How does a Telephone work?

The creation of the telephone has made communication a lot cheaper and more personal. Long before its creation, people travel just to relay an important message. Developments were made in the field of communication until March 10, 1876 came where the telephone was finally invented. What is a telephone? How does a telephone work?

A telephone is a telecommunication device that is used to send and receive sound which is the human voice. It is mainly used to allow two people to talk to each other even if they are separated by distance. The invention of the telephone is credited to Alexander Graham bell. The fundamental design of the telephone has not changed since its creation. It is a small device with a headset wherein a speaker and an earphone is attached inside which acts as a coder and decoder of sound signal. It has also a body wherein the numbers or keypad is located which is used to enter a specific number. The body of the telephone is then attached to a wire which is directed to a telecommunication network that decodes and codes sound waves. There are phones wherein the keypad is located on the headset and there are some that are wireless. For cordless telephones, it communicated through radio with a base station attached to a wire. Cordless telephones usually works within a limited distance from the base station (body of the phone).

Prior to the creation of the telephone, three developments were made in order to support the fundamentals of its functionality. These are the following: first is the comprehension and realization that an electrical current can create a magnetic field which helps in the development of acoustic energy. This was then established by Christian Oersted, a Danish physicist, in 1820. Second is the comprehension that the process of the first development can be reversed (magnetic field can create an electrical current). This was realized by Michael Faraday, an inventor, in 1821. Last development needed is the creation of battery which helps provide a continuous source of energy. The creation of battery was credited to two Dutchmen in the year 1746.

The telephone works through the interchange of two fields: electricity and acoustics. The principle of its operation is very simple. The speaker in the headset of the telephone has thin metal coating which is separated from an electrode by a plastic barrier. The electrode is connected to a wire which has a capability to carry electric current. When a person speaks through the speaker, the acoustic vibration of his/her speech pushes the thin metal coating near the electrode which results to the creation of vibration (in voltage) and then to electrical energy. The electrical energy is then sent to the telephone network and then to the other line of the phone (or the second phone). The speaker of the second phone allows the conversion of electrical energy into acoustic energy thus voice can be heard.

The above process happens very fast (close to the speed of light). That is the reason why communication through telephone feels like doing it face-to-face.

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