 provides a high voltage that creates an electric arc across tungsten electrodes. The arc excites mercury vapor atoms, which discharge ultraviolet photons. The photons strike phosphor coatings on the glass, causing them to emit visible light (fluoresce). The ballast then regulates voltage and power at a lower level to sustain the arc. Argon
(not shown) in the tube quickens start-up and enhances brightness.)
FLUORESCENT A ballast (far right) provides a high voltage that creates an electric arc across tungsten electrodes. The arc excites mercury vapor atoms, which discharge ultraviolet photons. The photons strike phosphor coatings on the glass, causing them to emit visible light (fluoresce). The ballast then regulates voltage and power at a lower level to sustain the arc. Argon
(not shown) in the tube quickens start-up and enhances brightness.
Image: Daniela Naomi Molnar
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Incandescent lightbulbs may be history. As of 2007, compact fluorescent lightbulbs (CFLs), which are more energy-efficient, had made only modest inroads because they were more expensive. But in December the U.S. Congress passed a major energy bill that included a new lighting standard. By 2012 manufacturers selling any 100-watt (W) bulb must make it 30 percent more efficient than today’s 100-W incandescent bulb. Similar requirements will phase in for 75-W bulbs in 2013 and 60-W and 40-W in 2014. Europe has passed its own rules, too. CFLs already meet the specs, and although makers will try to improve the old hardware, the new bulbs clearly have the edge and continue to improve.
The technology inside a lightbulb is quite advanced. The tungsten filament in an incandescent glows at more than 2,200 degrees Celsius and must be made perfectly uniform because any tiny imperfection will cause it to rapidly burn out. Yet only about 10 percent of the electricity entering the bulb is emitted as visible light; 90 percent or so is radiated as heat. A CFL is about four times as efficient as an incandescent bulb. A 26-W CFL can therefore shine as brightly as a 100-W incandescent, requiring only one quarter of the energy. The tubular fluorescent bulbs common in overhead lighting are slightly more efficient still but do not fit standard light sockets, as CFLs do.
CFLs still present some problems, which manufacturers are solving. For example, some consumers find the light too harsh. “The human eye wants to see all color wavelengths,” says James Dakin, senior consulting engineer at GE Lighting in Cleveland, but the phosphor coating inside the bulbs fails to emit certain wavelengths. Phosphor improvements are filling in those holes, Dakin explains.
Early bulbs took several minutes to reach full output and may have hummed or flickered, but the electronic ballasts that have replaced the original magnetic ballasts have ended those shortcomings and also allowed smaller tubular shapes. “We have a huge effort under way to create CFLs that are suitable for more applications,” says James Meyer, general manager of GE Lighting. Lowering cost further, he says, is now mostly a matter of even greater mass production.
Light-emitting diodes (LEDs) could also pose competition in years to come; the solid-state lights are about as efficient and last three times longer than CFLs. But the screw-in versions struggle to outshine even a 25-W incandescent and cost far more. For now, CFLs have the brightest future.
This article was originally published with the title The Switch Is On.
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11 Comments
Add CommentI was once told the mercury in those bulbs made them a problem if they broke, that supposedly you'd get stuck with thousands of dollars of enviromental cleanup costs... Anybody heard if that's true? And even if not what does one do with them when they burn out?
Reply | Report Abuse | Link to thisI've turned to as many cfl applications as possible with great savings, quite a few distributers will also replace or pro rate the cfl's that fail before full use just keep and date receipt and place date of installation on white part of bulb.Converted a 5000 sq ft bussiness to cfl's average savings over $300 a month.
Reply | Report Abuse | Link to thisI love the idea of using fluorescents, but so far the ones I have tried make everything look like a David Lynch set. Until they can work out that kink I'll be switching on the old warm and fuzzy incandescents.
Reply | Report Abuse | Link to thisHow is it that the mercury vapor, a known carcinogen and causer of brain damage is allowed in a glass container subject to easy breakage? If you drop one of these bulbs, you create a hazardous waste zone. This should be prevented before making every house have one.
Reply | Report Abuse | Link to thisI read the article and looked at the illustrations in the March 2008 issue and it was so pro CFL, making the traditional incadescent bulb out to be a terrible thing, but only in the illustration on pg 99 was there any mention of the mercury in the CFL which is a hugh issue.
Reply | Report Abuse | Link to thisFor me when the CFL's became mainstream late last year and I was buying light bulbs last year, I was considering buying the CFL, even though the price was higher, the extended life time and reduced energy cost seemed well worth the investment. What stopped me was what stopped about 3 others from buying- they contain Mercury.
CFL's having mercury are toxic to the environment and require special disposal, whereas the traditional bulb uses inert gas. Some of the CFL's I saw, also contained lead. What is the true environmental benefit of buying such a bulb that requires hazardous material destruction because it is toxic to the environment because it saves electricity? When does one outweigh the other?
Also the CFL's do not come in the softlight, reveal, or other types that incadescent bulbs do, which studies have shown are beneficial than spending long periods of time in artificial fluorescent light.
Cost wise, it is actually cheaper based on the 1200 hour lifetime for 6/hrs/day per 7 days operation, to purchase and use the incadescent bulb, even including the energy costs. Environmentally, the carbon impact of the energy generation will be nominal compared to releasing the mercury into the environment for those who do not properly dispose of the bulbs and just through them into the regular trash. In fact the money I left from buying the incadescent bulbs is enough to purchase a sapling that I can plant to scrub out the excess CO2 from my incadescent bulb usage.
A very useful article. It is the first time I have seen it admitted that to get the equivalent light from a CFL as from a 100watt incandescent requires a 26 watt CFL - we are generally told a 15 to 20W will do. CFLs rapidly lose their initial brightness. I am stuck with many I can't use for this reason alone
Reply | Report Abuse | Link to thisThe true figure creates a problem of size for the CFL which has yet to be solved in bulbs generally sold in Australia strong enough CFLs are aesthetically ugly and do not fit acceptable light fittings
The color and flicker are also major problems and as a largely recovered ME sufferer I still find CFLs largely unusable indoors. I use halogen downlights
Were they to be come unavailable I'd simply buy them on the black market. With present CFLs we can expect light bulb salesmen hanging round street corners standing alongside drug peddlers in the near future
"Feelthy lightbulbs anyone?"
There'll be a market for them!
Save money.Shows ways to lower oil imports.
Reply | Report Abuse | Link to thisLet us not be slaves to the Oil Cartel...
http://www.gomestic.com/Consumer-Information/How-to-Save-Big-Money-on-Your-Electric- Bill.21562
How to Save Big Money on Your Electric Bill
For as long as most of us can remember, when a lamp in our household fizzled out, we just reached into
our stock on the shelf somewhere and simply replaced it. We probably never gave any thought of the
extra heat being produced while we were trying to keep the temperature in our home down.
http://www.quazen.com/Science/Environment/The-Incandescent-Light-It-Must-Go.17579
The Incandescent Light, It Must Go
At the end of the 19th century, man was awakened with a fabulous new lighting for all to enjoy. the incandescent light bulb was born. thanks to the inventiveness and perseverance of one of the most famous inventors of our times, Thomas a. Edison, we are able to light our way.
Reply | Report Abuse | Link to thisLed Lighting, The World's Final Frontier
CFL's are a way to reduce energy usage, but to ban all incadescent bulbs
Reply | Report Abuse | Link to thisdoes not work since the CFL's can not be used in applications that are controlled by a dimmer. (package says so).
The Nonprescription Drug Manufacturers Association estimates that more than 200 OTC drug products on the market today were available by prescription only a decade ago. Among them are antihistamines and nasal decongestants for colds and allergies, sleep aids, pain relievers, cough medicines, antifungals, antimicrobials, and anti-itch medicines,<a href="http://www.toronto-condominiums.ca/toronto_condos.php">Condos Toronto</a> . These products contain ingredients in dose strengths that the Food and Drug Administration has deemed safe enough to use without a doctor's prescription.When this issue of FDA Consumer went to press, the most recent ingredient that FDA had approved for the switch from prescription to OTC sale was clotrimazole in cream and suppository dosage forms. Used to treat vaginal yeast infections, clotrimazole has been available by prescription for more than 10 years. It will be marketed OTC under the trade name Gyne-Lotrimin. In announcing the switch, Carl Peck, M.D., director of FDA's Center for Drug Evaluation and Research, said, "Clotrimazole is highly effective and carries a minimal risk. If initially diagnosed by a doctor, recurring symptoms of vaginal yeast infection, or candidiasis, can be recognized by the patient, who can treat herself with the over-the-counter drug without the inconvenience and expense of going back to the doctor."
Reply | Report Abuse | Link to thisPopular Mechanics designed a test pitting seven common CFLs against a 75-watt incandescent bulb. To gather objective data, we used a Konica Minolta CL-200 chroma meter to measure color temperature and brightness, and a Watts up? Pro ammeter to track power consumption. Our subjective data came from a double-blind test with three PM staffers and Jesse Smith, a lighting expert from Parsons The New School for Design, in Manhattan. We put our participants in a color-neutral [url=http://www.toronto-condominiums.ca/toronto_condos.php]Condos Toronto[/url]
Reply | Report Abuse | Link to thisroom and asked them to examine colorful objects, faces and reading material, then rate the bulbs’ performance.The results surprised us. Even though the incandescent bulb measured slightly brighter than the equivalent CFLs, our subjects didn’t see any dramatic difference in brightness. And here was the real shocker: When it came to the overall quality of the light, all the CFLs scored higher than our incandescent control bulb. In other words, the new fluorescent bulbs aren’t just better for both your wallet and the environment, they produce better light.