Практический курс обучения профессионально ориентированному иностранному языку. Электроэнергетика и электротехника. В 2 частях. Ч.1. Учебное пособие

James Clerk Maxwell (June 13, 1831 – ​November 5, 1879) was a Scottish theoretical physicist and mathematician. His most significant achievement was the development of the classical electromagnetic theory, synthesizing all previous unrelated observations, experiments and equations of electricity, magnetism and even optics into a consistent theory. His set of equations – ​ Maxwell’s equations – ​demonstrated that electricity, magnetism and even light are all manifestations of the same phenomenon: the electromagnetic field. From that moment on, all other classical laws or equations of these disciplines became simplified cases of Maxwell’s equations. Maxwell’s work in electromagnetism was called the “second great unification in physics”, after the first one carried out by Isaac Newton.

Maxwell demonstrated that electric and magnetic fields travel through space in the form of waves, and at the constant speed of light. Finally, in 1864 Maxwell wrote “A dynamical theory of the electromagnetic field”, where he first proposed that light was in fact undulations in the same medium that is the cause of electric and magnetic phenomena.

Maxwell also developed the Maxwell distribution, a statistical means to describe aspects of the kinetic theory of gases. These two discoveries helped usher in the era of modern physics, laying the foundation for future work in such fields as special relativity and quantum mechanics.

Maxwell is also known for creating the first true colour photograph in 1861.

Maxwell is considered by many physicists to be the nineteenth century scientist with the greatest influence on twentieth century physics. His contributions to the science are considered by many to be of the same magnitude as those of Isaac Newton and Albert Einstein. On the centennial of Maxwell’s birthday, Einstein himself described Maxwell’s work as the “most profound and the most fruitful that physics has experienced since the time of Newton”. Einstein kept a photograph of Maxwell on his study wall, alongside pictures of Michael Faraday and Newton.

51

Listening

12. Watch the video “What Are the Uses for Electromagnets?” Then choosethecorrectanswerforeachquestion.Youmayusethefollowinglink to watch the video: https://www.youtube.com/watch?v=wOcETR3iiSg& feature=bf_prev&list=SP74F3DB17AF185A6C.

1Mr. Jones considers electromagnetism to be… a a modern technology.

b an old technology.

c a developing technology.

2Electromagnetic devices are being replaced by… a relays.

b starter motors and microphones. c solid state devices.

3Loudspeakers and microphones… a use electromagnetic technology. b are becoming smaller and smaller. c are not produced anymore.

4The best way to sort aluminum from steel at a metal sorting plant is to use…

a a permanent magnet. b a big electromagnet. c an electric motor.

5The future of electromagnetic technology is in… a electric cars.

b relays (e. g. trip switches). c solid state devices.

Speaking

13. Work in pairs. Give a talk about electricity and electromagnetism using information from the unit and language you have studied in this unit. Take turns to listen to each other.

52

Student A

You should say:

–What electricity is and what the uses of electricity are

–What the types of electrical current are and how they are different

–What type of current the information in the diagram relates to and explain why you think so

Voltage

Time

Student B

You should say:

–Whatelectromagnetismisandhowelectricandmagneticfieldsarerelated

–Whatscientistscontributedtothedevelopmentofelectromagnetictheory

–What experiment is shown in the illustration and what discovery was madeduetoit

14.SpeakonthetopicofElectricityandElectromagnetism.Writeaseries of topic sentences which summarise the information in Unit 3. Start each paragraphwiththetopicsentenceandthenaddextradetailsandexamples. Use the monologue plan on p. 78, vocabulary on p. 96 and linking words and phrases on p. 108 to prepare your monologue.

You should cover the following topics: 1 What is Electricity?

2 Conduction of Electricity.

3 Types of Electricity.

4 Electromagnetism.

53

Translation

15. Match each phrase with its Russian equivalent.

oпрепятствовать движению электронов

16.Translate the text from English into Russian.

Everydaymodernlifeispervadedbyelectromagneticphenomena.When a light bulb is switched on, a current flows through a thin filament in

54

the bulb; the current heats the filament to such a high temperature that it glows, illuminating its surroundings. Electric clocks and connections link simple devices of this kind into complex systems such as traffic lights that are timed and synchronized with the speed of traffic. Radio and television sets receive information carried by electromagnetic waves traveling through space at the speed of light. To start an automobile, currents in an electric starter motor generate magnetic fields that rotate the motor shaft and drive engine pistons to compress an explosive mixture of gasoline and air; the spark initiating the combustion is an electric discharge, which makes up a momentary current flow.

Many of these devices and phenomena are complex, but they derive from the same fundamental laws of electromagnetism. One of the most important of these is Coulomb’s law, which describes the electric force between charged objects. Formulated by the 18th-century French physicist Charles-Augustin de Coulomb, it is analogous to Newton’s law for the gravitational force. Both gravitational and electric forces decrease with the square of the distance between the objects, and both forces act along a line between them.

17. Render the text into English using language you have studied in this unit.

Вещества, позволяющие току проходить через них, называются проводниками. Металлы и графит являются хорошими проводниками электричества. К материалам, которые обычно не проводят электричество, относятся янтарь, нефть, воск, стекло, бумага и пластмасса. Такие материалы называют диэлектриками.

В XVIII в. многие ученые проводили опыты с электричеством, используя машины, обеспечивающие трение одного материала о другой, для получения мощного электрического заряда. Однако такой заряд быстро исчезал в результате внезапного выброса тока при подсоединении проводника к оборудованию. Для опытов был необходим источник, способный производить достаточно стабильный ток в течение более длительного периода. В 1790-е гг. итальянский ученый А. Вольта нашел нужное решение – ​изобрел гальванический элемент и батарею.

55

Гальваническийэлементпреобразуетхимическуюэнергиювэлектричество.Такиеэлементычастосоединяютдругсдругомилигруппируют для получения более мощного источника электроэнергии в точках подключения, или полюсах. Такие соединения называются батареями. Однако единичные элементы также часто именуют батареями. Цепь состоит из источника электричества (такого источника, как батарея) и пути тока, по которому ток может протекать от одного полюса источника к другому. Электроток представляет собой поток электронов; его можно сравнить с потоком воды, движущимся по трубе. Чтобы заставить воду течь по трубе, необходимо создать давление, то же самое нужно сделать с электронами, чтобы заставить их протекать, но по проводу. Такое электрическое давление, или напряжение, создаваемое, например,батареей,измеряетсяввольтах,аобразуемыйприэтом ток – в​ амперах. Поток воды, получаемый при определенном давлении, зависит от вида используемой трубы. Например, длинная и узкая труба будет оказывать сопротивление потоку воды внутри нее. А длинный и тонкий провод будет оказывать большее сопротивление электротоку, чем короткий и толстый провод из того же материала.

Unit 4

ELECTRICAL CIRCUITS

LEAD-IN: vocabulary and speaking

1. Discuss the quotation below. Explain its meaning and say whether you agree or not, and why.

The force of the current in a galvanic circuit is directly as the sum of all the tensions, and inversely as the entire reduced length of the circuit.

Georg Simon Ohm, (1789–1854), German physicist

2. Study the list of words and their definitions. Give the Russian equivalents of the words. Consult the dictionary if necessary.

56

1 The most advanced chip technology, which uses ______ 65 nanometers apart, loses almost half of its power to leakage.

2 This series provides protection of AC or DC loads against damage from ______ currents.

3 Make sure the machine is ______ properly.

4With appropriate communications links built into the house a range of household ______ and systems can be monitored and controlled.

5A ______ box is a box in which conductors or wires are split or terminated.

6 Communication satellites ______ the local stations into a network.

7A bare printed circuit board (PCB), is a circuit board that has no attached electrical components. It just consists of the bare board, which has copper lines and pads but no useful parts. Contrarily,

57

a ______ PCB is a completely constructed board with all required electronic parts, including connectors, ICs, resistors, and capacitors, soldered onto the appropriate places.

8 The device ______ the flow of current in an electrical circuit under abnormal conditions.

9 Large gradients of electron density in this plasma ______ laser rays from their initial trajectories, thus deforming substantially the laser intensity distribution on the target.

10The lower section ______ into three parts.

4.Match common circuit components with their functions.

58

Reading 1

5. Read the text and answer the following questions.

1 Define the term electrical circuit.

2 What are the basic components of electrical circuits?

3 Name the basic types of circuits.

4 Explainhowvoltagediffersbetweenaseriescircuitandaparallelcircuit. 5 Explainhowcurrentdiffersbetweenaseriescircuitandaparallelcircuit.

6Explain how resistance differs between a series circuit and a parallel circuit.

CIRCUITS AND COMPONENTS

A complete path, or circuit, is needed before voltage can cause a current flow through resistances to perform work.

There are several types of circuits, but all require the same basic components. A power source (battery or alternator) produces voltage, or electrical potential. Conductors (wires, printed circuit boards) provide a path for current flow. Working devices, or loads (lamps, motors), change the electrical energy into another form of energy to perform work. Control devices (switches, relays) turn the current flow on and off. And, protection devices (fuses, circuit breakers) interrupt the current path if too

much current flows. Too much current is

called an overload,

which could damage conductors and work-

ing devices.

A list of five things to look for in any circuit:

1 Source of Voltage

2 Protection Device

3 Load

4 Control

5 Ground

59

Simple circuits

There are two basic types of circuits: series and parallel. The type of circuit is determined by how the power source, conductors, loads, and control or protective devices are connected.

A series circuit is the simplest circuit. The conductors, control and protection devices, loads, and power source are connected with only one path for current. The resistance of each device can be different. The same amount of current will flow through each. The voltage across each will be different. If the path is broken, no current flows.

A parallel circuit has more than one path for current flow. The points where the current paths split and rejoin are called junctions. The separate current paths are called branch circuits or shunt circuits. The samevoltageisappliedacrosseachbranch.Iftheloadresistanceineach branch is the same, the current in each branch will be the same. If the load resistance in each branch is different, the current in each branch will be different. If one branch is broken, current will continue flowing to the other branches.

The circuit diagrams below show lamps connected in a parallel circuit andinaseriescircuit.Thesupplyhasliveandneutralconductors.Onan alternating current (AC) supply, the difference between live and neutral isthatconductorsontheneutralsideofappliancesareearthed–​thatis, connected to earth (the ground).

Mains AC circuits and switchboards

Where an AC supply enters a building, it is connected to a switchboard. This has a number of switches to allow different circuits in the building

60