What is an LED Light?

What is an LED Light?



Type : Knowledge Article
Applicable Product: LED Lights
Tags : LEDLightled manufacture
Published Date : Mar/23/15
View : 12
Comments : 0




What is an LED Light?


A light-emitting diode (LED) is a two-lead semiconductor light source. It is a basic pn-junction diode, which emits light when activated.When a fitting voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.



An LED is often small in area (less than 1 mm2) and integrated optical components may be used to shape its radiation pattern.



Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still frequently used as transmitting elements in remote-control circuits, such as those in remote controls for a wide variety of consumer electronics. The first visible-light LEDs were also of low intensity, and limited to red. Modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.






Early LEDs were often used as indicator lamps for electronic devices, replacing small incandescent bulbs. They were soon packaged into numeric readouts in the form of seven-segment displays, and were commonly seen in digital clocks.






Recent developments in LEDs permit them to be used in environmental and task lighting. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are now used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, and camera flashes. However, LEDs powerful enough for room lighting are still relatively expensive, and require more precise current and heat management than compact fluorescent lamp sources of comparable output.


Comparison Chart LED Lights vs. Incandescent Light Bulbs vs. CFLs








Energy Efficiency
& Energy Costs




Light Emitting Diodes (LEDs)




Incandescent
Light Bulbs




Compact Fluorescents (CFLs)



Life Span (average)


50,000 hours


1,200 hours


8,000 hours



Watts of electricity used
(equivalent to 60 watt bulb).

LEDs use less power (watts) per unit of light generated (lumens). LEDs help reduce greenhouse gas emissions from power plants and lower electric bills


6 - 8 watts


60 watts


13-15 watts



Kilo-watts of Electricity used
(30 Incandescent Bulbs per year equivalent)


329 KWh/yr.


3285 KWh/yr.


767 KWh/yr.



Annual Operating Cost
(30 Incandescent Bulbs per year equivalent)


$32.85/year


$328.59/year


$76.65/year





Environmental Impact




Light Emitting Diodes (LEDs)







Incandescent
Light Bulbs









Compact Fluorescents (CFLs)





Contains the TOXIC Mercury


No


No


Yes - Mercury is very toxic to your health and the environment



RoHS Compliant


Yes


Yes


No - contains 1mg-5mg of Mercury and is a major risk to the environment



Carbon Dioxide Emissions (30 bulbs per year)

Lower energy consumption decreases: CO2 emissions, sulfur oxide, and high-level nuclear waste.


451 pounds/year


4500 pounds/year


1051 pounds/year









Important Facts





Light Emitting Diodes (LEDs)




Incandescent
Light Bulbs




Compact Fluorescents (CFLs)



Sensitivity to low temperatures


None


Some


Yes - may not work under negative 10 degrees Fahrenheit or over 120 degrees Fahrenheit



Sensitive to humidity


No


Some


Yes



On/off Cycling
Switching a CFL on/off quickly, in a closet for instance, may decrease the lifespan of the bulb.


No Effect


Some


Yes - can reduce lifespan drastically



Turns on instantly


Yes


Yes


No - takes time to warm up



Durability


Very Durable - LEDs can handle jarring and bumping


Not Very Durable - glass or filament can break easily


Not Very Durable - glass can break easily



Heat Emitted


3.4 btu's/hour


85 btu's/hour


30 btu's/hour



Failure Modes


Not typical


Some


Yes - may catch on fire, smoke, or omit an odor









Light Output





Light Emitting Diodes (LEDs)




Incandescent
Light Bulbs




Compact Fluorescents (CFLs)



Lumens


Watts


Watts


Watts



450


4-5


40


9-13



800


6-8


60


13-15



1,100


9-13


75


18-25



1,600


16-20


100


23-30



2,600


25-28


150


30-55

See Also

Do you spend a lot of time at your desk?

How To Choose The Best LED Desk Lamp