LED glossary

LED (light-emitting diode)	A semiconductor light-emitting diode, which emits light as soon as electric power is supplied to it. During direct recombination of the electron-hole pair, a photon of light is emitted. The semiconductors gallium arsenide (GaAs), gallium phosphide (GaP) and silicon carbide (SiC) have this property. This phenomenon is called electroluminescence. The color of the light emitted depends on the semiconductor, as well as impurities in it, and varies from infrared (remote controls) and visible to the ultraviolet part of the spectrum.
Luminous flux	The intensity of radiation emitted by the source of light in all directions; the unit of measure is 1 (lm) Lumen
Luminous intensity	Represents the luminous flux in a given direction. The unit of measure is 1cd (Candela)
Illuminance	Average illuminance of a surface is the luminous flux per surface unit; the unit of measure is 1 Lux, Lux = Lumen/square meter.
Luminance	Shows the impact of the lightness of a surface perceived by the eye. The unit of measure is Candela/square meter.
CRI – Color Rendering Index	Indicates how realistically a light fixture can render the color of an illuminated object, compared to the natural light. It is stated in the range from od 0 to 100.
Light source efficiency	Represents the efficiency of the light source with respect to the electric power source, expressed in (lm/W) lumens per units of input power in watts (W). Light sources convert electric power into light energy. Some examples: classic light bulbs have an efficiency of cca. 10 lm/W, energy-efficient bulbs cca. 55 lm/W, fluorescent tubes up to 80lm/W, and LED bulbs range from cca. 95 lm/W to 160 lm/W.
Light color	In order to indicate the color of a light source, the concept of color temperature is used, which is measured in Kelvins [K] and denotes the color of the light source in comparison to the color of the light radiated by the absolute black body.
Optics (lenses)	Changes the direction of visible light, most often by reflection through lenses.
Beam angle	Angle of light dispersion from the central part of the bulb light beam source, where the light intensity is at least 50% of the maximum.
Dimming	sposobnost rasvjetnog tijela da uz pomoć elektronike daje jačinu svjetlosti od 100% do 0%.
Technical light calculation	In short, this is the calculation of the level of illuminance. Taking into the account all the preconditions for the design of the illumination system, the designer must decide on the number of lamps and on their characteristics to be used in order to achieve the set level of illuminance.
IP protection	Level of protection from dust particles and water drops.
IK protection	Level of mechanical protection from the impact of foreign objects, ranging from 0-10.