Parabolic aluminized reflector

A PAR lamp consists of a light source, with lens and a parabolic reflector with a smooth aluminium surface determining the spread of the beam.

[5] In the United States of America, sealed-beam headlamps were introduced in 1939, becoming standard equipment across all American-market vehicles starting in 1940 and remaining the only type allowed for almost four and a half decades, until the 1984 model year.

Before and after those years, vehicles could have model-specific, nonstandard-shape headlamps, using any of a wide variety of replaceable light bulbs.

Between 1940 and 1956, all U.S. cars had to have two 7-inch (178 mm) round headlamps with dual filaments, so each lamp provided both a high and a low beam light distribution.

With only two round and two rectangular lamp sizes allowed, the sealed-beam headlamp mandate greatly restricted styling possibilities for automobiles.

PAR lamps and their fixtures are widely used in theatre, concerts and motion picture production when a substantial amount of flat lighting is required for a scene.

They are often mounted in can-shaped fixtures known as PARCANs, which can be used to generate colours by fitting them with colored sheets called gels.

PAR38 lamps, with an E22 base and with ratings up to 150W, were often used for domestic outdoor floodlight illumination for patios, backyards, and often combined with a PIR sensor switch as a security/convenience light, for example, in a driveway.

In situations where sunlight or other specular light is available, a white foam reflector is often used to accomplish the same effect as a PAR array.

[8] High-power, mains-voltage, theatrical PARs usually use the bi-pin GX16d "Mogul" lamp connector;[9] G9.5 and variants are common too.

Nevertheless, some degree of beam control can be obtained with aperture or lens, and LED PAR 38 replacements with a 40° spread is common.

Intelligent, moving PARs allow for the ability to pan and tilt the instruments through a lighting control console.