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

tobeswitchedonandoff.Circuitsincludepowercircuits.Thesesupply the power sockets (or sockets) for the plugs on appliances. Usually, a circuit-breaker is fitted to each circuit. This is a safety switch that switches off automatically if there is a problem. This may happen if a person touches a live conductor, or if there is a short circuit. A short circuit is when current flows directly from a live conductor to a neutral conductor – ​for example, due to damaged insulation. Circuit breakers also allow circuits to be switched off manually, to isolate them (switch them off safely) – ​for example, before maintenance work.

Note: The equipment in switchboards is often called switchgear.

Printed and integrated circuits

The circuits in electrical appliances are often printed circuits, on printed circuit boards (PCBs). These are populated with (fitted with) electrical components. Many appliances also contain small, complex integrated circuits – ​often called microchips (or chips) – ​made from silicon wafers (very thin pieces of silicon). They act as semiconductors, which can be positivelychargedatcertainpointsontheirsurfaceandnegativelycharged at other points. This principle is used to make very small circuits.

Electrical and electronic components

There are many types of electrical and electronic components. These canbeusedindividuallyorcombinedwithothercomponentstoperform different tasks. For example:

–Sensors or detectors can sense or detect levels of – ​or changes in – ​ values such as temperature, pressure and light.

–Control systems use feedback from sensors to control devices automatically. For example, mechanical devices such as water valves may be moved or adjusted by servomechanisms – ​electrically powered mechanisms that are controlled automatically by signals (‘messages’) from sensors.

–Logic gates are widely used in control systems. They send signals, in the form of low voltages, to other devices. An output signal from the logicgateisswitchedonoroff,dependingontheinputsignalsitreceives. Note: The term electronic, rather than electrical, generally describes small but often very complex circuits and components that operate at a low voltage.

61

Use of English 1: vocabulary

6.Makewordcombinationswithcircuitusingwordsfromthetext“Circuits and Components”. Then match the combinations with the descriptions 1–6 below.

a ­ circuit

a _______________ circuit a ­ circuit

a _______________ circuit a _______________ circuit an ______________ circuit

1 a circuit containing one or more sockets

2a simple circuit where all the components are placed one after the other along the same conductor

3 a microchip – ​a very small, often complex circuit

4what happens if live and neutral conductors touch while a current is flowing, and there is no component or appliance between them

5 a circuit which allows different components to be controlled independently by separate switches

6 a circuit that can be populated with a large number of components

7. Complete the task from an engineering textbook with the words from the box.

switch on switch off signal logic gate detector detect

In an experiment, the lights in a room are connected to two types of electronic (1) __________. The first is an occupancy sensor, which will

(2)__________ the movement of a person entering the room, and the second is some kind of photosensor, which can determine whether it’s daylight or dark. These two devices are connected to an AND gate – ​a

(3)__________ __________ that will produce an output current only if it receives two input currents – ​in this case, from both the occupancy sensor and the photosensor. Therefore, a (4) __________ will be sent to the light switch to (5) __________ the lights only if a person enters the

room and if it’s dark.

62

However, for this system to work, we are assuming that the type of photosensor used will be one which is designed to produce a current in the dark, and which will then (6) __________ as soon as daylight appears. But such a sensor may be designed to work in the opposite way–producing​ acurrentwhenitdetectsdaylightandnocurrentinthe dark. This would cause an obvious problem. In this case, what type of logic gate could be placed between the photosensor and the AND gate in order to solve the problem?

Use of English 1: grammar

The Absolute Participial Construction

8. Translate these sentences from English into Russian, paying attention to the use of the Absolute Participial Construction.

1 ThestudentknowingEnglishwell,theexaminationdidnotlastlong. 2 The work having been completed, he left London for Moscow.

3 Therebeingmanypeopleintheconferencehall,wecouldnotenterit.

4The electron is about as large as a nucleus, its diameter being about 10–12 cm.

5 Silver being very expensive, we only rarely use it as a conductor.

6 Radioactivity discovered, we made great progress in atomic physics.

7 The speed of light being extremely great, we cannot measure it by ordinary methods.

8 The article deals with microwaves, with particular attention being paid to radio location.

9 The engineer testing the motor, the workers helped him.

10 There being no desirable results, we had to proceed with our work.

Reading 2

9. Read the text and complete the table using information from the text (columns V, VI and VII) and your own knowledge of physics (columns II, III and IV).

63

AMMETER VS. VOLTMETER

Ammeters and voltmeters are based on the galvanometer, a device that is used to detect small currents. Galvanometers that are calibrated to measure currents of different amounts are called ammeters. When they are modified to measure voltages, they are called voltmeters.

Galvanometer

The galvanometer is named after Italian physicist LuigiGalvani.Whilehewasdissectingafrog’sleg, he found that the leg twitched when two different metals touched it. Alessandro Volta improved on Galvani’s theory and findings, and this discovery also led to the invention of chemical cells and batteries.

A galvanometer is constructed from coils on springs, a needle and a stationary magnet. When a current is passed through the coils, the needle

is deflected. This deflection is proportional to the amount of current. Galvanometers are modified to be either ammeters or voltmeters.

Ammeter

Ammeters measure current flowing in a circuit. They are galvanometers that are placed in parallel with a resistor. The resistor in this capacity is referred to as a shunt. Its value is chosen to be very small, in order to limit the amount of internal resistance of the galvanometer.

Galvanometers as ammeters can directly measure DC current but to measure AC, a diode is placed inside the device. The purpose of this

64

havingthevalueoftheresistorbeverylarge.

Once again, a diode must be placed inside in order for it to measure AC currents.

Ammeters vs. Voltmeters

Ammeters and voltmeters are the opposite of each other not only in terms of construction, but of circuit placement.

Ammetersmusthavecurrentpassingthroughtheminordertomeasure it, and so must be placed in series inside of a circuit. Polarity must be observed, and their positive and negative leads must be connected to the positive and negative sides of the circuit, respectively. Also, their internal resistance must not be large or it will block too much current, and this will affect the way the circuit functions and hence the reading.

Voltmeters should not have any current passing through them, and so areplacedinparallelwiththecircuittheyaretomeasure.Theirleadsare placedoneachsideofthecomponentofinterest,andaswithammeters, polarity must be observed. If their internal resistance is too small it will not block enough current, and this will affect the measurement.

Multimeter

Multimeters are devices that can function as ammeters or voltmeters. They also perform as ohmmeter, which means they can measure resistance. They have a knob or button which allows them to switch between the various functions. Digital multimeters are more commonly used than analog.

65

10. Complete the manuals for electrical testing equipment using sentences A–G. There is one extra sentence.

A Read amperage on the meter.

BRead voltage on the meter.

CConnect the meter across the load.

D Open the circuit and connect the meter in series.

E Close the switch and activate the circuit.

F Close the switch and activate the circuit.

G Isolate the load from the circuit.

Use of English 2: vocabulary

Word Building

11. Complete the word families in the table below. Consult the dictionary if necessary.

66

12. Choose the best word for each sentence.

1Theresearchactivitiesofthedepartmentareverywide,encompassing most areas of chemical/chemically engineering.

2 One way to answer this question is to consider it theoretical/ theoretically.

3Thisfactsupportsthetheory/theoretician thattheuniversebeganwith a single large explosion (the “big bang”), and that the pieces are still flying apart.

4 It hasn’t been scientific/scientifically proven though.

5If basic math stumps you, there might not be a future for you as a practical physics/physicist.

Use of English 2: grammar

The Absolute Participial Construction

13. Paraphrase the sentences using the Absolute Participial Construction instead of italicized clauses.

1 When the work was done, they went home.

2 If the weather permits, the experiment starts early in the morning.

3 As chromium had been added, strength and hardness of the steel increased.

4 The article was published and Igot my author’s fee.

5 The wood was placed in the warehouse and the wood shredding was forwarded to the factory.

6 As the professor was ill, the lecture was put off.

7 Aftertheengineerhadtestedthemotor,hisassistantsputitintooperation.

Listening

14. Watch the video “Physics Help: How to Build a Series Circuit”. Then complete the notes. You may use the following link to watch the video: http://www.youtube.com/watch?v=J3TTPcW39iI.

The main components of the circuit are a cell, a lamp and a (1)

__________.

67

Each component has two (2) __________: positive and negative. The case of the cell is a (3) __________ one.

Therearetwoofthemonthelamp.Thefirstoneisatthe(4)__________

of the little pointer. The second one is a (5) __________ __________. In the switch they are coming out at each (6) ___________.

In a series circuit there is one (7) __________ for current to flow. Electricity goes round the track and (8) __________ every component only once.

To build a series circuit you should (9) __________ components one after another with one wire coming out of one component and going into one side of the next component.

Writing

15. Study the diagram and the notes below. Write an explanation of how a room thermostat works.

Begin: First of all, the temperature sensor in the room detects…

DESCRIBING A PROCESS

68

Speaking

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

Student A

You should say:

–What an electrical circuit is and what its basic components are

–What type of circuit the diagram shows and what components it consists of

–What measuring devices are used to measure the basic parameters of electrical circuits and what their circuit placement is

R1 R2 R3

Student B

You should say:

–What simple types of electrical circuits are and what design they have

–What type of circuit the diagram shows and explain how to build this circuit

–How current, voltage and resistance relate in the circuit shown in the diagram

R1 R2

17.Think of a device or installation you are familiar with which is auto- matically controlled, and describe its control systems. What types of sen- sors are used? How does the control system react to different signals from the sensors? Use exercises 7 and 15 to help you.

18.Speak on the topic of Electrical Circuits. Write a series of topic sen- tences which summarise the information in Unit 4. Start each paragraph

with the topic sentence and then add extra details and examples. Use the

69

monologue plan on p. 80, vocabulary on p. 102 and linking words and phrases on p. 108 to prepare your monologue.

You should cover the following topics: 1 Circuits and Components

2 Simple Types of Electrical Circuits

3 Complex Circuits

4 Measuring Current, Voltage and Resistance

Translation

19. Match each phrase with its Russian equivalent.

70