How do LED lights function?

How do LED lights function?

Light emitting diodes (LEDs) lights work very differently compared to older traditional lighting sources, such as fluorescent or incandescent lights. Fluorescent lights work by using a sealed glass tube which contains a small bit of mercury and an inert gas under low pressure, the glass is coated inside with a phosphor powder, the tube should have two electrodes connected to an electrical circuit (AC).

When the electricity is turned on a considerable voltage goes across the electrodes, this energy changes some of the mercury form a liquid to a gas. There are electrons travelling through the gas to and from each electrode and they collide with the gaseous mercury atoms producing light photons, actually ultraviolet light is produced, here is where the phosphor powder intervenes and produces white light, because phosphors are substances that give off light when they are exposed to another light. In this way fluorescent lights emit light and some heat. Incandescent light bulbs produce light as a secondary output as the result of an electric current passing through a tungsten filament (very thin peace silvery-white metal) heating this filament to a temperature hot enough to produce light. The tungsten filament, the contact electric wires, the glass support and other support wires are inside a glass enclosure in a vacuum free of oxygen, oxygen would disintegrate the filament, in some cases this enclosure is actually filled with an inert gas, nitrogen or argon are the most common, inert gases, also known as noble gases, for this purpose should not react to other chemicals and thus preserve and protect the filament from evaporating. 95% percent of the energy is converted into heat and just 5% into light.

On the other hand LED lights derive their light energy from electrons that move within a semiconductor material. When a voltage is applied electrons are stimulated to create light-based energy. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons, that is why LEDs can convert about 95% of the energy applied to them into light. Hyperlite produces some of the most energy efficient LEDs, most of them have a 135 to 140 lumens per Watt ratio.

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