What is the primary purpose of the alternator in a truck?

The primary purpose of the alternator in a truck is to charge the battery and power the electrical systems. As the engine runs, the alternator generates electricity by converting mechanical energy into electrical energy through electromagnetic induction. This generated electricity replenishes the battery's charge, ensuring that it has enough power to start the engine and operate various electrical components, such as lights, radio, and other accessories.

Additionally, the alternator plays a crucial role in maintaining the vehicle's electrical system while the engine is running, providing a steady supply of power and preventing the battery from discharging. This is vital for the optimal performance of electrical systems necessary for safe and efficient vehicle operation. In this context, the other options do not accurately represent the primary function of the alternator.