Starters:

An electric starter is commonly used in petrol and diesel engines. These starters consist of either magnet or DC motor and a starter solenoid attached at the top of it. When you switch ignition on, DC power is supplied to a solenoid which meshes the pinion with the starter ring gear on the flywheel.

Alternators:

The alternator powers most car’s electronic components while you’re driving around or idling, including your headlights, electric steering, power windows, windshield wipers, heated seats, dashboard instruments, and radio. The alternator supplies all of them with direct current (DC) power.