Final answer:
An impulse coupling is used with a magneto to provide a spark for ignition in internal combustion engines. It stores energy from the spinning motion and releases it suddenly, creating a high voltage spark across the spark plug gap. This ensures reliable ignition for the engine.
Step-by-step explanation:
An impulse coupling is used with a magneto to provide a spark for ignition in internal combustion engines. When the magneto spins, it generates a magnetic field. The impulse coupling stores energy from the spinning motion and releases it suddenly, creating a high voltage that produces a spark across the spark plug gap. This high voltage spark ignites the fuel-air mixture in the engine, allowing combustion to occur and the engine to run. The impulse coupling ensures that the spark occurs at the right moment, providing reliable ignition for the engine.