Johtuajohdusta
Johtuajohdusta refers to the phenomenon of electrical conduction through a material. When a voltage is applied across a conductor, it causes free charge carriers, typically electrons in metals or ions in electrolytes, to move in a directed manner. This movement of charge constitutes an electric current. The ease with which a material conducts electricity is quantified by its electrical conductivity. Materials with high conductivity, like copper and silver, are called conductors and are used in electrical wiring. Materials with very low conductivity, such as rubber and glass, are called insulators and are used to prevent the flow of electricity. Semiconductors, like silicon and germanium, have conductivity between that of conductors and insulators, and their properties can be manipulated, making them essential components in electronic devices. The process of johtuajohdusta is governed by Ohm's law, which relates voltage, current, and resistance, the inverse of conductivity. Temperature also plays a significant role; in most conductors, conductivity decreases with increasing temperature due to increased atomic vibrations hindering electron flow. In semiconductors, however, conductivity often increases with temperature as more charge carriers are excited into a conductive state.