Light+Vocabulary


 * __[[image:http://www.hometips.com/articleimages/alternating_current009.jpg align="left"]]AC (Alternating Current) __**:

Current which flows in one direction and then the other.


 * __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 ‍

__**Bayonet **__  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.

__**Bollard **__  A short, thick post with a light at its top, used for grounds and outdoor walkway lighting.

__**Chromaticity **__ Measure to identify the color of a light source, typically expressed as (x,y) coordinates on a chromaticity chart.

‍

 __**Daylight Harvesting **__

Lighting design for building interiors that makes of daylight as a way of reducing energy consumption.

__**Dimming Control **__ A device used to lower the light output of a source, usually by reducing the wattage it is being operated at. Dimming controls are increasing in popularity as energy conserving devices.

<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Used to refer to the beam pattern of a reflector lamp, which disperses the light over a wide beam angle, typically 20 degrees or more. ("Flood" as opposed to "spot")
 * __<span style="font-family: Calibri,sans-serif; font-size: 14pt;">[[image:http://www.erco.com/products/indoor/recessed_spot/gimbal_134/images/eur_erco_gimbal_sysove_198903.jpg align="left"]]Flood __**

<span style="font-family: Calibri,sans-serif; font-size: 11pt;">A plot with lines connecting points of equal luminous intensity around a source.
 * __<span style="font-family: Calibri,sans-serif; font-size: 14pt;">Isocandela Plot [[image:http://www.fhwa.dot.gov/publications/research/safety/humanfac/04148/images/figure_18_web.jpg width="439" height="154" align="right"]] __**

<span style="font-family: Calibri,sans-serif; font-size: 11pt;">A line plotted to show points of equal illuminance on a surface illuminated by a source or sources.
 * __<span style="font-family: Calibri,sans-serif; font-size: 14pt;">solux Plot __**



<span style="font-family: Calibri,sans-serif; font-size: 11pt;">The average light output of a lamp over its rated life. Based on the shape of the lumen depreciation curve, for fluorescent and metal halide lamps, mean lumens are measured at 40% of rated lamp life. For mercury, high-pressure sodium and incandescent lamps, mean lumen ratings refer to lumens at 50% of rated lamp life.
 * __<span style="font-family: Calibri,sans-serif; font-size: 14pt;">Mean Lumens __**

<span style="font-family: Calibri,sans-serif; font-size: 11pt;">For most lamp types, rated lamp life is the length of time of a statistically large sample between first use and the point when 50% of the lamps have died. It is possible to define "useful life" of a lamp based on practical considerations involving lumen depreciation and color shift.
 * __<span style="font-family: Calibri,sans-serif; font-size: 14pt;">Rated Lamp Life __**