Light_Vocabulary



Current which flows in one direction and then the other, alternately.
 * AC (Alternating Current) **


 * Alternating Current (AC) **: the flow of electricity (electric current) in a circuit that frequently alternates direction every second. In the USA, the standard frequency of alternating current is 60 Hz (hertz or cycles/second) and AC (as opposed to direct current) is generally the method for delivering electric power to homes and buildings.

 ("Amps.") A measure of electrical current. In incandescent lamps, the current is related to voltage and power as follows: Watts (power) = Volts x Amps (current).
 * Amperes **

 A consensus-based organization which coordinates voluntary standards for the physical, electrical and performance characteristics of lamps, ballasts, luminaires and other lighting and electrical equipment.
 * ANSI (American National Standards Institute) **

Intense luminous discharge formed by the passage of electric current in a gaseous medium across a space between electrodes.
 * Arc **

An auxiliary piece of equipment required to start and to properly control the flow of current to gas discharge light sources such as fluorescent and high intensity discharge (HID) lamps. Typically, magnetic ballasts (also called electromagnetic ballasts) contain copper windings on an iron core while electronic ballasts are smaller and more efficient and contain electronic components.
 * Ballast **

The socket is the receptacle connected to the electrical supply; the base is the end of the lamp that fits into the socket. There are many types of bases used in lamps, screw bases being the most common for incandescent and HID lamps, while bipin bases are common for linear fluorescent lamps.
 * Base or Socket **

A style of bulb base which uses keyways instead of threads to connect the bulb to the fixture base. The bulb is locked in place by pushing it down and turning it clockwise.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Bayonet **

<span style="font-family: Verdana,sans-serif; font-size: 9pt;">The angular dimension of the cone of light from reflectorized lamps, encompassing the central part of the beam out to the angle where the intensity is 50% of maximum. The beam angle sometimes called "beam spread" is often part of the ordering code for the reflectorized lamps.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Beam Angle **


 * <span style="font-family: Verdana,sans-serif; font-size: 10pt;">Bulb **<span style="font-family: Verdana,sans-serif; font-size: 10pt;">: a colloquial term for a lamp.

<span style="font-family: Verdana,sans-serif; font-size: 9pt;">Windings of copper or aluminum wire surrounding the steel core in ballast. Also refers to the entire assembly comprising the inductor or transformer.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Coil **

<span style="font-family: Verdana,sans-serif; font-size: 9pt;">Component of electromagnetic ballast that is surrounded by the coil. Core is comprised of steel laminations or solid ferrite material.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Core **

<span style="font-family: Verdana,sans-serif; font-size: 9pt;">The periodic variation in light level caused by AC operation that can lead to strobe effects.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Flicker **


 * <span style="font-family: Verdana,sans-serif; font-size: 10pt;">Light Trespass **<span style="font-family: Verdana,sans-serif; font-size: 10pt;">: also known as "spill light". Light that is emitted into an unintended area.

<span style="font-family: Verdana,sans-serif; font-size: 9pt;">Power supply voltage required for proper operation of fluorescent or HID ballast.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Input Voltage **

<span style="font-family: Verdana,sans-serif; font-size: 9pt;">The ratio of light reflected from a surface to that incident upon it.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Reflectance **

<span style="font-family: Verdana,sans-serif; font-size: 9pt;">Lighting from light sources on a wall typically above eye level, shielded by horizontal panels. The light may be upward or downward directed.
 * <span style="font-family: Verdana,sans-serif; font-size: 9pt;">Valance Lighting **