Photoresistor is also known as light guide tube, commonly used to make materials for cadmium sulfide, in addition to selenium, aluminum sulfide, lead sulfide and bismuth sulfide and other materials. These materials have the property that their resistance value decreases rapidly under specific wavelengths of light. This is because the carriers generated by light are involved in conduction, drift motion under the action of applied electric field, electrons rush to the positive terminal of the power supply, and holes rush to the negative terminal of the power supply, so that the resistance value of the photoresistor rapidly decreases.

Photoresistor is a special resistor made of semiconductor materials such as sulfide or selenide insulation, photoresistor is a semiconductor photosensitive device, in addition to high sensitivity, fast reaction speed, spectral characteristics and R value consistency and other characteristics, in high temperature, wet harsh environment, but also to maintain a high degree of stability and reliability, can be widely used in cameras, solar garden lights, lawn lights, etc. Banknote detector, quartz clock, music cup, gift box, mini night light, light sound switch, street lamp automatic switch and all kinds of light control toys, light control lighting, lamps and other light automatic switch control field.

The symbol of the resistor

A photoresistor is a light-sensitive component, and its resistance value can change with the intensity of external light. The photoresistor is represented in the circuit by the letters "R" or "RL" or "RG"