Виконання вправ на закріплення граматичної теми

Вправа 12. Перекладіть речення з суб’єктивним інфінітивним комплексом.

1. I saw him look at the induction motor 2. Mary watched her disappear in the direction of the power station. 3. He made his brother read an article about resistance. 4. He seemed to be looking for the words. 5. We saw him enter the station.

Вправа 13. Перекладіть речення з суб’єктивним інфінітивним комплексом. 

1. Many books are known to be published in our country every year. 2. His invention is considered to be of great importance. 3. For a long time the atom was thought to be indivisible. 4. He was said to be one of the most promising nuclear physicists. 5. He appeared to be an excellent actor. 6. This work seems to take much time. 7. The percentage of carbon in this steel turned out to below. 8. They are sure to acknowledge your talent. 9. The article is likely to appear in the next issue of the journal. 10. She is not likely to change her opinion.

Заняття № 32

Тема: Змінний струм

Граматичний матеріал: Безсполучникова підрядність

Вправа 1. Прочитайте та перекладіть лексику за допомогою словника.

current [ʹkʌrənt] polarity [pəʹlærıtı]

direct сurrent (d.c.) [dıʹrekt ʹkʌrənt] rubbing [ʹrʌbıŋ]

alternating сurrent (a.c.) [ʹɔ:ltəneıtıŋ ʹkʌrənt] notably [ʹnəʋtəblı]

flow [fləʋ] predominately [prıʹdɒmınıtlı]

circuit [ʹsɜ:kıt] possess [pəʹzes]

source [sɔ:s] over time [ʹəʋvə taım]

frequency [ʹfri:kwənsı] switch [swıtʃ]

constant [ʹkɒnstənt] a bit [ə bıt]

Вправа 2. Прочитайте та перекладіть текст українською.

Types of Current

C urrent is a flow of electricity through a circuit. Let us consider two types of current: direct and alternating.

A direct current (d.c.) flows through a conducting circuit in one direction only. It flows provided a direct voltage source is applied to the circuit.

An alternating current (a.c.) is a current that changes its direction of flow through a circuit. It flows provided an alternating voltage source is applied to the circuit. Alternating current flows in cycles. The number of cycles per second is called the frequency of the current. In a 60-cycle alternating current circuit the current flows in one direction 60 times and in the other direction 60 times per second.

It is easy to transform a.c. power from one voltage to another by a transformer. Transformers are also used to step down the voltage at the receiving point of the line to the low values that are necessary for use. When necessary a.c. can be changed into d.c. but this is seldom necessary.

Most students begin their study about electricity with what is known as direct current (DC), which is electricity flowing in a constant direction, and/or possessing a voltage with constant polarity. DC is the kind of electricity made by a battery (with definite positive and negative terminals), or the kind of charge generated by rubbing certain types of materials against each other.

As useful and as easy to understand as DC is, it is not the only “kind” of electricity in use. Certain sources of electricity (most notably, rotary electro-mechanical generators) naturally produce voltages alternating in polarity, reversing positive and negative over time. Either as a voltage switching polarity or as a current switching direction back and forth, this “kind” of electricity is known as Alternating Current (AC).

With AC it is possible to build electric generators, motors and power distribution systems that are far more efficient than DC, and so we find AC used predominately across the world in high power applications. To explain the details of why this is so, a bit of background knowledge about AC is necessary.

Вправа 3. Дайте відповіді на питання до тексту.

1. What is current?

2. What types of current do you know?

3. How does current flow?

4. What is direct current? What is alternating current?

5. What is the frequency of the current?

6. When is applied AC and DC?

Вправа 4. Прочитайте речення. Знайдіть серед них вірні.

1. There are three types of current.

2. An alternating current changes its direction of flow through a circuit.

3. A direct current flows through a conducting circuit in many directions.

4. We find DC used predominately across the world in high power applications.

5. With AC it is possible to build electric generators, motors and power distribution systems that are far more efficient than DC.

Вправа 5. Знайдіть переклад поданих слів та словосполучень в тексті.

електрика	10. число циклів
ланцюг	11. частота струму
вимірювати	12. вимірювач
постійний струм	13. параллельно
змінний струм	14. напруга
напрямок
джерело напруги
величина опору
градуйований

Вправа 6. Закінчіть речення.

1. Current is ……………

2. The frequency of the current is…………………

3. Direct current is ………………………………..

4. It is easy to transform a.c. power from ………

5. Alternating current is …………………………

Вправа 7. Прочитайте та перекладіть текст без словника.

Дайте визначення різним видам струму.

Continuous, Direct, Pulsating, Alternating and Oscillatory Currents

A Continuous electric current is defined as a current which is always in the same direction but may vary or pulsate in value. The term “direct current” is ordinarily used to designate either a continuous current or a current which varies or pulsates only by an inappreciable amount, such as the current from a battery or direct current generator. A “pulsating” current is a direct current which pulsates by an inappreciable amount, such as the current from a rectifier. An “alternating” current is a direct current which reverses in direction, being first positive and then negative, but alternates between constant maximum positive and then negative, but alternates between constant maximum positive and negative values. An “oscillatory” current is a current which reverses in direction, oscillating between positive and negative values which either decrease or increase with time.

Граматичний матеріал: Безсполучникові підрядні речення

Підрядні означальні речення (attributive clause) виконують роль означення або займенника головного речення і з’єднуються з ним за допомогою сполучних займенників who, whose, which, that сполучних прислівників where, when, а також безсполучниковим способом:

The boy whose bicycle I took is my friend. ( Хлопець, велосипед якого я брав, мій товариш.) The engineer was interested in the method the students had applied during their work. (Інженер зацікавився методом, який студенти використовували в своїй роботі). We think the plow of the new type will be operated easily. ( Ми думаємо, що плуг нового зразка буде легко приводитися в дію).