Light. LED 1 Flashcards
An LED is what’s called a “solid-state lighting” technology, or SSL. 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.
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 :
60-watt incandescent light bulb, which makes them a viable technology for basic lighting needs at home.
The LED method of producing light loses far less energy to heat than do other lighting technologies. It’s dramatically more efficient than the vacuum/filament method used in incandescent bulbs – sometimes around:
85 percent more efficient; and it’s even about 5 percent more efficient than the CFL’s plasma-tube approach .
A single light fixture stocked with a 60-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:
525.
65 kWh. The annual CO2 reduction is in the hundreds of pounds for a single lamp.
You could go______ 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 ________ hours
20 years
Life of an incandescent: 750 hours
Life of an LED: 30,000 hours
A 60-watt LED replacement bulb runs in the area of $100, and even the lower-output versions, used for things like spot lighting, will cost between:
$40 and $80. That’s compared to a $1 incandescent and a $2 fluorescent bulb.
Even at $100 for a single bulb, LEDs will end up saving money in the long run, because you only need one every decade or two and you spend less money on home lighting, which can account for about :
7 percent of your electric bill
The other primary LED issue is the:
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.)
