A simple buzzer is an electromechanical device that produces a sound when an electrical current passes through it. It consists of a few key components:
Coil of Wire (Electromagnet): At the core of a buzzer is a coil of wire wound around a small metal core. When current flows through this coil, it generates a magnetic field around the core.
Diaphragm or Armature: Attached to the metal core is a diaphragm or armature, which is typically a thin, flexible piece of metal or plastic. This diaphragm is positioned close to the coil and is free to move back and forth.
Contact Points: The diaphragm is positioned in such a way that when it moves, it can either make or break contact with another piece of metal known as a contact point.
Power Source: The buzzer needs an electrical power source to operate. When voltage is applied across the coil of wire, a current flows through it, creating a magnetic field.
When the buzzer is connected to a power source:
Activation: As current flows through the coil, a magnetic field is generated around the metal core. This magnetic field pulls the diaphragm or armature towards the coil.
Contact Closure: As the diaphragm moves closer to the coil, it eventually makes contact with the contact points, closing the circuit and allowing current to flow through the coil.
Magnetic Attraction: The coil's magnetic field becomes stronger due to the increased current flow, which further pulls the diaphragm towards the coil.
Contact Opening: As the diaphragm gets pulled towards the coil, it can reach a point where it breaks contact with the contact points.
Release and Repeat: Once contact is broken, the current flow through the coil decreases, and the magnetic field weakens. This allows the diaphragm to move back to its original position due to its inherent flexibility.
Cycle: The process of the diaphragm moving towards the coil, making contact, then moving away and breaking contact repeats rapidly as long as the electrical power is supplied. This rapid oscillation of the diaphragm creates vibrations in the air, which we perceive as sound waves, producing the characteristic buzzing sound of the buzzer.
By controlling the frequency of the current (how fast the diaphragm moves back and forth) and the design of the diaphragm and contact points, buzzer manufacturers can produce different types of buzzing sounds.