sähköjohdinta

A sähköjohdin, or electrical conductor in English, is a material that allows electric charge to flow easily through it. This property is due to the presence of mobile charge carriers, typically electrons, within the material. Metals are the most common examples of electrical conductors. Their atomic structure features loosely bound valence electrons that can readily move from one atom to another when an electric field is applied. Copper and aluminum are widely used conductors in electrical wiring and components due to their excellent conductivity and cost-effectiveness. Silver is the best conductor among all metals, but its higher cost limits its widespread use.

In contrast to conductors, electrical insulators are materials that resist the flow of electric charge. They have tightly bound electrons that do not move freely. Examples of insulators include rubber, plastic, and glass, which are often used to coat electrical wires to prevent short circuits and protect users from electric shock. Semiconductors, such as silicon and germanium, fall between conductors and insulators in their ability to conduct electricity. Their conductivity can be controlled, making them essential components in electronic devices like transistors and diodes. The ability of a material to conduct electricity is measured by its electrical conductivity, with higher values indicating a better conductor.