A starter motor is a vital component in a car's electrical system. Its primary function is to initiate the engine's starting process. When you turn the ignition key, the starter motor engages with the engine's flywheel, spinning it at high speed. This, in turn, cranks the engine, allowing the pistons to start their combustion cycle. Once the engine starts, the starter motor disengages, and the engine's internal combustion takes over.

An alternator is like a power plant for your car. It generates electrical energy to charge the battery and power the car's electrical systems, such as the lights, radio, and power windows. When the engine is running, the alternator keeps the battery charged and provides power to the car's electrical components.