Schematic diagram of DC electric bell

An electric bell is a mechanical bell that functions by means of an electromagnet. A bell is a simple Sound -making device The bell is a Percussion instrument and an Idiophone. An electromagnet is a type of Magnet in which the Magnetic field is produced by the flow of an electric current.

In DC electric bells, when power is applied, current flows through the coil. Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere. The coil becomes an electromagnet, attracting the metal strip. This moves the clanger to hit the bell, but also breaks the circuit. The coil is no longer a magnet, so the clanger moves back. A magnet (from Greek grc μαγνήτης λίθος " Magnesian stone" is a material or object that produces a Magnetic field. The circuit is thus restored. An electrical network is an interconnection of Electrical elements such as Resistors Inductors Capacitors Transmission lines Voltage The process repeats continuously until the power is removed.

AC electric bells do not have interrupting contacts and their coils are powered directly by the source. Their hammers vibrate at same frequency as the frequency of voltage they are powered by. Lack of contacts makes them more reliable than DC bells.

Some electric bells have two cups which generate different tones. When the hammer goes in one direction, it hits one cup, when it moves back, it hits another cup. The sound of such two-tone electric bells is more pleasant.

Two early applications of the electric bell were the telephone and doorbell. Basic principle A traditional landline telephone system also known as "plain old telephone service" (POTS, commonly handles both signaling and audio information A doorbell is a signaling device commonly found near a Door. It commonly emits a ringing sound to alert the occupant of the building to a visitor's presence Early telephones used electric bells to indicate that there was an incoming call. Doorbells were used by visitors to indicate their presence at the external door of a dwelling or business. Though still in use, the electric bell mechanisms in both telephones and doorbells now compete with non-mechanical noisemaking technologies including electronic oscillators and digitally recorded sounds played back through a speaker. In digital recording, the analog signal of Video or Sound is converted into a stream of Discrete numbers representing the changes in Air

A common style of doorbell uses an AC solenoid coil and a plunger. When the doorbell button is depressed, the plunger is drawn into the solenoid and strikes a gong; a shading coil on the solenoid prevents the plunger from vibrating at the same frequency as the power supply. When the button is released, a spring retracts the plunger which then strikes a second gong, giving a two-tone sound. A variant has a second solenoid which is wired to the back door and only strikes one gong, allowing front or rear door callers to be identified.