Power Engineering. Соколова Е.В. - 22 стр.

       according to this broadcasting station,crystal detector, glass valve, due to
crossed wires , surface ,tension, space charge, minute current, a step down trans-
former, lighting circuit, copious stream, plate current, by means of modern receivers,
the plate battery voltage, with respect to the additional grid, a step up transformer

      7.7 Ответьте на вопросы

       1. What is the most important device known to radio science? 2. Do all the ex-
isting receivers use tubes? 3. How many tubes do most of receivers use? 4. What does
the vacuum tube consist of? 5. What material may the filament be made of? 6. What
is next to the filament? 7. What happens during the pumping process? 8. What do you
call the modern tube?

      7.8 Переведите предложения

      1. The longer rheostat wire included in the circuit, the greater the resistance. 2.
The higher the value of current, the higher is the temperature of a resistor.

      7.9 Прочтите диалог в ролях

      Dialogue

       A. Would you mind telling me, what a vacuum tube is?
       В It is the most important device known to radio science.
       A. Are there any receivers which do not use tubes at all?
       B. Yes, there are some, but the greater number of receivers use tubes.
       A. And what do receivers use instead of tubes?
       B. They can get along with a coil, a condenser, and a crystal detector.
       A. What does a vacuum tube consist of?
       В It consists of a glass valve within which are three metallic parts known as the
elements.
       A. Where is the filament?
       B. It seems to me that it is in the corner of a glass valve.
       A. What material is it made of?
       B. It may be made of tungsten, carbon, tungsten covered with thorium and
other chemical elements.
       A.      What is next to the filament?
       B.      A grid is next to the filament.
       A Have all the tubes three elements?
       B. No, some of them have only two elements, the filament and the plate.
       A.      According to what does the mechanical construction of a tube differ?
       B.      It differs according to the type of a tube.



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