Lux provides information about the illuminance. It is a measure of the brightness with which an area is illuminated. Lux indicates how much luminous flux (lumen) of a light source arrives per unit area of a receiver surface. The value lux is purely a receiver quantity.
Illuminance is calculated with the following formula: Lux [lx] = luminous flux [lm] / area [m2].
The illuminance is 1 lux if a luminous flux of 1 lumen falls uniformly on an area of 1 m².
Another formula for calculating illuminance at greater distances is as follows: Lux [lx] = luminous intensity [cd] / radius or distance squared.
The further away the area is from the light source, the lower the illuminance. The lux value determined can be used to determine whether certain areas are sufficiently well lit. For example, there are labor-law requirements for how brightly a work area should be illuminated for employees.
What does a luxmeter measure?
A luxmeter is a light inensity meter and measures the illuminance (lux). The value indicates how bright it is at the measuring point. The luxmeter consists of a photo sensor and a display. The photo sensor usually consists of photo diodes that detect the light. The measured lux value then appears on the display.
Exemplary lux values
|Full moon night||0.3lx|
Post time: Aug-17-2022