Setting for a dimmer that can be selected without readjusting the dimmer intensity level each time; usually activated by a rocker or pushbutton. A preset scene is a setting for several channels or zones in a multi-scene dimming system.

Refractor of transparent glass or plastic, with three or more straight sides. Light entering one side of the prism bends and exits another side.

Refractor of transparent glass or plastic, with three or more straight sides. Light entering one side of the prism bends and exits another side.

A light shielding that consists of many tiny prisms, which redirect the light rays so as to control fixture brightness.

Single-ended compact fluorescent lamp consisting of two twin tubes on a single base.

Or quartz-halogen; terms for a Halogen Lamp. The term derives from the quartz glass capsule that encloses the filament and halogen gas. Quartz glass can withstand the high pressure of the halogen lamp but it transmits more UV radiation than ordinary hard glass. Touching the quartz glass with bare hands leaves an oily residue that reduces lamp life.

Also known as reflector lamp. Soft-glass reflectorized lamp with a generally smooth distribution.

See Average Rated Life.

See Duplex Outlet.

Fixture mounted above the ceiling. With downlights, only the Aperture and Trim visible from below. With fluorescent troffers and luminous ceilings, only the covering is visible. Recessed fixtures provide direct downlighting.