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The color temperature of a metal-halide lamp can also be affected by the electrical characteristics of the electrical system powering the bulb and manufacturing variances in the bulb itself. If a metal-halide bulb is underpowered, because of the lower operating temperature, its light output will be bluish because of the evaporation of mercury ...
Streetlamp with a ceramic metal halide bulb Ceramic metal halide bulb with G12 socket. A ceramic metal-halide lamp (CMH), also generically known as a ceramic discharge metal-halide (CDM) lamp, [1] is a type of metal-halide lamp that is 10–20% more efficient than the traditional quartz metal halide [2] and produces a superior color rendition (80-96 CRI).
The suffix after the G indicates the pin spread; the G dates to the use of Glass for the original bulbs. GU usually also indicates that the lamp provides a mechanism for physical support by the luminaire: in some cases, each pin has a short section of larger diameter at the end (sometimes described as a "peg" rather than a "pin" [2]); the socket allows the bulb to lock into place by twisting ...
With HMI bulbs, color temperature varies significantly with lamp age. A new bulb generally will output at a color temperature close to 15,000 K during its first few hours. As the bulb ages, the color temperature reaches its nominal value of around 5600 K or 6000 K. With age, the arc length becomes larger as more of the electrodes burn away.
To reduce unintentional ultraviolet (UV) exposure, and to contain hot bulb fragments in the event of explosive bulb failure, general-purpose lamps usually have a UV-absorbing glass filter over or around the bulb. Alternatively, lamp bulbs may be doped or coated to filter out the UV radiation. With adequate filtering, a halogen lamp exposes ...
The choice of metal additives and their concentrations enables lamp manufacturers to create HID lamps with distinct color temperatures and spectral characteristics to meet different lighting needs. The majority of HID lamps are produced in the color temperature range of 5000K to 6000K, which is similar to natural daylight.
More than this: HID lamps like the metal halide lamps and high pressure sodium lamps have reduced reliability when operated at high frequencies in the range of 20 – 200 kHz, due to acoustic resonance; for these lamps a square wave low frequency current drive is mostly used with frequency in the range of 100 – 400 Hz, with the same advantage ...
Luminous efficacy can be normalized by the maximum possible luminous efficacy to a dimensionless quantity called luminous efficiency.The distinction between efficacy and efficiency is not always carefully maintained in published sources, so it is not uncommon to see "efficiencies" expressed in lumens per watt, or "efficacies" expressed as a percentage.