| HID, or high definition, lamps are typically required | | | | ballast (a device used to start gas discharge in a |
| when high levels of light are needed to cover | | | | lamp and limit the flow of electrical current) to |
| large areas. They are the lights you see at | | | | even start producing heat. If they don't have the |
| ballgames and theme parks, at stadiums and in | | | | ballast, the reaction won't begin, and there won't |
| gyms. | | | | be any light. |
| There is a high demand for HID lamps because of | | | | What are tungsten electrodes? |
| their efficiency on a wide scale and their ability to | | | | Tungsten is a chemical element that is known for |
| clearly cover huge areas. They come in several | | | | its high melting point and robust physical |
| versions: mercury vapor lamps, metal halide | | | | characteristics. It is used widely in electrical |
| lamps, and standard high-pressure sodium lights. | | | | applications like lighting because of these |
| Mercury vapor lamps were the first commercially | | | | properties. It is a hard, non-alloy metal that ranges |
| available high definition lamps (HID). They are | | | | in color from steel gray to tin white. It is shaped, |
| swiftly becoming outdated by newer more | | | | or "drawn" into the very thin metal wires you see |
| efficient counterparts like high-pressure sodium | | | | inside a light bulb. |
| lamps and metal halide lamps. | | | | What applications are there for HID lamps? |
| High-pressure sodium lamps generally emit a more | | | | There are numerous applications for HID. They |
| yellowish light, but are available with whiter light. | | | | are in high demand in areas that require lots of |
| They are usually the most efficient, and thus | | | | lights, like stadiums, football fields, warehouses, |
| most commonly used, type of HID light. Metal | | | | parking lots, roadways, sidewalks, and more. |
| halide lamps produce a beautifully white, natural | | | | However, they have come into habitual use in |
| light, but are also less efficient. | | | | smaller areas as well, such as department stores, |
| How do HID lamps produce light? | | | | houses, indoor gardening, and a number of other |
| High intensity discharge lamps produce light when | | | | applications. Because of their bright, natural light, |
| the gases inside the fused alumina tube are | | | | HID lamps can also cause those extra bright |
| heated to the point of evaporation. Tungsten | | | | headlights blinding you across the road. |
| electrodes are kept in the alumina tube, and when | | | | They are such a powerful light source, in fact, |
| the metal elements begin to heat up, they strike | | | | that high definition lights have come into use on |
| the tungsten electrodes, creating an arc of light. | | | | the airbus 380- super jumbo airplane. |
| Similar to fluorescent lights, HID lamps need a | | | | |