13.03.02 Электроэнергетика и электротехника / Английский / 3 симестр / 9-15-2023

I. Decode the following acronyms: e.m.f.; d.c.; a.c.; p.d.; V; A.

• e.m.f.: Electromotive Force

• d.c.: Direct Current

• a.c.: Alternating Current

• p.d.: Potential Difference

• V: Volts

• A: Amperes

III. Read and translate the following words and word combinations:

• excellent - отличный

• conductor - проводник

• current flow - поток тока

• good insulator - хороший изолятор

• semiconductor materials - полупроводниковые материалы

• electrical supply - электрическое напряжение

• potential difference - разность потенциалов

• supply source - источник энергии

• a measured electromotive force - измеренная электродвижущая сила

• charge carrier - носитель заряда

• electrical circuit - электрическая цепь

• series connection - последовательное соединение

• much higher velocity - значительно большая скорость

IV. Use the words and the word combinations from the exercises II and IV in the following sentences:

1. Semiconductor materials, including silicon, germanium, and cadmium sulfide, have various electronic applications.

2. A battery is the simplest source of direct current (d.c.).

3. Electrons are negative charge carriers in most electrical circuits.

4. Metal is an excellent conductor of electricity.

5. An electrical generator produces an electromotive force (e.m.f.).

6. The electrical potential between two points in a circuit is known as the potential difference (p.d.).

7. Two types of connections are known in electrical circuits: series and parallel connections.

8. The voltage (V) is what produces the current in an electrical circuit.

V. Find the sentences in the text about:

a) potential difference; b) charge carriers; c) measurements of potential difference and electromotive force; d) electrical equivalent of mechanical potential; e) conventional current flow; f) electromotive force; g) series connection.

a) The sentences about potential difference can be found in the text in the following locations:

• "The electrical potential between two points in a circuit is known as the potential difference or p.d. between the points."

b) The sentences about charge carriers can be found in the text in the following locations:

• "The charge carriers may be either electrons (negative charge carriers) or holes (positive charge carriers), or both."

• "Unless stated to the contrary, we will assume conventional current flow in electrical circuit that is we assume that current is due to the movement of positive charge carriers (holes) which leave the positive terminal of the supply source and return to the negative terminal."

c) The sentences about measurements of potential difference and electromotive force can be found in the text in the following locations:

• "Potential difference and e.m.f. are both measured in volts, symbol V."

• "A graph showing the relationship between the e.m.f. in the circuit and the current is a straight line passing through the origin; that is, the current is zero when the supply voltage is zero. This relationship is summed up by Ohm’s law."

d) The sentences about the electrical equivalent of mechanical potential can be found in the text in the following locations:

• "Voltage is the electrical equivalent of mechanical potential."

• "The potential energy of an electrical supply is given by its voltage and the greater the voltage of the supply source, the greater its potential to produce electrical current in any given circuit connected to its terminals (this is analogous to the velocity of the rock in the mechanical case)."

e) The sentences about conventional current flow can be found in the text in the following locations:

• "Unless stated to the contrary, we will assume conventional current flow in electrical circuit that is we assume that current is due to the movement of positive charge carriers (holes) which leave the positive terminal of the supply source and return to the negative terminal."

f) The sentences about electromotive force can be found in the text in the following locations:

• "A battery or electrical generator has the ability to produce current flow in a circuit, the voltage which produces the current being known as the electromotive force (e.m.f.)."

• "The voltage which produces the current is known as electromotive force (e.m.f.)."

g) The sentences about series connection can be found in the text in the following locations:

• "If two 10-V batteries are connected in series with one another, the e.m.f. in the circuit is doubled at 20 V; the net result is that the current in the circuit is also doubled."

VI. Answer the questions to the text using the following introductory phrases: as far as I know; I think quite so; it is really; as far as I remember.

1. What is voltage? - Voltage is the electrical equivalent of mechanical potential.

2. By what is potential energy of an electric supply given? - The potential energy of an electrical supply is given by its voltage.

3. The electrical potential between two points in a circuit is known as the potential difference, isn't it? - It is really.

4. What device has the ability to produce current flow in a circuit? - A battery or electrical generator has the ability to produce current flow in a circuit.

5. In what terms is e.m.f. measured? - E.m.f. is measured in volts.

6. Why does the current occur in the circuit? - The current in a circuit is due to the movement of charge carriers through the circuit.

7. May holes be charge carriers? - As far as I know, holes can be charge carriers.

8. In what terms are current measured? - Current is measured in amperes.

9. In what law is the relationship between e.m.f. and the current summed up? - The relationship between e.m.f. and the current is summed up by Ohm's law.

VII. Express the main idea of each paragraph of the text "Voltage and Current" in writing.

1. Voltage and Current: This paragraph introduces the concept of voltage as the electrical equivalent of mechanical potential. It explains how voltage determines the potential energy of an electrical supply and its ability to produce current in a circuit. The relationship between voltage and current is briefly mentioned.

2. Electromotive Force and Potential Difference: This paragraph defines potential difference and electromotive force (e.m.f.) and emphasizes the difference between the two. It clarifies that e.m.f. is associated with the source of electrical energy, while potential difference is the voltage between two points in a circuit.

3. Current and Charge Carriers: This paragraph explains that current in a circuit is the result of charge carriers (electrons or holes) moving through it. It mentions the measurement of current in amperes and the assumption of conventional current flow.

4. Effects of Voltage on Current: Here, the paragraph illustrates how changes in voltage impact the current in a circuit. It shows that increasing voltage increases current and describes this relationship as depicted in Ohm's law

VIII. Retell the text using the sentences, expressing the main idea of its paragraphs as a plan, and introductory phrases of exercise VII.

As far as I remember, the text "Voltage and Current" discusses fundamental principles of electricity. Here is a summary of the text using the main ideas of its paragraphs as a plan, along with the introductory phrases from exercise VII:

I. Introduction

• Voltage and Current: In this introductory paragraph, the text explains that voltage is the electrical equivalent of mechanical potential. It draws an analogy with potential energy in mechanical systems and introduces the concept of voltage as a key factor in electrical circuits.

II. Electromotive Force and Potential Difference

• Electromotive Force and Potential Difference: This section focuses on defining two important terms, electromotive force (e.m.f.) and potential difference (p.d.). It clarifies that e.m.f. relates to the source of electrical energy, while potential difference represents the voltage between two points in a circuit.

III. Current and Charge Carriers

• Current and Charge Carriers: The third paragraph discusses the nature of electric current and its connection to the movement of charge carriers in a circuit. It introduces the idea that charge carriers can be either electrons or holes and mentions the measurement of current in amperes.

IV. Effects of Voltage on Current

• Effects of Voltage on Current: The final paragraph explores how changes in voltage affect the current in a circuit. It highlights the direct relationship between voltage and current, explaining that increasing voltage leads to an increase in current. This relationship is summarized by Ohm's law.

In summary, this text provides a foundational understanding of electricity, emphasizing the role of voltage, current, and their relationship in electrical circuits. It distinguishes between electromotive force and potential difference while explaining the impact of voltage on current flow.