Incandescent/Halogen Lamps 1 of 15

Incandescent Lamps:
The word "incandescence" means the emission of visible light by an object when heated. The current heats the filament (thin wire) to temperatures as high as 5000°F, or 2800°C, causing it to give off light in addition to heat and a little UV.

When exposed to the surrounding air, a heated filament will literally burn up and disintegrate in a fraction of a second. This problem is solved by enclosing the filament in a glass bulb and eliminating all oxygen. Air is removed from the inside of the bulb at the time of manufacture.

For lamps of 25 watts or above, the air is replaced by a mixture of inert gases, usually nitrogen and argon, below 25 watts, the bulbs usually have a vacuum.