What are High-intensity discharge lamps

If you are an off roading expert then lights arecolour corrected whiter light. More people are
important to say the least. When you are out onmoving away from these lamps and opting to
your adventure, particularly if it is dark then youchoose the newer more efficient high pressure
want good visibility at all times. High-intensitysodium and metal halide lamps.
discharge (HID) lamps are the very best in lights. When off roading, particularly when it is dark or
When compared to the normal fluorescent andvisibility is poor then HID lamps are ideal as they
incandescent lamps, HID lamps produce a muchcan produce high levels of light over large areas. 
larger quantity of light in a relatively smallerRecently, HID headlamps have become very
package.popular vehicles. Many 4x4 owners prefer these
So here comes the technical part. HID lampswhen out on an off-road adventure as they
produce light by striking an electrical arc acrossproduce a clearer, brighter and more natural type
tungsten electrodes which are housed inside aof light than light emitted from normal headlamps.
specially designed inner fused quartz or fusedAll off road drivers are aware that the conditions
alumina tube. This tube is then filled with both gasare not those of normal roads. The lifespan of an
and metals. The gas aids in the starting of theHID bulb can be as long as 2500 hours which
lamps. Then, the metals produce the light onceexceed the normal life span of regular halogen
they are heated to a point of evaporation.bulbs. Halogen bulbs are heated by tungsten
HID lamps are available in different forms, includingflament which can be damaged or can overheat.
- Mercury vapour lamps(CRI range 15-55)HID bulbs are lit by gas ionisation which means
- Metal halide lamps (CRI range 65-80, ceramic MHthey will never produce high temperatures causing
can go to 90's)them to overheat. As long as the xenon gas in
- Low-pressure sodium lamps (CRI 0 owing tothe lamps has not been exhausted the HID lamps
their monochromatic light)will discharge excellent light.
- High-pressure sodium lamps (CRI range 22-75).If you are a regular 4x4 off road driver the High
The first commercially available HID lamps wereIntensity Discharge(HID) lamps should be fitted on
the mercury vapour lamps which producedyour vehicle so if you do get lost out on your
bluish-green light. These lamps today produceadventure you won't have to sit in the dark.