Question

Small one-cylinder gasoline engines sometimes use a device called a magneto to supply current to the spark plug. A permanent magnet is attached to the flywheel, and a stationary coil is mounted adjacent to it. Explain how this device is able to generate current. What happens when the magnet passes the coil?

Short answer

When flywheel rotates the magnet linked to it moves in relation to the stationary coil, thus magnetic field at the coil changes generating emf which causes current to flow.

Step-by-step solution

Step 1:

The flywheel is attached to the motor, so as the motor rotates, so does the flywheel. When the flywheel rotates, the magnet linked to it moves in relation to the stationary coil.

As a result, the magnetic field at the coil changes. This generates an emf, which causes a current to flow through the coil, according to Faraday's law.

Hence,