The Light Bulb

[twiglet4frog]

Ok, Wont try and make myself sound thick by asking how a light bulb works so calm down, but i was wondering the difference between a light bulb and a led as i saw u can get keyring led torches that the sas used to use and they are lifetime guarentee bulbs, so what exactly is the difference between a led and a normal light bulb?

[booksworth]

A light bulb has a bit of wire that gets white hot when you stuff electricity down it. An led is explained here http://acept.la.asu.edu/courses/phs110/expmts/exp13a.html The active part of an led is crystal, so it's very robust. The wire filament of a light bulb is quite fragile, and because it runs very hot, gets weaker throughout its life.

[Tweed]

LED give off photons as energy moves from one level to another lower one. As this happens the energy is released as light. Most LEDs give off this light, but not efficiently, or indeed, in the visible spectrum, unless designed for this purpose. Fillament bulbs heat a coiled coil of (usually) tungsten to produce light. It's inefficient, as most of the energy is being used to heat up the fillament, and the light is only produced as a result of this.

[Gandy]

Google gallium nitride.  It is supposed to be the most important semi conducter discovery since silicon.

[guest26]

Tweed has given you an excellent answer.  LED is light emitting diode.  LED are MUCH more efficient than bulbs, as Tweed said, bulbs are basically just little heaters that happen to produce light.  A great website is www.howstuffworks.com, lots of cool stuff on there.  Oh and LEDs have a much higher lifetime due to the robust structure.  They can have around 10,000 hours life, where bulbs are usually less than 2000 hours.  For some really cool and fun LED stuff http://ledmuseum.home.att.net/ledleft.htm

this dude is so funny!!  Hope this helped you!

[guest2634]

Tweed gave you a pretty good answer. LED stands for light emitting diode.  It is much more efficient than the old light bulb.  Like Tweed said bulbs are little heaters that just happen to give off light.  Some fun stuff for you would be this website  http://ledmuseum.home.att.net/

also you can check out www.howstuffworks.com and look up LEDs.  Oh and LEDs usually have a life of 10,000 hours where bulbs are only around 2000 hours.  LEDs are much more robust too.  They are "cooler" (do not give off that much heat, more energy efficient and smaller than the traditional light bulb.