AC TMI White Paper: How an Autombile Horn Works

The basic principle behind the functioning of an automobile horn involves the conversion of electrical energy into sound energy. Here is a simplified explanation of how an automobile horn works:

1. Power Source

The horn is powered by the vehicle's electrical system, usually a 12-volt DC (direct current) power source. The electrical system is connected to the battery or the alternator.

2. Horn Button/Switch

Inside the vehicle's cabin, there is a horn button or switch, typically located on the steering wheel. When the driver presses the horn button, it completes an electrical circuit.

3. Relay

When the electrical circuit is completed, the current flows through the horn relay. The relay acts as an electromagnetic switch and amplifies the electrical signal.

4. Vibrating Diaphragm

The amplified current then reaches the vibrating diaphragm or a set of electro-mechanical contacts inside the horn. The diaphragm is a thin metal plate or disc made of a flexible material, such as steel or plastic.

5. Electromagnetic Coil

Behind the diaphragm, there is an electromagnetic coil. When the current flows through the coil, it creates a magnetic field.

6. Attraction and Repulsion

The magnetic field generated by the coil interacts with the diaphragm. As the current fluctuates rapidly, the magnetic field alternates between attracting and repelling the diaphragm.

7. Sound Production

The attraction and repulsion of the diaphragm cause it to vibrate rapidly. These vibrations create pressure waves in the surrounding air, producing sound waves. The sound waves are then emitted through the horn's sound output, usually a horn grille or a trumpet-shaped opening.

8. Sound Variation

The design of the horn, including the shape and size of the horn grille or trumpet, influences the sound produced. Different horns may have distinct pitch, loudness, and tone.

By following these steps, the automobile horn converts electrical energy into sound energy,.