Sealed beam

Information about Sealed beam

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A burnt-out sealed beam, broken open to show internals. When the lamp burns out the whole assembly (reflector, lamp, lens array) must be replaced. The advantage is very good alignment, and being completely impervious to dirt, moisture, etc.


A sealed beam is a type of lamp that includes a reflector and filament as a single assembly, over which a front cover (lens), usually of clear glass, is permanently attached. The previous design was like that of common flashlights (electric torches), which have a separate small bulb which is fitted in front of a parabolic reflector and covered with a transparent cover, which in the case of a headlamp is ribbed to avoid glare from the filament. This cover would be clamped on with a grommet inbetween to try to seal it; the method's deficiencies were what prompted the sealed beam system. The subsequent design has the reflector sealed to the cover and the small bulb inserted through a hole in the rear of the lamp.

Headlights for automobiles may be of the sealed beam type, meaning that the reflector, the lens array on the front and the bulb are all one unit that must be replaced together in case of burnout. They are clamped into a structure for aiming the beams to meet safety requirements. Every time the headlight is replaced, the aiming of the beams must be checked. Headlights using sealed beams became mandatory in the United States in 1940; cars prior to that date could have a variety of shapes of headlamps.

In theatrical lighting, sealed beam type fixtures are often used. A common size, also used in rock concerts, as well as outdoor architectural lighting, is the Parabolic Aluminum Reflector 64 (PAR64). The PAR is a non-SI unit of measure equal to one eighth of an inch, so a PAR64 light is a light that is 8 inches in diameter. The fixtures that such sealed beam lights go into are called "PAR cans", so a PAR64 fixture is an 8 inch diameter can.

Other popular sizes are PAR56, PAR38, and PAR36.

Sealed beams come in various voltages, most commonly 6, 12, 28, 120 and 230 V. Aircraft landing lights, which are commonly used in open air concerts and for stage lighting, are sealed beams that have a very narrow beam spread.

Beam spreads are designated as FL (flood), SP (spot), NSP (narrow spot), and VNSP (very narrow spot), as stamped on the back of the lamp's reflector.

A PAR64 sealed beam typically comes in 250 W, 500 W, or 1000 watt.

Modern sealed beams have an additional envelope around the filament, whereas older types do not. The inner envelope contains halogen to improve the life of the filament and enable more light for the same power; for this to work, the halogen must be confined to the area around the filament by the second envelope, commonly made of fused quartz to withstand the filament's heat. These "halogen sealed beams" appeared on U.S. cars in 1978 to enable halogen technology under Federal Motor Vehicle Safety Standard 108, which at the time required sealed beam headlamps; they continued even after FMVSS 108 was amended to permit composite headlamps in 1983, and came to dominate the sealed beam lamp market.
Lamp (from Greek λαμπάς: torch) can be:
  • An oil lamp, the original use of the term.
  • A portable light fixture such as a table lamp or reading lamp (common usage)

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A reflector can mean one of several things:

Science
  • Reflector, a device that causes reflection (for example, a mirror or a retroreflector)
  • Reflecting telescope
  • Reflector the part of an antenna that reflects radio waves

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Filament may refer to:

In physics and electrical engineering:
  • Electrical filament
  • Current filament
  • Filament propagation, diffractionless propagation of a light beam
In astronomy:
  • Galaxy filament

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lens (or lense) is an optical device with perfect or approximate axial symmetry which transmits and refracts light, concentrating or diverging the beam. A simple lens is a lens consisting of a single optical element.
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headlamp is a lamp, usually attached to the front of a vehicle such as a car, with the purpose of illuminating the road ahead during periods of low visibility, such as night or precipitation.
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automobile (from Greek auto, self and Latin mobile moving, a vehicle that moves itself rather than being moved by another vehicle or animal) or motor car (usually shortened to just car) is a wheeled passenger vehicle that carries its own motor.
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Theatre (or theater, see spelling differences) (from French "théâtre", from Greek "theatron", θέατρον, meaning "place of seeing") is the branch of the performing arts defined as simply as what "occurs when one or more
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Rock 'n' Roll (short for Rock and Roll), is a genre of music that evolved in the United States in the late 1940s and early 1950s, and quickly spread to the rest of the world. It later spawned the various sub-genres of what is now called simply 'rock music'.
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concert is a live performance, usually of music, before an audience. The music may be performed by a single musician, sometimes then called a recital, or by a musical ensemble, such as an orchestra, a choir, or a musical band. Informal names for a concert include "show" and "gig".
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Architecture is the art and science of designing buildings and structures. A wider definition often includes the design of the total built environment: from the macrolevel of town planning, urban design, and landscape architecture to the microlevel of construction details and,
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parabola (from the Greek: παραβολή) (IPA pronunciation: /pəˈrab(ə)lə/
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Aluminium (IPA: /ˌæljʊˈmɪniəm/, /ˌæljəˈmɪniəm/) or aluminum (IPA: /əˈluːmɪnəm/
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Par or PAR may refer to:

Computing

  • Page address register
  • ".par" and ".par2", Parchive file types containing recovery data used to fix other files
  • ".

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Si, si, or SI may refer to (all SI unless otherwise stated):

In language:
  • One of two Italian words:
  • sì (accented) for "yes"
  • si

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1 inch =
SI units
010−3 m 0 mm
US customary / Imperial units
010−3 ft 010−3 yd


An inch (plural: inches; symbol or abbreviation: in or, sometimes,  
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Voltage (sometimes also called electric potential difference or electrical tension) is the potential similarity of electrical potential between two points of an electrical or electronic circuit, expressed in volts.
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aircraft is a vehicle which is able to fly through the air (or through any other atmosphere). All the human activity which surrounds aircraft is called aviation. (Most rocket vehicles are not aircraft because they are not supported by the surrounding air).
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Stagecraft collaboration!
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Modern stage lighting is a flexible tool in the production of theatre, dance, opera and other performance arts.
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light beam or beam of light is a narrow projection of light energy radiating from a source into a beam. Sunlight is a natural example of a light beam when filtered through various mediums (clouds, foliage, windows, etc).
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A floodlight is an artificial light providing even illumination across a wide area. See:
  • Stage lighting instrument#Floodlights
  • Floodlights (sport)

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Spotlight can refer to at least three types of lighting:
  • a searchlight;
  • stage lighting used in theatre to focus an audience's attention on a performer or event, known as a Followspot;

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WATT

City of license Cadillac, Michigan
Broadcast area [1]
Branding NewsTalk 1240
First air date 1945
Frequency 1240 kHz
Format News-Talk-Sports
Power 1,000 watts
Class C
Owner MacDonald Garber Broadcasting
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halogens or halogen elements are a series of nonmetal elements from Group 17 (old-style: VII or VIIA; Group 7 IUPAC Style) of the periodic table, comprising fluorine, F; chlorine, Cl; bromine, Br; iodine, I; and astatine, At.
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Fused quartz and fused silica are types of glass containing primarily silica in amorphous (non-crystalline) form. They are manufactured using several different processes.
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Federal Motor Vehicle Safety Standard 108 (FMVSS 108) regulates all automotive lighting, signalling and reflective devices in the United States. Like all other Federal Motor Vehicle Safety Standards, FMVSS 108 is administered by the United States Department of Transportation's
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