Classification of substances according to their ability to conduct electric current.

Substances, according to their ability to conduct electric current, are divided into 3 groups:

1) conductors;

2) semiconductors;

3) dielectrics.

Conductors are substances that conduct electric current well.

These include metals, solutions of salts, acids, alkalis in water. They are characterized by the presence of free charged particles (electrons, ions), which move under the action of an electric field.

Semiconductors are substances in which electrical conductivity depends on external conditions. The number of free charged particles in them depends on certain conditions: temperature, illumination, the presence of impurities.

These include silicon, indium, germanium.

Dielectrics are substances that do not conduct electric current under any circumstances. They have a very small concentration of free charge carriers.