What is a magneto?

• A. A generator which produces alternating current and has a permanent magnet as its field.
• B. A device that stores electrical energy for later use.
• C. A sensor that detects magnetic fields in power lines.
• D. A circuit breaker used in DC systems.

Answer: (A)

A magneto is a generator that produces alternating current and uses a permanent magnet to provide the magnetic field. Because the field is supplied by permanent magnets, there’s no separate excitation winding or external power needed to energize the field. This makes the device a self-contained source of AC power, commonly used where a simple, reliable generator is desired.

It is not a device that stores electrical energy, so it isn’t a battery or capacitor. It isn’t a sensor for detecting magnetic fields, which would be a magnetometer or similar device. And it isn’t a circuit breaker, which is designed to interrupt current. The defining traits—self-contained generator, AC output, permanent-magnet field—are what identify it as a magneto.