What happens when the breaker points touch in an ignition system?

When the breaker points touch in an ignition system, it effectively completes the ignition circuit, allowing electrical current to flow through the primary winding of the ignition coil. This action energizes the coil and creates a magnetic field. The process is essential for generating the high voltage required to produce a spark at the spark plug, enabling the combustion process within the engine.

In a simple ignition system, when the points close, the current builds up in the primary winding until it reaches a certain level. At that point, the breaker points open, which disrupts the current flow, leading to a rapid collapse of the magnetic field and inducing a high voltage in the secondary winding. This high voltage is then sent to the spark plug, creating a spark and igniting the air-fuel mixture in the engine's combustion chamber.

Understanding this fundamental operation is crucial for diagnosing ignition systems and performing maintenance on small engines.