Light_Vocabulary

**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.

**Ballast Factor (BF)** This is the percentage of a lamp's rated lumen output that can be expected when operated on a specific, commercially available ballast. Note that the "rated output" is sometimes measured on a reference ballast unlike ones that actually operate the lamp in the field. For example, a ballast with a ballast factor of 0.93 will result in the lamp's emitting 93% of its rated lumen output. A ballast with a lower BF results in less light output and also generally consumes less power.

**Ballast Hum** Sound generated by the vibration of laminations in the iron core of the transformer or inductor present in the ballast.

**Ballast Losses** Power or energy dissipated in the ballast as heat and not converted to lamp energy.

**Base Temperature (Maximum)** The maximum operating temperature permitted for the base in Celsius. Fixture manufacturers need to ensure that these conditions are satisfied in their fixture.

**Biax®** GE trademark for its biaxial family of high-efficiency and long-life compact fluorescent lamps. A straight tube is bent back in the middle, constituting a biaxial tube.

**Bi-Pin** Any base with two metal pins for electrical contact. This is the typical base for a fluorescent tube of 1 to 4 feet in length. It consists of 2 prong contacts which connect into the fixture. Medium bi-pins are used with type T-8 and T-12 tubular fluorescent lamps, and miniature bi-pins are used for tubular T-5 fluorescent lamps.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Blackbody** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">A hot body with an incandescent black surface at a certain temperature used as a standard for comparison. Note that a black surface is the best radiator possible. A tungsten filament will emit slightly less radiation than a blackbody at the same temperature.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Ceramic Metal Halide (CMH®)** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">A type of metal halide lamp that uses a ceramic material for the arc tube instead of glass quartz, resulting in better color rendering (>80 CRI) and improved lumen maintenance. GE ConstantColor® CMH® lamps feature a 3-piece arc tube design that delivers excellent color consistency and lamp reliability.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**ChromaFit** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">A GE brand name for metal halide lamps designed to operate on HPS ballasts, allowing a user to switch from the yellowish color of HPS to the white color of metal halide without changing ballasts. These products are available in both quartz metal halide and ceramic metal halide (CMH) versions.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Chromaticity** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">Measure to identify the color of a light source, typically expressed as (x,y) coordinates on a chromaticity chart

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Chromaticity Coordinates** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">A system for measuring the color of the light emitted from a light source--either a primary source like a lamp or a secondary source like an illuminated object. Usually two numbers, x and y coordinates ranging from 0 to 1 specify the chromaticity. <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;"> <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Footlambert** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">An obsolete term referring to a luminance of 1/? candelas per square foot.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Four-Pin Compact Fluorescent Lamps** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">A "plug-in" compact fluorescent lamp with 4 pins in the base to make electrical contact with the ballast.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Hot Restart Time** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">Time it takes for a High Intensity Discharge lamp to reach 90% of light output after going from on to off to on.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Isocandela Plot** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">A plot with lines connecting points of equal luminous intensity around a source.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Isolux Plot (or Isofootcandle Plot)** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">A line plotted to show points of equal illuminance (lux or footcandles) on a surface illuminated by a source or sources.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">**Valance Lighting** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">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: Tahoma,Geneva,sans-serif; font-size: 90%;">**Veiling Reflection** <span style="font-family: Tahoma,Geneva,sans-serif; font-size: 90%;">Effective reduction in contrast between task and its background caused by the reflection of light rays; sometimes called "reflected glare." You might have dealt with veiling reflections when you have to tilt a shiny magazine to avoid glare so as to read it, or struggled with reading a computer monitor because of the reflection of a window or a light fixture.