LED Explained
How Light Emitting Diodes Work
Light emitting diodes, commonly called LED's, are real unsung heroes in the electronics world. They do dozens of different jobs and are found in all kinds of devices. Among other things, they form the 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, LED's are just tiny light bulbs that fit easily into an electrical circuit. But unlike the ordinary incandescent bulb, they don't have a filament that will burn out, and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor.
They are like electrical one-way only valves that glow instead of getting hot when a lot of pressure is put through them.
They simply put out light (glowing photons) instead of heat like a normal diode on a PCB board.
LED lighting is also called photon fusion and solid state lighting ( SSL).
These diodes are also then sealed in resin to make them shockproof and waterproof.
This is very different to the traditional filament bulbs that rely on a very thin piece of wire strung between two poles that burn very brightly when a current is passed through it.
The wire burns continuously whilst giving off quite a deal of wasted heat.
Glass filament bulbs are thin and also fragile which keeps an industry alive replacing light bulbs.
Advances from VHS to DVD get a lot more attention these days than cheaper, better lighting although the outdoor enthusiasts have recognize the incredible potential of LED lighting particularly in the form of headlamps and torches.
The difference at night time is incredible -you will see colors truly represented as they are seen during daytime - spiders and other insects eyes glowing back at you !
How long do LED's generally last.
The industry standard for LED is around 50000hrs.
As all things do they will degrade initially up to 10% over the first 1000hrs of operation followed by a slower rate of decline to 30% loss after 50000hrs.
Commercially available LED's are generally blue LED's with a fluorescence applied to them and its the fluorescence that degrades not the chip/diode itself.
It also depends if the LED's are being "driven" hard or voltage is variable.
The types of commercial dome-type LED's available these days are called "static sensitive" and can be badly affected by variations in voltage and current - that's why they're OK on batteries (if not run too low) but sensitive to other forms of power like 240vAC/12vAC transformers.
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