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Introduction
1. Word Knowledge
2. Mathematics Knowledge
3. Paragraph Comprehension
4. Arithmetic Reasoning
5. General Science
6. Mechanical Comprehension
7. Electronics Information
8. Shop Information
9. Auto Information
9.1 Engine
9.2 Cooling
9.3 Chassis
9.4 Electronic
10. Assembling Objects
Wrapping up
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9.4 Electronic
Achievable ASVAB
9. Auto Information
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Electronic

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Components

These are the core electrical components that work together to start the engine and power the vehicle’s systems.

Six labeled automotive parts: ignition switch with key inserted, a rectangular automotive battery, a cylindrical starter motor with gear teeth, a finned alternator, a lighting system showing two headlights and a taillight, and a vehicle computer module with circuit board and connector pins.
Vehicle components chart
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Component Description
Ignition switch A switch that completes the circuit between the battery and starter motor to begin the starting sequence.
Automotive battery A device that converts stored chemical energy to electrical energy to start a vehicle’s engine and provide power to its electrical systems.
Starter motor An electric motor that draws power from the battery to start a vehicle’s engine.
Alternator A device that converts mechanical energy from the engine into electrical energy to recharge a vehicle’s battery and provide power to onboard systems.
Lighting The system that provides all illumination for the car, including headlights, turn signals, and interior lights.
Vehicle computers A vehicle’s computer-controlled systems, such as the dashboard, alarm systems, and safety systems.

Flow

Three panels. Starting, engine off: the battery powers the starter motor through the ignition switch, and the starter turns the engine. Running, engine on: the engine drives the alternator, which recharges the battery and powers the electrical systems. Engine off: the battery powers the interior lights, the alarm and the electronics.
Engine flow
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When a vehicle is started, the ignition switch completes a circuit in the starter motor that connects to the battery. The battery provides power to the starter motor, which rotates the engine’s crankshaft and allows the engine to begin running on its own combustion power. The starter motor then disconnects from the circuit and crankshaft until the next time the vehicle starts.

While the vehicle is running, the alternator converts mechanical energy from the engine into electrical energy. This generated power recharges the battery and supplies electricity to the vehicle’s electrical systems. If the vehicle’s electrical demand exceeds what the alternator can provide, the battery will temporarily supply the additional energy needed.

When the engine is not running, the battery supplies power to the systems that remain active, such as a vehicle’s interior lights and alarm systems. It can also provide power to onboard electronics and headlights, if turned on. If the vehicle sits unused for too long, the battery can lose its charge, since the alternator has no opportunity to recharge it. This is why a car that hasn’t been driven in a while may need its battery jump-started or even replaced. Batteries will also naturally lose charge over time and typically need to be replaced every three to five years, depending on the vehicle.

Core components

  • Ignition switch: completes circuit between battery and starter motor to begin starting sequence
  • Battery: converts chemical energy to electrical energy; starts engine, powers electrical systems
  • Starter motor: electric motor using battery power to start engine
  • Alternator: converts engine’s mechanical energy into electrical energy to recharge battery and power systems
  • Lighting: headlights, turn signals, interior lights
  • Vehicle computers: control dashboard, alarms, safety systems

Starting sequence

  • Ignition switch closes circuit → battery powers starter motor
  • Starter motor turns crankshaft to start engine, then disconnects once engine runs on combustion

Running state

  • Alternator converts mechanical energy to electrical energy while engine runs
  • Recharges battery and powers electrical systems
  • Battery supplements power if electrical demand exceeds alternator’s output

Engine off state

  • Battery alone powers interior lights, alarm, electronics, and headlights if used
  • No recharging occurs (alternator inactive) → battery can drain if car sits unused
  • Batteries also lose charge naturally over time; typical replacement every 3–5 years

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Electronic

Components

These are the core electrical components that work together to start the engine and power the vehicle’s systems.

Component Description
Ignition switch A switch that completes the circuit between the battery and starter motor to begin the starting sequence.
Automotive battery A device that converts stored chemical energy to electrical energy to start a vehicle’s engine and provide power to its electrical systems.
Starter motor An electric motor that draws power from the battery to start a vehicle’s engine.
Alternator A device that converts mechanical energy from the engine into electrical energy to recharge a vehicle’s battery and provide power to onboard systems.
Lighting The system that provides all illumination for the car, including headlights, turn signals, and interior lights.
Vehicle computers A vehicle’s computer-controlled systems, such as the dashboard, alarm systems, and safety systems.

Flow

When a vehicle is started, the ignition switch completes a circuit in the starter motor that connects to the battery. The battery provides power to the starter motor, which rotates the engine’s crankshaft and allows the engine to begin running on its own combustion power. The starter motor then disconnects from the circuit and crankshaft until the next time the vehicle starts.

While the vehicle is running, the alternator converts mechanical energy from the engine into electrical energy. This generated power recharges the battery and supplies electricity to the vehicle’s electrical systems. If the vehicle’s electrical demand exceeds what the alternator can provide, the battery will temporarily supply the additional energy needed.

When the engine is not running, the battery supplies power to the systems that remain active, such as a vehicle’s interior lights and alarm systems. It can also provide power to onboard electronics and headlights, if turned on. If the vehicle sits unused for too long, the battery can lose its charge, since the alternator has no opportunity to recharge it. This is why a car that hasn’t been driven in a while may need its battery jump-started or even replaced. Batteries will also naturally lose charge over time and typically need to be replaced every three to five years, depending on the vehicle.

Key points

Core components

  • Ignition switch: completes circuit between battery and starter motor to begin starting sequence
  • Battery: converts chemical energy to electrical energy; starts engine, powers electrical systems
  • Starter motor: electric motor using battery power to start engine
  • Alternator: converts engine’s mechanical energy into electrical energy to recharge battery and power systems
  • Lighting: headlights, turn signals, interior lights
  • Vehicle computers: control dashboard, alarms, safety systems

Starting sequence

  • Ignition switch closes circuit → battery powers starter motor
  • Starter motor turns crankshaft to start engine, then disconnects once engine runs on combustion

Running state

  • Alternator converts mechanical energy to electrical energy while engine runs
  • Recharges battery and powers electrical systems
  • Battery supplements power if electrical demand exceeds alternator’s output

Engine off state

  • Battery alone powers interior lights, alarm, electronics, and headlights if used
  • No recharging occurs (alternator inactive) → battery can drain if car sits unused
  • Batteries also lose charge naturally over time; typical replacement every 3–5 years

More from Auto Information

  • Engine
  • Cooling
  • Chassis