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2. Luminous efficacy - Wikipedia

   en.wikipedia.org/wiki/Luminous_efficacy

   Luminous efficacy can be normalized by the maximum possible luminous efficacy to a dimensionless quantity called luminous efficiency.The distinction between efficacy and efficiency is not always carefully maintained in published sources, so it is not uncommon to see "efficiencies" expressed in lumens per watt, or "efficacies" expressed as a percentage.

3. Lumen maintenance - Wikipedia

   en.wikipedia.org/wiki/Lumen_maintenance

   Lumen maintenance is the most useful gauge to determine the lifetime or useful light output rating of an LED light source.Unlike traditional light sources such as incandescent lamps, LEDs rarely fail outright and instead continue to emit light, albeit at slowly diminishing rate over time. [1]

4. LED lamp - Wikipedia

   en.wikipedia.org/wiki/LED_lamp

   A 230-volt LED filament lamp, with an E27 base. The filaments are visible as the eight yellow vertical lines. An assortment of LED lamps commercially available in 2010: floodlight fixtures (left), reading light (center), household lamps (center right and bottom), and low-power accent light (right) applications An 80W Chips on board (COB) LED module from an industrial light luminaire, thermally ...

5. Candela - Wikipedia

   en.wikipedia.org/wiki/Candela

   The 26th General Conference on Weights and Measures (CGPM) redefined the candela in 2018. [10] [11] The new definition, which took effect on 20 May 2019, is: The candela [...] is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10 12 Hz, [a] K cd, to be 683 when expressed in the unit lm W −1, which is equal to cd sr W −1 ...

6. Light-emitting diode - Wikipedia

   en.wikipedia.org/wiki/Light-emitting_diode

   The Philips Lighting North America LED bulb won the first competition on August 3, 2011, after successfully completing 18 months of intensive field, lab, and product testing. [94] Efficient lighting is needed for sustainable architecture. As of 2011, some LED bulbs provide up to 150 lm/W and even inexpensive low-end models typically exceed 50 ...

7. Luminous flux - Wikipedia

   en.wikipedia.org/wiki/Luminous_flux

   The luminous intensity (in candelas) is a measure of how bright the beam in a particular direction is. If a lamp has a 1 lumen bulb and the optics of the lamp are set up to focus the light evenly into a 1 steradian beam, then the beam would have a luminous intensity of 1 candela. If the optics were changed to concentrate the beam into 1/2 ...