vastupanuväärtuse

Vastupanuväärtus, often translated as resistance value, refers to the physical property of a material or object that opposes the flow of electric current. This opposition is quantified by the unit of electrical resistance, the ohm, symbolized by the Greek letter omega (Ω). A higher resistance value indicates a greater opposition to current flow, meaning that for a given voltage, less current will pass through the material. Conversely, a lower resistance value allows for more current to flow.

The relationship between voltage, current, and resistance is described by Ohm's Law, which states that voltage (V) is equal to current (I) multiplied by resistance (R), or V = IR. This fundamental principle is crucial in understanding and designing electrical circuits.

Resistance values are influenced by several factors, including the material's resistivity, its length, and its cross-sectional area. Different materials exhibit varying degrees of resistivity; for example, metals like copper and silver have very low resistivity and are considered good conductors, while materials like rubber and glass have high resistivity and are good insulators. Longer conductors and smaller cross-sectional areas generally lead to higher resistance. Temperature also plays a role; for most conductors, resistance increases with increasing temperature. Components specifically designed to introduce a controlled amount of resistance into a circuit are called resistors.