How is an electrical resistor defined?

• A. Two terminal components that resist current flow
• B. A two-terminal device that stores energy
• C. A three-terminal device that regulates voltage
• D. A device that converts light energy to electrical energy

Answer: (A)

A resistor is a passive two-terminal component whose job is to resist the flow of electric current. It presents a defined resistance so the current that flows for a given voltage is limited, following Ohm’s law (V = IR). It doesn’t store energy like a capacitor or inductor; instead, it dissipates electrical energy as heat. It has two connections, not three, and it isn’t used to regulate voltage by itself or to convert light into electricity. So the best definition is a two-terminal component that resists current flow.