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8. Pair work. a) Match the questions and the answers, b) Ask the questions and let your groupmate answer them.
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8. Pair work. a) Match the questions and the answers, b) Ask the questions and let your groupmate answer them.
| 1. In what position does die switch have high (low) resistance? 2. What are die functions of the switch? 3. In what position is the switch open? Closed? 4. In what way is the switch connected to the circuit? | a) Switches are used to open and close the circuits. b) Closed is the on-position; open is the off-position. c) The switch is connected in series with the load. d) In the on-position the closed switch has a very low resistance, which results in maximum current in the load with zero voltage loss across the switch. When the switch is off it has a very high resistance and no current flows through the circuit. |
Unit Twenty-Three [23]
1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.
b) Cover the left column and translate the Russian words back into English.
| fuse | [fjuː z] | плавкий предохранитель |
| link | [lɪ ŋ k] | звено, связь |
| fault | [fɔ ː lt] | дефект, неисправность |
| faulty | неисправный | |
| equipment | [ɪ ˈ kwɪ pmə nt] | оборудование |
| installation | [ˌ ɪ nstə ˈ leɪ ʃ n] | установка; pl. сооружения |
| to protect | [prə ˈ tekt] | защищать, предохранять |
| to utilize | [ˈ juː tɪ laɪ z] | использовать |
| to equip | [ɪ ˈ kwɪ p] | оборудовать, снаряжать |
| to serve | служить | |
| to melt | плавить | |
| up to | вплоть до |
2. Read the words and put down their Russian equivalents. Then translate them back into English (orally).
| quartz | [kwɔ ː ts] | _________ | quartz-sand fuse | ______________ |
| base | [beɪ s] | _________ | fusible link | ______________ |
| principle | _________________ | faulty protection device | ______________ | |
| stress | _________________ | faulty fusible link | ______________ | |
3. Form the words according to the model and translate them.
Model: charge - overcharge - перегрузка
connect - disconnect - разъединять
| pressure | - _________________________ | - _________________________ |
| heat | - _________________________ | - _________________________ |
| stress | - _________________________ | - _________________________ |
| current | - _________________________ | - _________________________ |
| load | - _________________________ | - _________________________ |
| organize | - _________________________ | - _________________________ |
| place | - _________________________ | - _________________________ |
| stress | - _________________________ | - _________________________ |
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4. Form the nouns from the given verbs according to the model. Translate them.
Model: to protect - protection - защита
| to utilize | - ________________________ | -_________________________ |
| to install | - ________________________ | -_________________________ |
| to reduce | - ________________________ | - ________________________ |
| current | - ________________________ | - ________________________ |
| to connect | - ________________________ | -_________________________ |
5. Distribute the words below into the three columns:
| action | process | doer |
utilizer, utilize, installation, displace, overheater, displacement, overproduction, starter, equip, protection, disorganize
6. Translate into Russian. Mind both … and, in case, up to:
1. Both solid and gaseous insulators are highly in use.
2. In case a fuse gets faulty it should be replaced by a new one.
3. Capacitors of very high capacity - up to 1000 and more mF - are utilized in modem installations.
Fuses
Fuses are widely used nowadays as protection devices. They are utilized in various circuits, electrical equipment and installations. Fuses serve to protect them against overcurrents and short-circuits.
There are different types of fuses in use nowadays. Of them, quartz-sand fuses serve for voltages up to 500 volts; fuses of this kind are produced with current ratings of 15 to 60 amp and of 100 to 350 amp.
Fuses are commonly used in low-voltage industrial installations rated up to 1, 000 V.
Fuse protection is based on a very simple principle: in case of a short-circuit or overcurrent, when the maximum value of current has been exceeded, the fusible link of a fuse is heated to its melting point. This opens the circuit and disconnects the circuit from the power source. In case of a fault, one should replace the faulty fusible element by a new one.
Fuses are used both in direct current (d. c. ) and alternating current (a. c. ) circuits.
7. Complete the sentences using the correct variant:
| 1. A fuse serves | a) as a load. b) as a protection. |
| 2. Fuses are used | a) for d. c. only. b) for both a. c. and d. c. |
| 3. In case of a fault | a) the whole fuse should be replaced. b) the faulty link should be replaced. |
| 4. Fuse protection is based on | a) a simple principle. b) a complex principle. |
8. Memorize the questions. Use them in a talk with your groupmate:
1. What does a fuse serve for?
2. For what type of current are fuses used?
3. What should be done in case of a faulty fuse?
4. What principle is fuse protection based on?
Unit Twenty-Four [24]
1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.
b) Cover the left column and translate the Russian words back into English.
| incandescence | [ˌ ɪ nkæ nˈ desns] | накал, накаливание |
| incandescent lamp | [ˌ ɪ nkæ nˈ desnt læ mp] | лампа накаливания |
| copper | медь | |
| steel | сталь | |
| to convert | [kə nˈ və ː t] | преобразовывать |
| to deliver | [dɪ ˈ lɪ və ] | питать, подавать |
| according to | [ə ˈ kɔ ː dɪ ŋ tə ] | согласно |
| etc. = et cetera | [ˌ et ˈ setə rə ] | и так далее |
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2. Read the words and put down their Russian equivalents:
| [ˌ æ ljuˈ mɪ niə m] | aluminium | ___________________________ |
| [ˈ kemɪ kə l] | chemical | ___________________________ |
| [ˈ dʒ enə reɪ tə ] | generator | ___________________________ |
| [mə ˈ tɪ ə rɪ ə l] | material | ___________________________ |
| [mɪ ˈ kæ nɪ kə l] | mechanical | ___________________________ |
| [ˈ θ ə ː ml] | thermal | ___________________________ |
| [ˈ moutə ] | motor | ___________________________ |
3. Translate into Russian:
a. convertible values, protected power source, various fuses, variable resistors, chemical cells
b. cells delivering electric power
generator converting mechanical energy
circuits utilizing common fuses
c. Primary cells deliver electric power.
Different kinds of energy can be converted into electric energy.
Protection devices are utilized in any circuit.
Components of Electric Circuits
The main components of any circuit are devices that produce and utilize electric energy. They are: 1. power sources, 2. utilizing loads, 3. connecting conductors.
The most common power sources are electric generators and primary cells. Electric generators convert chemical energy into electric energy.
Loads include electric heaters, electric motors, incandescent lamps, etc. Motors convert electric energy into mechanical, incandescent lamps and heaters convert electric energy into light and heat. Utilizing devices or loads convert electric energy into thermal, mechanical or chemical energy.
Electric power is delivered from power sources to loads by electric wires. According to their material, wires can be aluminium, copper, steel, etc.
Besides, electric circuits use different types of switches, protection devices (relays and fuses), and meters (ammeters, voltmeters, wattmeters, etc. ).
2. Complete the sentences using the correct variant:
| 1. The main components of electric circuits are | a) loads and wires. b) power sources, load and wires. |
| 2. Power sources are used | a) to produce electric energy. b) to deliver it to the loads. |
| 3. Electric conductors are used | a) to connect the circuit elements. b) to deliver electric power. |
| 4. Protection devices are utilized | a) in some circuits. b) in any circuit. |
| 5. A switch is utilized | a) in some circuits. b) in any circuit. |
5. Answer these questions:
1. What are the main components of an electric circuit?
2. What is the function of an electric source?
3. What is the function of a load?
4. What is the function of wire conductors?
5. What other devices are utilized in a circuit?
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