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.

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.

Optical Spectrum

PDV-P5003

PDV-P5003 (continued)

How can it be used?