A relay is an automatic control device whose output will change leaps and bounds when the input （electricity, magnetism, sound, light, and heat） reaches a certain value.
And automobile relays are relays used in automobiles. This type of relay has high switching load power, high shock resistance and vibration resistance. Most power supplies in automobiles use 12V, and most of the coil voltages are designed to be 12V. Because it is powered by a battery, the voltage is unstable;