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
5.7 Feel the Light (Arduino Project)
6.6 Plant Monitor (Arduino Project)
5.7 Feel the Light (MicroPython Project)
6.8 Plant Monitor (MicroPython Project)