What is the function of a horn relay?
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I know that a horn requires more amperes to operate than other electrical systems.
A relay application is shown in a horn circuit.The coil has battery voltage applied to it.The current flow to ground is open because the horn button is normally open.Current can flow through the coil if the horn button is pushed.The contacts are closed by a magnetic field.The horn is grounded when the contacts are closed.The horn relay becomes a control of the high current needed to blow the horn.The control circuit may be wired with very thin wire.The control unit may only have 0.25 ampere flowing through it, and the horn may require 24 or more.
Why use a relay?I know that the relay coil completes the horn circuit using magnetism, but I can't understand why it's necessary.The relay is a fancy way to close the path to the horn device.
You don't understand how a relay works.The quote states that the control wire is very thin and can only handle.25A.The horn may need more than 24A.
The wiring is designed to take the load when the relay is activated.The steering wheel and column are small.In order to run wiring for everything which is controlled there, a relay is the way to go.
In most vehicles, you need to control things like the turn signals, lights, ignition system, wipers/washers, cruise control, and so on.If you wanted to control every item directly, you would have to increase the thickness of every wire and the size of the steering column.
The cost to run such wires should also be considered.It would cost more to extend the wiring to the larger devices.It would make the vehicle heavier.
The horn button has contact points.To handle the load which would be put through the horn button, you would have to build all of the points.A relay can run millions of cycles.The horn button has to be built to take the same amount of cycles.The relay handles the load and makes the circuit.The horn button isn't designed the same way.
A relay is controlled by a switch or button that causes an electric switch to make contact so that it now operates a device with a higher power demand.
Imagine a sports field with flood lights and it is time to turn on the lights.A person goes over to a simple wall switch and flips it up.This causes a reaction in the relay, causing it to trip the bigger switches that turn on the field lights.I know they are different, but the actions are the same.
A relay isn't necessary, it would operate just fine through the steering wheel switch in most cases, but a relay is designed in the circuit for many reasons.
Running a wire from the battery into the steering wheel and back out to the horn causes a long path of voltage drop.Head lights and spot lights will show a drop in voltage, but not in a horn.
Relays allow cabin switches to be small, silent and easy to operate.