UNIT 20

 

I. Find out the words in the dictionary. Write them down and learn.

 

processing, to convey, device, to manipulate, to reduce, to amplify, to vary, to be subjected, intermediate, lattice, to free, boron, excess, junction

 

II. Read the text. Use a dictionary, if necessary.

 

Text: “Electronics”.

 

Electronics is a general term for the production and processing of electric signals (consisting of moving electrons, hence the name electronics) that convey information – for example, the sound reproduction by a radio or record player and the data output of a computer. Electronics also includes the production and processing of beams of electrons, used in such devices as cathode-ray oscilloscopes, television sets, and electron microscopes.

Electric signals. Electric signals are produced by devices that convert the primary information source (which is in the form of another type of energy – sound or light, for instance) into small electric currents. For example, a microphone converts sound into an electric current, and in input unit of a computer converts data. These currents, which constitute a signal, are then transmitted along wires or, after conversion to radio waves, via radio links. On reaching a suitable receiver, they may be electronically manipulated – to reduce distortion in the signal, for instance – and are than amplified so that they can drive an output device, such as a loudspeaker, television set, or computer printer.

There are two types of electric signal: analog and digital. Analog signals vary continuously in voltage or current, corresponding to variations in the primary information source; thus the electric signals produced by a microphone are electrical “copies” of the original sound waves. Digital signals are not continuous but consist of numerous bursts of electric current between two voltage levels (one of which may be zero).

A computer uses digital signals. They consist of binary codes that represent the numbers, letters, and symbols in the input data and in the various program instructions. In the computer’s central processor, the data codes are subjected to processes of binary arithmetic or are compared with each other to obtain the results required by the program.

In modern electronics, electric signals may be processed in two main ways – by passing them trough semiconductor devices (such as transistors) or by converting them into a beam of electrons, as in the formation of a picture by a television set (which also uses semiconductors).

Semiconductors. Semiconductors are substances (such as silicon and germanium) whose electrical resistance lies between that of conductors and insulators. They have this intermediate resistance because they have a few free electrons that can drift from atom to atom – unlike conductors, which have many free electrons, and unlike insulators, which have none.

The semiconductors used in electronic devices are “doped” to change their electrical properties. Doping involves introducing minute traces of other elements into the semiconductor’s crystal lattice. Silicon and germanium each have four outer electrons per atom; doping them with an element with five outer electrons, such as phosphorus, frees the fifth electron so that the semiconductor has an electron excess. It is then known as an n-type (negative-type), because electrons have a negative charge.

Doping with an element that has only three outer electrons, such as boron, produces a crystal lattice with spaces, known as holes, which free electrons readily fill. This type of semiconductor has a lack of free electrons, which is equivalent to an excess of positive charges, and it is therefore known as p-type.

If a piece of n-type semiconductor is joined to a piece of p-type, the resulting device is called a p/n junction diode. If the diode is then connected to a battery so that the negative terminal is joined to the n-type semiconductor and the positive terminal to the p-type, current flows through the junction.

Transistors. Transistors are arrangements of semiconductor diodes that act as amplifiers. There are two main types: junction and field-effect transistors.

 

III. Find the sentences that can’t be found in the text.

 

1. The subject of electronics should, in its broadest sense, embrace all phenomena that are associated with the electron, the fundamental unit of negative electricity.
2. Electronics also includes the production and processing of beams of electrons, used in such devices as cathode-ray oscilloscopes, television sets, and electron microscopes.
3. There are two types of electric signal: analog and digital.
4. Semiconductors are substances (such as silicon and germanium) whose electrical resistance lies between that of conductors and insulators.
5. Semiconductors are materials which lie between conductors and insulators.
6. If a piece of n-type semiconductor is joined to a piece of p-type, the resulting device is called a p/n junction diode.
7. Transistors are arrangements of semiconductor diodes that act as amplifiers.

 

IV. Find English equivalents in the text.

 

1. движущиеся электроны ______________________________________
2. электронный (катодный) осциллограф ________________________
3. например __________________________________________________
4. уменьшать искажение ______________________________________
5. цифровой __________________________________________________
6. требуемые результаты ______________________________________
7. двумя основными способами ________________________________
8. полупроводниковые приборы ________________________________
9. промежуточное сопротивление _______________________________
10. кристаллическая решетка ___________________________________
11. внешний электрон __________________________________________
12. избыток электронов _________________________________________
13. недостаток свободных электронов _____________________________
14. соединение __________________________________________________
15. усилитель ___________________________________________________

 

V. Find Russian equivalents to the following expression in the text.

 

1. the production and processing of electric signals ______________________
2. convey information _____________________________________________
3. beams of electrons ______________________________________________
4. the primary information source ____________________________________
5. small electric currents ___________________________________________
6. are transmitted along wires _______________________________________
7. via radio links _________________________________________________
8. a suitable receiver ______________________________________________
9. may be electronically manipulated __________________________________
10. numerous bursts of electric current _________________________________
11. binary codes ___________________________________________________
12. minute traces __________________________________________________
13. act as amplifiers ________________________________________________

 

VI. Fill in the missing words.

 

1. Electronics is a general term for the _____ and _____ of electric signals that convey information.
2. Electric signals are produced by devices that the primary information _____ into small electric _____.
3. Digital signals consist of _____ codes that represent the numbers, letters, and symbols in the input data and in the various program instructions.
4. In modern electronics, electric signals may be processed in two main ways: by passing them through _____ _____ or by converting them into a _____ of _____.
5. Semiconductors are substances whose electrical resistance lies between that of _____ and _____.
6. Doping involves introducing minute traces of other elements into the semiconductor’s _____ _____.
7. Transistors are arrangements of semiconductor diodes that act as _____.

 

VII. Fill in the preposition, if necessary.

 

1. Electronics also includes ___ the production and processing ___ beams ___ electrons.
2. Analog signals vary continuously ___ voltage or current, corresponding ___ variations ___ the primary information source.
3. Digital signals are not continuous but consist ___ numerous bursts ___ electric current between two voltage levels.
4. ___ the computer’s central processor, the data codes are subjected ___ process ___ binary arithmetic or are compared ___ each other to obtain the results required ___ the program.
5. If the diode is then connected ___ a battery so that the negative terminal is joined ___ the n-type semiconductor and the positive terminal ___ the p-type, current flows ___ the junction.

 

VIII. Define whether the sentences are true or false.

 

1. Electric signals are produced by devices that convert the primary information source into small electric currents.
2. Digital signals vary continuously in voltage or currant, corresponding to variations in the primary information source.
3. Analog signals are not continuous but consist of numerous bursts of electric current between two voltage levels.
4. In the computer’s central processor the data codes are subjected to process of binary arithmetic or are compared with each other to obtain the results required by the program.
5. Semiconductors are substances whose electrical resistance lies between that of conductors and insulators.
6. Doping with an element that has only three outer electrons produces a crystal lattice without any spaces.

 

IX. Practice with someone asking and answering.

 

1. What is electronics?
2. What are electric signals produced by?
3. How many types of electric signal are there?
4. What signals does a computer use?
5. What do digital signals consist of?
6. In what ways may electric signals be processed in modern electronics?
7. What is semiconductor?
8. What does doping involved?
9. What is a transistor?
10. How many types of transistors do you know?

 

X. Put questions to the following sentences.

 

1. Electronics includes the production and processing of beams of electrons. (General)
2. Electric signals are produced by devices that convert the primary information source into small electric currents. (Disjunctive)
3. There are two types of electric signal. (Alternative)
4. The electrical resistance of semiconductors lies between that of conductors and insulators. (Special)
5. The semiconductors used in electronic devises are “doped” to change their electrical properties. (What …?)
6. Doping with an element that has only three outer electrons produces a crystal lattice with spaces, known as holes. (Disjunctive)

 

XI. Dictate the following sentences in English to your fellow-students. Check them together.

 

1. Electronics is a general term for the production and processing of electric signals that convey information.
2. Electric signals are produced by devices that convert the primary information source into small electric currents.
3. Analog signals vary continuously in voltage or current, corresponding to variations in the primary information source.
4. Digital signals are not continuous but consist of numerous bursts of electric current between two voltage levels.
5. Semiconductors are substance whose electrical resistance lies between that of conductors and insulators.

 

XII. Dictation-translation.

 

1. Электроника заключает в себе производство и обработку пучков электронов.
2. Электрические сигналы производятся приборами, которые превращают первоначальный источник информации в слабые электрические токи.
3. Существуют два вида электрического сигнала: аналоговый и цифровой.
4. В современной электронике электрические сигналы могут обрабатываться двумя основными способами – посредством происхождения их через полупроводниковые приборы или посредством превращения их в пучок электронов.
5. Полупроводники обладают промежуточным сопротивлением потому, что у них есть некоторое количество свободных электронов, которые могут превращаться от атома к атому – в отличие от проводников, у которых есть много свободных электронов, и в отличие от изоляторов, у которых их нет.