10 Lesson 10
10.1 Прочтите слова согласно транскрипции
envelope evacuate , collide , collision , ionization cumulative , argon ,neon , helium , mercury, therefore, vapour .
10.2 Прочтите слова, обращая внимание на смещение ударения
evacuate — evacuation; molecule — molecular; liberate —liberation; processprocess; impact-impact; necessary — necessity.
10.3 Сгруппируйте эквиваленты
therefore, destructive, liberate, envelope, evacuate, collide, likewise, to take
place
колба, разрежать(воздух), сталкиваться, освобождать, иметь место, подобным образом, следовательно, разрушительный
10.4 Сгруппируйте синонимы
remain, to take place, definite, steady, emit, nearly, liberate, stay, occur, certain, constant, give off, almost, free.
10.5 Прочтите и переведите текст
Effect of gas
1.If the envelope of the tubes is not completely evacuated, so that a small amount of gas remains enclosed, some electrons in travelling toward the plate may collide with molecules of the gas. Such collisions may result in releasing electrons from their orbits within the gas atoms, and once free these electrons likewise are attracted to the plate. They may in turn collide with other gas molecules, and liberate more electrons. This process is known as ionization, and it may be cumulative in nature if enough gas is present so that a large number of collisions take place in the space between cathode and plate.
2.A definite amount of energy is required to dislodge an electron from an atom of any particular gas, and the voltage
necessary to furnish this amount of energy is called the ionization potential for the gas. Typical values are listed below.
Gas Ionization potential Argon .... 15.7 Neon..... 21,47 Helium.... 4.0
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Mercury (vapour) 10.38
3. The atom or molecule which has lost an electron, and therefore also a definite amount of negative electricity, has acquired a net positive charge. It is attracted to the cathode, but on account of its greater mass the atom or molecule moves much more slowly than an electron travelling toward the plate. It may, however, acquire considerable kinetic energy before completing its journey, and the impact of large numbers of such positively charged particles can have a destructive action on the cathode surface, particularly if this is of the coated type. This action is referred to as cathode bombardment; it may be quite important in such tubes as the mercury-vapour rectifiers.
10.6Переведите словосочетания
a)cathode bombardment, mercury-vapour rectifiers, ionization potential,
a large number of collisions; this phenomenon takes place in the space; on account of its greater mass; this action is referred to as cathode bombardment; they are likewise attracted to the plate.
10.7 Ответьте на вопросы
1. When may some electrons collide with molecules of the gas? 2. What process is known as ionization? 3. What is a definite amount of energy required for? 4. What has the atom or molecule which has lost an electron acquired? 5. What action is referred to as cathode bombardment?
10.8 Переведите предложения
1. The envelope of the tube is completely evacuated. 2. This action is referred to as cathode bombardment. 3. This subject will be dealt with in the next chapter. 4. The reaction is followed by temperature rise. 5. When the molecules of even a good insulator are acted upon by an electric field, there is a motion of electrons due to this field. 6. When the microphone is not acted upon, the diaphragm remains stationary. 7. Amplifiers are needed in long-distance telephony. 8. A convenient graphical construction may be employed to find the output components for any operating condition.
10.9 Определите, какой частью речи являются слова
completely, destructive, rectifier, action, considerable, negative, positive, collision, necessary, ionization, stimulative, potential.
10.10 Переведите диалог, используя следующие слова и словосочета-
ния
title, to occur, completely evacuated, in this case, to collide, to result in, releas-
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ing, to be attracted, in turn.
А: Как называется эта статья?
В: Название этой статьи — «Действие (эффект) газа». А: Что происходит, если в лампе нет полного вакуума?
В: В этом случае электроны могут столкнуться с молекулами газа.
А: К чему могут привести такие столкновения?
В: Они могут привести к освобождению электронов с их орбит внутри атомов газа.
А: Что происходит с этими свободными электронами? В: Они притягиваются к аноду, и
они могут, в свою очередь, столкнуться с другими молекулами газа и освободить
больше электронов.
А: Как называется этот процесс?
В: Этот процесс известен как ионизация.
11 Lesson 11
11.1 Прочтите слова согласно транскрипции
encounter, inverse , failure , transmit, transfer, helix , spiral, control.
11.2 Прочтите слова, обращая внимание на смещение ударения
increase-increase; limit —limitation; generate— generation; possible — possibility; vary — variation.
11.3 Сгруппируйте эквиваленты
attempt, encounter, harmful, inverse, failure, breakdown, melt, helix, serve,
rate
повреждение, величина, (неожиданно)встретиться, служить, вредный, обратный, попытка, авария, плавить(ся), спираль
11.4 Сгруппируйте антонимы
harmful, possible, failure, attract, modern, seldom, out-of-date, success, impossible, frequently, repel, harmless.
11.5 Прочтите и переведите текст
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Limitations in operating conditions
1.In attempting to operate tubes at high power, certain limitations are encountered. One of these is the peak emission current; it represents the maximum rate at which electrons can be given off without harm to the cathode structure, and without causing harmful increase of voltage drop within the tube.
2.Another limitation is the peak inverse voltage, or the maximum voltage that can be impressed across the tube elements without causing failure, either by electrical breakdown or by ionization of the gas within the tube.
3.The third important limitation is plate dissipation. When an electron arrives at the plate, its kinetic energy is transformed to heat and serves to raise the temperature of the plate structure. If the temperature goes too high the plate may melt, or electron emission from the plate may take place. Many high-power transmitting tubes have heat-radiating fins attached to the anode for the purpose of transferring heat generated at the plate as quickly as possible to the surrounding air; others are designed to permit water circulation around the anode structure.
4.The maximum amount of heat that can be safely dissipated by the plate of any tube is stated in terms of the corresponding electrical power, in watts, and is referred to as the maximum plate dissipation. With tubes containing grid structures, the heating of each grid must also be taken into account.
5.A triode is a tube which contains a third element, the grid, located between cathode and plate. The grid usually takes the form of a helix or spiral of fine wire, so that electrons may pass freely through it. Since the grid is nearer to the cathode, the potential of the grid has a greater effect in controlling electron flow than does the plate potential. If the grid potential is negative with respect to the cathode, as is usually true, electrons will not be attracted to the grid itself, and there will be no grid current.
11.6 Переведите словосочетания
a) peak emission current; cathode structure; voltage drop; plate dissipation; high-power transmitting tubes; heat-radiating fins; water circulation; grid structure.
b) the heating of each grid must be taken into account; within the tube; across the tube elements; without causing harmful increase of voltage drop; in terms of variations of the grid potential.
11.7 Ответьте на вопросы
1. What is the peak emission current? 2. What is the third important limitation? 3. When may electron emission take place? 4. What is referred to as the maximum plate dissipation? 5. What is a triode? 6. When will there be no grid current?
11.8 Переведите предложения
1. If the temperature goes too high, electron emission from the plate may take
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