The Role of Relays in Automobiles

[McMelanie]

When the starter motor operates, it requires a substantial amount of current. The ignition key is used to control the starter motor. If a large current were to flow directly from the ignition key to the starter, the key would need to be made significantly larger and heavier to withstand frequent high current without burning out. Additionally, thick wires would be required to connect the battery, ignition key, and starter motor, which would be impractical, unreliable, and inconvenient for maintenance. Here is additional information: Automotive relay: When the ignition key is turned off, the electromagnetic coil inside the starter relay loses power, and the magnetic force disappears. The starter circuit contacts disconnect under the action of a spring, cutting off the current to the starter motor, which then stops working. Starter relays are built to be robust, allowing frequent high current flow, thereby improving circuit reliability. Similar to the function of general relays, relays in the electrical automation industry serve as "switches," acting as an intermediate link that controls the on/off of one circuit to manage the next circuit. Automotive relays typically use electromagnetic or solid-state designs.