LED 101

A Light Emitting Diode (LED) is a semiconductor device that converts electricity into light.
Most white light LEDs are coated with phosphors to change the color characteristics of the emitted light.


The ability of a lamp to dim from 100% to 0% brightness by some electronic control. Many LED bulbs are not compatible with existing dimmer switches, or do not dim within the full range. Look for the icon pictured left for dimmable products.


A measure of the correspondence between the color of an object and its appearance under a light source.


The color the lamp or fixture appears when on. Measured in Kelvin (K):

Light Appearance Key

   soft white - 2700K         bright white - 3000K

   cool white - 4000K         daylight - 5000K


The perceived brightness of a lamp or fixture is measured in lumens.


The angular dimension of the cone of light from reflector lamps encompassing the central part of the beam out to the angle where intensity is 50% of maximum. Categories from narrow angle to wider angle are Spot, Narrow Flood, Flood, Wide Flood.