Magneto

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A magneto provides pulses of electrical power to the spark plug in most mopeds. As no battery or other source of energy is required, the magneto is a self-contained solution to providing ignition and lighting.

Inside most magnetos, the engine rotates permanent magnets around coils of wire to provide a basic source of electrical energy. On each revolution, a cam opens the contact breaker points, interrupting the electrical current, causing the voltage in the ignition coil to reach a very high value, enough to arc across the electrodes of the spark plug. A condenser is wired from the points to a ground to prevent the points from arcing when they open.

Most moped magnetos also contain separate coils for providing electrical current for a lighting system.

In some modern magneto designs, an electronic switch (CDI ignition) replaces the points.