What is the primary role of a resistor in a circuit?

The primary role of a resistor in a circuit is to limit the flow of current. Resistors are passive components that offer resistance to the flow of electric current. By doing this, they control how much current can flow through different parts of a circuit, which is essential for protecting sensitive components from excessive current that might cause them to fail.

In various applications, resistors are used to set operating points for transistors, divide voltages, and adjust signal levels. Their ability to limit current is governed by Ohm’s Law, which states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to the resistance. Thus, when a resistor is added to a circuit, it effectively ensures that the current remains within safe and functional limits for the other components in the circuit.

The design of circuits often relies on this property to achieve desired performance, stability, and safety.