The electric light source of the light source of the street light fixtures, which can be classified according to its principle, structure and performance, can be classified according to its principle, structure and performance. Classification of electric energy by transformation:
(1) thermal radiation light source for the use of electric current to heat the object to the extent of the incandescent light source. Such as the use of a wide range of incandescent and halogen tungsten lamp.
(2) a source of light emitted by a gas (or steam) by a gas discharge light source. The light source can be classified in two different ways. But in general this kind of light source has the advantages of high luminous efficiency, long service life, etc.. (a) according to the discharge medium and divided into: gas discharge lamp, mainly using the gas discharge, such as xenon lamp, neon lamp, etc.; metal vapour lamps, mainly using metal vapor discharge, produced by metal vapor light, such as mercury lamp, sodium lamp, metal halide lamp. (b) in the form of the discharge can be divided into: glow discharge lamp, the lamp by JAMES glow discharge column produces light and discharge characteristics is cathode cathode electronic specific heat emission is much (CCFL), this kind of lamp usually need to very high voltages, such as neon; arc discharge lamp, the lamp mainly use is arc discharge column to produce light and discharge characteristics is cathode potential drop is smaller (is a hot cathode lamp). This kind of lamp usually need special starter and line to work properly, such as fluorescent lamp, mercury lamp, sodium lamp etc..
According to other characteristics of the discharge light source according to the type of filling gas (or steam) and air pressure. Such as high pressure mercury lamp, low pressure sodium lamp, high pressure sodium lamp, metal halide lamp etc.. In any case, the current commonly used electric light source for city street is the main LED street lights,metal halide lamp, high-pressure mercury lamp, high-pressure sodium lamp and incandescent lamp. The yield of metal halide lamp is small, but it is the development direction of city street lamp.
