7. Change the following complex sentences given below according to the example and translate them:

a) Example: The process which will be described in this article is known as ionization.

The process to be described in this article is known as ionization.

1. The method which will be used is reliable.

2. The results which will be received will be published next month.

3. The data that are to be obtained will be of great interest.

4. The measurements that must be made should be accurate enough.

5. The experiments which will be demonstrated are closely related to our research.

6. The problem that must be solved is very difficult.

7. The work that must be done is of great importance.

8. The method that will be used was developed in our laboratory.

9. The equipment that is to be installed is very effective.

10.The instrument which will be used must make precise measurements.

b) Example: Yablochkov was the first who realized the advantages of the alternating current.

Yablochkov was the first to realize the advantages of the alternating current.

1. Franklin was the first who developed a new theory of electricity.

2. Lomonosov and Franklin were the first who made their experiment in the field of atmospheric electricity.

3. The engineer was the last who made report at the conference.

4. The famous scientist was the first who proved this theory.

5. Newton was one of the first who studied light.

6. Lodygin was the first who invented the electric lamp.

7. These metals were the first that were used in industry.

8. This scientist was the first who developed the new process.

9. These devices were the first that were tested in our laboratory.

10. Einstein was the first who provided a new conception of time, space and gravitation.

Lesson Two

I. Pre-text Exercises

1. Learn the meaning and pronunciation of the following words:

evacuate [i'vækjueit], cathode ['kæθoud], anode ['ænoud], repel [ri'pel],

bipolar [bai'poulə], bias ['baiəs], unimpeded ['Λnim'pi:did], superimpose [,sju:pərim'pouz], silicon ['silikən], germanium [dʒə:'meiniəm].

2. Read and remember the Plural of the following nouns:

nucleus ['nju:kliəs] — nuclei ['nju:kliai]

focus ['foukəs] — foci ['fousai]

apparatus [æpə'reitəs] — apparatuses [æpə'reitəsiz]

thesis ['θi:sis] — theses ['θi:si:z]

II. Read the following text carefully. While vou are reading look for the answer to the questions:

1. How many categories are components of electronic circuits classified into?

2. How can diode be produced?

3. Which transistors operate more efficiently - bipolar or field-effect ones?

Text в Electronic Components. Vacuum Tubes and Transistors

1. Electronic circuits consist of interconnections of electronic components. Components are classified into two categories - active or passive. Passive elements never supply more energy than they absorb; active elements can supply more energy than they absorb. Passive components include resistors, capacitors, and inductors. Components considered active include batteries, generators, vacuum tubes, and transistors.

2. A vacuum tube consists of an air-evacuated glass envelope that contains several metal electrodes.

A simple, two-element tube (diode) consists of a cathode and an anode that is connected to the positive terminal of a power supply. The cathode - a small metal tube heated by a filament - free electrons, which migrate to the anode - a metal cylinder around the cathode (also called the plate). If an alternating voltage is applied to the anode, electrons will only flow to the anode during the positive half-cycle; during the negative cycle of the alternating voltage, the anode repels the electrons, and no current passes through the tube. Diodes connected in such a way that only the positive half-cycles of an alternating current (AC) are permitted to pass are called rectifier tubes; these are used in the conversion of alternating current to direct current (DC). By inserting a grid, consisting of a spiral of metal wire, between the cathode and the anode and applying a negative voltage to the grid, the flow of electrons can be controlled. When the grid is negative, it repels electrons, and only a fraction of the electrons emitted by the cathode can reach the anode. Such a tube, called a triode, can be used as an amplifier. Small variations in voltage at the grid, such as can be produced by a radio or audio signal, will cause large variations in the flow of electrons from the cathode to the anode and, hence, in the circuitry connected to the anode.

3. Transistors are made from semiconductors. These are materials, such as silicon or germanium, that are "doped" (have minute amounts of foreign elements added) so that either an abundance or a lack of free electrons exists. In the former case, the semiconductor is called n-type, and in the latter case, p-type. By combining n-type and p-type materials, a diode can be produced. When this diode is connected to a battery so that the p-type material is positive and the n-type negative, electrons are repelled from the negative battery terminal and pass unimpeded to the p-region, which lacks electrons. With battery reversed, the electrons arriving in the p-material can pass only with difficulty to the n-material, which is already filled with free electrons, and the current is almost zero.

4. The bipolar transistor was invented in 1948 as a replacement for the triode vacuum tube. It consists of three layers of doped material, forming two p-n (bipolar) junctions with configurations of p-n-p or n-p-n. One junction is connected to a battery so as to allow current flow (forward bias), and the other junction has a battery connected in the opposite direction (reverse bias). If the current in the forward-biased junction is varied by the addition of a signal, the current in the reverse-biased junction of the transistor will vary accordingly. The principle can be used to construct amplifiers in which a small signal applied to the forward-biased junction causes a large change in current in the reverse-biased junction.

5. Another type of transistor is the field-effect transistor (FET). Such a transistor operates on the principle of repulsion or attraction of charges due to a superimposed electric field. Amplification of current is accomplished in a manner similar to the grid control of a vacuum tube. Field-effect transistors operate more efficiently than bipolar types, because a large signal can be controlled by a very small amount of energy.

III After-text exercises

1. Agree or disagree with the next statements:

1) Passive components include batteries, generators, vacuum tubes and transistors.

2) A diode consists of a cathode and an anode that is connected to the positive terminal of a power supply.

3) When a grid is positive, it repels electrons.

4) By combining n-type and p-type materials a diode can be produced.

5) Field-effect transistors operate less efficiently than bipolar types.

2. Find the information about:

l) the function of the cathode;

2) the controlling of the flow of electrons;

3) such materials as semiconductors;

4) the bipolar transistor;

5) the principle of the field-effect transistor's operation.

3. Put questions to each other.

4. Summarize the general ideas of the text Use the following plan:

1) Active and passive components of electronic circuits.

2) The main elements of a diode.

3) Using of diodes and triodes.

4) Different kinds of semiconductors.

5) Types of transistors.

5. Underline Complex Object with the Infinitive in the following sentences and translate them:

1) We consider the circuit to be too strong for our purpose.

2) We believe the programming to have been done very skillfully.

3) Modern discoveries allow science and engineering to be developed rapidly.

4)We know silver and copper to be very good conductors of electricity.

5) We know him to be the first inventor of electrical measuring instruments.

6) When the state or condition of a body is such that it can do work, we know the body to possess energy.