Light Sensor Circuits

1
Light Sensor Circuits
There are many ways to assemble light sensor
elements into sensor devices that can be employed
on a robot. A CdS photocell is a very simple
transducer that one can use for transforming
changes in light intensity into changes in
resistance.
2
How does a CdS work?
CdS is a semiconductor. When photons on light
strike the semiconductor, electrons are excited
into the conduction band, leaving behinds holes
(vacancies in the valence band). The more
intense the light, the more carriers which are
created and hence the more conductive (less
resistive) is the photocell.
3
Optical Spectrum
4
PDV-P5003
5
PDV-P5003 (continued)
6
How can it be used?