Applied electrical engineering

 

Vocabulary

 

field - область

applier - прикладной

power engineering - теплоэнергетика

efficient - эффективный

distribution - распределение

transmission line - линия передачи

frequency - частота (тока)

power load - нагрузка

communications -связь

magnetic recording - магнитная запись

area - зд. специальность, отрасль

message - сообщение

modulation - модуляция, изменение характеристик

channel capacity - пропускная способность каналов

waveguide - волновод

is basic to - лежит в основе

branch - отрасль

to handle - зд. выполнять

unbelievably - невероятно

decision - решение

 

Electrical engineering is a broad field. Power engineering deals with problems of efficient generation and distribution of electrical power. Some of the problems of distribution of electrical power concern, for example, the voltage in the transmission lines, the frequency of the current and the power loads. The voltages and the loads increase all the time. The frequency should not change; it has a standard value equal to 50 Hertz (60 Hertz in the USA).

Communications, though a part of electrical engineering, is a quite separate and a very important and complex field including also electronics, computers and many new areas such as television, magnetic recording, etc.

The general object of communications is to send messages of various types from one location to another, by telephone, telegraph and by radio. Modulation, channel capacity and waveguides are only a few of the problems that come up.

Though electrical engineering is basic to computers, this branch has grown so tremendously that it is an industry in itself.

The term "computer" is often misunderstood. Some computers handle basically simple arithmetic problems at unbelievably high speeds. However the more vital problem now is to develop a computer that allows automatic control of industrial processes, gives information and makes decisions.

 

 

Text.

RADIOBROADCASTING

 

Radiobroadcasting, which has become such a part of our life, would be impossible without electronics. The microphone transforms the music or speech it "hears" into electrical currents: it makes an electrical pattern of the sound coming to it. But what is sound? Sound consists of vibrations in the air. When you speak, your vocal cords and your mouth cavity generate these air vibrations, which then spread out in all directions.

Microphones which pick up sound are of many forms, but they all have a light metal or paper diaphragm which vibrates in response to the sound and which by means of its movement generates a tiny electrical signal.

The simplest microphone is the carbon-button microphone which is used in your telephone set.

The carbon-button microphone has been largely displaced for radio use by several other types of microphones. The most important of these are the dynamic microphone, the velocity microphone, and the crystal microphone.

The dynamic and velocity microphone employ the same principles as are used in an electric generator to convert the vibration of the diaphragm into an electric current.

This remarkable ability of crystals is called the piezoelectric effect. Natural piezoelectric crystals of quarz have a very important use in radiobroadcasting transmitters.

 

Words and word combinations:

it makes an electric pattern of the sound coming to it – он преобразует входящий в него звук в электрический эквивалент

vocal cords and mouth cavity generate – голосовые связки и полость рта создают

spread out – распространяются

pick up – принимать

in response to – в ответ на

 by means of – зд. благодаря

telephone set – телефонный аппарат

has been largely displaced – был в основном заменен

 

Text.

PHOTO-ELECTRICS CELLS.

The photo-electric cell has become one of the most important servants of industry.

Its characteristic property is sensitivity to light. The light causes changes in electrical pressure.

There are some types of photo-electric cells (photo tubes). The commonest type looks rather like a valve. Within the clear glass bulb there are two electrodes: a curved metal sheet (cathode) and a wire in front of it (anode). Light falling on the photosensitive sheet releases electrons.

Photo-electric cells can he used in exactly the same wav as an ordinary switch for turning an electric current on or off. Doors can be opened automatically. For instance, if somebody approaches, the interruption of a beam of light focused on a cell brings into action the opening device. The door opens and remains, by the action of a relay, for a given time, after which it shuts again. Sometimes infra-red or ultra-violet light is used; in this case, a cell is being chosen which is sensitive to this "invisible ray".

This "off" and "on" is only one of the applications of the photo-electric cell. If, every time the light-beam is interrupted, the working circuit is made to turn a counter, we get an automatic device for registering objects passing at a given spot. This is used in many industries.

In much the same way the cell can be used for automatically measuring size.

The photo-electric cell is sensitive not only to the mere switching on and off of light, but also to the degree of light.

In the metal industries, the photo-electric cell can be employed to measure temperature with great accuracy. Heat control by photo-electric ceils has special applications in welding. The applications of the photo-electric cell are almost limitless.

 

Words and word combinations:

causes changes – вызывает изменения

looks rather like – во многом похоже на

a curved metal sheet – изогнутая металлическая пластина

in front of – впереди

for turning an electric current on or off – для включения или выключения электрического тока

a beam of light – луч света

brings to action – приводит в действие

for а given moment – на определенный момент

in this case – в этом случае

this "off" and "on" – такое «выключение» и «включение»

at a given spot – в данной точке

in much the same way – точно так же

degree of light – сила света

 

Text.

WHAT IS RADAR?

The word "radar" means Radio Detecting and Ranging. Radar is a very special kind of location by radio. Radar equipment is capable of determining by radio the presence of objects, their direction and recognizing their character.

All types of radar sets principally consist of some six essential components: 1) a transmitter, 2) a receiver, 3) an antenna system, 4) an indicator, 5) a timer, 6) a power supply.

A radar set detects objects by sending out short powerful pulses of ultra-high frequency radio waves energy. As the transmitted energy strikes target it returned back to a receiver. Why wireless waves should return to the place from which they were sent out? Radar uses very short wireless waves. These wireless waves behave in a good many ways like those of light. If light waves meet a suitable smooth surface, lying at right angles to their path, they arc bent right-round and reflected back.

Very short wireless waves are bent and scattered, by a surface of a radar target. But a small part of the radiation comes back to the receiver.

The receiver picks up the returning echo through its antenna and translates it into a visual readable signal on a fluorescent screen.

Words and word combinations:

 

a very special kind of location – особый вид локации

radar sets – радарные установки

power supply – источник энергии

in a good many ways like those of light – во многом точно так же, как световые волны

lying at right angles to their parth – лежащие под прямыми углами их траектории

they are bent right-round – они отклоняются точно на 180°

in the same way – точно так же

picks up – принимает

translates it into – превращает его в

 

 

Text.

 

USES OF RADAR

The uses of radar give great reliability to sea and air travel. A radar set on a ship can provide the captain and the pilot with complete information about the objects around the ship. Radars will prevent collisions in fog and aid a ship to sail safely regardless of night or weather. Similarly airplanes will be able to fly over mountain ranges in storms and effect blind landing during poor visibility. The wide use of radar sets in our everyday life will make air and sea entirely safe.

Radar is useful in the investigation of the ionosphere. Reflections from the various regions of ionisation in the upper atmosphere are easily obtained and it provides very useful results. Meteorology is making increasing use of radar for cloud and thunderstorm detection. Radar is successfully used in launching rockets into space and in radar navigation of space ships

 

Words and word combinations:

regardless of night or weather – независимо от ночного времени или погоды

launching rockets into space – запуск ракет в космос

blind landing – посадка по приборам

during poor visibility – при плохой видимости

radar sets – радарные установки

is making increasing use – применяется все шире

space ships – космические корабли

launching rockets into space – запуск ракет в космос

 

 

                               EXERCISES.