Resistance to illuminance conversion

[hateem12]

I have conducted an experiment to measure the changes in voltage/current due to the resistance changes of a photocell present in an LDR.
I wanted to know how I could use those values in order to calculate the illuminance present on the surface of the photocell.
I did not use a voltage differential circuit.
I looked at some websites and all the related experiments were simply using differential circuits.

Is there an LDR resistance to luminance conversion equation or something similar.
Thanks.

 

[jbsteele]

Yes, there is a formula that can be used to calculate the illuminance (measured in lux) from the resistance of an LDR. The equation is Lux = 10^6 / (resistance in ohms). This equation applies when the LDR is illuminated by a standard light source, such as a tungsten bulb. If a different light source is used, then a different equation may be required.