Light_Vocabulary

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

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

=Ballast = 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 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.

=Beam Spread = a measure of the spread of light from a reflectorized light source, a special-shaped lamp with a reflective coating inside the bulb to direct the light forward. The beam spread may be very narrow (narrow spot), very wide (wide flood), or something in-between (narrow flood, for example). Examples of "reflectorized light sources" are MR11, MR16, PAR20, PAR30, PAR38, R40, ER30, and BR30 lamps.

=Bulb = A loose way of referring to a lamp. "Bulb" refers to the outer glass bulb containing the light source.

=Capacitor = Device in ballast that stores electrical energy. Often used for power factor correction and lamp regulation.

=Cathode = Metal filaments that emit electrons in a fluorescent lamp. Negatively charged free electrons emitted by the cathode are attracted to the positive electrode (anode), creating an electric current between the electrodes.

=Dimmable = Whether or not the lamp lumens can be varied while maintaining reliability.

=<span style="color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 12pt;">Ecolux = <span style="color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 12pt;">A term for GE lamps that have reduced mercury content and pass the TCLP test

=<span style="color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 12pt;">Field Angle = <span style="color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 12pt;">The angular dimension of the cone of light from reflectorized lamps (such as R and PAR types) encompassing the central part of the beam out to the angle where the intensity is 10% of maximum

=<span style="color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 12pt;">Harmonic = <span style="color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 12pt;">An integral multiple of the fundamental frequency (60 Hz) that becomes a component of the current.