The Case of Sammy The Show-off

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Text: ELECTRON TUBES

Let us consider electron tubes. Electron tubes in use nowadays are a diode, a triode, a tetrode and a pentode. The main parts of electron tubes are electrodes. Electrodes are placed into a glass or metal bulb.

A diode contains the cathode and the plate. When a diode operates the cathode emits electrons, the plate collects.

A triode contains the cathode, the plate and the control grid. When the tube operates the cathode emits electrons, the plate collects them and the grid controls the flow of electrons. There-fore, the grid is called a control grid.

A tetrode contains the cathode, the plate, the control grid and the screen grid.

When a tube operates it may oscillate. The function of the screen grid is to eliminate oscillations. There-fore it is called a screen grid.

A pentode contains two electrodes and three grids: the control grid, the screen grid and the suppressor grid. When a pentode operates the suppressor grid eliminates the secondary emission.

Common troubles in tubes are an open heater and low emission. These troubles result from constant use or from some other reason. In case a tube has a trouble it stops operating or operates badly. A tube with a trouble should be replaced by another one.

EXERCISES

A

Find the correct variant. Remember it:

A pentode contains

a) the cathode, the plate, two screen grids and the suppressor grid

b) the cathode, the plate, the control grids, the screen grid and the suppressor grid

Tetrode contains

c) the cathode, the plate, the suppressor grid and the screen grid

d) the cathode, the plate, the suppressor grid and control grid

Answer the questions:

1.What electron tubes are in use?

2.What are the main parts of electron tubes?

3.What does a diode contain?

4. What does a triode contain

5.What does a tetrode contain?

6. What electrodes contain a pentode?

7.What common troubles in tubes?

Test

.1. The main parts of electron tubes are_________

a}batteries b}electrodes c}wires d}plates

2_____ contains the cathode and the plate.

a}a pentode b}tetrode c}triode d}diode

3. _____ contains the cathode, the plate and the control grid.

a}a pentode b}tetrode c}triode d}diode

4._____contains the cathode, the plate, the control grid and the screen grid.

a}a pentode b}tetrode c}triode d}diode

5. _______ contains two electrodes and three grids: the control grid, the screen grid and the suppressor grid.

a}a pentode b}tetrode c}triode d}diode

Glossary

SIW

Find and learn 10-12 words, write examples

SIWT

Retelling the text

Literature:1.Orlovskaya I.V.”English”-Moskow-2007

2.Raymond Murphy”Essential Grammar in Use”

Lesson-35

VOCABULARY phrasal verbs

Match the question 1-7 with the pictures A-G

1What time do you wake up in the morning ?

2Do you use an alarm clock to wake up ?

3Do you turn off the alarm clock to wake up ?

4What's the first thing you turn on after you wake up ?

5Do you get up immediately after you wake up ?

6How do you fell when you first get up ?

7When you fell when you first get up ?

GRAMMAR word order of phrasal verbs

b) Complete the rules about separable phrasal verbs in each sentence.

1 If the object of a phrasal verb is a ______ , you can put it after the verb +up, on, etc.

OR betweenthe verb and up, on, etc.

2 If the object of a phrasal verb is a ______ , you mustput it betweenthe verb and up, on, etc.

D) Match the sentences. Then cover the sentences on the right. Try to remember them.

1Your mobile's ringing. [ ] AA You need to give it up.

2This is an important rule. [ ] BPut them away.

3I can't hear the music. [ ] CTurn it up.

4If you don't know what the words mean. [ ] DThrow it away.

5This is an immigration form. [ ] ETurn it off.

6Coffee is bad for you. [ ] FPlease fill it in.

7Your clothes are on the floor. [ ] GWrite it down.

8That's rubbish. [ ] Hlook them up.

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READING

Do you know what these scientific words and expressions mean?

_______________________________________

a gene DNA your 'body clock' research_

Read the a article about morning and evening people.

Choose a, b,or c.

Scientists say that if we are bad at getting up