Which device charges the battery and powers electrical systems?

• A. Alternator
• B. Starter
• C. Battery
• D. Fuse box

Answer: (A)

An alternator is the device that charges the battery and powers electrical systems once the engine is running. It’s driven by a belt from the engine and converts mechanical energy into electrical energy, supplying DC current to recharge the battery and run electrical loads like lights, radio, and ignition. A voltage regulator keeps the output at a safe level (roughly 13.8–14.4 volts) so the battery charges properly without overcharging. The battery, by contrast, mainly stores chemical energy and provides power to start the engine and to smooth out power when the engine is not yet charging. The starter uses battery energy to crank the engine, and the fuse box simply routes power to circuits rather than generating or charging electricity.