, especially if most of their use is at lowest light levels. (Especially if much use of low levels is the practice, occasional cycling to "full power" for a while may allow the bulb to clean itself up some?)

The glass envelope must operate at a high enough temperature for evaporation of the tungsten halide compound, and ordinary soda-lime glass likely would at least "sag" at the required temperatures, and certainly would not stand up to the rapid temperature changes during on/off cycling, so the glass envelope for a halide lamp must be a very high-silica type. Glasses of this kind (often called quartz-glass, and simplified to just "quartz" by the careless) have extremely high melting points, so they're somewhat more difficult to handle in molding the parts. Common molding processes top out with the "Pyrex®" class of glasses that are refined to high purity before molding. To get to the "Vycor®" level, usually a pyrex part is molded, the small amount of residual lime is leached out by acid etching, and the part is then "re-fused" at very high temperature without the benefit of a mold to get the final part. I don't know whether available lamps get by with pyrex-grade tubes, or if higher grades are required, but they definitely are not "window glass" like older incandescents.

The required glass temperature is high enough that any "contamination" – even a fingerprint consisting of nothing more than "body oil" – on the glass surface may cause a "hot spot" that can cause breaking of even the high quality glass used, hence the caution to "never touch the glass" during installation of a halide lamp and the common use of protective shields and "guard glasses" to keep the bugs away from the actual lamp/bulb. ("June bugs" and common moths make a marvelous smoke plume when the get past the guards.)

John

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,redhorse at work
Date: 08 Oct 07 - 08:18 AM

Sorry to correct Mr Red, but power hasn't been the legal limit for vehicle lighting in UK for about 30 years. Vehicle lighting is required to meet UNECE regulations, which specify in terms of intensity (cd.). Tail lamps are 4-12cd irrespective of what's used as a light source.

nick

Subject: RE: BS: Replacements for incandescent lights
From: Grab
Date: 08 Oct 07 - 07:48 AM

Dick, that's true enough. However the interval between pops is such that you're likely to need to replace the ceiling before the LEDs... :-)

Yeah, LEDs don't give "proper" full-spectrum light, just an approximation of it by having three (or more) peaks. But then incandescents don't give fully even lighting either - they're much more biased to the yellow end of the spectrum, which is why you can get "daylight" bulbs with compensating filters to give a more accurate colour.

Re LED lamps and Mr Red's earlier comment, has anyone tried LED pars for stage lighting? We're contemplating getting a few lights for our band, and I'm quite taken with the idea of using a couple of LED pars which can do colour fades independently without needing a DMX power block, don't get hot, and don't need bulbs or filters replacing. They're more expensive than fixed pars, but if you compare them to a standard four-colour setup with DMX faders, they start looking pretty damn appealing. But what's the light like from them, both in brightness and quality?

Graham.

Subject: RE: BS: Replacements for incandescent lights
From: Rowan
Date: 07 Oct 07 - 06:39 PM

John wrote:
"Halogen lamps are incandescent lamps, with the only difference being that the addition of a halogen in the gas surrounding the filament permits the filament to operate at a higher temperature with reasonable life. (The higher temperature mandates the high-silica tube and the reduced gas volume that's typical.) The higher temperature theoretically at least provides somewhat more intensity at short wavelengths, and hence gives a higher "color temperature," while at the same time giving slightly more light across the longer wavelengths - hence a somehat "brighter" light. Halogen task lights can be "too bright" for some people if applied without some care, but problems with proper application are not materially different than for older incandescents."

While my understanding of them is broadly similar, it may be that some other information is relevant; it's been a while since I was seriously into the technical details so feel free to correct my misapprehensions.

There are two or three differences between quartz halogen (as they're often called here) lamps and the routine incandescents when used in routine domestic lighting.

1 The higher temperature (both degrees Celsius and 'colour'; the latter implies better approximation of flesh tones when using "daylight" colour film indoors) means they not only emit more light across the spectrum (including the longer wavelengths John mentioned) but also the shorter wavelengths. This means their UV output is a bit higher and not all of it is absorbed by the glass envelope. Most such lamps used in Oz domestic situations are housed in a reflective housing about 40mm diameter. If using them for reading lamps rather than area lighting or ceiling-mounted task lighting, the routine advice is to use the versions that have a glass pane between the bulb and the user. The pane absorbs the UV.

2 Most 'older' incandescents used in reading lamps and task lighting have a bulb that is at least 50mm in diameter; many people prefer 'pearl' bulbs as they diffuse the light so it appears to be emanating from the full diameter of the bulb, but even 'clear' bulbs will have a filament that is almost 20mm long emitting light from its full extent. Both these characteristics make close work more or less shadow-free. The reflective housing of most quartz halogen bulbs used in similar situations is usually not smoothly parabolic but is facetted. This may have been the cause of the multiple shadows in her close work that frustrated Bee.

Cheers, Rowan

Subject: RE: BS: Replacements for incandescent lights
From: Mr Red
Date: 07 Oct 07 - 07:31 AM

Yes - and in the UK the power in is the legal limit, so they will blind us. A lot of cars use red for rear lights (EG Puegot) and HP (now Agilent) were selling indicators to the US car makers 10 years ago.

white LED's are actually flourescent, they are UV/blue and the case is loaded with phosphors that glow as they absorb UV and emit at lower frequencies. The ballance of blue is a combination of getting the mix right and the fact that our eyes and expectations are at for incandescent and sunlight spectra so more blue looks blueish to us. Hence the blue seen in rooms from outside when the TV is on, true white has a blue cast at night. The white LED's are peaky at the phosphor frequencies but look better than EL.

Subject: RE: BS: Replacements for incandescent lights
From: Peace
Date: 07 Oct 07 - 01:14 AM

This gonna happen in the auto industry, too?

Subject: RE: BS: Replacements for incandescent lights
From: JohnInKansas
Date: 07 Oct 07 - 01:10 AM

As a general rule LEDs produce a single very narrowly defined frequency of light. The most common emit either green or red frequencies.

By using multiple LEDs in combination, or with "multi-doping" techniques, sufficient frequencies can be combined to produce an impression of white light, and there are a couple of kinds of LEDs that can produce "sort of an almost white" emission; but for uses requiring light adequate for activities such as reading, particularly for sustained periods, the quality of light produced is actually rather poor.

LED power consumption and life are excellent. Original cost of purchase of LED devices is variable, but is dropping some and in some cases is quite reasonable. For area lighting, accent lights, spot lighting, and other (mostly decorative?) uses, they can be an excellent choice.

New devices are announced frequently, and I haven't had a need to keep up on what's the latest in commercially available LEDs, but I'd have to see some accurate and fairly detailed spectral data before recommending them for any "task lighting" purposes. While you may be able to buy some few specific devices that are "wider spectrum," the advertising doesn't reveal whether the one you are about to buy meets any standards for spectral distribution, so there's not really a good way to select the "good one" (if one really exists).

Early fluorescents, that used only one or two phosphers, suffered from similar limited spectral distribution, and tubes of this kind are still available. "Daylight" (probably ®) and other more advanced constructions can use multiple phosphors to get adequate task light spectra for most people and for most uses. A few people may still be bothered by the "impure color" of even the best of these.

Since the "wide spectrum multi-phospher" constructions were well established in older tubes, it should be reasonable to expect similar spectral quality from any competently manufactured compact fluorescents. I'll note that I haven't seen any reliable data on whether (or which) compact fluorescents are wide-spectrum (aka multi-spectral) devices, but the ones I've used appear to give reasonably good light quality, at least for area lighting applications.

The incandescent light emits simple blackbody radiation, and in normal constructions should have no peaks or blanks across the spectrum. For people sensitive (or insensitive) to specific frequencies, or for those unusually sensitive to "flicker" and similar effects, the incandescent is about the only easily available and economical light source that may be usable for critical task lighting.

Halogen lamps are incandescent lamps, with the only difference being that the addition of a halogen in the gas surrounding the filament permits the filament to operate at a higher temperature with reasonable life. (The higher temperature mandates the high-silica tube and the reduced gas volume that's typical.) The higher temperature theoretically at least provides somewhat more intensity at short wavelengths, and hence gives a higher "color temperature," while at the same time giving slightly more light across the longer wavelengths - hence a somehat "brighter" light. Halogen task lights can be "too bright" for some people if applied without some care, but problems with proper application are not materially different than for older incandescents.

Encouraging people to use compact fluorescents and/or other more energy efficient lighting solutions, even including "penalties" for suboptimum usage, is a "mostly sound" policy; but a total ban on incandescents is stupidity in the guise of political correctness and expediency. (Note opinion content at end - it's my opinion and I don't particularly care if you agree.)

John

Subject: RE: BS: Replacements for incandescent lights
From: The Fooles Troupe
Date: 06 Oct 07 - 11:40 PM

BTW, the comments about the Chinese CFLs having lousy light colour refers to them using the 'older formulations' for the fluorescing powders. The newer ones are much better - but not as cheap to make.

Subject: RE: BS: Replacements for incandescent lights
From: The Fooles Troupe
Date: 06 Oct 07 - 11:36 PM

CFLs heat up far less than incandescents and especially, halogens.

There has been talk here in Aus in the electric/electronic community about the excessively poor performance of 'Chinese made' CFLs - this seem to be related to the use of substandard components - especially the High Voltage capacitors. Stories have been told of enthusiasts replacing the capacitors, and reviving the dead CFLs for several hundred hours extra life.

This is not normally economical - the cost of a qualified person to do the work exceeds the cost of a new unit - and you need to be capable of working safely on the HV circuits, and the units are not designed for easy opening and maintenance. Also comments have been made about the substandard design - inadequate gaps for the high voltage areas on the circuit boards, etc.

Moral - buy the non-Chinese ones - they do cost more, but they last longer - this may change as the manufacturers improve.

Subject: RE: BS: Replacements for incandescent lights
From: Keef
Date: 06 Oct 07 - 07:41 AM

I've bought about 20 compact fluoro globes over the years. Depending on which room they have been used in and how many hours a day, they have all lasted only about 2 years before deteriorating or failing completely.
They also give a rather horrible light and are made in China which has a dubious record on human rights and the environment.
And now we will be forced to buy them???
Leds are better, they run completely cold unlike compact fluoros in which do heat up.
Still too expensive though....improvements including colour adjustment are promised real soon now?
Lighting uses only a small percentage of the household power (unless you use a lot of those horrid halogen firestarter globes)

Subject: RE: BS: Replacements for incandescent lights
From: Mr Red
Date: 06 Oct 07 - 07:04 AM

and LEDs last 100,000 Hrs normally unless they are driven too hard. Like lughting apps - still better than energy saving bulbs on MTBF (life).

Subject: RE: BS: Replacements for incandescent lights
From: Mr Red
Date: 06 Oct 07 - 03:57 AM

LED arrays - depends on the confiuration - one PSU and multiple outlets means parallel. And you can get those in DIY stores. And diodes can burn short so a series connected array may go brighter then go pop. If they are fed with AC pairs of diodes would be back to back so some light continues. Ya get wot ya pays for.

Eye - peaks at the yellow frequencies.

Magnetics - simple (ie cheap) dimmers use thyristors which switch on at varying angles to effect control of an average voltage. Magnetics don't like transients too much, and then as folk1e says the current is still positive when the voltage goes negative which electronics don't like too much. (similarly in the negative part of the cycle)

Subject: RE: BS: Replacements for incandescent lights
From: dick greenhaus
Date: 05 Oct 07 - 12:08 PM

One major problem with multiple-LED arrays is that, like old Xmas tree lights, they're series connected. If one goes, they all go.

Subject: RE: BS: Replacements for incandescent lights
From: mouldy
Date: 05 Oct 07 - 08:45 AM

Well just about all the lights in my house have been "energy savers" for years, and now they do small ones that actually fit the shades, my wall lights are too. That's made 240w go down to 42w. The range and style of the bulbs is improving all the time.
Because I'm on my own a lot I tend to just use a 20w bulb in the standard lamp next to my chair and remember to switch other lights off when not needed. However I have to confess that in having my bathroom modernised I have gone down the halogen light route from fluorescent tube lights, and I have a halogen reading lamp at the side of my bed. But I still have 2 fluorescent tubes in my kitchen.

Andrea

Subject: RE: BS: Replacements for incandescent lights
From: folk1e
Date: 04 Oct 07 - 08:15 PM

I was taught that we see more "efficiently" at the yellow point of the spectrum. Fairly close to that of sunlight!
A choke is just a magnetic coil, the reason dimmers "don't like magnetics" is that with A.C. a magnetic coil will alter the phase angle and cause more power to be used with less effect. Our teacher (yes I still remember him) demonstrated a "dimmer" that used that effect. He called it Wattless power! He also showed us how to dim any normal 240v flourescent fitting!

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,The black belt caterpillar wrestler
Date: 04 Oct 07 - 04:39 PM

Does a light that is more to the blue end of the spectrum give a false impression of being brighter?
I'm asking because I have one of those wind up LED lanterns that have a quite blue light that glares a lot but in contradiction doesn't seem to illuminate well.

I know that the human eye works best in the green part of the spectrum and is more efficient at detecting colour differences in that range.
Some evidence for saying we evolved in jungles rather than on the savanah?

Subject: RE: BS: Replacements for incandescent lights
From: Mr Red
Date: 04 Oct 07 - 01:50 PM

The problem with LED lights when sold as 240 Volts is that they have some form of step-down, like a transformer and choke circuitry (magnetics). It is the magnetics that the dimmers don't like.

Flourescents have chokes, energy saving bulbs still have magentics - albeit at a higher freqency and gawd knows what on the 240v side to chop (techie term) the 50Hz.

They had banks of LED lights in the ceilidh tent at Shrewsbury FF and they were bright. I bet it saved on the power cable size though. And the weight in the roof.

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,Keinstein
Date: 04 Oct 07 - 07:33 AM

Quite right JiK, but the point I was trying to make is that it's the AC that's being controlled- so with LEDs or other lights that go instantly on/ off the dimmer will produce unpleasant flicker at 100/120Hz. With incandescents the thermal inertiaof the filaments is enough to mask this effect.

It's quite possible to make HF pwms that won't flicker, but in these days of costs pared down to nothing, they won't happen until the market's hand is forced.

Another thing that annoys me is the difficulty of comparing specs when some units are quoted in candelas, others in lux, others in lumens, others in watts/ square metre, and yet others (the incandescents) in just watts. These all measure different aspects- the consumer only needs four parameters: How much visible light it emits, what is its angle of illumination, what colour(s) is the light, and how much power it takes.

Subject: RE: BS: Replacements for incandescent lights
From: JohnInKansas
Date: 03 Oct 07 - 11:54 PM

Reducing the amount of energy used, whether it's by using more efficient methods to do the same things, or omitting the frivolous energy hogs that advertising urges everyone to have.

I've chosen, in one instance, the removal of a power hog, by de-commissioning and attempting to remove the busted hot tub.

My primary observation from that effort is that it is extremely difficult and time consuming to cut up a heavy, structural, fiberglass object to get it through the door, after some

          F***G IDIOT

builds the room around it after installing the monster.

John

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,petr
Date: 03 Oct 07 - 05:06 PM

the question is - what to do about backyard patio heaters, or driveway de-icers etc..

the light bulb thing is a step toward higher efficiency but doesnt address higher energy use - we may encourage a higher efficiency refrigerator but its pointless if people put the old fridge in the basement - or get a wine cooler or water cooler etc..

Subject: RE: BS: Replacements for incandescent lights
From: McGrath of Harlow
Date: 03 Oct 07 - 01:41 PM

Gas gives much pleasanter lighting. I wish they'd kept on developing the technology to make it less inconvenient. I don't know how it measures on the eco-scale though.

Subject: RE: BS: Replacements for incandescent lights
From: JohnInKansas
Date: 03 Oct 07 - 01:10 PM

Keinstein - What you describe is exactly what PWM is. Pulses occur at regular intervals. The "width" of the pulse is controlled/varied to change the net power transmitted. If you do the math, almost any "signal conditioning" can be described as a "phase effect," "frequency effect," etc. (FM radio should properly be called Phase Modulation, since the signal is carried in the phase difference between the received signal and a reference frequency, according to some.) While the textbooks often illustrate the theory with square waves or sawteeth, that isn't what really happens in most real-world devices. Improperly designed or inappropriately applied, the simplest "peak clipping" devices, like those used for common incandescent light dimmers can generate lots of noise, but it's not really necessary with slightly more sophisticated components.

A problem commonly encountered with solid state switching devices, like LEDs, is that the do not tolerate being "sort of on" or "pretty much off." In the vicinity of the "on" switch point they carry large currents but still have significant resistance, so they heat up and go "POP!." In the vicinity of the "off" switch point, they have high resistance but still have significant current, so they heat up and go "BANG!."

Back in the olden times, much attention was devoted to designing effective "crowbar circuits" that would assure that when the device was switched on it would go instantly to "FULLY ON" and when it was switched off it would be instantly "FULLY OFF." Most solid state devices that resemble LEDs now usually contain additional components on the same chip to assist the flip between ON and OFF states, and to prevent dwell in the nether region between, but a clean drive signal that makes the transition quickly and cleanly is still important.

A "clipping circuit" of the kind Grab suggests, and that Keinstein describes, has a tendency to "soft switching" that is potentially destructive when used with solid state switching devices. A circuit of that kind would likely be used to detect when the actual drive voltage/current would switch on and off, but would likely be the "control" circuit to switch the actual bulb/tube voltage/current between two fairly stable ON and OFF states. To avoid flicker (and to minimize component size) the switching would likely be at a much higher frequency than is available from ordinary line sources.

If one still needed to solder a bunch of components together to convert AC line to DC, oscillate at higher frequency, transform to preferred voltages, and PWM the ultimate output to apply it to the bulb, questions of "complexity" would be of very real significance; but in today's world one just "buys a chip" and plugs it in. It's a lot like building a radio - since about 1950 or so.

A difficulty with the "compact fluorescent" replacement bulbs is that "on the inside" they don't operate off line voltage. The line voltage is converted inside the base to what is needed to light up the tube. A dimmer for bulbs of current design would need to be part of the conversion circuitry to be effective, so each bulb would need its own built-in-the-base dimmer knob.

The situation is similar for halogen bulbs/lamps, but for a different reason. The lamp must be operated at full power in order for the glass/silica tube to come to proper operating temperature. If the outer tube does not reach proper operating temperature the filament will self-destruct fairly rapidly. The tolerance on temperature is sufficient to allow halogen elements to be used in most "livable" environments, but they don't last as long in extremely cold areas as more common incandescents. If "visibly dimmed" they most likely would cool off too much to provide the "halogen effect" for which they're named.

John

Subject: RE: BS: Replacements for incandescent lights
From: GUEST,Keinstein
Date: 03 Oct 07 - 06:18 AM

Most dimmers don't do PWM on the AC, they do phase control. That means the AC doesn't turn on (if you're dimming) at the start of the cycle, but is delayed until some later point. This results in a horrible current waveform like ripsaw teeth.

Subject: RE: BS: Replacements for incandescent lights
From: Grab
Date: 03 Oct 07 - 05:30 AM

That's what I was thinking too, John - a simple array of multiple LEDs is the only sensible way to do it. As for dimming, the problem with square-wave PWM is that you need to be starting with DC. But a dimmer switch is just doing PWM on the AC anyway, so the effect will be basically the same.

Graham.

Subject: RE: BS: Replacements for incandescent lights
From: JohnInKansas
Date: 03 Oct 07 - 01:52 AM

One of the very real problems I've had with my ~60 year old house is that ceiling fixtures - whether loaded with rated size bulbs or with "something bigger" to get more light - eventually bake both the insulation on the wiring/wires and the ceiling panels (plaster board) to the point that any movement of the wire invites spectacular fireworks and interrupted circuits, and replacing a fixture quite often involves breaking out enough "fried and powdered" plaster board to get to something solid enough to start a patch from.

At least the new lower watt lamps (can) dump a little less heat into the fixture and surrounds, so that potentially things may last a little longer, and perhaps be a little safer from the structural/fire resistance standpoint.

Sixty or seventy years shouldn't be long enough for anything to show the wear and tear I've seen in some of the stuff around my place.

[Excuse me for a moment now. LiK seems to be having some sort of convulsive gigglefit.]

John

Subject: RE: BS: Replacements for incandescent lights
From: San Francisco Bill
Date: 03 Oct 07 - 12:48 AM

Thank you all for this discussion. I had no idea that so many people were 'allergic' to CFL lights, but it seems like the older ones are at fault.

Some years ago, following a kitchen remodel, my wife (for the moment) insisted on 150 Watt bulbs for our 6 ceiling lights. They blew out our 600 W dimmers in short order - the math is not that difficult to do to explain why THAT happened.

I switched to 65 watt 'miser' bulbs, and nobody noticed - I even stopped having to replace dimmers! Once it was over, she started using the 150 watt bulbs, with the inevitable dimmer blow-outs.

To the point, you don't have to be a tree hugger to try to eliminate waste. I manage a vacation property at Lake Tahoe. I was shocked - so to say - when the summer electricity bill was over $400 a month!

The highest cost - by far and away - is, as a rental, when the maintenance man has to come out and replace a bulb, he charges $25 for the trip! Plus the cost of the bulb!

I just came back after replacing about 20 bulbs with CFLs. When I go back in November, I plan on replacing 20 more. Soon, the electric dryer and cooktop will be toast as well, as I plan to replace them with gas!

Subject: RE: BS: Replacements for incandescent lights
From: mg
Date: 03 Oct 07 - 12:05 AM

Gee..how about sunlight..solar tubes etc. The devil herself might have invented flourescent lights, at least the older ones. They have so many health hazards associated with them. Sit in the dark before you sit under them, and protect children from them. It is like drinking sewage water from an electromagnetic standpoint. mg

Subject: RE: BS: Replacements for incandescent lights
From: JohnInKansas
Date: 02 Oct 07 - 10:55 PM

Grab -

I haven't seen LED lighting that's other than as arrays of multiple individual LEDs - usually a fairly large number of individual emitters for reasonable amounts of light. I would suspect that the most practical way of providing a dimmable LED array would be via a square wave with the width of the "squares" varied (Pulse Width Modulation = PWM). Each element would turn on at each cycle of power, but the duration of each "on" would be varied. If done at sufficiently high frequency, flicker would be undetectable, and could be additionally reduced by using different sets of emitters out of phase with each other. Polyphase square wave PWM control modules should be available¹ from Radio Shack if you'd like to try it out.

¹ I will admit I haven't looked for one recently, but the control circuits are quite simple, and probably are available as integrated circuit modules.

John