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15. Study the text and translate the following:

  • способность хорошо проводить ток

  • применять теорию (к)

  • положительные и отрицательные носители зарядов

  • подсоединить батарею к диоду

  • двигаться к электронно-дырочному переходу

  • замещаться новыми носителями заряда

  • получающиеся в результате разделения связанной электронно-дырочной пары

  • двигаться во внешней цепи

  • поддерживать движение тока

  • способ соединения

  • приводить к результату

  • прямое/обратное смещение

  • прямое сопротивление

  • отсюда/поэтому

  • незначительный ток

  • этот ток образуется благодаря неосновному носителю зарядов

  • резкое повышение тока

  • избыточный ток

  1. Look at the English variant of the words of the previous exercise for 30 seconds, divide into three groups and see which group can remember more.

  1. Complete the following sentences.

  1. When P- and N-type silicon are joined …

  2. This two-element device has a unique characteristic: …

  3. The holes in the P-type silicon are repelled by …

  4. The current carriers lost in these combinations are …

  5. The free electrons created in the P-type silicon are …

  6. The process is …

  7. If the voltage at the terminal is increased, …

  8. The manner of connecting …

  9. In the reverse-bias connection the positive terminal of the battery …

  10. Thus the majority current carriers in the diode do not …

  11. … there is a minute current in the diode.

  12. Only a few microamperes of current flow …

  13. The reverse-bias connection results in …

  14. There is a limit not only… but also …

  15. … there is a sharp increase in forward or reverse current.

  16. This increase may destroy the diode by …

18. Choose some sentences from the text and transform them using Gerundial Construction.

For example: Let us apply the theory of negative and positive carrier to this diode. – Our applying the theory of negative and positive carrier to this diode helps us to understand the processes better.

Speaking

19. Summarize the text “Operation of a Semiconductor Junction Diode” in 150 words using at least 4 cases of Gerund and Gerundial Construction.

20.Act as an interpreter.

  1. Translate the summary given by your group-mates from English into Russian.

  2. Give a reverse translation of the summary (from Russian into English).

21.Translate the text “Laser Diodes. Theory of Operation” with a dictionary in writing and compare the operation of a semiconductor junction diode with that of a laser diode.

A laser diode, like many other semiconductor devices, is formed by doping a very thin layer on the surface of a crystal wafer. The crystal is doped to produce an n-type region and a p-type region, one above the other, resulting in a p-n junction, or diode.

Laser diodes form a subset of the larger classification of semiconductor p-n junction diodes. As with any semiconductor p-n junction diode, forward electrical bias causes the two species of charge carrier – holes and electrons – to be "injected" from opposite sides of the p-n junction into the depletion region, situated at its heart. Holes are injected from the p-doped, and electrons from the n-doped, semiconductor. (A depletion region devoid of any charge carriers is formed automatically and unavoidably as a result of the difference in chemical potential between n- and p-type semiconductors wherever they are in physical contact.)

As charge injection is a distinguishing feature of diode lasers as compared to all other lasers, diode lasers are traditionally and more formally called "injection lasers." When an electron and a hole are present in the same region, they may recombine or "annihilate" with the result being spontaneous emission — i.e., the electron may re-occupy the energy state of the hole, emitting a photon with energy equal to the difference between the electron and hole states involved. Spontaneous emission is necessary to initiate laser oscillation, but it is one among several sources of inefficiency once the laser is oscillating.

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