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Question
Choose any one machine or device and prepare a short note about it. It should include
- The structure of the device
- How it works (functions)
- A labelled diagram
- One or two lines about when and how it evolved.
Solution
- An electric bell comprises an electromagnet, a switch, a soft iron bar connected by a spring, a contact screw, a striker and a metal gong.
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- An electric bell is a mechanical bell that functions by means of an electromagnet.
- An insulated copper wire (coil) is wound around the iron core.
- When the switch is pressed, the circuit is completed, and the electric current flowing through the coil transforms the iron core into an elector magnet.
- The soft iron bar and striker are drawn to the electromagnet. The striker hits the gong, causing a sound.
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- In 1823, William Sturgeon invented an oscillating electromagnetic device that led to the development of the electric bell.
- In 1850, John Miranda added a clapper (striker) and a gong to transform it into a regular electric bell.
- Modern electric bell consists of a contact breaker (switch) to break the current.
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