The telephone is one of the most creative and prized inventions in the
world. It has advanced from its humble beginnings to its wireless communication
technology today and for the future. The inhabitants of the earth have long
communicated over a distance, which has been done by shouting from one hilltop
or tower to another. The word "telephone" originated from a combination of two
Greek words: "tele", meaning far off, and "phone", meaning voice or sound, and
became the known term for "far- speaking."
A basic telephone usually contains a transmitter, that transfers the
caller's voice, and a receiver, that amplifies sound from an incoming call. In
the transmitter there are two common kinds of transmitters: the carbon
transmitter, and the electret transmitter. The carbon transmitter uses carbon
granules between metal plates called, electrodes, with one consisting of a thin
diaphragm that moves by pressure from sound waves and transmits them to the
carbon granules. These electrodes conduct electricity flowing through the
carbon. The sound waves hit the diaphragm causing the electrical resistance of
the carbon to vary. The electret transmitter is composed of a thin disk of
metal-coated plastic held above a thicker, hollow metal disk. This plastic disk
is electrically charged, and creates an electric field. The sound waves from
the caller's voice cause the plastic disk to vibrate, changing the distance
between the disks, thus changing the intensity of the electric field. These
variations are translated into an electric current which travels across the
telephone lines. The receiver of a telephone is composed of a flat ring of
magnetic material. Underneath this magnetic ring is a coil of wire where the
electric current flows. Here, the current and magnetic field from the magnet
cause a diaphragm between the two to vibrate, and replicate the sounds that are
transformed into electricity.
The telephone is also composed of an... [continues]
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(1999, 10). The Telephone System. StudyMode.com. Retrieved 10, 1999, from http://www.studymode.com/essays/Telephone-System-873.html
"The Telephone System" StudyMode.com. 10 1999. 10 1999 <http://www.studymode.com/essays/Telephone-System-873.html>.
"The Telephone System." StudyMode.com. 10, 1999. Accessed 10, 1999. http://www.studymode.com/essays/Telephone-System-873.html.