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LED Lighting Glossary

LED Lighting Glossary2020-01-06T10:03:52+00:00



AC: This is an acronym for alternate lighting. This refers to a source where the voltage polarity changes several times in a second, in the frequency of 50Hz-60 Hz. Alternating current is mostly used in commercial spaces and homes. It is referred to as the line voltage. In the US, the line voltage is usually 90V – 220V. However, it is much higher in Europe.

Accent Lighting: A term for directional lighting. As the name suggests, this type of lighting is mainly used to focus on a particular object during the product display in the retail applications and galleries.

Active Cooling: A process of cooling where power is used to cool components. For instance, a fan is used to exhaust heat from components.

ALA: It is an abbreviation for the American Lighting Association, which focuses on the residential lighting trends. This trade organization has members from the US, Canada, and the Caribbean nations. ALA offers membership to event organizers, designers, as well as manufacturers from the said states. The organization member showrooms boast of providing the highest quality indoor and outdoor lighting solutions for new or retrofit projects.

Ambient Lighting: The lighting that is widely used to improve the visibility of any built or well-designed environment. Ambient lighting may include natural and artificial lighting. However, this term is not suited for any accent or task lighting used in various open areas and industries.

Ampere or Amp: This is the measurement for the electric current in the International System of Units. A current of one ampere is defined as one coulomb of charge in a second. It is expressed as 1 A= 1 C/s. During the lighting installations, the protection and wiring is mainly calculated on the basis of the ampere needed for the operation of the circuits. Along with the ampere, the voltage of these circuits is also taken into the account.

Amp Calculations: As the name suggests, these are the calculations performed to determine the current required by a circuit comprising multiple lighting fixtures or a single lighting fixture. Once the current is analyzed, then it becomes easy to identify the right wiring needed for the lighting circuit, and other protection devices used in the circuit.

Angle of Light: This is the angle that is formed between the viewing direction, as well as a light source. For instance, the light angle will be high, if you are looking at it from the distance, however, it becomes zero, when you look at it from a nearby angle.

ANSI: It is an abbreviation for the American National Standards Institute, which develops standards and voluntary guidelines for electrical industries.

ANSI Ballast: This term refers to a ballast that is ANSI compliant.

Application: It refers to the intended use of light in a particular environment. For instance, retail, residential, healthcare, hospitality, and high bay lighting are some examples of LED applications.

Arc Tube: A sealed ceramic or quartz tube where the light is produced through the electric discharge (arc).

Arc Lamp: A light source that produces an arc between two electrodes. The light arc stimulates a gas, which produces a glow.

Architectural Lighting: This refers to the decorative lighting used to light a building. Architectural lighting may also serve as ambient lighting.

Argon: It is one of the noble gases. Argon is used in the bulbs of traditional incandescent lights. The gas helps prevent oxidation of filaments made of metals. Argon gas is also used in gas discharge lamps that emit blue or the violet light on mixing with mercury.

ASHRAE: This stands for the American Society of Heating, Refrigerating, and Air-Conditioning Engineers.

Average Rated Life: Depicted in hours, the average rated life of a lamp is calculated through various lamp life testing procedures. This depicts the time of failure of a large group of lamps, when they are operated at nominal current and lamp voltage. Typically, manufacturers employ 10 hours and 3 hours per start for HID and fluorescent lamps while performing the tests on them. Every lamp has a mortality curve that provides information on its life expectancy.

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Backlight: In some applications, outdoor fixtures may emit light in the opposite direction than intended, and this is known as a backlight. This backlight may produce undesirable results. For instance, the pole lamps fitted in a parking lot may produce backlight that may fall on apartments or homes nearby. This may sometimes be discomforting for residents. Backlights are not the same as backlighting.

Backlighting: An object is illuminated from its back to create a halo-like effect. This lighting creates a glow on the edges of the object. Backlighting is usually done to highlight the artworks in museums and art galleries.

Baffle: It is a translucent or opaque component that blocks the sight of a lighting source.  

Ballast: It is an integral component of an HID and fluorescent lighting fixtures. This component is designed to control the electric current and voltage required for the lamp during the operation or ignition phase. A ballast helps prevent premature heating or overheating. Dimming ballasts are used with dimmer to manage the output in various settings. Ballasts can be electronic or magnetic depending on their construction. The lighting ballasts used in the US are ANSI compliant.

Ballast Efficiency Factor: This is a term for ballast factor divided by power in watts. This factor is used to compare the efficiency of a ballast.

Ballast Factor (BF): A value that defines the effect of the ballast on a lamp’s lighting output. This value is taken in reference to the ANSI ballast factor. The light operated on a ballast is compared to the lamp operated on a reference ballast adhering to ANSI. The lamp is operated on the reference ballast in nominal value of power rating specified by ANSI. The reference value of BF is 1.0. However, in the case of fluorescent lamps, it may differ up to a great extent.

Base: It is a part of the lamp that is connected to the lighting fixture to produce a strong connection. This part provides both electric power as well as support to the electric lamp. The bases of LED lights used in residential applications are fixed using multiple pins or screws.  

Base Down: When the lamp is inserted in a socket with its base pointing downwards, it is called base down position. This position is common to the HID lighting.

Base Temperature: It is the maximum allowable temperature for a lamp base to operate. It is one of the important considerations when designing a lamp.

Base Up: The lamp is inserted in a socket with its base pointing upwards, and this is called a base up position. This is another common specification for the HID lighting.

Bayonet: It is one of the important types of base that is connected to socket utilizing keyways. This lamp base is unlike other bases, which use threads for connection.  

Beam Angle: A downward cone of light produced by the lighting fixture possessing a reflector. It is often measured between the two directions – where high light intensity is produced by the lamp and in the direction, where the light intensity is 50% lesser. This angle is measured respective to the downward direction of light. The lamp having a large angle will spread light in a wider cone.

Beam Spread: It is the range of the surface illuminated. The beam spread is often expressed in the units of distance. It is calculated by multiplying the beam angle by 0.18. The result is then multiplied by the distance of the surface and the light source. This beam spread is not the same as the field spread, which refers to the outermost area illuminated by the light source.

Bi-Pin Base: Any light base that uses two pins is known as bi-pin base. 

Binning: LEDs are grouped according to specifications such as their light output, voltage, and color. This grouping is called binning.

Bollard: A type of outdoor lighting fixture, which features a short and broad post having a lamp on its top. The bollards are used for both purposes – decoration and outdoor lighting.

Brightness: When light is reflected in a specific direction it is called brightness.

Bug Rating: It is an acronym for backlight, uplight, and glare. Developed by the International Dark-Sky Association (IDA) and the Illuminating Engineering Society (IES), this term refers to the amount of light produced by fixtures in those directions, where they are not appreciated. Backlight refers to the light that is produced behind the luminaire. Uplight is the light that is directed upwards, where it may not be required. Glare is an undesirable visual impact produced by light. The effects of lighting are indicated in BUG rating on the scale of 0 to 5. 0 is the minimal bug rating, whereas 5 is the highest bug rating. The BUG rating of B0 U0 G0 is considered the best, whereas the rating of B5 U5 G5 is the worst.

Bulb: The glass casing that contains a light source. The glass casing produces light when electricity passes through the bulb.

Burn Position: Every lamp is designed for some operating position, which is known as the burn position. For instance, a few types of lamps can only perform when they are placed in a base-up position. If the lamp is placed in a position for which it is not designed then its performance may reduce over time, and it may even face short-term failure.

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