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

A resistor's primary function in an electrical circuit is to limit current. Resistors provide resistance to the flow of electric current, which is essential for controlling the amount of current that can pass through a circuit. This regulation is vital for protecting components that may be sensitive to high levels of current, ensuring that they function correctly and preventing damage.

When current flows through a resistor, it converts some of the electrical energy into heat due to its resistance, effectively reducing the overall current available in that part of the circuit. This property is used in various applications, such as setting bias levels in transistor circuits, ensuring safe operating conditions for components, and controlling voltage drops across different parts of a circuit.

In contrast, while the other options mention functions like increasing voltage, storing energy, and amplifying signals, those are roles served by other components. For instance, capacitors are used to store energy, while amplifiers (which can include transistors) are designed to amplify signals. Therefore, the resistor's role is distinct and clearly focused on limiting current within electrical circuits.