A.c. flows provided

a) a direct voltage source is applied

b) an alternating voltage source is applied

In an alternating current circuit

a) current flows in one direction 60 times per second

b) current flows in one direction 60 times and in the other direction 60 times per second.

A.c.

a) can be change in to d.c.

b) cannot be changed into d.c.

There are

a) two main types of current

b) three main types of current

c) four main types of current

3. Make up sentences, using words and word-combinations.

Inductance, inductor, definite, provide, mutual, unit, touch, coils, transformer, primary winding.

Additional material for card № 8

1. Read the text, translate it and answer the questions.

Types of current

Current is a flow of electricity through a circuit. Let us consider two main 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.

1. What types of current do you know?

2. What is an alternating current?

3. What is a direct current?

2. Find the correct variant.

Any conductor has

a) Some definite value of resistance

b) Some definite value of inductance

Any conductor can provide

a) Electric power

b) Induced voltage

Elements with a definite value of inductance

a) Are called inductors

b) Are called coils

c) Are called sources

The inductance of a coil depends on

a) Its size

b) Its core

c) Its material

d) The number of turns

An iron core

a) Increases the value of inductance

b) Decrease the value of inductance

3. Make up sentences, using words and word-combinations.

Couple, indirect, tight, loose, self-inductance, field, separate, close together, primary winding, secondary winding

Additional material for card № 9

1. Read the text, translate it and answer the questions.

Не знайшли потрібну інформацію? Скористайтесь пошуком google:

Генерація сторінки за: 0.006 сек.