Electrical resistance is a measure of the opposition that a circuit presents to the flow of electric current. It is measured in ohms (Ω), named after German physicist Georg Ohm. Resistance depends on the material properties, dimensions (length and cross-sectional area), and temperature of the conductor. Understanding resistance is fundamental to designing and analyzing electrical circuits.

Ohm's Law (R = V/I) describes the relationship between voltage (V), current (I), and resistance (R). For a given voltage, a higher resistance results in lower current flow. This principle is used extensively in electronics for current limiting, voltage division, and signal conditioning.

Several factors influence the resistance of a conductor: Material - Different materials have different resistivities; copper and silver are excellent conductors with low resistivity, while rubber and glass are insulators. Length - Resistance increases proportionally with the length of the conductor. Cross-sectional area - Resistance decreases as the area increases, which is why thicker wires have lower resistance.Temperature - For most metals, resistance increases with temperature due to increased atomic vibrations that impede electron flow.