What is the primary function of a resistor in an electrical circuit?

The primary function of a resistor in an electrical circuit is to limit current flow. Resistors are components specifically designed to introduce a precise amount of resistance into the circuit, which directly affects the current that can pass through. According to Ohm's Law, which states that voltage equals current multiplied by resistance (V = I × R), increasing the resistance will result in a decrease in current for a given voltage. This is essential for controlling the amount of current that flows in various parts of a circuit, preventing damage to components that can occur if too much current passes through them.

Resistors can also play a role in voltage division, adjusting signal levels, and dissipating heat in circuits but fundamentally, their key role is to control and limit the flow of current. This function is crucial in various applications, such as in protecting delicate components from excessive current, setting bias points in transistors, and in signal processing.