What is Electromagnet
To understand about electric bell, first of all we will have to understand that what is electromagnet. Electromagnet is the magnet which produce magnetic field by passing electric current through the wire loop on some metal core. A simple electromagnet can be made by wrapping a wire on iron nail as shown below
A current which flows in wires are create a magnetic field which attracts any iron objects towards it the power of electromagnet is dependent on the amount of current pass through the wires. The more power you will pass through the wires will produce more electromagnetic field.
Electromagnet are used in different components such as generators,hard disk,motors etc.
How Electromagnetic bell works
An electric bell consists of an electromagnet, battery and hammer attaches with copper spring and a metal dome. To make the bell one end of the wire of electromagnet is directly connected to one terminal of the battery and other end of wire to be connected to the screw that is attached to the steel rod which acts like a spring for the hammer touching the screw contact.
When electric current flows through the electromagnetic coil then the iron core attracts the hammer towards it. The hammer hits the bell and produces a ringing sound.
The circuit break as soon as it attracts toward the iron core and electromagnetic field become disabled which cause spring to come at its original position. The circuit is complete as soon as spring is touched to the screw and current flows through the coil , and the hammer strikes the bell again. The process repeats itself and you hearing a ringing sound since the hammer keeps hitting the bell, until the switch is released.
Let’s see below video to understand the complete concept and how to make a door bell using this principle.