How can i determine intensity of light from a lamp using an LDR? - experiments using ldr
I received an allocation of physical inevstigate, as the intensity of light emitted by a lamp with a wavelength varies. In the experiment I will use diffraction grating to produce a spectrum and then measuring the impact on the LDR at regular intervals. From my experience, I explain how the intensity can be obtained from the GDR, this is the part I do not understand what I can find no link between resistance and intensity, can someone tell me, in the right direction?
Monday, February 15, 2010
Experiments Using Ldr How Can I Determine Intensity Of Light From A Lamp Using An LDR?
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You are a part of the answer already. No connection between the resistance and the intensity of light of a particular range of wavelengths. But as the wavelength decreases (increases in the frequency or energy), it reaches a threshold, so that the resistance increases with light intensity.
The disadvantage is that if the light energy is not sufficient () above the cutoff frequency, no matter how high the intensity (brightness) of light increases, so no electrons are released, the resistance is not affected.
An easy way to find the connection between resistance and intensity, not the distance of the detector from a source varying directions, like a light bulb around without reflectors. The intensity of the light bulb, from 1 / vary R ^ 2, where r is the distance between the sensor bulb. Measuring resistance, the intensity is expected from different distances you an approximate response function.
Assuming you're using a standard LDR should respond pretty well throughout the visible spectrum, but it is probably a variation of the wavelength. If you want to improve your experience, you can try some of the following:
Compare what the answer depends on the wavelength of the light closer or further away from the fence / LDR configuration.
Compare your results with a measured spectrum known as the midday sun (a search in the D65 spectrum), or any other source. You can use this to compensate for the wavelength sensitivity.
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