An electric bell operates using the principle of electromagnetism, which is the interaction between electric current and magnetic fields. Here’s a detailed explanation of how it works:
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Step 1: Electromagnet Creation: When an electric current flows through a coil of wire (also called a solenoid) within the electric bell, it generates a magnetic field around the coil. The coil acts as an electromagnet, meaning that it behaves like a magnet only when current flows through it.
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Step 2: Attraction of the Iron Armature: The electromagnet inside the bell is positioned near a soft iron armature (a movable piece of iron). The magnetic field generated by the electromagnet attracts the armature, causing it to move. This armature is connected to a hammer or striker that is positioned near a bell.
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Step 3: Hammer Strikes the Bell: As the electromagnet attracts the armature, it pulls the hammer towards the bell, causing the hammer to strike the bell and produce a sound.
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Step 4: Breaking the Circuit: As the armature moves toward the electromagnet, it typically moves away from a set of contacts that complete the electrical circuit. When the armature moves away from the contacts, the current stops flowing through the electromagnet, causing the magnetic field to collapse.
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Step 5: Returning to the Rest Position: When the electromagnet loses its magnetic field, the armature springs back to its original position. This action closes the circuit again, allowing current to flow and the process to repeat. This creates a continuous ringing sound as long as the circuit is intact.
In summary, the electric bell works through the continuous action of electromagnetism: the flow of current through a coil generates a magnetic field, which attracts the armature to strike the bell and produce sound, and this process repeats cyclically.