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Diodes

Read and translate the text.

Translate the definitions.

Learn the vocabulary.

Task 2. Make a list of ways in which you think electronics may be used in the home in the future.

Task 1. Fill in the gaps in this table with the help of the text.

DateInventionApplications in the home

early 20th century

transistor

1958 automatic washing-machines

future

Alternating – переменный Apply – применять, прилагать Application – применение As well as – так же как Circuit – схема, цепь Compare (to, with) – сравнивать Comparatively – сравнительно Conduct – проводить (ток) Conduction = conductivity – проводимость Conductor – проводник Semiconductor – полупроводник AC (а.с.) = alternating current – переменный ток DC (d.c.) = direct current – постоянный ток Define – определять Definition – определение Direct – прямой, направлять Direction – направление Directly – прямо Emit – испускать Emission – эмиссия Figure (Fig.) – рисунок Flow – поток, течь

Heat – тепло, нагревать Heater – нагреватель Оссur – происходить Оperate – работать Operator – оператор Operation – работа Science – наука Scientist – ученый Scientific – научный Source [so:s] – источник Switch n – выключатель Switch on – включать Switch off – выключать Thus – таким образом Toward(s) – по направлению к Unit – блок, элемент Produce – производить Product – продукт, изделие Production – производство Productivity – производительность Develop – разрабатывать, создавать Development – разработка, развитие Obtain – получать Repel – отталкивать Attract – притягивать

Anode is an electrode for the collection of electrons.

Cathode (in electron tubes) is the electrode from which emission takes place.

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

Rectifier is a device used for the process of rectification.

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, etc.

Оборот There is/are

Если в русском языке предложение начинается с обстоятельства места (где?), то в английском языке оно начинается с оборота there is/are, а обстоятельство места находится в конце предложения.

Этот оборот обозначает местонахождение, наличие, существование. Он может переводиться словами «есть, существует, находится, имеется, стоит, лежит, висит, присутствует, состоится и т.п.» в зависимости от контекста, или может никак не переводиться. Например:

На заводе много рабочих. – There are many workers at the plant.

There is a good machine-tool in the work-shop. – В цехе есть хороший станок.

В Past Simple этот оборот имеет форму there was / were, a в Future Simple – there will be. Например:

There were two engineers from the works at the meeting yesterday. – Вчера на собрании присутствовали два инженера с завода.

There will be a scientific and technical conference in our university tomorrow.

Завтра в нашем университете состоится научно-техническая конференция.

Отрицательная форма образуется при помощи not:

There are not any students in the classroom. – В аудитории студентов нет.

Вопросительная форма образуется путем изменения порядка слов:

Are there any students in the classroom? – В аудитории есть студенты?

Grammar exercises:

1. There are several vacant seats in the bus.

2. There are some factories in this region.

3. There is a chair in front of the desk.

4. There are some people in the office.

5. There are some flowers in the living-room.

6. There is a photo on the television.

7. There are some magazines on the table.

8. There are some Chinese students in our class.

9. There is a post box in front of the shop.

2. Put in is or are.

1. There... one window in my room.

2. There... white curtains on the window.

3. Under the window there... a desk.

4. There... a vase on it.

5. There... three roses in the vase.

6. To the right of the window there... a lamp.

7. In front of the desk there... a chair.

8. There... a computer to the left of the desk and there... a box of computer discs under the computer.

9. On the wall behind the computer there... a calendar.

10. There... two pictures on the wall to the left of the computer.

Дата добавления: 2014-12-17