 |
|
Telephone communication.
Another important kind of wired communication is telephony. It is the transmission of speech over a considerable distance by means of electric current. Telephone set includes a transmitter, and an electric network in addition to receiver.
The transmitter or microphone consists of a diaphragm, carbon chamber with carbon granules and insulating spacer and conductor. The electric current passes through the diaphragm and carbon granules. When we speak we produce sound waves which make the diaphragm vibrate. The diaphragm in its turn pushes the carbon granules which makes more or fewer contacts and decreases or increases the resistance. Thus the waves of electric current vary depending on the sounds we produce and pass along the line and finally reach the receiver. The receiver consists of electromagnet coils, a steel magnet and a diaphragm. A variable current passing through the magnet's coil makes the diaphragm vibrate. The frequency of these oscillations is the same as that of the transmitter. Therefore the receiver reproduces the same sounds as are spoken into the microphone.
The telephone was designed in 1875 by Alexander Bell, Later on the development of the telephone changed its construction, it became more complex. Auxiliary elements were used in the circuit to provide better transmission of speech. Further on the development improved the switching system. Now very complex telephone constructions are used and a new kind of telephone appeared - radiotelephone.
Вариант 12
Задание 1. Измените число существительных с единственного на множественное и внесите соответствующие изменения в остальные члены предложений.
1. This mountain has never been climbed before.
2. There was a potato in the basket.
3. A bird sang on the branch of a tree.
4. The guide organized excursion well.
5. This program will be shown by him.
6. That boy is my brother.
Задание 2. Измените форму прилагательных, данных в скобках, и переведите предложения на русский язык.
1. My dog is (good) than yours.
2. My dog is the (good) of the three.
3. The cat will be much (happy) in hernew home.
4. My cold is (bad) today than it was yesterday.
5. This mountain is the (high) in Europe.
6. This piece of homework is as (bad) as your last one.
Задание 3.Вставьте модальные глаголы may, can, must, need.
1.... he ride a bike?
2. If you want to be healthy, you ... drink much coffee.
3. ... I take a sweet? Yes, of course.
4. You ... choose any instrument if you like.
5. You ... learn music.
6. ... I listen to the music?
Задание 4. Поставьте глаголы, данные в скобках, в нужную форму.
1. I (tell) you the answer yesterday.
2. He (arrive) at 12 o'clock.
3. You (lock) the door before you leave house?
4. I (read) this book when I was at school.
5. He usually (live) with family for six month every year.
6. I (leave) home at 8 .00 and (get) here at 15.00.
Задание 5. Переведите предложения на английский язык.
1. Вы не забыли отправить открытку?
2. Мы все верим, что это была ошибка.
3. Все любят слушать, как он поет.
4. Я помню, что отправил все ваши письма.
5. Я думаю, вам следовало тогда извиниться перед ними.
6. Я предпочитаю езду на велосипеде путешествию пешком.
Задание 6. Образуйте отрицательную и вопросительную формы предложений.
1. His dad was an architect.
2. He went to the pond.
3. They noticed that the sun had gone down.
4. She was very beautiful.
5. My friends know all the best places to go.
Задание 7. Задайте вопросы к каждому члену предложения.
1. I always drink orange juice in the morning.
2. We have English lessons twice a week.
3. He was on vacation in Moscow with his family.
4. We've been playing games together all the time.
5. They collect stamps and coins.
Задание 8. Задайте общий, специальный, альтернативный и разделительный вопросы к каждому предложению.
1. I was repairing my car the whole day yesterday.
2. My friend knows Spanish very well.
3. Yesterday I came home at 3 o'clock.
4. The cat is sleeping before the fire.
5. There were three mistakes in my test
Задание 9. Переведите текст на русский язык.