how a measure of the intensity can be obtained from an LDR?

Answer 1

Measure Light Intensity using Light Dependent Resistor (LDR)
The resistance of the Light Dependent Resistor (LDR) varies according to the amount of light that falls on it. The relationship between the resistance RL and light intensity Lux for a typical LDR is

RL = 500 / Lux Kohm

With the LDR connected to 5V through a 3.3K resistor, the output voltage of the LDR is

Vo = 5*RL / (RL+3.3)

Reworking the equation, we obtain the light intensity

Lux = (2500/Vo - 500)/3.3

For a low cost LDR, at the same light intensity, the part to part variation in resistance can be as high as 50%. Therefore such a low cost LDR is seldom

Dr. H

Answer 2

One ordinary thanks to discover the relationship between resistance and intensity is to determination the area of the detector from a non-directional source, along with a mild bulb without reflectors round it. The intensity from the kind of bulb will determination as a million/r^2 the position r is the area from the bulb to the detector. Measuring resistance as against the intensity you assume from diverse distances provide you with an approximate reaction function. Assuming you take advantage of a common LDR, it is going to reply truly nicely by the seen spectrum, regardless of if there'll likely be some version with wavelength. in case you want to refine your attempt, you may want to attempt dissimilar the following: evaluate how the reaction varies with wavelength through shifting the lamp closer or added from the grating/LDR setup. evaluate your measured outcomes with a nicely-regular spectrum along with mid-day solar (do a search for for D65 spectrum) or different source. you should use this to make amends for the wavelength sensitivity.

Answer 3

I assume that you are referring to light intensity and (LDR) light dependent resistor.
LDR is a transducer device, its resistance depend on the light. LDR resistance lower when light intensity is high.You can make a simple light meter by connecting a LDR, a potentio meter , a battery and a moving coil meter(VU meter) in series circuit. you can adjust the indication to your useful range however it need a lot of trial and error if you don't have electrical knowledge to do calculation.LDR might not be a linear device but at least you can measure light better than our eyes.

Answer 4

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