II. Translate the sentences paying attention to the words underlined.

1. Current starts flowing at the very moment when we close the circuit.

2. He was sent for as he was the only one to help us in this case.

3. At present the only thing for you to do is to work systematically.

4. Electrical conductors of the same substance, but different diameters have the same conductivity.

5. Tungsten is the very metal we use in the manufacture of electric lamps.

6. The Ural mountains are very rich in minerals.

7. Not only metals can be used in electrical engineering.

8. This glass rod has the same kind of electric charge.

9. Amber is not the only substance that attracts light objects,

10. The only deposits of niobium in the world were found in the Ural mountains.

11. Only in the Urals there arc deposits of niobium.

 

                                 TEST YOURSELF

 

Упр. 1. Подберите правильные переводы для слов левой колонки.

1. commutator           1. якорь

2. brush                      2. вал

3. shaft                             3. масло

4. armature                      4. отверстие

5. bearing               5. щетка

6. oil                                6. пыль

7. dust                              7. капля

                                         8. коллектор

                                         9. подшипник

                                         10. двигатель

 

Упр.2  Подберите правильные переводы для слов левой колонки.

1. rotate                      1. падать

2.equal                             2. нагревать

3. pick up               3. охлаждать

4. slide                             4. отверстие

5. hole                              5. смазывать

6. lubricate                      6. скользить

7.cool                               7. собирать

                                         8. равный

                                         9. вращать

                                         10. исчезать

 

Упр. 3. Подберите синонимы для слов левой колонки.

1. convert               1. rotate

2. revolve            2. lubricate

3. pick up             3. supply

4. oil         4. transform

5. provide             5. take place

6. occur             6. collect

 

Упр. 4. Вставьте нужное слово.

1. some: 2. the same. 3. the only; 4. only; 5. very; 6. the very

 

1. This generator must have... frequency as the first one.

2. All countries should use nuclear power... for peaceful purposes.

3.... students work and study at the same time.

4. Current starts flowing at... moment, when we close the circuit.

5. Rubber is a... poor conductor of electricity.

6. The hydroelectric station is by no means... source to be used for generating electric power.

 

 

UNIT II. Electronics.

Lesson 1.

Text.                          

                                 Electron emission

                               

Electron emission is the liberation of electrons from substances under particular conditions. There are a number of ways in which the electrons of a substance can break through its surface, for example, the application of heat. If the metal is heated, the electrons move faster than their normal speed of motion. When electrons of a metal are freed by heating it is called thermionic emission.

Then there is the application of light. When electrons are liberated by the energy of the light rays it is called photo­electric emission.

The third type of emission is the liberation of electrons as a result of the bombardment of the substance with fast-moving electrons.

The fourth method is called cold-cathode emission. In this case the electrons are liberated from a substance by the attract­ing power of a strong electric force.

 

Words and word combinations:

emission – эмиссия

liberation - освобождение

under particular conditions — при особых условиях

a number of ways — ряд способов    

as a result of — в результате
can break through its surface — могут вырываться с поверхности

bombardment – бомбардировка (частицами)

 

I.        I. Choose  the synonym to the word, translate them into Russian:    

1. to heat – a)to convert; b) to warm; c) to cause;

2. to operate – a)to include; b) to build; c)to function;

3. to apply – a) to admit; b) to use; c) to approach;

4. substance – a) screen; b) matter; c) sylphide.

5. speed - a) point; b) motion; c) velocity. 

 

Lesson 2

Text.                 

 

                                   The diode.

Of the many types of tubes which are in use, the simplest is the diode.

This is a two-element tube which consists of an emitter of electrons (the cathode) and a collector of electrons (the plate or the anode).

The term diode refers to the number of electrodes within the tube. The main function of the two-element tube is as con­verter of power. By this we understand that by means of the diode the electric power can be converted. Alternating voltage is converted in the form of pulsating direct current (the convertion of a. c. power into d. с power). This is the process of rectification.

The triode.

The triode, or three electrode tube, is an elaboration of the diode.

The diode consists of two electrods. They also appear in the triode and they constitute the basis of the triode. In the triode the third electrode (the control grid) is added in the space between the emitter and the plate.

The control grid is a metal structure which may be of different shape, depending upon the design of the tube.

The basic function of the triode is to amplify the current, or voltage or electric power. In this process of amplification the control grid plays a most important role.

 

                              The tetrode.

A triode with an electrode placed between grid and anode Is called a tetrode. This additional electrode is a screen grid. The screen grid surrounds the control grid using solid metal at top and bottom. The screen has a very small mesh compared with the control grid. It has a profound effect on the characte­ristics of the valve (tube).

The pentode.

In the pentode valve an additional grid called the suppres­sor grid is placed between the anode and screening grid and is connected to the cathode either with the valve itself or externally.

The suppressor grid greatly reduces the power of the screen grid to draw electrons from the vicinity of the anode, since electrons so placed will be attracted by the anode and repelled towards it by the suppressor grid.

 

Words and word combinations:

 

refers to the number of electrodes within the tube — относится к числу электродов в лампе     

by this — под этим

an elaboration of — является развитием, разработкой

in the space between — в пространство между

control grid — управляющая сетка

screen grid — экранная сетка

at top and bottom — вверху и внизу

иby means of — при помощи

suppressor grid — защитная (антидинатронная) сетка

 

Lesson 3.

Text.

ELECTROMAGNETIC WAVES

Radio waves, light, X-rays, and some cosmic rays — they all belong to the same family. They travel at the velocity of light.

The wave has both electric and magnetic components which are bound together. At the end of its travel the wave gives up energy. The ether waves are those we.. know as wireless waves.

When the waves are too long they are "seen" as infra-red, when they are too short they are "seen" as ultra-violet. Shorter than the ultra-violet are X-rays and far shorter than the shortest of these are the "gamma" rays, and finally the cosmic rays.

The penetrative power of these increases as the wavelength decreases.

To sum up: all these electromagnetic waves travel through the ether at the same enormous speed; the different effect which they produce depends entirely upon their length.

Some more words about ultra-violet and X-rays.

Ultra-violet rays are familiar to most people as the particular art of sunlight that is "health-giving".

The effect of the ultra-violet rays is to produce in the skin the vitamin that is important for the promotion of bone-growth.

The use of these rays in diagnosis is a powerful weapon of medicine.

One of the most valuable uses of ultra-violet rays in industry is the testing of the quality of certain goods.

X-raying is very important in metallic welding's.

X-rays were discovered by Rontgen after whom the rays are sometimes called. The discovery of X-rays was quickly followed by its application to medicine.

 

Words and word combinations:

they all belong lo the same family- все они принадлежат к одному семейству

gives up – отдает

wireless waves – радиоволны

and far shorter than the shortest of these – гораздо короче, чем самые короткие из них

to sum up – подведем итог

depends entirely upon their length – всецело зависит от их длины

are familiar to most people – известны большинству людей

bone-growth – рост кости

after whom – по имени которого

 

Lesson 7.

Text.

WIRELESS WAVES.

 

What is wireless wave? The well-known analogy of a stone dropped into a pool of water and producing ripples on the surface of the water gives a useful idea of what a wave might look like if only it were visible to the human eye. The waves are actually set up by the very rapid to-and-fro motions of the electrons which constitute the current in the aerial. They move backwards and forwards at the frequency of the current and the waves are sent out, or radiated, in all directions.

The waves travel outwards at a very high speed, in fact they travel at the speed of light.

The waves travel on medium. This medium is called the ether. We cannot see or feel this ether, in fact we are only aware of it by means of such indirect effects as listening to a wireless programme. The medium enables wireless waves to travel from one place to another at the enormous velocity.

 

Words and word combinations:

wireless wave – радиоволна

what a wave might look like – как бы выглядела волна

are... set up – создаются

to-and-fro motions – возвратно-поступательное движение

at the frequency of the current – с частотой тока

waves are sent out, or radiated, in ail directions – волны посылаются, или излучаются, во все стороны

аt the speed of light – со скоростью света

travel on medium – передвигаются в среде

we are only aware of it by means of – мы знаем о нем только посредством

at the enormous velocity – с громадной скоростью

 

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

 

 

SOUND WAVES

When a piano key is struck, the string vibrates and causes the air round it to be compressed. These air vibrations travel outwards in all directions, they have velocity, wavelength and amplitude.

High notes cause a much faster vibration than low notes, in other words, the number of complete vibrations per second, or the frequency, of a high note is greater than that of a low note. Many sounds arc made up of a number of vibrations of different frequencies, for instance, when a gong is struck, a series of notes, high and low and intermediate are emitted at the same time and the resultant sound wave is fairly complicated.

 

Words and word combinations:

piano-key – клавиша пианино

and causes the air round it to be compressed – и вызывает попеременное сжатие и разрежение воздуха вокруг нее

the number of complete vibrations per second – число полных колебаний в секунду

are made up of – состоят из

the resultant sound – результирующая звуковая волна

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

 

 

Lesson 4

Text.

 

TRANSISTORS

 (Транзисторы)

The transistor has become an important member of electronic devices and surpasses the vacuum tube in many applications in the electronic industry. The term "semi-conductor" means "half-conductor", that is a material whose conductivity is between that of conductors and insulators. They include such elements as silicon, germanium, selenium, phosphorus and others. The conductivity of semi-conductors increases with heating. Light as well as heat increases the conductivities of semi-conductors. Engineers and physicists see in them the way of solving many engineering problems. Converting heat into electricity without using boilers is one of them. This could be done by means of the thermocouples made of semi-conductors. Photocells made of semi-conductors are capable of transforming 10 per cent of sunray energy into electric power. The electricity produced by semi-conductor thermocouples can give not only heat but cold as well, on this principle refrigerators operate.

Semi-conductors make a great progress of radio engineering, automation, electrical engineering and many other branches of science and technique.

 

Words and word combinations:

as well as – так, как и

engineering problems – технические задачи

by means of – при помощи

 

made of – сделанных из

as well – также

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

 

                                APPENDIX

              ADDITIONAL ASSIGNMENTS:

FIVE LAMPS IN SERIES

Vocabulary

 

in series [in ′siəri:z] последовательно

incandescent lamp [ֽinkæn'desnt ′læmp] лампа накаливания

town [taun] городской

supply network [sə′plai ′netwə:k] электросеть

to calculate [′ kælkjuleit] вычислять, рассчитывать

Carbon block current [′ kлrənt] ток

additional [ə′di∫ənl] дополнительный

resistance [ri′zistəns] сопротивление

required [ri′kwaiəd] необходимое, требуемое

circuit [′sə:kit] цепь

to determine [di′tə:min] определять

Ohm’s law [′oumz ′ l :] закон Ома

 

 

Five 12-volt incandescent lamps are connected in series to the 220-volt town supply network. Calculate the current in the lamps and the additional resistance required in the circuit if the resistance of each lamp equals 20 ohms.

Solution. The current in the circuit is determined by Ohm’s law:

 , A.

7777777777777777777777777 (ВСТАВКА _ ЛАМПОЧКИ)

The voltage across  lamps connected in series equals .

The voltage across the additional resistance is equal to .

Let us find the value of the additional resistance:   ohms.

 

AN ELECTRIC KETTLE

 

Vocabulary

 

kettle [′ ketl] чайник

heater [′ hi:tө] нагреватель

section [′ sek∫n] секция

to connect [kə′ nekt] присоединяться

to boil [b  il] кипеть

in parallel [in ′pærəlel] параллельно

quantity [′ kw  ntiti] количество

to deliver [di ′livə] производить, выделять

voltage [′ voultid  ] вольтаж, напряжение

to solve the equation [tə′ s  lv ∂I i′kwei∫n] решить уравнение

in respect to [ri′ spekt] относительно

 

An electric kettle has a heater with 2 sections. With one connected to the circuit the water in the kettle boils in 20 min, with the other – in 30 min. How long will it take to boil water with both sections connected: (a) in series, (b) in parallel?

 

 

 

An electric kettle and a heater

 

G i v e n: min; min;

F i n d: ? and ?

Solution. The quantity of heat delivered by the sections is in both cases the same. The voltage of the circuit is also the same. Let  be the resistance of the first section of the heater,  - the second. Then  (read: Q equals U square (or squared) over R sub two, the whole times t sub two) or

, ,

For a series connection of both sections the total resistance

and

Solving this equation in respect to  we find

min.

For a parallel connection

, and .

Solving this equation in respect to  we find

min.

 

 

Text.