What is the function of a circuit breaker in an aircraft?

A circuit breaker in an aircraft serves the essential function of protecting electrical circuits from overcurrent. When the current flowing through a circuit exceeds a predetermined level, the circuit breaker automatically interrupts the flow of electricity, preventing potential damage to the circuit components and reducing the risk of electrical fires. This safety mechanism is crucial in aircraft, where reliable electrical systems are vital for safe operation.

The other options provide functions that are not aligned with the primary role of a circuit breaker. Amplifying electrical signals, regulating voltage levels, and enhancing the power supply pertain to different types of electrical devices and systems, such as amplifiers, voltage regulators, and power management systems. Thus, while these components play significant roles in an aircraft's electrical system, they do not directly relate to the protective purpose of a circuit breaker.