Like the name
implies, high intensity discharge lighting creates a very bright light
that is ideal for night time driving. Though the color of the light is
often perceived as having a bluish tint when viewed at night, most of
the light that is produced by HID headlamps is actually very close in
color to natural noontime sunlight -- though some of the light produced
is also in the blue and ultraviolet spectrum. Halogen headlamps, by
comparison, are more yellowish in appearance but are brighter and
whiter than older incandescent style headlamps.
The near-white light produced by HID headlamps improves visibility and makes it easier to see distant objects.
color of light can be measured in "degrees Kelvin," which refers to the
"temperature" (shade) of light. Natural sunlight at noon is 4870
degrees K. Light produced by a HID xenon bulb is 4100 degrees K. Light
from a standard halogen bulb is 3200 degrees K, and that from an
ordinary incandescent bulb is 2800 degrees K. The lower the temperature
rating, the more yellowish the light appears.
light is better for visual perception, but yellow light is actually
somewhat better for reducing glare in fog, rain and snow (that's why
fog lights are yellow).
The xenon bulbs that are
used in HID lighting systems also produce three times the light output
of standard halogen headlamps (3000 lumens versus 1000 lumens), and
require less energy (35 to 42 watts versus 55 watts). This is possible
because HID lighting systems work like a vapor-filled street light or
metal halide lamp. HID bulbs typically produce 71 lumens of light per
watt compared to 18 lumens of light per watt for standard halogen
lighting systems use a special quartz bulb that contains no filament
and is filled with xenon gas and a small amount of mercury and other
metal salts. Inside the bulb are two electrodes separated by a small
gap (about 4 mm or 3/16th inch). When high voltage current is applied
to the electrodes, it excites the gases inside the bulb and forms an
electrical arc between the electrodes. The hot ionized gas produces a
"plasma discharge" that generates an extremely intense, bluish-white
CAUTION: Once ignited, the pressure
inside an HID bulb builds to over 30 atmospheres due to heat (up to
1500 degrees F inside the bulb!). This creates a potential explosion
hazard so do not attempt to power a HID bulb outside of the headlamp
assembly to "test" it. Also, the bulb must be in a horizontal position
when it is on, otherwise it may overheat and fail.
street lamps and fluorescent bulbs, HID headlamps require a high
voltage ignition source to start. It typically takes up to 25,000 volts
to start a xenon bulb, but only about 80 to 90 volts to keep it
operating once the initial arc has formed. The normal 12 volts DC from
the vehicle's electrical system is stepped up and controlled by an
igniter module and inverter (ballast), which also converts the voltage
to AC (alternating current) which is necessary to operate the HID
The ballast adjusts the voltage and
current frequency to operating requirements. The AC ballast frequency
is usually in the 250 to 450 Hz range.
Power to the HID system is usually routed through a relay and fused at the power distribution center.
HID headlamps are first turned on, the light appears more bluish but
quickly brightens as the bulbs warm up. On most applications, the HID
headlamps are only used for low beams (conventional halogen high beams
are used). But on some of the newest HID systems, the position of the
shielding around the bulb changes position to provide both high and low
Because there is no brittle filament
inside a xenon HID bulb to break or burn out, the headlamps typically
last up to three times longer than halogen headlamps (3000 hours versus
1000 hours of continuous operation, which is equivalent to 5 to 10
years of normal driving).
people believe that the higher the color temperature the brighter the
lamp. This is totally wrong. The color temperature is purely a scale to
measure the color of the light output. It is a reference purely for
color and could equally be called White, Green or Blue. The reality is
the higher up the scale the lamps are the less bright they become.
5200K lamps are approx 10% brighter (measured in Lumens, not degrees K)
than the 7000K. If you want lighting performance the 6000K HID lamps
are the best. In our opinion 7000K has the best and most attractive
Degrees K = ONLY COLORLumen= BRIGHT
should be noted that halogen technology is not comparable to the Xenon
discharge technology, fitted as original equipment to more and more of
the world's finest cars." - Philips
international unit (SI) of luminous intensity. The term has been in use
since the early days of lighting when a standard candle of a fixed size
and composition was used as a basis for evaluating the intensity of
other light sources. This unit is used in measuring headlight output;
basically the higher the number is, the brighter the light is.
international unit (SI) of luminous flux (quality of lights). For
example, a dinner candle produces about 12 lumens and a standard
60-watt incandescent bulb produces 830 lumens. The higher the number
is, the brighter the light is
basic unit of thermodynamic temperature (color temperature) used to
measure the whiteness of the light output. The higher the number is,
the whiter the light is. When over 5000K the light begins to turn to
blue as daylight.
Teaka Toys 1725 San Felipe Road Suite 10 Hollister CA 95023 (831) 630-1545