LED Lighting Terminology
What are lumens in lighting?
In basic terms, lumen is the word used to describe the amount of, or the intensity of the light emitted from the source. The lower the lumens, the lower the brightness. And vice versa, the higher the lumens, the brighter the light is. For reference, a candle may be around 10 lumens. A small cabinet light may be a couple hundred lumens. A single dome light inside an ambulance may be 1500 lumens. Finally, a high bay light could be a couple hundred thousand lumens. You will commonly see lumens abbreviated as “lms” on packaging or in literature. Lumens should not be confused with Watts, which is a unit power, or Lux, which is the amount of light that hits a surface.
What is lux and how is it measured?
Lux is a measure of how much light, emitted from the source, falls on a surface. One lux is equivalent to one lumen per square meter, thus carrying the units of lm/m2. Lux is important if you are trying to determine how much light will be present at a select distance from the light source. In theory for lighting, the higher the lumens, the higher the lux. Lux can be measured utilizing a lux meter or light measuring device. For reference, a completely dark room would have a lux reading of zero. A dark, cloudy, gloomy day may have a lux reading of around 1,000. General, indirect sunlight may have a reading around or greater than 8,000. Direct sunlight could have a lux reading of 100,000. In general, most household and commercial applications will utilize enough light to produce a lux reading in the hundreds to low thousands.
What is CRI (Color Rendering Index)in lighting?
CRI, short for color rendering index, is the ability for a light source to precisely display or render an objects true color. CRI is measured on a scale of 0 to 100 with 100 being the most accurate or “true” color rendering of an object if it were displayed under direct sunlight (~5000 Kelvin). CRI is particularly important for mission critical applications & services such as the military and emergency services, where color is identification is imperative. For the military, it would be important to have high CRI lighting to properly distinguish map colors and for health care, properly identifying skin tones and vein location, or for reading charts. In general, a CRI of 80 is considered good, CRI of 90 is great, and CRI 100 is the best.
What is CCT (Correlated Color Temperature) in lighting?
CCT, short for correlated color temperature, is the color of white light emitted by the light source. White light can have an array of color appearances ranging from an amber glow, like a candle, to a bluish glow, like the sky. This range of colors is based on a color temperature scale and carries the units of Kelvin. The Kelvin scale ranges from 1000 – 10000, with 1000 being amber and 10000 being sky blue. The lower the Kelvin, the “warmer” the light will be. The higher the Kelvin, the “cooler” the light will be. Refer below for color scaling.
1900 K: Candlelight (Very Warm Light)
3000 K: Halogen Light Bulb (Warm Light)
5000 K: Direct Sunlight (Neutral/Cool White)
6000 K: Cloudy Sky (Daylight)
10000 K: Clear Blue Sky (Sky Blue)
As a reference, lower Kelvin lighting is commonly found in residential applications where a warmer lighting is preferred. The 5000 K lighting is commonly found in commercial and work environments, where crisp lighting is needed. Anything above 6000 K is commonly found in commercial and industrial applications in which bright task lighting is required.
What is a LED in lighting?
LED is the short name for a light emitting diode. An LED is a semiconductor and is one of the most important parts of a light fixtures’ infrastructure. The LED is the electrical component that will produce light as current is flowed through it. LEDs use different materials to alter light wavelengths, thus producing different colors. They are typically manufactured as a bulb or a chip.
What is a watt or wattage in lighting?
A watt is a measure of electrical power used or consumed by an electrical device or lighting fixture. It is the direct product of voltage and amperage, power = amps x voltage. The higher the wattage, the more energy required to make the device operate. Typically, lower wattage devices are preferred as they require less energy, thus cutting down electric consumption costs. Wattage is expressed with the unit “W.”
What is voltage in electronics?
Voltage is the electric potential for electrons to flow from one location to another within a circuit. Voltage is measured in volts which is reflected as the unit “V.” In basic terms, voltage is often thought as the “pressure” of a system. The higher the voltage, the more “pressure” or force that is exerted to assist in the movement of electrons.
What is amperage in electronics?
Amperage is the amount of electrical current flowing in a circuit. Essentially it is the “flow rate” of electrons. Current is measured in amps and is reflected as the unit “A.” The higher the amperage, the more current there is flowing in the circuit. Amperage needs to be treated as an electron count and not direction of flow. Direction of current is indicated by AC (alternating current) or DC (direct current).
What is a heat sink and how does it apply to lighting fixtures?
A heat sink is material or device, typically composed of metal, that is used to help dissipate heat. In lighting, heat is produced by the light engine, and needs to be removed in order to maintain the integrity and longevity of the electrical components. A combination of air, heat dissipating material, and a large surface area will help cool important electrical elements.
What is a light fixture extrusion?
An extrusion is the result of a material, typically metal, being pushed through a die machine. The die will shape or mold the material into the desired form and profile. Linear LED lighting fixtures may utilize an aluminum extrusion to support desired length and profile requirements.
What is LED tape lighting?
Tape light is a low profile, flexible, LED lighting fixture. There are two forms of tape light, which include resistor based (traditional) or constant current regulator based (IC regulated). The IC regulated tape is considered a premium and higher quality tape as current is maintained throughout the entirety of the fixture, thus preventing flicker, and dimming over length.
Tape light is often manufactured in 16 ft. reel lengths and can be found in single or multiple colors. This fixture style also utilizes an adhesive backing and can easily conform and mount to different landscape patterns and designs, such as outlining a cabinet or compartment. It is recommended to follow the manufacturer’s directions and properly prepare the receiving surface prior to mounting. Additionally, some tape lights have cut locations in which desired lengths can be yielded. It is recommended that a certified electrician cuts the tape and solder new connection wires.
What is a linear light?
A linear light fixture is a rectangular, elongated luminaire. This can be any type of lighting fixture with a nominal length. Linear lighting should be considered an optimization strategy as one long length can replace multiple smaller fixtures. Read our blog here for more information on considering or using “lighting as a strategy.”
What is high efficiency lighting?
High efficiency lighting is a low wattage/low power draw luminaire. This is acheived through special circuit boards designs that utilize engineered traces and advanced, quality, energy saving, electrical components. The lower wattage is primarily achieved through reducing the amperage/power draw all while maintaining the necessary voltage requirement (typically 12V). A high efficiency circuit is often used in applications that run off a battery or have power limitations and are often requested by manufacturers and upfitters that utilize a electric vehicle chasis or batteries as a generator substitute. A high efficiency style light engine helps the environment and supports the green energy transistion.