The magnetic effect of electric current is the foundation of how an electric bell works. When current flows through a coil of wire (the electromagnet), it creates a magnetic field. This field attracts an iron strip with a hammer attached, causing the hammer to strike the bell, producing a sound. When the strip strikes the bell, it breaks the circuit, stopping the current and the magnetic field, allowing the strip to return to its original position. This cycle repeats as long as the button is pressed.
Here’s a more detailed explanation and a visual representation:
Working Principle:
1. Electromagnet:
An electric current flowing through a coil of wire (the electromagnet) creates a magnetic field.
2. Iron Strip:
A soft iron strip with a hammer attached is positioned near the electromagnet.
3. Hammer and Gong:
The hammer is connected to the iron strip and strikes a metal gong (the bell).
4. Circuit Completion:
When the push button is pressed, current flows through the circuit, energizing the electromagnet and making it magnetic.
5. Striker Movement:
The magnetic field of the electromagnet attracts the iron strip, causing the hammer to swing and strike the bell.
6. Circuit Break:
When the hammer strikes the bell, it breaks the circuit, stopping the current and causing the electromagnet to lose its magnetic field.
7. Return to Position:
The iron strip returns to its original position due to a spring, restoring contact and allowing the circuit to complete again.
8. Repeating Cycle:
The cycle of striking, circuit break, and return repeats rapidly as long as the push button is held down, creating the ringing sound of the electric bell.
Diagram Explanation:
Electromagnet: A coil of insulated wire wrapped around an iron core.
Iron Strip (Armature): A strip of soft iron that is attracted to the electromagnet.
Hammer: Attached to the iron strip, it strikes the bell.
Bell (Gong): The metal object that vibrates and produces the sound.
Push Button: A switch that completes the circuit, allowing current to flow.
Spring: Restores the iron strip to its original position when the electromagnet loses its magnetism.
Contact Screw: Ensures electrical contact when the iron strip is in its original position.
Battery (or Power Source): Provides the electrical current to power the electromagnet.