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The light bulb that has lit up our homes since the 1800s was officially on its way out after former President George W. Bush signed the Energy Independence and Security Act of 2007. Although the act didn't ban the use, purchase, sale or manufacture of incandescent bulbs, it did require household light bulbs to have 25 percent greater efficiency (which means 25 percent less energy use) than the traditional bulbs that used between 40 and 100 watts of electricity. The inefficient incandescent, where 90 percent of its energy is given off as heat, had fallen out of favor with the financially and ecologically concerned.
When the new lighting standards began in 2012, prime replacements for the incandescent light bulb were the higher-efficiency compact fluorescent lamps (CFL) and the light emitting diodes (LEDs). The CFL, though, has its own problems, primarily the inclusion of toxic mercury in the design and a strange, sometimes unpleasant color that even gives some people headaches.
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Enter the LED lights. LEDs have been around for many years — they light up digital clocks, Christmas lights, flashlights, traffic signals, etc. But as far as household lighting goes, LEDs weren't taking off. Certain drawbacks had kept companies from manufacturing them in standard, replacement-size light bulb form. But in the last decade or so, these LED replacement bulbs, the kind you just screw into a lamp like you do an incandescent bulb, have become much more common — which is to say a large number of businesses and households are using them.
A 2017 survey showed that 70 percent of Americans had bought at least one LED light bulb and 38 percent had switched over from incandescent bulbs to LEDs. This percentage has likely increased since 2017.
In this article, we'll look into how LED light bulbs work, why they're a desirable lighting choice, and some of the pros and cons surrounding them. Let's begin with the basics: How does an LED produce light?
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Light emitting diodes, commonly called LEDs, are real unsung heroes in the electronics world. They do many different jobs in all kinds of devices. They form numbers on digital clocks, transmit information from remote controls, light up watches and tell you when your appliances are turned on. Collected together, they can form images on a jumbo television screen or illuminate a traffic light.
Basically, LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike incandescent bulbs, they don't have filaments that burn out, they use less electricity, and they don't get especially hot. They're illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor. The life span of an LED surpasses the short life of an incandescent bulb by thousands of hours. Because of these advantages, tiny LEDs are one of the most popular technologies used to light LCD TVs.
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LEDs have several advantages over conventional incandescent lamps, but their main advantage is efficiency. In incandescent bulbs, the light-production process involves generating a lot of heat (the filament must be warmed to illuminate). This energy is completely wasted unless you're using the lamp as a heater, because a huge portion of the available electricity isn't going toward producing visible light. LEDs generate very little heat, relatively speaking. A much higher percentage of the electrical energy is going directly to generating light, which cuts down the electricity demands considerably.
Per watt, LEDs output more lumens (or quantities of visible light) than regular incandescent bulbs. Light emitting diodes have a higher luminous efficacy (how efficiently electricity is converted to visible light) than incandescents – a 60-watt incandescent bulb can generate between 750-900 lumens, but you can get the same output from a LED bulb using only 6-8 watts. And that same LED bulb can last 25,000 hours, but the 60-watt incandescent is only likely to light up for about 1,200 hours. In other words, one LED bulb can last as long as 21 60-watt incandescent bulbs burned consecutively [source: EarthEasy].
Until recently, LEDs were too expensive to use for most lighting applications because they're built around advanced semiconductor material. The price of semiconductor devices plummeted after the year 2000, however, making LEDs a more cost-effective lighting option for a wide range of situations. While they may be more expensive than incandescent lights up front (about $5 versus $1 for incandescent bulbs), their lower cost in the long run can make them a better buy. Several companies have begun selling LED light bulbs designed to compete with incandescent and compact fluorescents that promise to deliver long lives of bright light and amazing energy efficiency.
In this article, we'll examine the technology behind these ubiquitous blinkers, illuminating some cool principles of electricity and light in the process.
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