Hi All,
I am wondering what is the relationship between light intensity (photons/sec/mm2) and the resistance of a CdS photocell?
I want to make a light meter from a CdS photocell. The units can be arbitrary, but I would like to get the form of the function correct. I have failed to find that information by Google and I am hoping that someone here might know the answer. My current guess is that the resistance is logarithmically related to light intensity much in the same way that a thermistor's resistance is related to temperature. However, I have no real basis for this belief and realize that the photocell has a finite resistance in the dark (I have not measured the resistance of a thermistor at 0K , but the form of the equation is well documented).
Thanks for the help.
I am wondering what is the relationship between light intensity (photons/sec/mm2) and the resistance of a CdS photocell?
I want to make a light meter from a CdS photocell. The units can be arbitrary, but I would like to get the form of the function correct. I have failed to find that information by Google and I am hoping that someone here might know the answer. My current guess is that the resistance is logarithmically related to light intensity much in the same way that a thermistor's resistance is related to temperature. However, I have no real basis for this belief and realize that the photocell has a finite resistance in the dark (I have not measured the resistance of a thermistor at 0K , but the form of the equation is well documented).
Thanks for the help.