ASVAB Practice

Electrical and Ignition System

• Battery: Stores electrical energy; provides current to start the engine and power accessories when the alternator isn't running.
• Alternator: Driven by the belt; generates AC, converts to DC, charges the battery and powers the car while running.
• Starter motor: Electric motor that cranks the engine to start it.
• Spark plugs: Create the high-voltage spark that ignites the compressed air-fuel mixture.
• Ignition coil: Steps battery voltage (12V) up to the 20,000–50,000V needed to jump the spark plug gap.
• Voltage regulator: Controls alternator output to prevent overcharging the battery.