Photoconductive Substance

A substance that changes its electrical resistance when illuminated by light is called a photoconductive substance.

Working Principle

The photoconductive effect is the phenomenon of increasing the electrical conductivity of a material due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, or infrared radiation. When light falls on a photoconductive material, it generates electron-hole pairs, which increases the conductivity of the material. The photoconductive effect is used in various applications such as photodiodes, phototransistors, and solar cells.

Types of Photoconductive Materials

There are various types of photoconductive materials available, including:

1. Cadmium Sulfide (CdS)
2. Cadmium Selenide (CdSe)
3. Lead Sulfide (PbS)
4. Lead Telluride (PbTe)
5. Silicon (Si)

Applications of Photoconductive Materials

Photoconductive materials are widely used in various applications such as:

1. Photodiodes: A photodiode is a semiconductor device that converts light into an electrical current. Photoconductive materials such as CdS and Si are used in photodiodes.

2. Phototransistors: A phototransistor is a type of transistor that converts light into an electrical signal. Photoconductive materials such as CdS and PbS are used in phototransistors.

3. Solar cells: A solar cell is a device that converts light into electricity. Photoconductive materials such as CdS and Si are used in solar cells.

Conclusion

In conclusion, a substance that changes its electrical resistance when illuminated by light is called a photoconductive substance. The photoconductive effect is used in various applications such as photodiodes, phototransistors, and solar cells.