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

Accent Lighting:   Directional lighting to emphasize a particular object or draw attention to a display item.

Adaptation:   The process by which the human eye adjusts to a change in light level.

Additional Information:   Typical application and/or other important information including footnotes, operating information, features and benefits.

Ambient Lighting:   The general lighting present in an area --excluding task lighting and accent lighting but including general lighting and daylight streaming in.

Amperes:   ("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).

ANSI (American National Standards Institute):   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 Ballast Type:   Ballast type used to operate lamp in accordance with ASNI standard.

ANSI Codes:   These are 3-letter codes assigned by the American National Standards Institute. They provide a system of assuring mechanical and electrical interchangeability among similarly coded lamps from various manufacturers. General Electric uses the assigned ANSI Codes as Lamp Ordering Codes for most Projection Lamps.

Application:   Also called "lighting application," it refers to the particular use the lamp is being put to. (e.g. high-bay industrial application or retail lighting application.) The term can also refer in a general way to "application engineering" which deals with specific paramters and usage of light sources. (e.g. how to do a lighting layout, where to place fixtures and so on.)

Arc:   Intense luminous discharge formed by the passage of electric current in a gaseous medium across a space between electrodes. (See ELECTRICAL DISCHARGE).

Arc Lamp:   A light source containing an arc (see above). Also called a discharge lamp, or an arc discharge lamp (See ELECTRICAL DISCHARGE).

Arc Length:   In High Intensity Discharge lamps this is the distance between the electrode tips, which represents the physical length of the electrical discharge.

Atmosphere:   This field designates the type of gas or vacuum filling a volume or chamber of the lamp. This chamber might contain a filament or it might refer to the bulb which contains the arc tube.

Auto Rest Shutdown Circuit:   Circuit senses lamp end life and will automatically shut off power to the lamp(s). When a new lamp is inserted in the socket, the ballast resets, and turns on the lamp automatically. Some shutdown circuits require the power to be interrupted before a new lamp will re-light.