High Intensity Discharge (HID) Lamps

High Intensity Discharge (H.I.D) Lamps are the latest advancement in lighting technology. The High Intensity Discharge Lamps operate at a completely different principle from incandescent (filament) lamps. Electrical discharge between electrodes causes the filler materials in the discharge tube to emit light. The light is generated directly by an arc discharge.

The arc discharge may be at low or high pressure of gasses and vapours. H.I.D. Lamps operate at high pressures. These lamps are classified as High Pressure Mercury Vapour lamps (HPMV), High Pressure Sodium Vapour lamps (HPSV) and Metal Halide lamps (MH). These are filled with pure mercury / mercury and sodium / halogen compounds of Sodium, Indium, Thallium, Dysprosium, along with a rare gas filled in the discharge tube at low pressure when arc is initiated. These materials are efficient in light production as they are vapourised by heat from electric discharge in the rare gas. Some minutes after starting, both light output and colour will vary until lamp stability is achieved.