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Glossary Of LED Lighting Terms: Everything You Need To Know

Posted by Paul Tuson on September 7th , 2021

LED Lighting - Glossary Of Terms

With so much new technology in the lighting sector, we thought a small glossary of LED lighting terms might help when choosing which LED lamps might best suit your needs. The following is a list of general lighting terms and LED-specific terms.

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Light Emitting Diode (LED)

A solid element which converts electricity to light. Different elements are used to alter the character of the light, while changing colour temperatures govern the type of light created for different applications.


Watts denote the energy the bulb will use, not the brightness of it. Nonetheless, most of us use watts when choosing the brightness of the lamps we need, working on the basis the greater the power the brighter the light, which is not true.


The dictionary definition of lumen is rather technical: “a unit of luminous flux in the International System of Units, that is equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions.” Lumen simply means ‘brightness’. An 800 lumens output is brighter than a 600 lumens output, and a 600 lumens output brighter than a 400.

Accent Lighting

What might be called a spotlight – a lamp which highlights an object or display area.

Ambient Lighting

General lighting which is used for overall room lighting, rather than to highlight specific areas.

Daylight Harvesting

Maximising the use of natural daylight while having alternative auxiliary lighting incorporated in the system.

Dimmer Control

Often used in place of a normal toggle light switch in a lounge or bedroom when used with incandescent or halogen lamps.

Leading-edge Dimmer

A more common form of dimmer which uses a triode for alternating current with LED lighting.

Trailing-edge Dimmer

More expensive than leading-edge dimmers but uses a transistor. This provides a smoother option when operating LEDs.

Digital Series Interface (DSI) & Digitally Addressable Lighting Interface (DALI)

Sophisticated dimming options which require control cables and can be operated from a PC control centre. Often installed for a variety of commercial projects.


Excessive discomfort to the eyes caused by disproportionate lighting. The amount of glare can be calculated, most often used when determining the floodlighting required at outside sports venues.

Emergency Lighting

Termed maintained lighting or non-maintained lighting. In the former, the lights glow continuously and will continue to do so after a power cut. Non-maintained lighting will only become active after a power cut to illuminate exit paths and signage.

Passive Infrared Sensor (PIR)

Commonly used in exterior security lighting circuits, the sensor detects a heat source or movement and triggers the security lighting.

Find Out More

If you would like more information on commercial LED installations, download our free e-book – Why Upgrade to LED Lighting. Alternatively you can speak to one of our advisers at our offices in Oxford (01865 322200) or Southampton (023 80614700).

Why Upgrade To LED Lighting

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Topics: LED Lighting

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