Which device serves as the electromagnetic switch between the ignition and starter motor?

• A. Battery
• B. Starter Solenoid
• C. Ignition Coil
• D. Alternator

Answer: (B)

The device that serves as the electromagnetic switch between the ignition and the starter motor is the starter solenoid. When you turn the key to start, a small current flows into the solenoid coil, creating a magnetic field that pulls a plunger. This action closes the heavy-duty contacts inside the solenoid, routing battery power directly to the starter motor so it can turn the engine over. The solenoid also typically pushes the starter’s gear (the Bendix) into engagement with the engine’s flywheel, enabling the actual cranking. This arrangement keeps the high current for the starter separate from the ignition switch and other circuits, protecting them and ensuring reliable engagement. The battery provides the power, the ignition coil creates the spark, and the alternator recharges the battery while the engine runs; none of those perform the high-current switching needed to run the starter.