Semiconductors

The periodic law of elements discovered by Mendelyeev had a number of important scientific and industrial results, one of them being the discovery of germanium. Germanium is the semiconductor used in most transistors available at present.

But what are semiconductors? They include almost all minerals, many chemical elements, a great variety of chemical compounds, alloys of metals, and a number of organic compounds. Like metals, they conduct electricity but they do it less effectively. In metals, all electrons are free and in insulators they are fixed. In semiconductors electrons are fixed, too, but the connection is so weak that the heat motion of the atoms of a body easily pulls them away and sets them free.

It is not difficult to understand that the term “semiconductor” has been used because the material in question really occupies a place between the conductors of the electric current and the non-conductors, that is insulators. The term shows that they conduct electricity less readily than conductors but much better than insulators.

Minerals and crystals appear to possess some unexpected properties. For instance, it is well known that their conductivity increases with heating and falls with cooling.

As a semiconductor is heated, free electrons in it increase in number, hence, its conductivity increases as well. However, heat is by no means the only phenomenon influencing semiconductors. They are sensitive to light, too. Take germanium as an example. Its electrical properties may greatly change when it is exposed to light. With the help of a light ray directed at a semiconductor, we can start or stop various machines, effect remote control, and perform control and perform lots of other useful things. Just as they are influenced by fall in light, semiconductors are also influenced by all radiation. Generally speaking, they are so sensitive that a heated object can be detected by its radiation.

As previously mentioned, such dependence of conductivity on heat and light has opened up great possibilities for various uses of semiconductors. The semiconductor devices are applied for transmission of signals, automatic control of a variety of processes, switching on engines, the reproduction of sound, protection of high-voltage transmission lines, speeding up of some chemical reactions, and so on. On the one hand they may be used to transform light and heat energy directly into electric energy without any complex mechanism with moving parts, and on the other hand, they are capable of generating heat or cold from electricity.

 

Notes on the text:

the material in question – материал, о котором идет речь

on the one hand (on the other hand) – с одной стороны (с другой стороны)

 

VII. Ответьте письменно на вопросы по содержанию текста:

When does a semiconductor conductivity increase?

What are the semiconductor devices used for?

Are semiconductors sensitive to light?

 

Вариант II

I. Перепишите предложения, подчеркните глагол-сказуемое в Passive

Voice. Переведите на русский язык.

Students of technological institutes are trained to analyse various facts and theories.

Much is being done to improve old power plants.

Electricity has replaced other sources of energy as it has been recognized that it offers improved service and reduced cost.

Before Faraday’s inventions in the field of electricity and magnetism, the only source of electricity that was used was the galvanic battery.

II. Определите функции глаголов to be, to have, to do. Предложения

переведите на русский язык.

The latest laser devices have found application in medicine.

At first, the induction motor was a device which had a constant and unchangeable speed.

In fact, computers can do many things we do, but faster and better.

Metals conduct electricity better than semiconductors do.

 

III. Перепишите предложения. Переведите на русский язык, обращая

внимание на функцию инфинитива (подлежащее, часть сказуемого,

дополнение, определение, обстоятельство).

However, the electricity to be obtained by rubbing objects together cannot be used to light lamps, to boil water, to run electric trains and so on.

To develop the supercomputer, highly developed electronics and new materials were required.

These electrical devices can work for a long time provided they are made of high-quality material.

The engineer must know the conditions under which the new material is to be utilized.

To transform water into steam is not a complex process.

 

IV. Переведите предложения на русский язык, обращая внимание на

инфинитивные конструкции (Complex Subject, Complex Object).

Recent discoveries in superconductivity made scientists look for new conducting materials and for practical applications of the phenomenon.

We know the electron to be a minute particle having an electric charge.

Lasers are sure to do some jobs better and at much lower cost than other devices.

Superconductors are likely to find applications we don’t even think of at present.

 

 

V. Переведите на русский язык, обращая внимание на значения слов: as,

because, because of, due to, for, since, either... or, neither... nor,

both... and.

As a cold object and a hot one are brought into contact, the former gets warmer and the latter gets colder.

Automatic control in the simpliest form has been known since the beginning of the steam age.

The high level of nuclear physics research made it possible for Russia to become the first country to start using atomic energy for peaceful purposes.

Both chemical energy and mechanical energy can be transformed into electricity.

He will make the report either on conductors and insulators or on superconductivity.

Every year more and more people use the Internet due to its popularity and possibility to exchange an immeasurable amount of information, electronic mail and news.

We had to stop the experiment because of the damage of the device.

Neither this nor that method of producing electricity may be used under these conditions.

VI. Прочитайте текст, перепишите, письменно переведите на русский

язык.