What is the purpose of a resistor in a circuit?

The purpose of a resistor in a circuit is to limit current flow. Resistors are passive components that provide resistance, thus impeding the flow of electric current. By doing this, they help protect sensitive components from excess current that could lead to damage.

When a voltage is applied across a resistor, Ohm's Law (V = I × R) indicates that the current (I) through the resistor is directly proportional to the voltage (V) across it and inversely proportional to the resistance (R). Therefore, by adjusting the resistance value, the amount of current in the circuit can be controlled. This is critical in ensuring that circuits operate within their designed specifications, thereby enhancing safety and functionality.

In other contexts, while increasing voltage or generating power might involve other components or configurations such as transformers or power supplies, and storing electrical energy typically refers to components like capacitors or inductors, resistors specifically serve the important role of managing current within a circuit.