Sähköresistanssi

Sähköresistanssi, or electrical resistance, is a fundamental property of electrical conductors that describes their opposition to the flow of electric current. It is measured in ohms, symbolized by the Greek letter omega (Ω). A higher resistance means that a greater voltage is required to drive the same amount of current through the material. Conversely, a lower resistance allows current to flow more easily with a given voltage.

The resistance of a material is influenced by several factors. The resistivity of the material itself is a key property, with different materials having inherently different abilities to resist current. For example, metals like copper and silver have low resistivity and are good conductors, while materials like rubber and glass have high resistivity and are insulators. The physical dimensions of the conductor also play a significant role. Longer conductors exhibit higher resistance, and wider conductors have lower resistance. Temperature also affects resistance; for most conductors, resistance increases with increasing temperature.

Ohm's law is a fundamental relationship that describes the link between voltage, current, and resistance. It states that the voltage across a conductor is directly proportional to the current flowing through it, provided the temperature and other physical conditions remain unchanged. Mathematically, this is expressed as V = I * R, where V is voltage, I is current, and R is resistance. Understanding sähköresistanssi is crucial in the design and analysis of electrical circuits and systems.