Photoresistor¶
A photoresistor or photocell is a light-controlled variable resistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photo conductivity.
A photoresistor can be applied in light-sensitive detector circuits and light-activated and dark-activated switching circuits acting as a resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megaohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms.
Here is the electronic symbol of photoresistor.
Example
4.2 Feel the Light (Learning Project)
5. Home Environment Monitoring (IoT Project)
6. Plant Monitor (IoT Project)