Resistors are passive electronic components that limit the flow of electric current in a circuit. They are characterized by their resistance, measured in ohms (Ω). Resistors are commonly used to control the amount of current, divide voltage, and protect components from excessive current. They come in various types, such as fixed resistors with a constant resistance value and variable resistors (potentiometers) whose resistance can be adjusted. Resistors are fundamental components in electronics and are essential for shaping and controlling electrical signals in a variety of applications.