luxemozione

And here comes a big demand a nice article on the technical unit basic lighting. in this article I will try to give some 'fundamentals of lighting, especially the definitions of intensity and luminous flux, lighting concepts necessary for newbies (and not). Particularly needed to introduce a series of articles I publish inenzione
First of all we talk about light intensity, which is a little 'as the point geometry that is the basic unit lighting, light intensity expressed in candelas (cd) and expresses the concentration of light in a specific dirzione for radiata Second: This is the textbook definition of "The light intensity is quantified as candles in a given direction, of a source that emits monochromatic radiation difrequenza equal to Hz and with a radiant intensity in that direction watt per steradian. "(definition of 1982) uhfff difficilina say ... I will try to translate it in an easy manner as possible.

Then we say that a point source (a dot that emits light), which emits light in all directions can be abstracted as a set of many carriers of light, each represents a luminous intensity.

1 / 683 is nothing but a term that relates the current definition of a candle with the old definition of the '20s.

This was the most dificil say ...

now the luminous flux, where the unit of measurement is the lumen (lm), is related to the intensity by the following relation: flow = Intensity * Ω where Ω = solid angle of the intensities or are contained within a solid angle subtended an area.
the definition of photometric flux is closely related to the definition of a candle, because the flow is equal to the product of the radiant power of a point source (in watts) and the coefficient of visibility y (λ) (which as we have seen is maximum, ie 1 for the green light), so for example if a point source emits 1 W at a wavelength corresponding to the green (or 555nanometri Hz) we have issued a stream pear 683lm.

where
K = 683 lm / W which is the maximum spectral efficiency
Pλ = spectral power in W
V (λ) = coefficient of visibility.
To summarize this definition tells us that the light flux is only part of the radiation emitted (W) from a source within the visible range that is between 380nm and 780nm.

here on the representation of the curve of visibility

wow that was too soon!!

I hope it is clear (but I'm not very convinced)

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