What does the alternator do?

What does the alternator do?

• A. Powers the exhaust system
• B. Drains the battery
• C. Charges the battery and powers electrical systems
• D. Starts the engine

Answer: (C)

The alternator’s job is to keep the electrical system charged while the engine is running. It uses the engine’s motion, via a belt, to generate electricity, which is then rectified to direct current and regulated to a steady voltage. This current charges the battery and powers the car’s electrical needs—lights, ignition, fuel injectors, ECU, radio, sensors, and more. The battery provides starting power and acts as a buffer, but once the engine is running, the alternator supplies the power and keeps the battery topped up. It doesn’t power the exhaust system, it doesn’t drain the battery (in a healthy system it actually recharges it), and starting the engine is the job of the starter motor.