Present Simple. Affirmative

For example:

· Diodes permit current to flow in only one direction.

· The dictionary defines electronics as the study of conduction of electricity.

Spelling

-es after -s / -sh / -ch: pass – passes, finish – finishes, watch – watches

-y – -ies: study – studies, rectify – rectifies

also: do – does, go – goes

Reading

Remember:

I/we/you/they have

he/she/it has

For example:

· Diodes have 2 basic elements.

· Every diode has a cathode and a plate.

Negative (with the auxiliary verb)

For example:

· Diodes don’t permit current to flow in opposite directions.

· Positive voltage on the plate doesn’t repel electrons.

Negative (with no auxiliary verb)

For example:

· These devices can’t be amplifiers.

· They are not physicists.

· This gadget doesn’t have a/has no heater.

Remember: There is no grid in a diode. But: There isn’t a grid in a diode.

A diode has no grid. A diode hasn’t a grid.

Questions (with the auxiliary verb)

For example:

· Do diodes permit current to flow in only one direction?

· Does the dictionary define electronics as the study of conduction of electricity?

Questions (with no auxiliary verb)

For example:

· Can these devices be amplifiers?

· Are they physicists?

· Has this gadget a heater? or Does this gadget have a heater?

Remember:

1. I am a physicist, aren’t I?

2. In the following examples, do is also the main verb (do you do /doesn't do etc.): *What do you do? I work in a shop.

*He's always so lazy. He doesn't do anything to help.

The verb to be

For example:

· I am/am not a physicist.

· He is/is not a famous scientist.

· Rectifier isn’t an electrical device.

· It isn’t easy to explain the operation of semiconductor devices.

1. Fill in the table.

2. Read and translate the following international words:

Nouns (n): academy, anode, author, battery, cathode, detector, diode, electricity, electrode, electron, electronics, element, energy, engineer, experiment, expert, gas, hobby, institute, method, million, operation, patent, pharmacology, principle, process, profession, radio, rouble, signal, student, symbol, vacuum, voltage.

Adjectives (adj): effective, electric, medical, negative, official, positive.

Verbs (v): register, process.

3. Consult the table above and write full sentences. Use is/are. Where possible change sentences to use isn’t/aren’t.

1. Rectifier …. an electrical device.

2. There … an anode and a cathode in a diode.

3. … it easy to explain the operation of semiconductor devices?

4. New devices … more powerful.

5. In some diodes there … a gas and current flows from one element to the other through a gas.

6. Look at Fig. X. This … a cathode and these … a plate and a battery.

7. The physical principles of this phenomenon may … quite different.

8. Anodes … positively charged electrodes by which the electrons leave a device.

9. Electronics … a science which studies the conduction of electricity in a vacuum, gases and semiconductors.

10. Cathodes (in electron tubes) … electrodes from which emission takes place.

11. Diode … a device that permits current to flow through it in only one direction.

12. There … a lot of analogue and digital equipment at our university.

4. Complete the sentences using the following verbs: emit(s), occur(s), flow(s), define(s), repel(s), attract(s), have(has).

1. We can … electronics as the study of conduction of electricity in a vacuum, in gases and in semiconductors.

2. The conduction of electricity in a vacuum for example … in vacuum tubes.

3. Though in some vacuum tubes current … from one element to the other through a gas.

4. Every vacuum tube diode … a cathode with a heater and a plate.

5. When the circuit is completed the cathode … electrons.

6. Negative voltage on the cathode … electrons.

7. Positive voltage on the plate … electrons.

5. Put the verb in brackets into the correct form. Insert always/never/

often/sometimes/usually.

1. The current (flow) through the tube.

2. If a negative voltage is applied to the plate current (not flow).

3. Thus a diode (permit) current (flow) in only one direction.

4. A semiconductor diode also (conduct) current in one direction, but the physical principles, which (permit) it to do this (be) different.

5. We (use) diodes as rectifiers of alternating voltages, as detectors of radio signals, as switching devices, etc.

6. An English dictionary of electronics (define) this science as "the study of conduction of electricity in a vacuum, in gases and in semiconductors".

7. Do you (know) that in some diodes there is a gas, and current (flow) from one element to the other through a gas?

8. And can you (give) an example of conduction of electricity in a vacuum? This (occur) in vacuum tubes.

6. Mind the word-order and compile sentences from the following words:

For example:

A\tube\is\this\vacuum. – This is a vacuum tube.

1. Different\in\vacuum\doesn’t\diodes\current\flow\directions\in.

2. What\through\the\flows\tube?

3. Do\diodes\know\you\that\gas\is\some\a\there\in?

4. Does\element\current\flow\one\from\to\other\through\a\gas\the?

5. The\you\describe\a\can\circuit\of\diode?

6. Cathode\a\the\heater\has?

7. The\heater\have\another\must\energy\source\of?

8. Emits\the\when\electrons\heated\cathode.

9. Diodes\are\used\where?

10. Diodes\are\rectifiers\of\alternating\voltages\as\detectors\of\radio\signals\

and\as\switching\devices\used.

11. Negative\on\the\cathode\repel\voltages\electrons\toward\the\the\plate.

12. Attracts\the\electrons\what?

13. Tube\in\vacuum\diode\there\is\a\with\a\heater\and\cathode\a\plate\every?

14. Is\easy\to\the\it\explain\operation\of\semiconductor\devices?

7. Put questions to the following sentences:

1. This occurs in vacuum tubes. – Where…

2. A dictionary of electronics defines this science as "the study of conduction of electricity in a vacuum, in gases and in semiconductors". – How …

3. In vacuum diodes, for example, current flows through a vacuum in only one direction. – In what direction …

4. Current flows from one element to the other through a gas. – Through what …

5. If a negative voltage is applied to the plate, current does not flow. – When …

6. Positive voltage on the plate attracts the electrons. – What …

7. When heated the cathode emits electrons. – When …

8. Diodes are used as rectifiers of alternating voltages, as detectors of radio signals and as switching devices. – Are …

8. Form nouns from the following verbs using the suffix –tion and translate them:

For example:

amplify – усиливать (ток); amplification – усиление (тока)

attract – притягивать;

define – определять;

describe – описывать;

direct – направлять;

rectify – выпрямлять (ток).

9. Guess the meaning of the following adjectives paying attention to the suffix – ic:

atomic, automatic, classic, cubic, economic, dynamic, elastic, harmonic, geometric, kinetic, magnetic, periodic.

10. Read and translate word-combinations

A. start from the first component

В. start from the second component

11. Match the following sentences with their translations.

12. Choose as many words from the table оf ex. 1 as you can and form sensible sentences in Present Simple (affirmative, negative and interrogative).

For example: The operation of a vacuum diode is described in the text.

SPECIALIST READING

13. Mark the following sentences as true (T) or false (F). Then read the text “Diodes” and check yourself.

1. Electronics is the study of conduction of electricity.

2. In some vacuum tubes current flows through a gas.

3. A diode has a cathode with a heater and a plate.

4. The cathode emits electrons.

5. Negative voltage on the plate repels electrons.

6. If a positive voltage is applied current does not flow.

7. A diode permits current to flow in only one direction.

8. Diodes are used as rectifiers of alternating voltages, as detectors of radio signals, as switching devices, etc.

We can define electronics as the study of conduction of electricity in a vacuum, in gases and in semiconductors. The conduction of electricity in a vacuum, for example, occurs in vacuum tubes. Though in some vacuum tubes current flows from one element to the other through a gas.

Every vacuum tube diode has a cathode with a heater and a plate. When the circuit is completed the cathode emits electrons. Negative voltage on the cathode repels the electrons. Positive voltage on the plate attracts the electrons. The current flows through the tube. If a negative voltage is applied to the plate current does not flow. Thus a diode permits current to flow in only one direction.

A semiconductor diode also conducts current in one direction, but the physical principles, which permit it to do this are different. Diodes are used as rectifiers of alternating voltages, as detectors of radio signals, as switching devices.

14. Read the text again and complete the sentences with the correct ending.

1. Electronics is …

2. The conduction of electricity in a vacuum …

3. In some vacuum tubes current …

4. Every vacuum tube diode …

5. When the circuit is completed …

6. Negative voltage on the cathode …

7. Positive voltage on the plate …

8. If a negative voltage is applied to the plate…

9. A diode permits current to …

10. Diodes are used as …

15. Work in pairs. Ask your partner questions based on the text. Make sure you use correct auxiliary verb.

For example: Define electronics (How) - How can we define electronics?

1. The conduction in a vacuum occurs (Where) – …

2. Every vacuum diode has (What) – …

3. The cathode emits (What) – …

4. Negative voltage (Where) – …

5. … attract the electrons (What?) – …

6. The current flows through the tube (When?) – …

7. Current does not flow (Under what conditions?) – …

8. … to flow in only one direction (What?) – …

9. Diodes are used as (Where?) – …

Match the terms in Table A with their definitions in Table B

SPEAKING

16. In groups draw a circuit of a diode and describe it. Start your description like this: This is a cathode. Its function is …. And this is a plate …

17. Summarize the text “Diodes” in 150 words paying special attention to the highlighted verbs in Present Simple.

18. Act as an interpreter. Translate the description of the operation of a semiconductor diode given by your group-mates from Russian into English.

19. Translate the text “Types of Diodes” with a dictionary in writing paying attention to the use of Present Simple.

There are several types of junction diodes, which either emphasize different physical aspects of a diode often by geometric scaling, doping level, choosing the right electrodes, or just an application of a diode in a special circuit, or are really different devices like the Gunn and laser diode and MOSFET.

Normal (p-n) diodes are usually made of doped silicon or, more rarely, germanium. Before the development of modern silicon power rectifier diodes, cuprous oxide and later selenium were used. Their low efficiency gives a much higher forward voltage drop (typically 1.4–1.7 V per “cell”) and requires a large heat sink (often an extension of the diode’s metal substrate) much larger than a silicon diode of the same current ratings would require. The vast majority of all diodes are p-n diodes found in some integrated circuits, which include two diodes per pin and a lot of internal diodes.

Avalanche diodes are the ones that conduct in the reverse direction when the reverse bias voltage exceeds the breakdown voltage. These are electrically very similar to Zener diodes, and are often mistakenly called Zener diodes, but the break down has a different mechanism, the avalanche effect. This occurs when the reverse electric field across the p-n junction causes a wave of ionization, reminiscent of an avalanche, leading to a large current. The difference between the avalanche diode (which has a reverse breakdown of above about 6.2 V) and the Zener diode is that the channel length of the former exceeds the “free path” of the electrons, so there are collisions between them on the way out. The only practical difference is that the two types have temperature coefficients of opposite polarities.

There also exist crystal diodes, constant current diodes, Esaki or tunnel diodes, gun-diodes, light-emitting diodes (LEDs), laser diodes, photodiodes, etc.

Indicators such as some "magic eye" tubes and the type 6977 fluorescent-anode type have glowing electrodes.

20. In Russian write a content-based summary of the text you have translated.

21. Make a reverse written translation (from Russian into English) of your summary.

22. Find more information about conduction of current in a semiconductor diode and tell your group mates.

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