XI. Translate the following sentences paying attention to the functions of the Gerund:

1. Encoding is the function of the transmitter. 2. Visual and audible signals are used for conveying information. 3. Коtelnikoy and Wierner's having recognized clearly the fundamental role of noise in limiting the performance of communication systems had an important influence in modulation theory. 4. Our having mastered a foreign language help us in our work. 5. We suggested the plan being discussed at the conference. 6. He prevented the letter from being sent of.

7. He is proud of having been trusted with this task.

XII. Translate the following sentences:

1. Він наполягав на проведенні експерименту. 2. Вимірювання температури потрібно для проведення багатьох експериментів. 3. Вчені почали працювати над конструюванням напівпровідників у кінці 19 сторіччя. 4. Ми цікавимось дослідженням в області електорніки. 5. Вивчення властивостей електронів вплинуло на створення мікроскопів.

XIII. Explain the means of the “over”

Overproduce, overcharge, overestimate, overload, overfulfil.

XIV. Retell the text; speak about the “Electronic principles”

Lesson 2

Text: “Physical constructions of cathodes”

Pre-text exercises:

1. Arrange antonyms in pairs:

heat, directly, frequently, increase, use, raise, internal, harm, cool, indirectly, seldom, decrease, lower, external.

2. Read and translate the text: “PHYSICAL CONSTRUCTIONS OF CATHODES”

Two types of cathodes are employed in vacuum tubes, the filamentary and the indirectly heated. The filamentary cathode consists of a wire filament, usually bent in the form of a V and W, and is heated by passage of a current, either direct of alternating, through it. If alternating current is used for heating, as is most frequently the case today, the different parts of the cathode are not at constant potential, or account of the IR drop of this current. Since the electron stream is determined by potentials of the other tube elements with respect to the cathode, this may cause fluctuations which result in the development of hum is the tube output. To reduce these fluctuations as much as possible, it is common practice to connect the return circuit from the other elements to a center tap on the transformer winding which supplies filament-heating current. This point is always at the average potential of the entire filament.

The indirectly heated cathode consists of a metallic sleeve coated with emitting substance, and is heated by wires passing through channels in a ceramic insulating core placed inside the sleeve. The advantage of this construction is that the entire cathode is at a uniform potential, since it carries none of the heating current. It is therefore referred to also as a unimpotential cathode. Another advantage is that the heater wires are so close together, that the current in them produces practically no magnetic field, which other wise would also affect the electron flow and thereby contribute to the hum in the tube output.

Post-text exercises:

1. Translate the word combinations:

a) wire filament, electron steam, tube elements, tube output, transformer winding, filament-heating current;

b) this may cause fluctuations; they result in the development of hum in the tube output; as much as possible; it is common practice.

II. Give the Ukrainian equivalents for the following English word com­binations:

consists of a wire filament, common practice, return circuit from the other elements, alternating current is used for heating, the different parts of the cathode, the current produces practically no magnetic field

III. Put the words in order:

1. the, at, parts, potential, cathode, different, of, the, are, not, constant. 2. the, with, indirectly, cathode, heated, of, a, metallic, substance, coated, consists, sleeve, emitting. 3. the, heated, filamentary, is, by, of, cathode, passage, a, current. 4. filamentary consists, the, wire, cathode, of, a, filament.

IV. Fill in the blanks with the following words:

are employed, flows, consists, are, plays

1. Industrial electronics equipment … a very important role today. 2. Two types of cathodes …. in vacuum tubes, the filamentary and the indirectly heated. 3. The indirectly heated cathode … of a metallic sleeve coated with emitting substance. 4. There are a few fundamental principles which … the basis all the electrical means of communication. 5. Electricity … when electrons move from one atom of a substance to the next.