Bell Telephone

In 1876, Alexander Graham Bell made the first Telephone, called the Bell Telephone, Figure 1. Telephone comes from the Greek word "tele," meaning "from afar", and "phone", meaning voice or voiced sound.

Figure 1: Bell Telephone

The main parts of the Bell Telephone are: an Iron Diaphragm with attached Permanent Magnet and a Coil of Copper Wires, Figure 2.

Figure 2: Cross Section of the Bell Phone

By talking to the Sender's Telephone, the voice of the Sender makes the Diaphragm vibrating. Since the Magnet is attached on the Diaphragm, the vibration of the Diaphragm also makes the Magnet vibrating in the Coil and a Current is induced. This Induced Current signal is then sent to the Receiver's Telephone through the Copper Wires.

At the Receiver's Telephone, the process is vice versa. The Telephone takes the Induced Current signal and translates it back into physical vibrations of the Diaphragm. The Sound is reproduced and can be heard.

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