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What are HID flashlights and what can
they do for me?
- High Intensity Discharge (HID)
lighting technology replaces the filament of the light bulb with a
capsule of gas. The light is emitted from an arc discharge between two
closely spaced electrodes hermetically sealed inside a small quartz
glass tubular envelope capsule.
- To operate, they require
ballasts, which supply proper voltage and control current. The amount of
light produced is greater than a standard halogen bulb, while consuming
less power, and more closely approximating the color temperature of
natural daylight.
- In all High Intensity Discharge lamps, light
is produced by passing a current through a metal vapor. Free electrons
colliding with an atom in the vapor momentarily knock an electron into a
higher orbit of the atom. When the displaced electron falls back to its
former level, a quantum of radiation is emitted. The wavelength of
radiation depends on the energy zone of the disturbed electron and on
the type of metal vapor used in the arc tube.
- Although it
produces 5% of its output when first ignited, HID lights require a few
seconds (usually 15-20) to come up to full output. Also, if power to the
lamp is lost or turned off, the arc tube must cool to a given
temperature before the arc can be re-struck and light produced.
- As
technology evolves, manufacturers are producing HID Searchlights with
"instant strike," meaning the initial output of light is much higher
than 5%. This results in an HID light that is capable of being used in a
Tactical Situation where instantaneous light is required.
- HID
flashlights have several advantages over conventional halogen primary
lights.
- HID Searchlights offer more light output. An 18W HID
light source produces approximately the same lumens at the light source
as a 55 Watt halogen bulb at three to five times the halogen's
efficiency.
- An HID light provides whiter light. The color
temperature of HID lighting more closely approximates the color
temperature of natural daylight than does a halogen system, which
appears yellowish in comparison.
- The term "color
temperature" indicates that the light appears as if the discharge lamp
is operating at a given color temperature-- traditional measurements of
color temperature are drawn from the properties of the metal used in the
bulb's filament. Typical color temperatures are 2800K (incandescent),
3000K (halogen), 4100K (cool white or SP41 fluorescent), and 5000K
(daylight-simulating fluorescent colors). Most HID lights produce a
light with a color temperature approaching or above 5000K. A white light
has a perceived brightness which may equate to the higher stated
efficiencies-- i.e., although an HID lamp might have equivalent lumens as a
higher wattage halogen bulb, the HID will appear brighter and more
pleasing to the eye than the output of a halogen lamp.
- HID
flashlights have longer service life. An HID searchlight lamp will last,
on the average, 3 to 5 times as long as a halogen bulb. In normal use,
an HID bulb should last beyond one thousand ignitions.
If
your mission calls for an intensely bright light in a portable package,
an HID flashlight may be a choice for you to consider.
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