III. Transformers

I.Words to be remembered

1. voltage - напряжение

2. to increase - увеличивать, увеличиваться

3. to decrease - уменьшать, уменьшаться

A transformer is used for increasing or decreasing voltage.

4. a winding - обмотка

5. a core - якорь

A transformer consists of two windings and an iron core.

6. primary - первичный

7. secondary - вторичный

The winding is connected to a source of supply and the secondary winding

is connected to a load.

8. a step-up transformer - повышающий трансформатор

A step-up transformer is used for increasing voltage.

9. a step-down transformer - понижающий трансформатор

A step-down transformer is used for decreasing voltage.

II. Fill in the blanks with suitable words

1. A transformer is used for increasing or decreasing...

2. The principal parts of a transformer are two... and an iron...

3. A coil which is supplied with current is called a... winding.

4. A winding from which current is taken is called a... winding.

5. A... consists of thin sheets of steel.

6. Voltage is increased by means of a... transformer.

7. Voltage is decreased by means of a... transformer.

step-up, core, secondary, winding, voltage, primary, step-down

III. Find suitable attributes from B for the nouns from A

A. iron, television, secondary, power, transmission, long, electric, principal, induction, step-down

B. current, station, coil, parts, core, winding, transformer, distance, line, set

IV. Translate and retranslate the sentences

1. A transformer is used for changing electric current from one voltage to another.

2. A simple transformer is a kind of an induction coil.

3. The principal parts of a transformer are two windings (coils) and an iron core.

4. A primary winding is connected to a source of supply.

5. A secondary winding is connected to a load.

6. A core consists of thin sheets of steel.

7. A step-up transformer is used for increasing voltage.

8. A step-down transformer is used for decreasing voltage.

9. Large transformers are used in long distance transmission lines.

V. Form sentences

1. A primary winding is... 2. A step-up transformer is... 3. A transformer is... 4. A secondary winding is... 5. A step-down transformer is... 6. A core is...	1. a ring of thin sheets of steel 2. a winding from which current is taken 3. a transformer for increasing voltage 4. a winding which is supplied with current 5. a device for changing electric current from one voltage to another 6. a transformer for decreasing voltage

VI. Read the text and be ready to answer the questions

Transformers

A transformer is a device for changing electric current from one voltage to another one. It is used for increasing or decreasing voltage.

A simple transformer is a kind of an induction coil. In its usual form a transformer has no moving parts.

The principal parts of a transformer are two windings (coils) and an iron core.

A coil which is supplied with current is called a primary winding, or "primary",

for short.

A winding from which current is taken is called a secondary winding, or "secondary", for short.

A primary winding is connected to a source of supply and a secondary winding

is connected to a load.

A core consists of thin sheets of steel.

In large power stations voltage is usually increased by means of a step-up transformer for transmission over long distances.

At a place where power is needed voltage is decreased by means of a step-down transformer to a value suitable for use consuming devices.

Large transformers are used in long distance transmission lines.

Two or more kinds of transformers are used in all radio and television sets.

VII. Answer the questions

1. What is a transformer?

2. Has a transformer moving parts?

3. What parts does a transformer consist of?

4. What is a primary winding?

5. What do we call a secondary winding?

6. What is a core?

7. What transformer is used to increase voltage?

8. What is a step-down transformer used for?

9. Where are large transformers used?

VIII. Work in pairs. Translate your Russian sentences

Student A

1. - Что такое трансформатор?

- A transformer is a device for changing electric current from one voltage to another one.

2. - Has a transformer moving parts?

- В своей обычной форме трансформатор не имеет подвижных частей.

3. - Из каких частей состоит трансформатор?

- A transformer consists of two windings and an iron core.

4. - What is a primary winding?

- Обмотка, которая снабжается током, называется первичной.

Она соединяется с источником тока.

5. - Что такое вторичная обмотка?

- A secondary winding is a winding from which current is taken.

It is connected to a load.

6. - What does a core consist of?

- Сердечник состоит из тонких листов стали.

7. - С помощью какого трансформатора повышается напряжение?

- Voltage is increased by means of a step-up transformer.

8. - By means of what transformer is voltage decreased?

- Напряжение понижается с помощью понижающего трансформатора.

9. - Где используются большие трансформаторы?

- Large transformers are used in long distance transmission lines.

Student B

1. - What is a transformer?

- Трансформатор - это прибор для измерения электрического тока

из одного напряжения в другое.

2. - Есть ли у трансформатора подвижные части?

- In its usual form a transformer has no moving parts.

3. - What parts does a transformer consist of?

- Трансформатор состоит из двух обмоток и железного сердечника.

4. - Что такое первичная обмотка?

- A winding which is supplied with current is called a primary winding.

It is connected to a source of supply.

5. - What is a secondary winding?

- Вторичная обмотка - это обмотка, из которой забирается ток.

Она соединяется с нагрузкой.

6. - Из чего состоит сердечник?

- A core consists of thin sheets of paper.

7. - By means of what transformer is voltage increased?

- Напряжение повышается с помощью повышающего трансформатора.

8. - С помощью какого трансформатора напряжение понижается?

- Voltage is decreased by means of a step-down transformer.

9. - Where are large transformers used?

- Большие трансформаторы используются на линиях передач большого

расстояния.

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