Now I use LED as a light sensor but what I have faced one problem. When I use some LED colors e.g. pink (450 nm) or UV (400 nm), they don’t respond to the different light intensity. They give the same output voltage.
For example, I inputted 2.75 V or 3.6 V to the UV LED light source then the output voltage from the UV LED light sensor was the same at 6.60 V.
Is it because of my amplification unit or semiconductor material of UV LED or the plastic of the UV LED absorb the light?
Please give me some suggestions about this problem.