III. Perfect Tenses (Active / Passive)

1. Translate the following sentences paying attention to the use of perfect forms:

1. High frequency amplification has made it possible to receive signals from weak transmitters over long distances.

2. As a recognized engineering subject, electronics has come into its own only recently.

3. Electronics has entered nearly every field of technical progress and has supplied well-established methods in many fields, including control, measurement and testing.

4. Electronic devices have revolutionized life.

5. We have found that the core, or nucleus of the atom is a tremendous storehouse of energy.

6. Most of the robots have involved a computer of some kind or another.

7. When all of the grouping, editing, and selecting has taken place, the computer prints its results.

8. Recently, scientists have been able to build electronic robots that really can play chess.

9. Science and technique have changed human life during the last hundred and fifty years, and the changes continue at an increasing speed.

2. State the tense forms and translate the following sentences:

1. They had completed all the operations on electrical quantities by that time.

2. This unit will have converted the information into pulse form before that procedure.

3. The instrument partly lost its former efficiency after we had used it for a long time.

4. We learned that Maxwell’s equation had led to Hertz discovering radio waves which, in turn, had resulted in Popov’s invention of wireless telegraphy and developments in radio engineering.

5. They will have covered all parts of mechanism with a thick coat of paint before the start of the experiment.

3. Translate the following sentences paying attention to the Passive Voice:

1. During the past few years, a machine of this type has been developed.

2. Silicon has been prepared successfully in rather pure, single – crystalline form.

3. The analog computer performs mathematical operations on electric quantities which have been converted from the physical variables of the problems.

4. Simple counting devices have been known since ancient times.

5. The various systems have been brought to such a state of perfection that almost any fault can be traced in a few minutes.

6. By that time electronic means had been devised to keep the tension of the moving material at exactly right value.

7. New equipment of air-conditioning will have been employed to maintain interiors at a comfortable temperature, summer and winter, and free from draughts.

4. State the tense forms of the verbs and translate the sentences:

1. An excessive current will flow until a speed has been reached which will provide a sufficient counter e.m.f. to hold the current down to a normal value.

2. The coil will be energized to force the contacts open.

3. Power is fed to the commutator through carbon brushes that slide on its surface.

4. Some motors are mechanically built for one way rotation only.

5. New uses are being found for all types of thermionic tubes.

6. All materials are composed of positive and negative charges.

7. Automatic and relay operations of all kinds are being made faster and more dependable through introduction of tube control.

8. Electrons are emitted by the application of heat to the emitting surface.

9. Tungsten and nickel have been considered as the best cathode materials.