what is the formula for luminance(lux) - Electronic Circuits Projects Diagrams Free

yuchween · 24th July 2006, 05:05 PM

how to find the light intensity?
i looked for it in the internet but i couldnt find
what is the formula to determine light intensit?
doesnt matter if the formula is in candela or luminance
help me please.
i will be having a viva test on my project
thank you

dknguyen · 24th July 2006, 06:37 PM

What do you mean? Your questions sounds analogous to what is the equation to find distance/mass/speed. It's something that has to be measured?

Or do you mean you want to find the intensity at distance Y given that you know the intensity at distance X? In this case intensity decreases by the distance squared. So if you are given the intensity at X meters you have to normalize it to 1 unit distance by multiplying the intensity by X^2.

Then you divide the intensity at 1 unit distance by Y^2 to find the intensity at distance Y.

You can combine X and Y in one equation to get:

[New Intensity] = [Given Intensity]*(X/Y)^2

where Y is the distance for [new intensity] and X is distance for [given intensity]

At least that's how I think it is.

zevon8 · 24th July 2006, 08:58 PM

Have a look at this link:
http://www.electro-optical.com/whitepapers/candela.htm
and here also:

http://www.ledtronics.com/pages/tech4.htm

They cover the basics as well as the relationships between the different units.

24th July 2006, 05:05 PM	#1 (permalink)
yuchween New Member Join Date: Jul 2006 Posts: 20	what is the formula for luminance(lux) how to find the light intensity? i looked for it in the internet but i couldnt find what is the formula to determine light intensit? doesnt matter if the formula is in candela or luminance help me please. i will be having a viva test on my project thank you

24th July 2006, 06:37 PM	#2 (permalink)
dknguyen Experienced Member Join Date: May 2006 Location: Alberta, Canada Posts: 3,779	What do you mean? Your questions sounds analogous to what is the equation to find distance/mass/speed. It's something that has to be measured? Or do you mean you want to find the intensity at distance Y given that you know the intensity at distance X? In this case intensity decreases by the distance squared. So if you are given the intensity at X meters you have to normalize it to 1 unit distance by multiplying the intensity by X^2. Then you divide the intensity at 1 unit distance by Y^2 to find the intensity at distance Y. You can combine X and Y in one equation to get: [New Intensity] = [Given Intensity](X/Y)^2 where Y is the distance for [new intensity] and X is distance for [given intensity] At least that's how I think it is. Last edited by dknguyen; 24th July 2006 at 06:41 PM.*

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24th July 2006, 08:58 PM	#3 (permalink)
zevon8 Experienced Member Join Date: Apr 2004 Location: Toronto, Canada, eh Posts: 913	Have a look at this link: http://www.electro-optical.com/whitepapers/candela.htm and here also: http://www.ledtronics.com/pages/tech4.htm They cover the basics as well as the relationships between the different units.