II. Make up 10 questions to the text.

III. Speak on:

1) conductors:

2) insulators,

III. Translate into English.

1. Электрический ток течет по медному проводу.

2. Медный провод хорошо проводит электричество.

3. Бумага - плохой проводник.

4. Это вещество обладает высокой проводимостью.

5. Оба проводника необходимы для нашего эксперимента.

6. Как проводники, так и изоляторы необходимы к практике.

7. Бумага часто используется как изоляция.

8. Необходимо изолировать эту часть провода.

IV. Form adjectives with new meanings using:

a) prefix "im" — possible, measurable, movable:

b) prefix "un" — necessary, usual, changeable;

c) prefix "in" — definite, effective, sufficient;

d) prefix "ir" — regular, removable, resistable.

V. Give Russian equivalents.

to conduct, conductor, conductive, conductivity; lo apply, application, appliance, applicable, applicability; to depend, dependence, dependent, independent; to insulate, insulation, insulator; to repel, repulsion, repulsive

VI. Translate the following sentences paying attention to the words underlined.

1. Lodygin and Yablochkov lived at the same time: both worked in the field of electricity. Both Lodygin and Yablochkov were inventors.

2. Electricity is used by man both to help him in his work and to give him more comfort in his home.

3. Both insulators and conductors are widely used in industry.

4. Lomonosov was both a scientist and a poet.

VII. Translate the sentences paying attention to the Participle and Participle Phrases.

1. The technology having reached a high stage of development, new methods of work became possible.

2. Electrons forming an atom are in motion.

3. No special cooling arrangements arc necessary for small transformers, natural cooling being sufficient.

4. When finishing his experiment, he carefully noted the results.

5. The sparking is sometimes observed when starting up a machine, (he sparking often taking the form of a ring fire around the commutator.

6. While flowing along a conductor, a current heats it.

7.  When speaking about a direct current, we mean a continuous current.

8. The circuit having been broken, the flow of current slopped.

9. Russian scientists and inventors always tried lo find a practical application for the phenomena discovered,

VIII. Translate into English.

1. Мы используем этот прибор в нашем эксперименте.

2. Этот прибор используется в нашем эксперименте.

3. Используя этот прибор, мы получаем хорошие результаты.

4. Использовав этот прибор, мы получим хорошие результаты.

5. Прибор, использованный в нашем эксперименте, был только что получен.

 

 

Lesson 3.

Text.

                               Semiconductors.

A semiconductor is often defined as an electrical conductor that has a conductivity intermediate between that of an insulator and that of a metal.

             

           Michael Faradey           A.F.Yoffe

 

Some of the properties which we know associate with semiconductors have been known for a century or more.

In 1833 Michael Faradey reported that silver sulphide exhibited a negative temperature coefficient of resistance. W.Smith discovered in 1873 that the resistance of a circuit element made of crystalline selenium decreased upon exposure to light.

A great contribution to the study of semiconductor physics has been made by the prominent Soviet scientist academician A.F.Yoffe. It was in 1930 that A.F. Yoffe and his co-workers started a systematic research of the physics of semiconductors. A.F.Yoffe showed the increasing technical importance of semiconductor devices.

      Among the semiconductors will be found some of the chemical elements, such as silicon, germanium, selenium and others. Semiconductors can be classified according to the nature of the particles which carry current. Thus, we have ionic semiconductors and electronic semiconductors.

        The most important among the semiconductor devices, the transistor, was invented in 1948. Semiconductor devices can usually perform all the elementary functions of oscillation, amplification, modulation and demodulation, rectification, etc. Semiconductor devices are used in measuring technique, automatics, computers, radio and TV sets, etc. 

                          

             Words and word combinations:

semiconductor –полупроводник

upon exposure to light – под действием света

conductivity – удельная проводимость, электропроводимость

intermediate - промежуточный

the properties - свойства

oscillation – генерирование колебаний

 sulphide – сульфид, сернистое соединение

 amplification – усиление;

prominent - выпуклый

 modulation – модуляция;

 demodulation – демодуляция;

 rectification - выпрямление

resistance - сопротивление

Assignment:

I. Find in the text the following words and word combinations:

Электрический проводник,  некоторые из свойств, коэффициент сопротивления, кристаллический селен, начали систематические исследования, важность полупроводниковых приборов, в соответствии с, проводят электрический ток.