Lighting Glossary

Beam angle is the angle across which a luminaire's intensity falls to 50% of its peak, describing how concentrated or spread the o…

The candela is the SI unit of luminous intensity — luminous flux emitted per unit solid angle in a specific direction. Where lumen…

CRI (Ra) quantifies how faithfully a light source renders object colors compared with a reference source, on a scale where 100 is …

CCT describes the color appearance of white light, in kelvin, by comparison to an ideal blackbody radiator. Lower values are warme…

The foot-candle is the imperial unit of illuminance used chiefly in North America: one lumen per square foot. One foot-candle equa…

Illuminance is the density of luminous flux arriving at a surface, measured in lux (or foot-candles). It answers the practical que…

L70 is the operating time after which an LED product's light output is projected to fall to 70% of initial — the industry's standa…

The lumen is the SI unit of luminous flux — the total quantity of visible light a source emits in all directions, weighted by the …

Luminance is the luminous intensity per unit area leaving a surface in a given direction, measured in candela per square metre. It…

Luminous efficacy is the ratio of luminous flux delivered to electrical power consumed, expressed in lumens per watt. It is the he…

Lux is the SI unit of illuminance: one lumen of luminous flux spread over one square metre of surface. It is the number lighting s…

SDCM (Standard Deviation of Colour Matching) expresses chromaticity tolerance in MacAdam ellipse steps — how tightly the actual wh…

UGR is the CIE metric for discomfort glare from indoor lighting installations, computed from the luminance of each fixture toward …

ATEX refers to the EU legal framework for explosive atmospheres — chiefly Directive 2014/34/EU covering equipment placed on the EU…

CCC (China Compulsory Certification) is China's mandatory product certification for goods sold on the Chinese domestic market, cov…

CE marking is the manufacturer's declaration that a product meets all applicable EU directives — for LED luminaires principally th…

EN 13201 is the European road-lighting standard series, used worldwide as the reference for street lighting tenders. Part 1 select…

FCC rules govern electromagnetic interference for electronic products sold in the United States. LED luminaires fall under FCC Par…

GB/T 3836 is China's national standard series for electrical equipment in explosive atmospheres, aligned part-for-part with the in…

IEC 60079 is the international standard series for equipment used in explosive gas and dust atmospheres, defining the protection c…

IECEx is the international certification scheme that tests and certifies equipment directly against the IEC 60079 series, issuing …

The IK code (IEC 62262) rates an enclosure's resistance to mechanical impact, from IK00 to IK10 (20 joules — a 5 kg mass dropped f…

The IP code (IEC 60529) rates an enclosure's protection with two digits: the first against solids (6 = dust-tight), the second aga…

LM-79 is the IES-approved method for photometric and electrical testing of complete SSL (LED) products: total luminous flux, effic…

LM-80 is the IES method for measuring lumen maintenance of LED packages: chips are operated at controlled case temperatures and dr…

RoHS (Restriction of Hazardous Substances, Directive 2011/65/EU) restricts lead, mercury, cadmium, hexavalent chromium, PBB/PBDE f…

An all-in-one solar street light integrates panel, LiFePO₄ battery, controller, LED array, and motion sensor into a single pole-to…

The cobra head is the classic roadway luminaire silhouette — a slim arm-mounted head whose curved profile resembles a cobra's hood…

An explosion-proof light is a luminaire certified for classified hazardous areas — refineries, chemical plants, mines, grain handl…

A high bay light is an industrial luminaire designed for mounting heights of roughly 6 metres and above — factories, warehouses, l…

High-mast lighting mounts multiple high-output floodlights on masts of roughly 20–50 metres to cover large areas with few structur…

An LED flood light is a projector-style luminaire that throws a controlled broad beam onto areas, facades, yards, and fields from …

An LED street light is a pole-mounted roadway luminaire engineered to put uniform light on a carriageway with controlled glare — t…

A linear high bay is a rectangular LED fixture whose elongated emitting area suits it to aisle-structured spaces: warehouse rackin…

A split (or semi-integrated) solar street light separates the solar panel from the lamp head, connecting them by cable, with the b…

A tri-proof (vapor-tight) light is a sealed linear luminaire protected against the three enemies of ordinary fittings — water, dus…

The UFO high bay is the compact circular LED format that has become the default industrial high-ceiling fixture: a finned die-cast…

0–10V is the simplest widely deployed dimming interface: a two-wire analog control pair on the driver, where 10 V commands full ou…

COB (chip-on-board) LEDs mount many bare diode dies directly onto a single substrate under one phosphor layer, creating a compact,…

DALI (Digital Addressable Lighting Interface, IEC 62386) is a two-wire digital protocol in which each driver is an addressable dev…

Die-casting injects molten aluminum alloy into steel molds under high pressure, producing luminaire housings that are simultaneous…

Gas groups rank explosive gases by how easily equipment can ignite them and how violently they explode, setting construction requi…

The heat sink is the thermal path that moves waste heat from the LED junction into the air — and thermal design, more than chip ch…

LED binning is the manufacturer's sorting of produced chips into narrow performance groups — flux bins, forward-voltage bins, and …

The LED driver is the power-conversion electronics that turn mains AC into the regulated DC current LEDs require — and it is the c…

Power factor is the ratio of real power (watts) to apparent power (volt-amperes) drawn from the grid, from 0 to 1. A fixture with …

SMD (surface-mounted device) LEDs are discrete packaged chips — familiar package names include 2835, 3030, and 5730 — soldered in …

Surge protection defends LED drivers against voltage transients from lightning activity and grid switching, specified in kilovolts…

THD measures how much a driver's input current deviates from a pure sine wave, expressed as a percentage of the fundamental. Switc…

Zones classify hazardous gas areas by how probable an explosive atmosphere is: Zone 0 — present continuously or for long periods (…