To understand the operations of an electric bell, you should understand what an electromagnet is. An electromagnet works as a standard magnet (generating magnetic fields) but only with an electrical influence. When the power generation to an electromagnet stops, the production of the magnetic field also stops.
The image below shows the internal mechanism of an electric bell.
An electric source powers the electromagnet used in an electric bell. The switch which you press to sound an electric bell acts as the circuit breaker or the switch which completes the circuit.
When the switch is pressed, the circuit loop is complete which causes current to flow through the circuit. The arm which strikes the gong is connected to a spring at one end and an iron ball at the other end. This is called a clapper or a striker. The arm is attached to an iron strip which is attracted to the electromagnet when the circuit is complete and current is flowing through it.
This is because the magnetic field created by the electromagnet attracts the iron strip towards it when the circuit is complete. At its rest position the clapper is held away from the gong on account of the spring attached to its arm. This is an anchored arm.
Now that you have an understanding of the important parts in an electric bell, the step by step process of the working of the electric bell is described below
- The switch is pressed and current flows through the circuit
- The electromagnet is powered and generates a magnetic field that attracts the iron strip towards it
- The striker strikes the gong (bell)
- When the striking arm strikes the gong, the contact is broken and current stops flowing through the circuit
- This causes the electromagnet to lose its magnetic field
- The connected spring arm returns the striker to its original rest position
- The contact is restored and current flows through the circuit (provided the main switch is still pressed)
- The process is repeated from the beginning
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