How LED Light Bulbs Work
What is LED Lighting? A light-emitting diode is a semiconductor device that emits visible light when an electrical current passes through it. It is essentially the opposite of a photovoltaic cell (a device that converts visible light into electrical current). LED Lighting The light-emitting diode (LED) is one of today's most energy-efficient and rapidly-developing lighting technologies. Quality LED light bulbs last longer, are more durable, and offer comparable or better light quality than other types of lighting. Check out the top 8 things you didn't know about LEDs to learn more.
The light-emitting diode LED is one of today's most energy-efficient and rapidly-developing lighting technologies. Quality LED light bulbs last longer, are more durable, and offer comparable or better light quality than other types of lighting. Check out the top 8 things you didn't know about LEDs to learn more. LED is a highly energy efficient lighting technology, and has the potential to fundamentally change the future of lighting in the United States. Widespread use of LED lighting has the greatest potential impact on energy savings in the United States.
Learn more about how energy-efficient lightbulbs compare with traditional incandescents. Key differences include the following:. LED lighting is currently available in a wide variety of home and industrial products, and the what are the different types of weight loss surgery is growing every year.
The rapid development of LED technology leads to more products and improved manufacturing efficiency, which also results in lower prices. Below are some of the most common types of LED products.
The high efficiency and directional nature of LEDs makes them ideal for many industrial uses. LEDs are increasingly common in street lights, parking garage lighting, walkway and other outdoor area lighting, refrigerated case lighting, modular lighting, and task lighting.
Because LEDs are small and directional, they are ideal for lighting countertops for cooking and reading recipes. The color can appear more cool or blue than is typically desirable in a kitchen, and there can be some excessive shadowing in some fixtures, so it is important to compare products to find the best fixture for your space. Recessed downlights are commonly used in residential kitchens, hallways, and bathrooms, and in a number of office and commercial settings.
DOE estimates there are at least million recessed downlights installed in U. With performance improvements and dropping prices, LED lamps can replace 40, 60, and even 75 Watt incandescent bulbs.
It's important to read the Lighting Facts Label to make sure the product is the right brightness and color for the intended location. When chosen carefully, LED replacement products can be an excellent option. LEDs consume far less electricity than incandescent bulbs, and decorative LED light strings such as Christmas tree lights are no different. Not only do LED holiday lights consume less electricity, they also have the following advantages:. Estimated cost of electricity to light a six-foot tree for 12 hours a day for 40 days.
Prices of lights based on quoted prices for low volume purchases from major home improvement retailers. All costs have been discounted at an annual rate of 5. Life span assumed to be three seasons 1, hours for non-LED lights.
Energy Savings. How LEDs are Different. Key differences include the following: Light Source: LEDs are the size of a fleck of pepper, and a mix of red, green, and blue LEDs is typically used to make white light.
Direction: LEDs emit light in a specific direction, reducing the need for reflectors and diffusers that can trap light. This feature makes LEDs more efficient for many uses such as recessed downlights and task lighting. With other types of lighting, the light must be reflected to the desired direction and more than half of the light may never leave the fixture.
Heat: LEDs emit very little heat. LED Products. Industrial and Commercial Lighting. Kitchen Under-Cabinet Lighting.
Recessed Downlights. LED Replacement Bulbs. LED Holiday Lights. Not only do LED holiday lights consume less electricity, they also have the following advantages: Safer: LEDs are much cooler than incandescent lights, reducing the risk of combustion or burnt fingers. Sturdier: LEDs are made with epoxy lenses, not what is led lights bulbs, and are much more resistant to breakage.
Longer lasting: The same LED string could still be in use 40 holiday seasons from now. Easier to install: Up to 25 strings of LEDs can be connected end-to-end without overloading a wall socket.
Feb 28, · Wi-Fi-connected LED bulbs, such as those from Connected by TCP, can be operated from a smartphone. Taking it a step further, platforms such as Philips Hue and LIFX combine red, green, blue, and. Mar 16, · Technically, LED bulbs aren’t bulbs – LED stands for “light-emitting diode.” They’re tiny semiconductors (diodes) wrapped in plastic to protect the elements and focus the light. According to waltergretzky.com, a diode is “a semiconductor device with two terminals, typically allowing the flow of current in one direction only.”. In this style LED bulb, clusters of LEDs are covered by a lens which spreads the light over a wider area, like standard incandescent bulbs. Available in standard Edison bases, these bulbs are used as area lighting for rooms, porches, reading lamps, accent lamps, hallways and low-light applications where lights remain on for extended periods.
By: Julia Layton Updated: Apr 7, The light bulb that has lit up our homes since the s is officially on its way out. The inefficient incandescent, which loses most of its energy as heat, has fallen out of favor with the financially and ecologically concerned; starting in , U.
The government is taking the little energy suckers off the market. The prime replacement for the incandescent light bulb is the higher-efficiency compact fluorescent, or CFL. 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.
Enter the LED, or light-emitting diode. LEDs have been around for many years -- they light up digital clocks, Christmas lights, flashlights and traffic signals, and they tell you when you've got a new voicemail message on your cell phone. But as far as household lighting goes, LEDs have never really taken off.
Certain drawbacks have kept companies from manufacturing them in standard, replacement-size light bulb form. In the last few years, though, 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 fair number of businesses and a handful of households are using them.
In some ways, LED light bulbs are a perfect technology. But they still have a way to go before they become the higher-efficiency bulb of choice. In this article, we'll find out why. We'll look into how they work, why they're a desirable lighting choice, and what will have to change before the rest of us start using them in our bedside lamps.
Basically, instead of emitting light from a vacuum as in an incandescent bulb or a gas as in a CFL , an SSL emits light from a piece of solid matter.
In the case of a traditional LED, that piece of matter is a semiconductor. Stated very simply, an LED produces light when electrons move around within its semiconductor structure. A semiconductor is made of a positively charged and a negatively charged component. The positive layer has "holes" -- openings for electrons; the negative layer has free electrons floating around in it.
When an electric charge strikes the semiconductor, it activates the flow of electrons from the negative to the positive layer. Those excited electrons emit light as they flow into the positively charged holes. The problem with LEDs as primary home lighting is that while they emit a lot of light, the structure of an LED causes some of that light to get trapped inside.
So an LED bulb has traditionally been dimmer than an incandescent bulb, and most people want their lamps and ceiling fixtures to be pretty bright. Recently, though, LEDs bulbs have brightened up. You can now find LED replacement bulbs that emit light equivalent to a watt incandescent light bulb, which makes them a viable technology for basic lighting needs at home. And in some ways, they're much more than viable: An LED replacement light bulb called GeoBulb emits watt equivalent light using 7.
While you won't find LEDs in too many household lighting fixtures these days, there are a couple of good reasons to want them there in greater numbers.
First, there's the reduced energy use. The LED method of producing light loses far less energy to heat than do other lighting technologies. A single light fixture stocked with a watt incandescent bulb consumes about kWh of electricity in a year; put a GeoBulb LED bulb in that light fixture, and the annual energy use is more like 65 kWh [source: Sundance ].
The annual CO 2 reduction is in the hundreds of pounds for a single lamp. But energy-efficiency is just part of the story. The other part is time-efficiency: You could go 20 years without having to change an LED light bulb. Solid-state lights like LEDs are more stable light sources than incandescent or fluorescent bulbs, and the difference is startling: A typical incandescent bulb lasts about hours; a Geobulb lasts 30, hours [source: Sundance ]. Some LED bulbs last up to 50, hours [source: Linden ].
Because of that time benefit, things get a bit more muddled when you get into the cost issue. But the upfront cost is still pretty prohibitive. Lots of people simply can't spend a thousand dollars for 10 light bulbs. The other primary LED issue -- degradation in the color of the light to something bluish -- has been solved in newer models. LEDs can produce the same soft, white light as a regular bulb.
Although Energy Star does recommend looking for the Energy Star label when shopping for LED bulbs, since the organization tests for color stability as part of its certification criteria. So price is really the only problem with LED light bulbs right now. But that could change pretty soon. LEDs are poised to take over household lighting.
Or so believe lots of research scientists and some big lighting companies. Philips, for one, has stopped putting money into research and development of fluorescent technologies and is now putting all of its energy into LEDs [source: Taub ]. If you look at what the scientists are saying about LEDs, the picture does look pretty rosy. Breakthroughs are popping up at a breakneck pace. Two recent developments are predicting a major price reduction in the high-efficiency, long-lasting bulbs.
One has to do with the light-loss issue in bulb design. One way to release more of an LED's light is to put microscopic holes in the casing. The problem is that making all of those holes is time-consuming and expensive. A team of researchers at the University of Glasgow in Scotland has found a new way to do it, though. They've found that using a nano-imprint lithography technique can reduce the time and expense of putting billions of holes in tiny LEDs.
Another team of scientists, this one at the University of Cambridge in England, approached the issue from the supply side. They've found a new, less-expensive way to create gallium -nitride semiconductor material, a common basis of LED lighting.
At present, gallium-nitride semiconductors are grown on expensive sapphire wafers. The new way uses silicon wafers and affects a dramatic reduction in manufacturing cost for the LEDs.
Gallium-nitride LED light bulbs could be on the market by The lighting industry in general expects LED costs to come down quickly. Lighting Science Group, a company that develops and manufactures LED lighting, estimates a 50 percent price reduction within two years [source: Linden ]. Businesses, which have much more extreme lighting expenses and so can recoup upfront bulb expenditures very quickly, will likely flock to LEDs with that kind of price drop.
For more information about LED light bulbs and related topics, look over the links on the next page. Environmental Science. Green Technology. Sustainable Technologies. Sustainable Technologies at Home. The LED light bulb is making waves in the lighting market. See more green science pictures.
Image courtesy C. Crane Company Inc. Energy-efficiency has been popular since at least , when this poster was published by the U. An LED produces light when electrons move around within its semiconductor structure. What are the advantages of LED bulbs? LED bulbs consume less power than other lighting technologies. They are also energy-efficient, safe to use and have a longer life. Can LED lights be left on all the time? Yes, LED lights are ideal for places where light needs to be left on all the time.
Do LED lights burn out? Typically, LED lights can last for up to 25, hours. However, just like other electronic components, LED lights may burn out before that, due to extreme voltage fluctuations or premature part failures.
Does turning LED lights on and off shorten their life? This usually happens with fluorescent bulbs. What really shortens the life of LED bulbs is overheating. Sundance Solar. April 22, July 28, Cite This! More Awesome Stuff.
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