sähköeristävyys

Sähköeristävyys, often translated as electrical resistivity, is an intrinsic property of a material that quantifies how strongly that material opposes the flow of electric current. It is the reciprocal of electrical conductivity. A material with high electrical resistivity will not allow electric current to flow easily through it, acting as an electrical insulator. Conversely, a material with low electrical resistivity will allow current to flow readily, behaving as an electrical conductor.

The unit of electrical resistivity in the International System of Units (SI) is the ohm-meter (Ω⋅m). Resistivity depends on the material's composition and temperature. For most conductors, resistivity increases with increasing temperature. Semiconductors exhibit a more complex relationship, where resistivity can decrease with increasing temperature due to increased charge carrier generation. Insulators, by definition, have very high resistivity.

Common examples of materials with high electrical resistivity include rubber, glass, and plastic, which are used as insulators in electrical wiring and devices to prevent short circuits and electric shocks. Materials with low electrical resistivity, such as copper, aluminum, and gold, are excellent conductors and are used for wires and electrical components. Understanding sähköeristävyys is fundamental in electrical engineering and materials science for designing and selecting appropriate materials for various applications.