Home / Style Guide / Learn About LED / LED Terminology and Language LED Terminology and Language How LED Light is Produced Historically lighting used standard bulb shapes and bases (Example: A19 with a medium base). In contrast, LED lighting products use custom light sources and application-specific electronics. Compared to the traditional Incandescent (light is produced by heating a tungsten wire) and Compact Fluorescent (light is produced by exciting phosphors with the emission of mercury), LEDs produce visible light by passing current through a solid state diode which converts electrical energy into photons. LED The acronym LED stands for Light Emitting Diode. White LEDs are made of 3 distinct elements: A semicondutor chip consisting of epitaxial layers capable of producing photons Phosphor materials that are embedded in encapsulation and produce energy in the visible spectrum A package structure that houses the materials and enables placement into lighting systems Diode - A Diode is a semicondutor device that that acts like a switch and allows current to flow when the appropriate potential/voltage is place across its terminals. Semiconductor - A solid substance that has conductivity properties between that of an insulator and most metals. Silcon is a typical semiconductor material and used for most solid state devices. Color Rendering Index (CRI) & Color Temperature CRI (Color Rendering Index) – A quantitative measure of the ability of a light source to reveal the colors of various objects accurately in comparison with an ideal light source.. The higher (1 to 100) the CRI, the better the color rendering, given the color temperature of the lamp. CCT (Correlated Color Temperature) – The appearance of white light, in terms of warmth or coolness. A warm color corresponds to a lower CCT while cool colors are associated with higher CCT. Kelvin - The appearance of white light. CCT is defined in degrees Kelvin and correlates to the Black Body on the CIE color diagram. Warm colors correspond to a lower CCT value (2400K), while cooler or bluish light is associated with higher CCT values (10,000K). Watts vs. Lumens Watts is the measure of energy required to light the product. The lower the wattage the less energy consumed. Lumen/Light Output measures the light output. The higher the lumens, the more light that is emitted. Lumens per Watt/ Efficacy is the measure of efficiency. The higher the lumen per watts, the more efficient the product is. Total Lumens vs. Delivered Lumens Total Lumens represents the total amount of light emitted from the LED module itself. This figure does not take into account any light losses from filtering light through the LED lens or luminaire cover lens, losses from distribution of light from an internal reflector or luminaire positioning for example. It is in reality only a theoretical number with no bearing on real performance. Delivered Lumens does represent real exit lumens that are projected from a lamp or luminaire. These are the actual working lumens projected toward the horizontal or vertical plane, and account for any system losses that may exist within a fixture or lamp. L16 Throughout the Kichler product assortment, you will see the suffix "L16" on many of our fixtures. When you order these items, you will get 2016 Energy Star Rated LED bulbs included with the fixture. This means: Enhanced energy efficiency - The L16 options deliver highly efficient LED operation and make the fixtures Energy Star certified. Delivering added value. Added convenience - Since everything ships together there is no searching around for bulbs or additional inconveniences.