Контрольная работа № 2 Вариант № 3
Переведите предложения с модальными глаголами и их заменителями.
. We can measure voltage and potential difference with a voltmeter. 2. What instrument may we usein measuring current? 3. He willbe able to draw a circuit diagram. 4. They might know safety rules. 5. He lad to remember properties of metals. 6. You must_dothis work in time.
. II. Вы собираетесь строить дом. Составьте рекомендации, употребив глаголы в
повелительном наклонении:
0 make a design, to choose the right place, to work hard, not to forget about the landscape, to choose
modern building materials, to calculate money
III. Перепишите и переведите письменно предложения и словосочетания, обратите внимание
на многозначность предлогов.
I. We must try to bring the government down. 2. The new government promises to bring down prices. 3. How did you bring it off?4. Our firmis bringing out a new product. 5. There are a lot of interesting places in our town. 6. We are going nd course. 3. There are 5 flowers in the vase. 4. In his garage there are 3 cars. 5, The diagram of voltaic cell is number 9. 6. Each eel! produces an emf of 1,5 volts.
VII. Прочитайте текст, переведите его письменно и составьте план.
Electrical Measuring Units and Instruments
Any instrument, which measures electrical values, is called a meter. An ammeter measures the current in
amperes. The unit is named after Andre Marie Ampere, a French scientist, who discovered a great number
of facts about electricity over a hundred years ago.
A voltmeter measures the voltage and potential difference in volts. The volt is named after Alessandro
Volta, an Italian scientist.
Two things determine the current in a conductor, the voltage across the conductor and the resistance of the
conductor. Every material object offers some resistance to the flow of an electron current through it. Good
conductors like the metals, copper, silver and aluminum offer very little resistance, while nonconductors
such as glass, wood and paper offer a very high resistance. The unit by which resistance is measured is
called the ohm. The resistance in practice is measured with ohmmeter.
A wattmeter measures electrical power in watts.
Very delicate ammeters are often used for measuring very small currents. A meter whose scale is calibrated
to read a thousandth of an ampere is called amilliammeter. One whose scale is calibrated in millionth of an
ampere is called a micro ammeter or galvanometer.
Whenever an ammeter or voltmeter is connected to a circuit to measure electric current or potential
difference the ammeter must be connected in series and the voltmeter in parallel.
As it is shown on the picture, the ammeter is so connected that the entire electron current passes through it.
To prevent a change in the electron current when such an insertion is made, all ammeters must have a low
Most ammeters therefore have a low resistance wire, called a shunt, and connected across the armature
A voltmeter, on the other hand, is connected across that part of the circuit for which a measurement of the
potential difference is required. If the potential difference between the ends of the resistance R is wanted,
ELECTRICAL MEASURING UNITS AND INSTRUMENTS
The current in a conductor is determined by two things, the voltage across the conductor and the resistance of the conductor. Every material object offers some resistance to the flow of an electron current through it. Good conductors like the metals, copper, silver and aluminium offer very little resistance, while nonconductors 
such as glass, wood and paper offer a very high resistance. The unit by which resistance is measured is called the ohm. The resistance in practice is measured with the ohmmeter. A wattmeter measures electrical power in watts.
Answer the questions:
1. What is called a meter?
2. What does an ammeter measure?
3. What is the current determined by?
4. What can you say about non conductors?
Для спеціальності КВП
TEXT 16
Read and translate the text with a dictionary, analyze the words and define the tense forms.
PREFERRED VALUE RESISTANCE BOX
This Resistance Box consists of four separate switches which will select resistances in the 10% preferred value range. Dial 1 resistors from 100 ohms to 820 ohms. Dial 2 resistors from 1 Kohm to 8.2 Kohms. Dial 3 resistors from 10 Kohms. Dial 4 resistors from 100 ohms to 820 Kohms.
The individual resistors are high stability carbon types with an accuracy of ± 1%.
Each dial is individually connected and screened from the other three dials in the box so that separate dials can be used in different boxes of the same circuit without interconnection. Connection is by co-axial plugs. The whole is contained in a metal case.
Answer the questions:
1. What does the Resistance Box consist of?
2. What are the individual resistors?
3. How is each dial connected and screened?
TEXT 17
Read and translate the text with a dictionary, analyze the words and define the tense forms.
DUAL TRANSISTOR POWER SUPPLY TYPE 423
The Type 423 Power Supply is manufactured on an open chassis and is intended to be incorporated into professional equipment but it can equally well be used on the laboratory bench.
The unit provides two completely independent and isolated supplies and the output can easily be adjusted by the purchaser. The voltages provided cover those commonly used by transistor circuit designers.
SPECIFICATION
(the following specification applies to both supplies)
Output Voltages: 10-12v,15-18v, and 24v.
Output Current: 0-1Amp.
Ripple and noise:(at 1 Amp) Less than 5 mV pk.
Supply Voltage: 100/220 v
Height 5.0 ins.(12.70 cms)
Width 6.0 ins. (15.24 cms)
Weight 8.0 lbs.(3.6 kg)
Answer the questions:
1. How can the Type 423 Power Supply be used?
2. What does the unit provide?
3. What is the voltage supplied?
4. What are the dimensions?
TEXT 18
Read and translate the text with a dictionary, analyze the words and define the tense forms.
AUTO-TRANSFORMERS
The transformer effect can also be obtained with a single tapped winding instead of separate primary and secondary windings. The arrangement is called an auto-transformer. If the primary winding represents the whole coil, the secondary voltage will be substantially the same proportion of the applied voltage as the proportion between the turns up to the secondary tapping and the total number of turns. By interchanging the voltage so that the supply is connected to the smaller number of turns, a voltage larger than the supply voltage appears across the whole coil. The auto-transformer can thus be used to obtain a higher or lower voltage than the supply, as in the case of the convential transformer with two separate windings.
In practice, the use of auto-transformers is limited to fairly small voltage ratios, one reason being that if a break occurs anywhere in the secondary section of the winding, the primary voltage is applied to the apparatus connected to the secondary. With a high primary voltage this would give dangerous conditions. The chief uses of auto-transformers, are in a. c. voltage regulation and for infrequent service such as the low-voltage starting of induction motors.
Answer the questions:
1. How can the transformer effect be obtained?
2. How is the arrangement called?
3. Where are the chief uses of auto-transformers?
TEXT 19
Read and translate the text with a dictionary, analyze the words and define the tense forms.
PRECISION D.C. AMPLIFIER.
Silicon transistors have been used wherever possible in the interests of reliabibility and stable performance. Indication is provided by a front panel meter and provision is made to operate an external meter or recorder.
Construction
The first stage of the amplifier uses an electrometer valve and this, together with the associated range switch and high value resistors, is housed in a robust sealed box, which is protected from the effects of moisture by a desiccator. The remaining amplifier stages are mounted on a printed circuit board, connections to which are effected by two quick-release multi-plugs and sockets. In the case of breakdown, it is thus possible to replace either or both the electrometer box and the printed circuit board easily and quickly.
The cabinet is made of sheet steel finished in hammered grey enamel and will withstand the sort of environment likely to be found in laboratories and schools.
Answer the questions:
1. What does the first stage of the amplifier use?
2. How is the box protected from the effect of moisture?
3. What is possible to do in the case of breakdown?
TEXT 20
Read and translate the text with a dictionary, analyze the words and define the tense forms.
Перевод текста electrical measuring units and instruments
1. The capacity to absorb heat varies between substances.
2. Each object in nature has a particular temperature which can be compared with the temperature of other objects.
3. To make this comparison accurate thermometer is used.
4. Each atom is known to have a name and symbol.
5. To know the melting point of the metal in use is necessary.
6. I consider him to be the best qualified person in the laboratory.
7. Whenever the speed or velocity of a body changes, the body is said to have acceleration.
8. Laws and theories are formulated from the results of the experiments and then used to predict the results of new experiments.
Batteries
An Italian scientist Alessandro Volta made a` lot of experiments with electricity. Batteries as sources of electrical energy are the result of his experiments.
Today battery cells are produced in two common forms: dry cells, used in flashlights, portable radios, clocks, cameras and (well) wet cells, used in automobiles, airplanes, boats.
The voltaic cell is composed of three parts: a pair of dissimilar metal plates called electrodes, a dilute acid solution called electrolyte, and a nonconducting container called the cell. In a glass container filled with sulphuric acid there are two plates: one copper and are connected by a copper wire, electricity will flow through it from the copper plate to the zinc plate.
For the voltaic cell the copper plate is the positive electrode and the zinc plate the negative electrode a copper wire will convey electricity and is called an electrical conductor. Copper, aluminium and silver are good conductors. They must be surrounded by protective material which does not conduct electricity. Such materials are called electrical insulators (glass, wood, rubber, some plastics, insulation tape)
Remember that faulty insulation is dangerous and leads to unwanted electrical flow and probably to local overheating.
Words to the text
3. Flashlight-сигнальный огонь
7. Wire-проволока, провод
9. Rubber-резина, каучук
10. Tape-лента, тесьма
11. To use-использовать
12. To compose-составлять
13. To fill-наполнять
14. To connect-соединять
16. To convey-переправлять
17. To surround-окружать
18. To remember-помнить
19. Common-общий, частый
Вставьте пропущенные слова
1. A battery is a source of ….
2. Battery cells are manufactured in ….
3. The voltaic cell is composed of ….
4. Cells connected together form ….
5. The positive electrode is ….
6. The negative electrode is ….
7. Series connection means ….
8. Materials which do not conduct electricity are called ….
Electrical, insulators, two common forms, electrical energy, copper plate, Zink plate, three parts, battery, the terminal of one cell is connected to
Electrical Measuring Units and Instruments
Any instrument which measures electrical values is called a meter. An ammeter measures the current in amperes. The unit is named after Andre Marie Ampere, a French scientist. A voltmeter measures the voltage and the potential difference in volts. The volt is named after Alessandro Volta, an Italian scientist.
The current in a conductor is determined by two things, the voltage across the conductor. The unit by which resistance is measured is called the ohm. The resistance in practice is measured with the ohmmeter, a wattmeter measures electrical power in watts. Very delicate ammeters are often used for measuring very small currents. Whenever an ammeter or voltmeter is connected to a circuit to measure electric current or potential difference the ammeter must be connected in series and the voltmeter in parallel.
Answer the questions
1. What does an ammeter measure?
2. Was Andre m. ampere a French or Italian scientist?
3. How is the current in a conductor determined?
4. What is the unit called by which resistance is measured?
5. Does a wattmeter measure electrical power?
6. How does an ammeter measure electric current?