II. Прочтите и переведите предложения, определив тип бессоюзного придаточного предложения:

1. The experiments showed this substance was unique in its properties.

2. We know the value of voltage is the same in all the ele­ments of a parallel circuit.

3. The weight of an atom depends on the number of protons and neutrons it contains.

4. The test we have made is of great importance for our laboratory.

5. The problem we shall deaf with is connected with new electronic devices.

6. The devices we are speaking about are constructed on the basis of photoemission.

7. The computer the engineer is testing was produced in Minsk.

8. The transmitter we have spoken about is suitable for this system.

9. We think cadmium is very useful for the application in transistors.

10. The rays he referred to differ from X-rays.

III. Прочтите слова и группы слов:

(to) rectify [ai], rectifier, rectifying, rectification; charac­teristic , linear characteristics; symmetrical, symmetrical characteristics; (to) permit, (to) permit easy flow; a surface , on the surface of the contact; some features [i:], some typical features; to oppose, opposing, opposite [zit], the opposite flow; through , through the surfaces, imme­diate immediately, immediately connected; adjacent , adjacent surfaces, immediately adjacent; ideal , an ideal rectifier; infinite ['infinit], infinite conduc­tance

TEXT

varistors

I. A solid rectifier or diode is a varistor having a volt-current characteristic which is not only non-linear but also non-symmetrical about the origin of currents and voltages.

2. The shape of a rectifier characteristic permits easy flow of current through the device in one direction but presents high resistance to current flow in the opposite direction. 3. The device we are speaking about is called a non-symmetrical varis-tor.4. A semiconductor contact rectifier, whatever its size, or electrical properties, consists of a layer of the semiconductor material with two metal contacts on its surface or surfaces. 5. If both of these contacts were rectifying, then the device would really be a series combination of two rectifiers in series opposing.6. In order to use the properties of the device in the best way, it is necessary that the rectification at one of these contacts be as ideal as possible. 7. It is also necessary that the •rectification at the other contact would be eliminated at the same time.

8. This can be done through the proper choice of a nonrectifying metal for the second contact or through suitable rectification-destroying treatment of the semiconductor surface before applying the contact metal. 9.The place of the rectification at the non-ohmic contact is often called the barrier layer or blocking layer l0. It consists of a very thin layer of semiconductor, immediately adjacent to the metal contact in which the local resistivity is many times greater than in the bulk material. II. The magnitude of the local resistivity, as well as the thickness of the layer itself, depends upon the direction and the magnitude of the voltage applied across the contact. 12. Typical barrier layer thickness runs from 10-6 to 10-³ cm. 13. The primary function of a rectifier is to serve as one-way valve allowing current to flow easily in one direction and only with great difficulty in the other. 14. The ideal rectifier would of course present infinite conductance in one direction and infinite resistance in the other.

15. Rectifying devices of various kinds using contacts between metals and semiconductors approach this ideal with certain characteristic features which are more or less common to all such devices.

16. The features we have just mentioned above must be discussed in details if one wants to understand the operation of these devices much better.

Слова для запоминания

п feature, origin, rectifier, surface, thickness, treatment

v destroy, mention, permit, rectify, serve

a adjacent, local, solid

adv immediately

prep as well as

Слова для повторения

n layer, magnitude, shape

v allow, approach, eliminate, present, run (ran, run)

a opposite, thin