Valgusallikad

Valgusallikad is Estonian for "sources of light." The term is used in physics, engineering, and everyday language to denote anything that emits visible light, including natural sources such as the Sun, stars, and bioluminescent organisms, as well as artificial sources such as lamps, LEDs, fluorescent tubes, and laser devices. In Estonian, the plural form "valgusallikad" is common when discussing multiple sources.

Natural light sources provide daylight and are critical for ecosystems and human circadian rhythms. Artificial light sources are designed to produce specific characteristics, including luminous flux, color temperature, and color rendering. Key metrics used to characterize light sources include luminous flux (measured in lumens), luminous intensity (candela), illuminance (lux), color temperature (kelvin), and color rendering index (CRI). Luminous efficiency, typically expressed in lumens per watt, is a major consideration in lighting design.

Common types of artificial light sources include incandescent lamps (traditionally used but energy-inefficient), fluorescent lamps, high-intensity discharge lamps (HID) such as high-pressure sodium and metal-halide, and LEDs and OLEDs. LEDs have become dominant in many applications due to high efficiency, long life, and flexible form factors. Lighting design also considers glare, efficiency, life cycle, and environmental impact, including the disposal of lamps containing hazardous materials.

Standards for measuring and specifying light sources are developed by international bodies such as the International Commission on Illumination (CIE) and the International Electrotechnical Commission (IEC). Valgusallikad thus encompass a broad range of devices and concepts, from basic physics to applied lighting technology.