In fact with the emergence of the idea of lighting the road in front of speeding car, several types of light sources replaced each other. First cars were equipped with gas, namely propane lamps. Soon, they were replaced by came the vacuum bulb, then halogen lamps. Now is the time of xenon lamps, xenon, that is. The first gas-discharge xenon lamp for the car was not designed by someone, and by Philips, it was of ascetic name D2S (R). HID-lamp (High Intensity Discharge or vulgar "xenon lamp") have been used in automotive lighting fixtures since 1992.
The aim of the company Philips – the increase in brightness. The xenon light stream high intensity is obtained by the glow of gas, initiated by an arc discharge between two electrodes. The electrodes are in the lamp bulb filled with xenon and metal salts under high pressure. Xenon lamp has a color temperature of about 4,300 degrees Kelvin (for example, Philips (Osram) D2S). For example, – halogen lamp has a color temperature of the glow of the order of 2.800 degrees Kelvin. To make it quite clear – color temperature luminescence is of key importance in the light. So, the sun has a color temperature of about 5,000 – 6,000 degrees Kelvin.
Xenon lamp has a maximum priblezhennym to sunlight radiation spectrum providing more natural light. On average, consumes 35W xenon lamp. 55W and more – the usual. Luminous flux provided by xenon – 3,000 Lumens 1,550 against the standard halogen lamps of 55W. Average time of xenon lamps is around 2,800 – 4,000 hours. Guaranteed service life of halogen 100 – 500 hours. High vibration resistance is provided by the absence of the filament. The moral is – no threads – there is nothing to break. We know how important visibility in the dark, rainy, foggy or snowy weather. The light emitted by xenon, having compared with the usual 2.5-fold greater intensity, greatly help to improve the visibility of the driver road. The geometry of the illuminated section of the road is improved, since the beam of light lights, equipped with a xenon lamp, wider. It is also important is that the "xenon" light because of its spectral features composition allows the driver to see objects in the roadway and roadside (including signs) to a much greater distance. Even in the rain and fog xenon lights do not create before your eyes "Light wall". Rays xenon easily "punched" the fog and light rain or no fog, namely the road surface. Xenon lamp heats a lot less than a halogen. So when the power consumption of 35 W for xenon in the heat requires 7% of energy, while at the halogen bulb while consuming a minimum of 55 watts into heat takes about 40% of energy. Disadvantages of the xenon headlights are relative. We can distinguish two obvious flaws: 1. Expensive. In addition to the large the cost of the lamp must bear in mind the following: in case of replacement xenon bulbs is better to change them in pairs, as with time (all the lights turn white after about 200 hours of operating time), the emission spectrum of xenon lamp is changed. 2. The need for special programming unit (You must first apply to the lamp voltage of about 25,000 volts, and continue to maintain 80 volts at a frequency of 300 Hz, used for this device, called "blocks ignition" or "Ballast blocks").