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How does the telephone work?
The telephone rings. You rush to answer it. ‘Hello’ you say into the mouthpiece. The caller responds and you are thrilled to hear your nani’s voice at the other end! Grandma is calling from another city, and though she is miles away, her voice is so clear that it seems she is only next door.
The telephone is a popular means of communication. Through it we are able to keep in touch with friends and relatives, not only within Pakistan, but all over the world. What a wonderful invention!
It was in the year 1876 when a Scotsman, Alexander Graham Bell devised an instrument now known as the telephone. He used an iron diaphragm set in front of a magnet for the mouthpiece and the basic idea is still the same today.
When you speak into the mouthpiece your voice causes a vibration behind the diaphragm (a thin sheet of carbon). The collection of carbon grains which are located behind the diaphragm, are squeezed. An electric current flows through those carbon grains.
Due to the squeezing and letting go of the grains (primarily caused by the various levels of sound) the strength of the current changes in time with this action. This electric current flows away to the earpiece of the telephone held by the person calling you. The current is eventually turned back into sound, and your caller is then able to hear you.
Today, telephone instruments come in various shapes and sizes, and in different colours. Cordless or mobile? Take your pick.
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