- Electrical filament
An electrical filament is a thread of
metal , usuallytungsten , which is used to convertelectricity into light inincandescent light bulb s (as developed in1874 byAlexander Lodygin and in1878 byJoseph Wilson Swan , among others), and into heat invacuum tube devices.The first successful light bulb filaments were made of
carbon (frombamboo ), later replaced with tungsten.Explanation
An
electrical current travels through the filament and because of theelectrical resistance of the filament makes it white-hot and generates light and heat. It is normally in avacuum or anoble gas orinert gas inside aglass enclosure to stopoxidation . Small amounts of ahalogen can be added to facilitate transport of evaporatedtungsten atoms back to the filament, resulting in significantly prolonged lifetime when used at higher temperatures, which is exploited inhalogen lamp s.Electrical filaments are used inhot cathode s of various types ofvacuum tube s andelectron gun s as sources ofelectron s.Types of filament
There are several different types of filament configuration available and it all depends on the lamp itself, and what characteristics are required. Some of these include but are not limited to C-6, CC-6, C-2V, CC-2V, C-8, CC-88, C-2F, CC-2F, C-Bar, C-Bar-6, C-8I, C-2R, CC-2R, Axial.
External links
* [http://filament.bravehost.com/light.htm An brief article explaing the light bulb - "The Composition of the Light Bulb"]
* [http://inventors.about.com/library/inventors/bllight.htm The history of the light bulb]
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