ПРАКТИЧЕСКОЕ ЗАНЯТИЕ 21

Провода и кабели

Wires and cables

Теоретическая часть

Данный лексический материал предназначен для того, чтобы студенты могли понимать специальные тексты на иностранном языке, необходимые им для работы а своей области, а также составить собственное высказывание по заданной теме.

Задание 1. Выучите следующие слова и словосочетания:

wire проволока

standard wire gauge стандартный калибр провода

to tarnish окисляться

to solder паять

to tin лудить

bare оголенный

short circuit короткое замыкание

varnish глазурь

rigid жесткий

to bend (bent) сгибать

flexible гибкий

strand провод

to screen out отразить

interference интерференция

multicore многожильный

to terminate оканчиваться

plug вилка

socket розетка

strippers кусачки

brittle хрупкий, ломкий

wicking капиллярный эффект

Задание 2. Прочитайте и переведите текст:

Wires and cables

Wires are mostly made from copper, which is cheap and has a low resistance to the flow of electric current.

Wires come in standard wire gauges (S.W.G.) where the smaller the diameter of the wire the bigger the SWG. e.g 22 swg has a smaller diameter than 16 swg. Copper oxidizes (tarnishes) making it difficult to solder. It is therefore tinned giving us 22 swg tinned copper wire, for example.

If two bare wires touch it forms a short circuit. To avoid this wires are insulated using PVC etc. When wires are used for coils such as transformers the insulation is varnish. Since this is very thin wires will take the minimum of space. A broken wire is called an open circuit and prevents current flowing.

A single strand of wire 0.6 mm in diameter is called 1/0.6; this is very rigid and snaps if bent too often. Flexible leads are made from several strands of wire. 7/0.2 is 7 strands of wire each 0.2 mm in diameter. Fine strands of wire can be woven into a mesh or braid, which can be used to screen out unwanted interference (the sunglass effect). Television aerial lead uses screened cable called coaxial cable. Leads, which carry small signals such as audio, are often screened to reject external interference. Where several leads are needed they can be combined into a single cable. This can be a multicore cable, a cableform or a cable loom. Cables are often terminated in plugs or sockets, which may take some time to connect. A quicker technique is to use insulation displacement connectors (IDC), which take only seconds to fit.

Thicker wires can carry higher currents than thin ones, as bigger pipes can carry more water than thin ones.

7/0.2 can carry 1 amp maximum

16/0.2 can carry 3 amp maximum

24/0.2 can carry 5 amp maximum

32/0.2 can carry 10 amp maximum

Use wire strippers to remove insulation. Avoid nicking the wires or breaking strands in ilexes.

When soldering avoid whiskers, burning insulation and wicking (allowing solder to run up under the insulation of flex which makes it rigid and brittle). Fiber optics is often used instead of wires in some applications.

Задание 3. Найдите значения данных аббревиатур:

S.W.G., е. g., mm, IDC, amp, etc, PVC.

Задание 4. Поставьте глаголы в скобках в нужную форму. Употребите пассив там, где это необходимо:

1. Wires (to make) from copper.

2. IDC (to take) only seconds to fit.

3. Thicker wires (to carry) higher currents.

4. Wires and cables (to use) to transmit various types of signals.

5. It (to take) some time to со meet a wire and a socket.

6. Several leads combined into a single cable (to call) multicore cable.

Задание 5. Переведите предложения на английский язык. Обpaтume внимание на перевод побудительных предложений:

1. Залудите провод, чтобы не дать ему окислиться.

2. Избегайте соприкосновения оголенных проводов, т. к. может произойти короткое замыкание.

3. Пользуйся кусачками, чтобы снять изоляцию.

4. Возьми 20 метров экранированного кабеля.

5. Спалите провода и постарайтесь избежать капиллярного эффекта.

Задание 6. Перескажите текст, используя следующие речевые модели:

1. The head-line/title of the article/text/passage is ….

2. The article is devoted to ….

3. The purpose of the article is to give a reader some information on ….

4. The article opens with ….

5. At the end of the article the author draws the conclusion that ….

6. I found the article informative /interesting/dull/ useful and easy/difficult to understand.

[ Литература: 1-4 ]

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