Question

Choose any one machine or device and prepare a short note about it. It should include

1. The structure of the device
2. How it works (functions)
3. A labelled diagram
4. One or two lines about when and how it evolved.

Answer 1

1. 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.
2. 1. An electric bell is a mechanical bell that functions by means of an electromagnet.
   2. An insulated copper wire (coil) is wound around the iron core.
   3. 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.
   4. The soft iron bar and striker are drawn to the electromagnet. The striker hits the gong, causing a sound.
3. 
   
4. 1. In 1823, William Sturgeon invented an oscillating electromagnetic device that led to the development of the electric bell.
   2. In 1850, John Miranda added a clapper (striker) and a gong to transform it into a regular electric bell.
   3. Modern electric bell consists of a contact breaker (switch) to break the current.