вар 3 On semiconductors

  вар 3 тексты On semiconductors и Miniaturization, ответы на вопросы A semiconductor is often defined as an electric conductor that has a conductivity intermediate between that of an insulator and that of a metal. The more important semiconductors are: boron, germanium, silicon, phosphorus, gray tin and others.
The mechanical properties of semiconductors vary greatly. However, in hardness, and fracture strength, semiconducting crystals resemble insulating ays- tals more than they do metals. Besides their electric properties, which in themselves may be of great variety, semiconductors vary in such physical qualities as magnesium, specific heat and thermal conductivity.
Semiconductors are widely used in electronics. They challenge vacuum tubes in many applications in the electronic industry. Engineers and physicists are going to solve many engineering problems by means of semicondiictors.
Answer the questions1 .Is a semiconductor defined as an electric conductor?
2. What important semiconductors do you know?
3. How do semiconductors vary?
4. Where are semiconductors widely used? Miniaturization Also important in modern electronics is miniaturization and superminiaturization of electronic instruments and their elements. Certain achievements can be reported in this field too.
Semiconductor devices which are being used to help electron valves reduce the size of instrumentsconsiderably. As new synthetic materials appear, parts of electronic instruments like capacitors, resistors, transformers, etc., can be cut in size dozens and hundreds of times.
Vast prospects for the miniaturization of electronic instruments open up with the development of micro-modules - tiny ceramic plates carrying the necessary parts of a circuit - miniature semiconductor devices, capacitors, resistors, transformers.
The next step in microminiaturization is the development of microthin film circuits. Use is not made of separate, even superminiature elements but of extremely thin films of a particular shape placed one upon another. A film of this type, one square centimeter in size, would take the place of up to 100 elements of a circuit. A unit of this type would be no thicker than a few microns.
Molecular electronics open up absolutely new horizons.
There is good reason to assume that if superminiature elements can be developed - artificial models of nerve cells of loving organism - neurons - it will be possible to get about 200 million “parts” in one cubic centimeter. This is approximately the density of elements in the human brain.
Translate the following sentences 1.Much of the success of electronics depends on the methods used to obtain an electric signal that can be used to simulate1 the electronic device into action.
2. The apparatus to be assembled is very complicated.
3. It is hard to overestimate the role of radio-electronics in technical progress.
4. The resistance being very large, the current in the circuit was small.
5. We are to take into consideration all the advantages and disadvantages of this device for the future work.