12. Translate the following attributive word-combinations:

semiconductor thermo-electric generator, current-carrying conductor, electrical engineering problem, emergency sygnal system, high-temperature range, cotton insulation layer, energy accumulation process, electronic counting machine.

13. Translate the following sentences and make up questions to them:

1. The first practical use of semiconductors was as crystal detectors in the earliest radio receivers.

2. At present semiconductors have found wide use in all kinds of complicated devices such as television and radio sets, refrigerators and many others.

3. Owing to semiconductors we are able to convert heat directly into electricity without boilers or other machines.

4. Thermocouples made of semiconductors are capable of producing both heat and cold.

5. A photo-cell is also a small electric station feeding on light.

Text 9 b Semiconductor Laser

Give a summary of the text.

Semiconductor quantum generators occupy a special place among the optical quantum generators. The size of a ruby crystal laser comes to tens of centimetres while a gas generator is about a metre long. A semiconductor laser is a few lengths of a millimetre long. Whereas the density of its radiation is hundreds of thousands of times as great as that of the best ruby lasers. For example, the device shown in Fig. 1 is 0.4 mm on each edge, with the junction lying in a horizontal plane through the centre.

All previous solid-state lasers needed energy supplied from external light sources, usually an intense burst of light from a flashtube. In the new gallium-arsenide injection lasers, pump energy is supplied directly by injecting electrons into the diode. Now modulation of the laser beam can be achieved by modulating the input current source. Semiconductor lasers operate under pulse and permanent regimes.

Notes

1. Burst – спалах

2. Flashtube – спалахуюча лампа

3. By injecting – вводячи

4. Input – вхiд

Junction region

|not to scale|

Fig. 1.

Text 9 c Semiconductors in modern technology

Translate the text using a dictionary:

During the past several decades technology has posed problems that have required new methods and new materials for their solution. There have appeared heat-resisting alloys, superhard and light alloys, plastics, organic glass, sponge-glass and new building materials. The electric industry has added to its metals and insulators a group of semiconductors.

An investigation of the physical nature of semiconductors and a scientific explanation of semiconductivity have broadened the theory of semiconductors and have elucidated fresh facts that make possible the solution of many new technical problems.

The study of semiconducting materials which revealed their unique properties, such as dependence of conductivity on heat and light, opened up great possibilities for various uses of semiconductors.

There are altogether several hundred materials which have been studied and identified as semiconductors. Germanium and silicon seem to be the most useful semiconductor materials at present. They are widely used in modern electronic techniques, for example, in rectifiers, transistors, thermopiles, non-linear resistors and so on.

At present two semiconductors, germanium and silicon, are of special interest as they form the basis of the transistor – an electronic amplifier – in which the amplified current is emitted and transported within the semiconducting solid. As long as transistors are constructed of solid materials, their size can be made smaller as compared with tubes of corresponding electrical performance. They are stronger and more reliable. The highest quality radio receivers and the most complex apparatus for signalization, automation and remote control become more and more tiny in size and cheaper thanks to the application of semiconductors.

The semiconductor devices are used in measuring technique, computers, radio and TV-sets for transmission of signals, for automation and remote control of a variety of processes, for switching on engines, for the production of sound, protection of high-voltage transmission lines, speeding up some chemical reactions, and so on. Semiconductors convert alternating current into direct current, amplify high-frequency oscillations and generate radiowaves, thereby replacing vacuum devices. They can convert heat energy into electric energy without machines, store light and release it on demand, etc.

Although this list could be continued, the number of applications named is sufficient to appreciate the importance and role of semiconductors in modern technology.

The introduction of semiconductors into industry began not long ago. Some fifty or sixty years ago semiconductors did not exist either in electric industry or in radio engineering. Now the semiconductor industry is developing very rapidly. Its very first steps showed that they may change our technological patterns entirely. Broad automation of all technical processes and their control from one centre will become a method easily attained in various industries. It will bring to a steep rise in labour productivity.

Semiconductors help to solve such fundamental problems as the direct conversion of thermal energy and the solar energy into electric power, and also electric energy into mechanical energy, and vice versa, without any complex mechanism with moving parts. Semiconductor couples convert heat directly into electricity just as a generator does it. A new industry – helioengineering – has emerged. Solar batteries are successfully operating on sputniks and spaceships.

This special place occupied by semiconductors in modern physics and engineering and potential possibilities of application are due to the peculiarities of their properties which are not found in other materials. When considering the future development of semiconductor technology, we must keep in mind that it is one of the youngest branches of science and technology – of the same age as nuclear physics.