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Дидактичнi розробки для студентiв 4 курсу РТФ.doc
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V. Answer the following questions:

1. How is a key used to send an electrical impulse through a circuit? 2. What is an "earth return"? 3. How can the cir­cuit be closed? 4. Why could the Morse code be trans­mitted more quickly by "double current working" than by "single current working"? 5. Which sign takes the longest to transmit by the Morse code? 6. How is a teleprinter used to receive a message started? 7. What kind of current is mostly used in telegraphy nowadays? 8. What is the highest frequen­cy to transmit messages by alternating current? 9. Why was it necessary to increase the number of messages that could be sent along one telegraph line? 10. Why are machines now used instead of human operators to transmit and receive telegraph messages?

VI. Translate the following definitions and memorize the terms:

Alternating current. A periodic current the average value of which over a period is zero.

Circuit. A conductor or system of conductors through which an electric current is intended to flow.

Direct current. A unidirectional current in which the changes in value are either zero or so small that they may be neglected.

Frequency. The number of periods per unit time.

Noise. Unwanted disturbances superposed upon a useful signal that tend to obscure its information content.

Range. The region between the limits within which a quantity is measured, expressed by stating the lower.

VII. Open the brackets using the correct tense form:

1. The remarkable properties of transistor (to open) the doors to a new era in telephone switching. 2. Tremendous changes in telecommunication (to take place) in the last de­cade. 3. The scientists (to develop) these new units from the beginning of the year to the end of March. 4. Microelectronics (to take) a big leap forward with the development of silicon integrated circuits which (to find) already many uses in space projects. 5. They (to test) these new units for the repeaters for some weeks. 6. I suppose the laboratory (to develop) the new electronic telephone system for the whole year.

VIII. Translate the following sentences paying attention to the verbs in the Passive Voice:

1. Our group was joined by some new persons. 2. The tel­ephone connects you to a person directly and your question will be answered immediately. 3. The lecture will be attended by all the students. 4. The experiment was watched with great interest. 5. Morse invention was followed by a number of new machines. 6. The underwater cable is affected by sea wafer so it is well isolated. 7. The letter will be answered at once. 8. In telegraphy direct current was substituted by al­ternating current. 9. Modern telegraph systems have been influenced by achievements of science and technology. 10. The delegation was joined by a group of students. 11. The mes­sage must be sent immediately.

IX. Use the Passive Voice (with the preposition "by") in the following sentences:

1. Impulses signal a dash and a dot. 2. Most modern systems use alternating current. 3. The telephone connects you to a person directly. 4. Many examples illustrate this fact. 5. The laboratory has developed a new receiving machine. 6. The new inventions minimize the experimental errors.7. Several examples demonstrate this idea. 8. Man has in-creased the speed of the machine. 9. Telegraph lines connect telephone stations. 10. The first underground cable linked] America and Britain in 1866.