On 2008-10-12 02:56:49 -0400, swapna said:

Photosensors or photodetectors are sensors of light or other
electromagnetic energy. There are several varieties:
¥ Optical detectors, which are mostly quantum devices in which an
individual photon produces a discrete effect.


A photoresistor or Light Dependent Resistor or CdS Cell is a resistor
whose resistance decreases with increasing incident light intensity.
It can also be referred to as a photoconductor.




http://electronicstopics.blogspot.co...hotoresistor.h
tml

And this cross post from (where else) Google Groups is relevant how?
--
Michael