A Cadmium Sulfide (CdS) photocell is a passive optoelectronic component whose electrical resistance changes according to the amount of light falling on its surface. It is widely used for light sensing and automatic control circuits.
5. Advantages
Simple and inexpensive
No polarity (can be connected either way)
Wide resistance change range
Good sensitivity to visible light
Easy to use in analog and digital circuits
Common Applications
Automatic street lights
Night lamps and garden lights
Light-activated switches
Camera light meters
Alarm and security systems
Brightness control in displays
Educational electronics projects