Resistors are electronic components that restrict the flow of electric current in a circuit. They are passive devices, meaning they do not generate or amplify electrical signals like active components such as transistors or amplifiers. Instead, resistors introduce resistance to the flow of current, helping control the amount of current in a circuit.

Resistors come in various types, including fixed resistors with a constant resistance value and variable resistors (potentiometers or rheostats) that allow for manual adjustment of resistance. They are fundamental components in electronic circuits, finding application in virtually every electronic device and system.