Rezistor

Rezistor is a passive two-terminal electronic component that provides a defined resistance in an electrical circuit. It is used to limit current, divide voltages, bias active devices, terminate transmission lines, and provide a predictable load. The resistance is measured in ohms (symbol Ω). Fixed resistors come in many materials and constructions, including carbon film, metal film, metal oxide film, carbon composition, and wirewound varieties for higher power. Most resistors are identified by color bands or printed markings that encode the resistance value and tolerance. Standard tolerance values include ±1%, ±5%, and ±10%. Power rating indicates how much heat they can safely dissipate; typical small resistors are 1/8 to 1/2 W, with larger power resistors rated at several watts. They rely on Ohm's law V = IR and on the relation P = V^2 / R or P = I^2 R. Variable resistors, such as potentiometers and rheostats, change resistance by mechanical adjustment. Applications include voltage division, current limiting, load replacement, and sensor interfaces. Design considerations include temperature coefficient, drift, tolerance, size, power rating, and resistance range. Resistors have been essential components in electronics since the early development of circuits; carbon-based resistors were among the first mass-produced types, with metal films offering improved stability.