Final answer:
A magneto operates on the principle of electromagnetic induction, where spinning a magnet in front of a coil induces a high voltage across the coil's ends. This voltage can jump across an air gap in the distributor to create a spark used for ignition in engines.
Step-by-step explanation:
An air gap type distributor is typically used on a high-tension magneto system, which is commonly found in aircraft engines, for example. A magneto is an electrical generator that produces periodic pulses of high voltage for spark plugs. The principle behind its operation is electromagnetic induction. Here's how it works:
When a magnet is spun very quickly in front of a wire coil, the magnetic field around the coil changes rapidly. According to Faraday's law of electromagnetic induction, a changing magnetic field in a circuit induces a current through the circuit. As the magnet spins, it generates alternating pulses of electricity due to the changing polarity and strength of the magnetic field.
To produce a spark, the magneto system needs to generate a sufficiently large voltage. The very fast spinning of the magnet creates a rapidly fluctuating magnetic field, which, according to the law of induction, results in a commensurately high voltage across the coil's ends. When the voltage is high enough, it can jump across the air gap in the distributor, and this creates the necessary spark for ignition.