Vocabulary. 2. carbon - углерод, уголь
1. cap - копыто телефона 2. carbon - углерод, уголь 3. cell - ячейка, клетка 4. cellular - сотовый; клеточный 5. cellular structure - ячеистая (сотовая) структура 6. chamber - помещение, камера 7. coil - виток, катушка 8. cord - провод, шнур 9. cross section - поперечное сечение 10. degree - степень, ступень 11. diaphragm - мембрана 12. expanded reproduction -расширенное воспроизведение 13. extended aerial - удлиненная антенна 14. fuse - предохранитель, пробка 15. granules - зерна 16. ground - заземление, земля 17. jack - гнездо 18. lightning - молния 19. nevertheless - тем не менее 20. plug switch - штепсельный выключатель 21. plug - штепсель, штепсельная вилка 22. portable - портативный, переносной 23. public lighting - уличное освещение 24. safety - безопасность 25. spacer - спейсер, промежуточная часть 26. square - квадратный, квадрат 27. up to - вплоть до 28. vehicle - перевозочное средство (автомобиль, повозка)
Telephony is the transmitting of sounds over a considerable distance by means of electric current, using wires. Telephony as a means of communication is widely used in modern life all over the world. By means of a telephone apparatus people can communicate with each other at distances of thousands of kilometers. The transmission of sounds over a distance is known to be transmission of oscillations. In order to carry on communication, the frequency of the transmitted oscillations should be constant during the whole period of communication. The circuit, which is closed when the line is connected, consists of a transmitter and a receiver connected by an electric conductor. A telephone transmitter is usually a carbon microphone. Its main parts are microphone housing, carbon chamber, carbon diaphragm, carbon granules, insulating spacer, and conductor. By means of the carbon microphone, variable electrical impulses are caused to flow through the circuit. These variable impulses depend on the nature of the sounds supplied into the microphone. During the process of communication current passes through the diaphragm, carbon chamber, and carbon granules. The sound pressure on the diaphragm varies the pressure on the granules of carbon. These granules either make more contacts and decrease the resistance of the granules, or make fewer contacts and increase the resistance.
Sound waves produce oscillations of the same frequency as those of the sounding body. As a result, both the transmitter resistance and the current in the circuit change. The varying current passes through the receiver connected to the network. The receiver of a telephone apparatus consists of electromagnetic coils, a steel magnet, and a diaphragm. The diaphragm, magnets, and the coils are housed in a plastic cap. During the process of communication, the cap of the receiver is pressed to the ear. A variable current passing through the magnet's coils changes the position of the diaphragm; it makes it vibrate. The frequency of these oscillations is the same as that of the transmitter. Therefore the receiver reproduces the same sounds as those that are spoken into the microphone.
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