4. Read and translate text 15a. While reading the text find answers to the following questions.

1. What is a vacuum tube?

2. What’s the function of magnets out side the tube?

3. What does the outer part of vacuum tubes look like?

4. What are the basic electrodes in a vacuum tube?

5. What does a grid consist of?

6. What is the function of the grid?

7. What other parts may a vacuum tube involve?

8. What are the kinds of vacuum tubes.

5. Give derivatives of the following words and translate them unto Ukrainian.

emit, create, collect, transform, receive, apply, locate, direct.

6. Fill in the blanks with the words given below:

plates, mesh, emitter, circuits, electrons,container, signal, negativ.

1. The outer part of a vacuum tube is a glass or metal ….

2. The electrodes create and control a flow of … within the tube.

3. The electrodes usually are connected to electric … outside the tube by wires that pass through the base of the envelope.

4. The filament heats the … causing it to give off electrons.

5. The emitter usually has a … electric charge.

6. The grid consists of a wire … located between the emitter and ….

7. The strength of the charge on the grid corresponds to the strength of the electronic … entering the vacuum tube.

8. A vacuum tube may also have charged metal … that can “bend” a stream of electrons created in the tube

7. Find synonyms among the following words:

outer, inner, certain, some, flow, current, heat, cool, different, various, conduct, operate, work, release, set free, drop, fall, consume.

8. Find antonyms among the following words:

strong, hard weak, disconnect, simple, soft complicated, affect, emit, influence, develop,

connect.

9. Find in the text the appropriate word-combinations:

   1. виділяти електрони

   2. одержувати заряд від батареї

   3. відштовхувати електрони

   4. притягувати один одного

   5. потік електронів

   6. електронно-променева лампа

   7. іонна лампа

   8. простір низького тиску

   9. високопотужний передавач

   10. заряджені металеві пластини

   11. дротяна сітка

   12. частковий вакуум

   13. металева оболонка

   14. джерело постійного струму

   15. високоякісне відтворення звуку

10. Make up sentences using the following words:

1. the, get, from, charges, battery, or, source, of, other, direct, electrodes, their, a, current.

2. is, used, a, to, device, amplify, switch, vacuum tube, or, a, an, signal, create, electrical.

3. metal, envelope, called, the, encloses, two, more, parts, electrodes, or.

4. many, of, vacuum tubes, various, functions, and, sizes, having, are, there, hundreds.

device, widely, is, a, used, electronic, vacuum tubes, equipment, in.

5. help, them tubes, signals create, the, electronic, and, strengthen.

XI. Make up questions to the words in italics:

1. The electrodes usually are connected to electric circuits by wires that pass through the base of the envelop.

2. The electrodes get their chargas from a battery.

3. The grid consists of a wire mesh located between the emitter and collector.

4. The emitter has a negative electric charge.

5. The strength of the charge on the grid corresponds to the strength of the electronic signal entering the vacuum tube.