Classification of Materials – Conductors – Semiconductors – Insulators

Electrical Conductivity

Electrical conductivity is a physical property of materials that represents a material’s ability to conduct electric current. The SI unit of electrical conductivity is siemens per meter (S/m). 

The electrical conductivity of a material is determined by several factors, including the density and mobility of charge carriers (such as electrons or ions), the structure of the material, temperature, and other environmental factors.

Materials with high electrical conductivity, such as metals and some types of salts and solutions, are commonly used in electrical and electronic applications, where they are used to carry electric current with minimal resistance or loss of energy. Other materials with low electrical conductivity, such as insulators and semiconductors, are used in applications where they can be used to control or manipulate the flow of electric charge.

Electrical conductivity is closely related to electrical conductance. Electrical conductivity is a property of the material itself (like silver), while electrical conductance is a property of a particular electrical component (like a particular wire).

Classification of Materials according to Electrical Conductivity

Materials can be classified into different categories based on their electrical conductivity. Here are some common categories:

1. Conductors: Materials with high electrical conductivity, such as metals and some types of solutions, are known as conductors. They are able to carry an electric current with minimal resistance and are commonly used in electrical and electronic applications.
2. Insulators: Materials with low electrical conductivity, such as plastics, rubber, and glass, are known as insulators. They are not able to carry an electric current easily and are commonly used to isolate and protect electrical components.
3. Semiconductors: Materials that have intermediate levels of electrical conductivity, such as silicon and germanium, are known as semiconductors. They can be used to control and manipulate the flow of electric charge and are used extensively in electronics and computer applications.
4. Superconductors: Materials that have zero electrical resistance at very low temperatures are known as superconductors. They are able to carry electric current without any loss of energy and are used in specialized applications such as MRI machines and particle accelerators.
5. Ionic conductors: Materials that conduct electricity through the movement of ions rather than electrons, such as some types of salts and electrolytes, are known as ionic conductors. They are commonly used in batteries, fuel cells, and other electrochemical devices.

Generally, most metals have high conductivity (which is another way of saying metals tend to be conductors) because the electrons in their outermost shell can move easily. Non-metals tend to have low conductivity.