I know that a horn requires a larger amount of amperes to operate than many other electrical systems.
I am reading a book and I stepped into this situation:
..shows a relay application in a horn circuit. Battery voltage is applied to the coil. Because the horn button is a normally open–type switch, the current flow to ground is open. Pushing the horn button will complete the circuit, allowing current flow through the coil. The coil develops a magnetic field, which closes the contacts. With the contacts closed, battery voltage is applied to the horn (which is grounded). Used in this manner, the horn relay becomes a control of the high current necessary to blow the horn. The control circuit may be wired with very thin wire because it will have low current flowing through it. The control unit may have only 0.25 ampere flowing through it, and the horn may require 24 or more amperes
from "automotive electricity and electronics by Barry Hollembeak".
Why bother using a relay? I know that the relay coil completes the horn circuit using magnetism, and I know that the relay is necessary but I can't understand why. For me the relay is just a fancy way to close the path to the horn device.