sähkönjohtavuutena

Sähkönjohtavuus, often referred to as electrical conductivity, is a fundamental physical property of a material that quantifies its ability to conduct electric current. It is the reciprocal of electrical resistivity. Materials with high electrical conductivity allow electric charge to flow easily through them, while materials with low conductivity impede the flow of charge.

The conductivity of a material is determined by the availability and mobility of charge carriers, which are typically electrons in metals and ions in electrolytes. In metals, valence electrons are delocalized and form a "sea of electrons" that can move freely under the influence of an electric field. In ionic conductors, charged ions are responsible for carrying the current.

The SI unit for electrical conductivity is siemens per meter (S/m). A material with a conductivity of 1 S/m means that a 1-meter cube of the material will have a resistance of 1 ohm.

Common examples of highly conductive materials include silver, copper, gold, and aluminum. These metals are widely used in electrical wiring and electronic components due to their excellent conductivity. Insulators, on the other hand, have very low conductivity and are used to prevent the flow of electricity, such as in rubber and plastic coatings for wires. Semiconductors, like silicon and germanium, have conductivity values between those of conductors and insulators, and their conductivity can be controlled by external factors, making them essential for electronic devices. Temperature also significantly affects electrical conductivity; for most conductors, conductivity decreases with increasing temperature due to increased scattering of charge carriers.