How LEDs Work
A modern form of light bulb is the LED, or light emitting diode. These use semiconductor technology and are very effective. These also come in many different forms and can be used in many different applications. For example there are LEDs that produce infrared light or ultraviolet light as well as light in the human visual spectrum.
LEDs function just like every other form of semiconducting diode. A current flows in one side and then out the other. However a current cannot flow the reverse direction through an LED. Inside the LED there is a very small hole that is part of he components. When the charge flows through this area it releases photons. These are considered the smallest quantifiable particle of light.
This hole is called a band gap. How big the band gap is is what allows different LEDs to have different wavelengths of light. Many people notice that LEDs that were produced a long time ago are much dimmer than modern LEDs. This is because the components comprising the band gap were made up of a material called gallium arsenide which is very reflective.
LEDs are also extremely efficient. Incandescent light bulbs are notorious for losing the majority of the energy put into them to heat. Some estimates who that they lose 98% of the energy put into them. LEDs produce hardly any heat at all. I have never actually felt a LED flashlight get hot. This also allows them to last much longer. Some sources claim that many of the LEDs produced in the seventies are still glowing today.
For more information using a LED flashlight for self defence or for more general information about LED flashlights please Visit 21 LED Flashlight. You may also be interested in Rechargeable Lantern Battery
Related Reviews
HP TouchSmart 600-1050 Reviews and Ratings (Top 10)
![]() | Top #1 Compaq Presario CQ5500F Desktop PC - BlackOverall Rating (6/10)![]() | |
| Review by Holistic Doc (IDAHO) 2010-07-28 ...because, after almost 6 hours having to endure the unproductive, absolute farce called "technical support," it was determined that the unit was shipped with defective software and has since been taken back to factory default. That done, for the one week of service, the machine seems to have been ... Read more reviews | ||
![]() | Top #2 Compaq Presario CQ1-1020 All-in-One PC (Black)Overall Rating (8/10)![]() | |
| Review by Rodney (USA) 2010-07-26 Sets up very easy. I had to download a decoder to watch movies...but they are free. This is my first all in one computer and so far I love the space savings.... Read more reviews | ||
![]() | Top #3 HP Pavilion 21.5-Inch All-in-One Desktop PC - BlackOverall Rating (10/10)![]() | |
| Review by Noorah101 (ARIZONA) 2010-07-09 I just got this computer and set it up last night. Just had to comment on how great it is so far! Everything was very easy to set up. It took me longer to dismantle my old computer equipment than it did to set this new one up! I was surprised to find that the keyboard and mouse that come with it... Read more reviews | ||
![]() | Top #4 HP TouchSmart 600-1120 All-in-One PC (Black)Overall Rating (6/10)![]() | |
| Review by Kyle C. Abt (USA) 2010-07-28 One star is way too many for this product. I purchased this computer about a month ago. Within a week it was locking up and freezing. AND I DONT EVER USE INTERNET!! i did the basic upgrades that i needed at a friends house and registered it and then brought it home. it worked fine for a short while ... Read more reviews | ||
![]() | Top #5 HP Pavilion P6320F Desktop PC (Black)Overall Rating (6/10)![]() | |
| Review by Happy Customer (S.C.) 2010-07-02 Great price, fast and quiet.No complaints with tower, I am having somewhat of a problem with the keyboard and placement of space bar. It is so compact that I am having to learn how to type again. Keep hitting keys near the space bar and numbers near the top row of letters. This is proably because... Read more reviews | ||
![]() | Top #6 HP TouchSmart 300-1120 All-in-One PC (Black)Overall Rating (4/10)![]() | |
| Review by nextep (USA) 2010-07-23 Bought this on Amazon 2 mths ago. Shipment arrived on time, and in good conidition. Unit was really easy to install and configure, and works like a dream out of the box. Everyone at home loves using it. Great value, and AMD performance does not seem to be any inferior to Pentium on this one.... Read more reviews | ||
![]() | Top #7 HP Pavilion p6540f Magnesium Grey Edition PCOverall Rating (0/10)![]() | |
| Review by nextep (USA) 2010-07-23 Bought this on Amazon 2 mths ago. Shipment arrived on time, and in good conidition. Unit was really easy to install and configure, and works like a dream out of the box. Everyone at home loves using it. Great value, and AMD performance does not seem to be any inferior to Pentium on this one.... Read more reviews | ||
![]() | Top #8 HP Pavilion Slimline s5510f Desktop PC - BlackOverall Rating (0/10)![]() | |
| Review by nextep (USA) 2010-07-23 Bought this on Amazon 2 mths ago. Shipment arrived on time, and in good conidition. Unit was really easy to install and configure, and works like a dream out of the box. Everyone at home loves using it. Great value, and AMD performance does not seem to be any inferior to Pentium on this one.... Read more reviews | ||
























