Elements of the electric circuit

The simplest electric circuit consists of a source of energy, or power source,(for example, a primary cell, accumulator, or generator), a receiver of energy (for example, an electric lamp, electric-heating device, or electric motor) and two conductors connecting the receiver and power source terminals. The power source (or, for short, the source) transforms mechanical, chemical, thermal, or other energy into electromagnetic energy, which, for brevity, is often simply called electric energy, the energy receiver (or simply receiver), on the contrary, transforms the electric energy to other forms of energy: radiant, thermal, mechanical and so on. The power source together with the conductors and receiver (load) connected to it form a closed loop, along with an uninterrupted stream of electric charge (an electric current) flows. This is called an electric circuit. With respect to the source, the conductors and receiver (load) form the so-called external circuit.

The direct cause of flow of electric current in circuit is the electromotive force (EMF) of the power source. Conventionally, the direction of the current in the circuit is taken to coincide with the direction of the EMF. The terminal of the source through which the current “leaves” for the external circuit is called positive (+) and the terminal through which the current enters the source from the external circuit, the negative (-). The direction of the current is thus from + to – in the external circuit and from – to + inside the source. Both the external circuit and the source possess resistance, the value of which depends upon the material, shape and dimensions of the conductors composing these parts of the electric circuit. The magnitude or the intensity of the current (or, simply, the current) in the circuit depends on the magnitude of the EMF and the resistance of the whole circuit. The relationship between these three quantities is expressed by Ohm’s law, which plays a very important role in electrical engineering, being the basis of many practical calculations. According to this law, the current I in the circuit is directly proportional to the EMF E and inversely proportional to the resistance R of the whole circuit.

Ohm’s law can be applied to the circuit as a whole and separately to any portion of the circuit outside the power source.

 

3. Find synonyms for the words in the right column:

- value - is named - device - all - to use - shape - to connect

- to join - form - instrument - to apply - is called - whole - quantity

4. Find antonyms for the words in the left column:

- internal - separately - positive - outside - to leave - plus

- jointly - minus - to come - inside - negative - external

 

5. Translate the following sentences into English:

1. Відносно джерела енергії провідник і приймач утворюють так званий

2. зовнішій ланцюг.

3. Електрорушійна сила є безпосередня причина появи електричного струму в електричному ланцюзі.

4. Напрямок струму в електричному ланцюзі збігається з напрямком

5. електрорушійної сили.

6. І зовнішній ланцюг, і джерело струму мають опір, величина якого залежить від матеріалу, форми і розмірів провідників, з якіх складаються частини електричного ланцюга.

7. Закон Ома грає важливу роль в електротехниці.

8. Згідно з законом Ома, струм в електричному ланцюзі прямо пропор-

9. ційний електрорушійній силі і обернене пропорційний опіру всього ланцюга.

10. Закон Ома може бути пристосован до ланцюга в цілому і окремо до

11. кожної частини ланцюга поза джерела енергії.

 

Do a written translation of the second paragraph of the text “ Elements of the Electric Circuit ”.

7. Answer the following questions:

1. What does the simplest electric circuit consist of?

2. What does the power sourse transform?

3. What does the energy receiver transform?

4. What is called an electric circuit?

5. Which terminal of the source is called positive and which is the negative one?

6. What does the magnitude of the current depend on?

7. What is expressed by Ohm’s law?

8. To what can Ohm’s law be applied?

 

8. Use the infinitives in brackets in the Present Simple:

1. He always (to be) short of time.

2. My mother (to have) no spare time.

3. A great many of different clocks and watches (to help) us to know the time.

4. We (to have) vacation in summer.

5. Peter usually (to set) his watch by the radio.

6. My watch (to be) slow.

9. Communicative situations:

1. Make a report on the topic “ The electric circuit and its elements “

2. Make up a dialogue on the topic “ The elements of the electric circuit “

 

Retell the text.

 

TOPIC: ELECTRONICS

GRAMMAR: PAST SIMPLE

1. Learn the following words and word-combinations:

device	пристрій
rarefied gas	розріджений газ
preparatory stage	підготовча стадія
profound	видатний
emission	випромінювання
incandescent lamp	лампа розпікання
filament	нитка розпікання
auxiliary electrode	допоміжний електрод
two-electrode valve	двоелектродний клапан
grid	мережа
amplifier	підсилювач
vacuum tube	вакуумна лампа-трубка
oscillator	випромінювач,осцилятор
mercury rectifier	ртутний випрямляч
conversion	перетворення
photocell	фотоелемент
electron beam	електронний промінь
cathode-ray tube	катодна трубка
so forth	і так далі
welding	зварювання
a margin of error	межа помілки
to increase	підвищувати
cutting	різання
drilling	свердління
horizon	кругозір, горизонт
i.e. (that is)	тобто

 

2. Read and translate the text:

Electronics

 

Electronics is the science that studies the principles and technology of devices based on the phenomena of electric currents in a vacuum (electronic devices) and in rarefied gases (ionic devices). It’s the basis of modern automation, because it solves the most complicated problems in automation and production processes by relatively simple means.

The preparatory stage in the development of electronic devices was laid primarily by the profound researches of the Russian physicist Stoletov who first formulated the law of electron emission by a heated body (1839-1896). Next, the discovery of the vacuum device (the electron valve) was prepared by Lodygin’s invention of the first vacuum device to be widely used – the incandescent lamp (1847-1923). The thermionic emission effect was observed in the incandescent lamp already in 1881 by T. A. Edison: when a galvanometer is connected between the filament and a special auxiliary electrode in the lamp, there passes through the galvanometer a small current from the filament to the electrode. This current is caused by the transfer of electrons from the hot filament to the cold electrode.

However, it was only the discovery of radio by A. S. Popov, that gave a powerful stimulus to the development of electronics. The first two-electrode valves (detectors for wireless communication receivers) were made in 1904 soon after this discovery. The use of a grid made it possible to use the three-electrode valve first as an amplifier and then as a vacuum tube alternating current oscillator.

The first ionic power device was the mercury rectifier – a device for economical conversion of alternating current into direct current. Especially important was the use in electronics of the photoelectric effect, i.e., the emission of electrons by a metal under the action of light. This effect was discovered by Stoletov in 1888. He made the first photocell (prototube). Photocells were first used in sound films.

The principle of an electric or magnetic field acting on the direction of an electron beam in a vacuum or rarefied gas is employed in cathode-ray tubes which found application in television sets, electron microscopes, radar (for locating objects at a distance), and so forth.

Electronic beams are successfully used for welding. It has found broad application in industry as a means of automation, control and inspection, and as a direct means of fulfilling such operations as melting, cutting of super hard materials, welding.

Scientists opened up a new field of research in electronics – quantum electronics or atomic radio engineering. Quantum electronics has made it possible to develop a clock which has a margin of error of up to one second in three thousand years. It has also been used in the development of instruments for the generation of a rather wide range of electromagnetic waves – from one-millimeter waves to waves shorter than those of light. Quantum generators can focus light in extremely narrow beams. These instruments are called lasers and they can be used for cutting, drilling, welding, and other treatment of materials.

Electronics has found its application in electronic computers and television which are now widely used in industry, science and economy. Molecular electronics opens up absolutely new horizons.

 

3. Translate the following groups of words into Ukrainian:

To amplify – amplifier –amplification; special – specialist – speciality – especially; current – direct current, alternating current, to rectify – rectifier – rectification; physics – physicist – physical; to mean – mean – means; list – to list; to solve – solution – to solve a problem; to heat – heat – hot; to use – use – useful – useless; power – powerful – powerless.

 

4. Group up the words with the same meaning (synonyms):

Because, basis, simple, modern, up-to-date, foundation, plain, as, to utilize, first, to employ, rapid, to use, quick, to solve, fast, profound, field, to find solution, to connect, deep, branch, to join, significant, important, for the first time.

5. Translate the following sentences into Ukrainian:

1. Electronics solves the most complicated problems in automation and production processes by relatively simple means.

2. The mercury rectifier is a device for economical conversion of alternating current into direct current.

3. A lot of problems find solution in modern electronics.

4. The development of electronic amplifiers has made it possible to utilize a number of familiar physical phenomena.

5. Photocells became widely used only in conjunction with electron valves.

6. Especially important was the use in electronics of the photoelectric effect, i.e., the emission of electrons by a metal under the action of light.

7. The first two-electrode valves were made in 1904.

8. The Russian physicist Stoletov was the first to formulate the law of electron emission by a heated body.

9. The preparatory stage in the development of electronic devices was laid primarily by the profound researches of the Russian physicist Stoletov.

 

6. Use the verbs in brackets in necessary tense-form:

1. Electronics (to be) the basis of modern automation.

2. It (to solve) the most complicated problems in automation.

3. It (to be) possible to use this method.

4. It (to be) necessary to solve this problem long ago.

5. The first two-electrode valves (to be made) in 1904.

6. The development of electronic amplifiers (to make) it possible to utilize a number of familiar physical phenomena.

7. The discovery of radio by A. Popov (to give) a powerful stimulus to the development of electronics.

8. The use of a grid (to make) it possible to use the three-electrode valve as an amplifier.

9. Great progress (to be achieved) in the field of electronics.

10. Photocells (to be used) in sound films.

11. The photoelectric effect (to be discovered) by Stoletov.

 

7. Answer the following questions:

1. What does electronics study?

2. Why is electronics the basis of modern automation?

3. Is it possible to list the industrial and scientific problems that find solution in modern electronics?

4. Who formulated the law of electron emission by a heated body?

5. What discovery gave a powerful stimulus to the development of electronics?

6. What made it possible to use the three-electrode valve as an amplifier?

7. What was the first ionic power device?

8. Who made the first photocell?

9. Where are photocells used?

10. What principle is employed in cathode-ray tubes?

11. Where are cathode-ray tubes used?

 

8. Write the following sentences in the Past Simple:

1. The train starts at 10 o’clock.

2. The operator will start the engine

3. The research institute of electronics designs produces electronics-mechanical table-clocks of highest precision.

4. Many workers of our plant work in the daytime and study in their spare hours.

5. The young operator of the machine will join the Culture University classes.

6. In our experiment we apply the latest instruments.

7. As the researchers work hard they achieve good results.

8. This famous newspaperman always reports very interesting news.

9. When the controller examines the machines they operate normally.

 

9. Put the following verbs in the Past Simple:

To be, to predict, to blow, to get, to drop, to come, to have, to know, to leave.

 

 

10. Communicative situations:

1. Make up a dialogue on the topic “The science of electronics, its help and broad application in industry”.

2. Make a short report on the topic” Electronics in the life of our society”.

Retell the text.