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Файл:Английский для студентов-энергетиков. Учебное пособие
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Some resistors have a constant value-these are fixed resistors; the value of
other resistors may be varied-these are variable resistors.
Electric Cells
An electric cell is used to produce and supply electric energy. It consists of an
electrolyte and two electrodes. Electrodes are used as terminals, they connect the cell
to the circuit – current passes through the terminals and the bulb lights.
Cells can be connected in series, in parallel and in series-parallel. In order to
increase the current capacity cells should be connected in parallel. In order to
increase the voltage output cells should be connected in series. In case a battery has a
large current capacity and a large voltage output, its cells are connected in seriesparallel.
When cells are connected in series the positive terminal of one cell is
connected to the negative terminal of the second cell, the positive terminal of the
second cell-to the negative terminal of the third … and so on.
When cells are connected in parallel their negative terminals arc connected
together and their positive terminals are also connected.
In case a cell has a trouble it stops operating or operates badly. This cell should
be substituted by another one.
Capacitors
A capacitor is one of the main elements of a circuit. It is used to store electric
energy. A capacitor stores electric energy provided that a voltage source is applied to
it. The main parts of a capacitor are metal plates and insulators. The function of
insulators is to isolate the metal plates and in this way to prevent a short.
In the diagram one can see two common types of capacitors in use nowadays:
a fixed capacitor and a variable one. The plates of a fixed capacitor cannot be
moved; for this reason, its capacity does not change. The plates of a variable
capacitor move; its capacity changes. The greater the distance between the plates, the
less is the capacity of a capacitor. Variable capacitors are commonly used by
radiomen; their function is to vary the frequency in the circuit. Fixed capacitors are
used in telephone and radio work.
Fixed capacitors have insulators produced of paper, ceramics and other
materials; variable capacitors have air insulators. Paper capacitors are commonly
used in radio and electronics their advantage is their high capacity: it may be higher
than 1,000 Pico farad.
Besides, electrolyte capacitors are highly in use. They also have very high
capacity: it varies from 0.5 to 2,000 microfarad. Their disadvantage is that they
change their capacity when the temperature changes. They can operate without a
change only at temperatures not lower than –40 C.
Common troubles in capacitors are an open and a short. A capacitor stops
operating and does not store energy in case it has a trouble. A capacitor with a
trouble should be substituted by a new one» [8].
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Task 3. Answer the following questions:
- to be rated
- to link
- to substitute
- to insulate
- to prevent
- to be equivalent
- to carry
- to transmit
- to be corresponding
- to avoid
- to isolate
- to replace
- to connect
- to be ranked
- to increase
- to connect
- to cool
- to close
- to fix
- to differ
- to move
- to fix
- to be the
same
- to change
- to open
- to heat
- to
disconnect
- to reduce
1. Is resistor one of the most common elements of any circuit?
2. Are resistors used to reduce the value of current in the circuit?
3. What kind of resistors have a constant value?
4. What for is an electric cell used?
5. An electric cell consists of an electrolyte and two electrodes, doesn’t it?
6. How can cells be connected: in series, in parallel or in series-parallel?
7. What are the main parts of a capacitor?
Task 4. Find in the text synonyms and antonyms for the following words.
SYNONYMS
translation of given statements in Russian:
повышается.
его можно без проблем нагреть.
ANTONYMS
Task 5. Combine the parts of English sentences from the chart below to get the
1. Когда ток проходит через резистор, его температура сильно
2. Каждый резистор имеет максимальную температуру, до которой
3. Мощность резистора указывается в ваттах.
52
4. Электрический элемент используется для производства и подачи
1. When current is passing
through a resistor its temperature
a) in series-parallel.
2. Each resistor has a maximum
temperature to which it may be
b) connected in parallel.
3. The resistor power is rated
c) the cell to the circuit – current
passes
through the terminals and the bulb
lights.
4. An electric cell is used
energy.
5. Electrodes are used as
terminals, they connect
e) in watts.
6. In order to increase the
current capacity cells should be
f) heated without a trouble.
7. In case a battery has a large
current capacity and a large
voltage output, its cells are
connected
g) rises high.
электроэнергии.
5. В качестве клемм используются электроды, они подключают
ячейку к цепи - ток проходит через клеммы, и лампочка загорается.
6. Для увеличения текущей емкости ячейки следует подключать
параллельно.
7. Если батарея/аккумулятор имеет большую емкость и высокое
выходное напряжение, ее элементы подключаются последовательнопараллельно.
Task 6. Read the statements and decide whether you agree or disagree with
them. Say to what extent you agree:
-agree strongly
-agree
-not sure
-disagree
-disagree strongly
1. The higher the value of current the lower is the temperature of a resistor.
2. When current is passing through a resistor its temperature rises high.
3. Some resistors have a constant value - these are variable resistors.
4. An electric cell is used to produce and supply electric energy.
5. An electric cell consists of an electrolyte and two electrodes.
6. Electrodes are used as terminals, they disconnect the cell to the circuit – current
passes through the terminals and the bulb lights.
7. Cells can be connected in series, in parallel and in series-parallel.
53
8. In order to increase the voltage output cells should be connected in parallel.
1) a wire conductor
2) a load resistance
3) voltage drop
4) carbon
5) a two-winding
transformer
6) a closed core
7) open in the winding
6) to step-up
a) увеличивать, усиливать, наращивать
b) обрыв (в обмотке)
c) закрытый сердечник
d) двух обмоточный трансформатор
e) углерод
f) падение напряжения
g) сопротивление нагрузки
h) проволочный проводник
Task 7. Read the following descriptions and decide which of cells should be
connected
a) in parallel
b) in series
c) in series-parallel
1. In order to increase the current capacity cells should be connected ……
2. In order to increase the voltage output cells should be connected ………
3. In case a battery has a large current capacity and a large voltage output, its
cells should be connected in …
Task 8. Talk about the differences between a fixed capacitor and a variable
one.
Unit 2
CONDUCTORS AND INSULATORS
Task 1. Match the following English words and phrases from text B with their
Russian equivalents:
through them. The lower the resistance of the material, the more current can pass
through it.
them. The advantage of copper is that it is much cheaper than silver. Thus copper is
widely used to produce wire conductors. One of the common functions of wire
conductors is to connect a voltage source to a load resistance. Since copper wire
conductors have a very low resistance a minimum voltage drop is produced in them.
Thus, all of the applied voltage can produce current in the load resistance.
Task 2. Read and translate text B:
Conductors and Insulators
«Conductors are materials having a low resistance so that current easily passes
The most common conductors are metals. Silver and copper are the best of
54
It should be taken into consideration that most materials change the value of
resistance when their temperature changes.
Metals increase their resistance when the temperature increases while carbon
decreases its resistance when the temperature increases. Thus metals have a positive
temperature coefficient of resistance while carbon has a negative temperature
coefficient. The smaller is the temperature coefficient or the less the change of
resistance with the change of temperature, the more perfect is the resistance material.
Materials having a very high resistance are called insulators. Current passes
through insulators with great difficulty. The most common insulators are air, paper,
rubber, plastics.
Any insulator can conduct current when a high enough voltage is applied to it.
Currents of great value must be applied to insulators in order to make them conduct.
The higher the resistance of an insulator, the greater the applied voltage must be.
When an insulator is connected to a voltage source, it stores electric charge and
a potential is produced on the insulator. Thus, insulators have the two main
functions:
1. to isolate conducting wires and thus to prevent a short between them and
2. to store electric charge when a voltage source is applied.
Transformers
A transformer is used to transfer energy. Due to the transformer electric power
may be transferred at a high voltage and reduced at the point where it must be used to
any value. Besides, a transformer is used to change the voltage and current value in a
circuit.
A two-winding transformer consists of a closed core and two coils (windings).
The primary winding is connected to the voltage source. It receives energy. The
secondary winding is connected to the load resistance and supplies energy to the load.
The value of voltage across the secondary terminal depends on the number of
turns in it. In case it is equal to the number of turns in the primary winding the
voltage in the secondary winding is the same as in the primary.
In case the secondary has more turns than the primary the output voltage is
greater than the input voltage. The voltage in the secondary is greater than the
voltage in the primary by as many times as the number of turns in the secondary is
greater than the number of turns in the primary. A transformer of this type increases
or steps up the voltage and is called a step-up transformer. In case the secondary has
fewer turns than the primary the output voltage is lower than the input. Such a
transformer decreases or steps down the voltage, it is called a step-down transformer.
55
Compare T1 and T2 in the diagram. T1 has an iron core. For this reason, it is
SYNONYMS
- to keep
- to transform
- to generate
- to replace
- to involve
- to deliver
- to function
ANTONYMS
- insulator
- disadvantage
- to be
dependent
- to disconnect
- to increase
- to begin
- to step-up
used for low-frequency currents. T2 has an air core and is used for high frequencies.
Common troubles in transformers are an open in the winding, a short between
the primary and the secondary, and a short between turns. In case a transformer has a
trouble it stops operating or operates badly. A transformer with a trouble should be
substituted» [9].
Task 3. Answer the following questions:
1) What are the most common conductors?
2) What is cheaper: copper, or silver?
3) What is widely used to produce wire conductors?
4) What is one of the common functions of wire conductors?
5) Do most materials change the value of resistance when their temperature
changes?
6) A two-winding transformer consists of a closed core and two coils (windings),
doesn’t it?
7) Is primary winding connected to the voltage source to receive energy?
8) Is the secondary winding connected to the load resistance to supply energy to
the load?
Task 4. Find in the text synonyms and antonyms for the following words.
56
Task 5. Combine the parts of English sentences from the chart below to get the
current
a) …. should be substituted.
be applied to insulators in order
b) …. stops operating or operates badly.
the secondary terminal depends
primary and the secondary, and a short between
turns.
steps up the voltage and is called
d) … a step-up transformer
transformers are an open
e) … on the number of turns in it.
trouble it
f) … to make them conduct.
7) A transformer with a trouble
g) … when a high enough voltage is
applied to it.
translation of given statements in Russian:
1) Любой изолятор может проводить ток при подаче на него достаточно
высокого напряжения.
2) К изоляторам необходимо приложить более высокую силу тока, чтобы
они стали проводящими.
3) Значение напряжения на вторичной клемме зависит от количества витков
в ней.
4) Трансформатор этого типа повышает или увеличивает напряжение и
называется повышающим трансформатором.
5) Общие проблемы в трансформаторах - это обрыв в обмотке, короткое
замыкание между первичной и вторичной обмотками и короткое замыкание
между витками.
6) В случае неисправности трансформатора он перестает работать или
работает плохо.
7) Трансформатор с неисправностью должен быть заменён.
Task 6. Read the statements and decide whether you agree or disagree with
them. Say to what extent you agree or disagree and try to give your arguments:
-agree strongly
-agree
-not sure
-disagree
-disagree strongly
1) A transformer is used to transfer energy.
2) Due to the transformer electric power may be transferred at a high voltage and
reduced at the point where it must be used to any value.
57
3) A two-winding transformer consists of an opened core and one coil (winding).
1) a coupling
2) a load
3) tight coupling
4) a loose coupling
5) a self-inductance
6) a metal bulb
7) to emit
8) the plate
9) a suppressor grid
10) to eliminate
oscillations
11) the secondary
emission
a) вторичное излучение
b) устранять колебания
c) сетка глушителя (подавляющая)
d) пластина
e) излучать
f) металлическая лампа
g) самоиндукция
h) слабая связь
i) тугая муфта
j) загрузка
k) сцепление
4) The value of voltage across the secondary terminal does not depend on the
number of turns in it.
5) A step-up transformer increases, or steps up the voltage, it is called a step-down
transformer.
6) Common troubles in transformers are an open in the winding, a short between
the primary and the secondary, and a short between turns.
7) In case a transformer has a trouble it doesn’t stop operating.
Task 7. Read the following descriptions and decide which one is about
a) a transformer
b) an insulator
c) air, paper, rubber, plastics
1. …… are the most common insulators
2. …… is used to conduct current when a high voltage is applied to it.
3. …… is used to transfer energy.
Task 8. Talk about the differences between the primary and the secondary
windings.
Unit 3
Coupling
Task 1. Match the following English words and phrases from text C with their
Russian equivalents:
Task 2. Read and translate text C:
58
Coupling
«When circuits are indirect-inductively coupled energy is transferred from one
circuit to another using electromagnetic field of the inductance through which a
varying current is flowing. The coupling device is a transformer. It is not in series
with the elements of the circuit therefore the coupling is indirect. The transformer
consists of two windings: the primary and the secondary. The primary circuit is
connected to the voltage source, the secondary-to the load circuit.
The coupling may be tight and loose. In case the coils of the coupling element
are close together, the coupling is tight. In case the coils are separated the coupling is
loose. In the loose coupling the mutual inductance is small compared with the selfinductance.
Electron Tubes
Let us consider electron tubes. Among the electron tubes in use nowadays there
are a diode, a triode, a tetrode and a pentode. The main parts of electron tubes are
electrodes. Electrodes are placed into a glass or metal bulb.
A diode contains the cathode and the plate. When a diode operates the cathode
emits electrons, the plate collects them.
A triode contains the cathode, the plate and the control grid. When the tube
operates the cathode emits electrons, the plate collects them and the grid controls the
flow of electrons. Therefore, the grid is called a control grid.
A tetrode contains the cathode, the plate, the control grid and the screen grid.
When a tube operates it may oscillate. The function of the screen grid is to
eliminate oscillations. Therefore, it is called a screen grid.
A pentode contains two electrodes and three grids: the control grid, the screen
grid and the suppressor grid. When a pentode operates the suppressor grid eliminates
the secondary emission.
59
Common troubles in tubes are an open heater and low emission. These troubles
inductance
a polarized electrical device. Cathode polarity with respect to the
anode can be positive or negative depending on how the device is
being operated.
2) a
winding
b) is an electronic device having five active electrodes. The
term most commonly applies to a three-grid amplifying
vacuum tube
3) a tap
c) is a device used to connect two shafts (tubes) together at
their ends for the purpose of transmitting power.
4) a core
area
d) The hole in the center of the coil is called the core area
or magnetic axis.
5) a
coupling
e) an additional electrical connection in winding along
their length, which are called taps.
6) a
pentode
f) the wire or conductor which constitutes the coil is
called the winding.[
7) a
cathode
g) is the tendency of an electrical conductor to oppose a
change in the electric current flowing through it. The flow
of electric current creates a magnetic field around the
conductor.
result from constant use or from some other reason. In case a tube has a trouble it
stops operating or operates badly. A tube with a trouble should be replaced by
another one» [11].
Task 3. Answer the following questions:
1) Is a transformer the coupling device?
2) Is the coupling indirect?
3) What does a transformer consist of?
4) What are the main parts of electron tubes?
5) Where are the electrodes placed?
6) What does a diode contain?
7) What does a triode contain?
Task 4. Match the following words from the text with their definitions:
Task 5. Complete the sentences using the following words or phrases from the
text in the correct form: inductance; coils; coupling; circuit; windings; elements;
energy
1) When circuits are indirect-inductively coupled …is transferred from one circuit
to another.
2) The transformer is not in series with the …of the circuit therefore the coupling
is indirect.
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