Light: Difference between revisions

376 bytes added ,  28 January 2021
=== μmol/s ===
The measure of photons per second produced by a light. Photons are measured in micro (10^-6) [https://en.wikipedia.org/wiki/Mole_(unit) moles] there are a huge amount of photons coming from any light source. One µmol is actually 602 quadrillion photons. Simply put this metric is the intensity per second from a light
=== μmol/J ===
The light intensity a horticultural light produces per Joule of power it uses. This is a measure of its efficiency. At the time of writing the most efficient LED package available is the [https://www.samsung.com/led/lighting/mid-power-leds/3030-leds/lm301h/ LM301H] by Samsung. It achieves 3.10 μmol/J @ 65 mA, 25°C. Note the efficiency will change depending on temperature and current supplied.
=== PPFD ===
Photosynthetic Photon Flux Density its unit is μmol/m^2/s. ThisIt is thea PARmeasure perof meterlight squared,intensity soover it incorporates thean area of photons that a horticultural lightper producessecond. This is important to note when buying a growing light, for example, light A may provide aan PARintensity of 800 μmol/s in a 1m^2 area while light B provides the same PARintensity in a 4m^2 area. Light B provides the same intensity but over a larger area, so it can support a larger plant. In this case, light B has a greater PPFD
 
== Horticulural light terms ==