Capacitors

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Translate into Russian and write down the Russian equivalents. Then translate the Russian variants back into English (orally).

B) Cover the left column and translate the Russian words back into

A) Cover the right column and read the English words. Translate them into Russian and check your translation.

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3. When cells are connected in series a) all the positive terminals are

connected together.

b) all the negative terminals are connected together.

c) the positive terminal of one cell is connected to the negative terminal of the second.

4. Cells are connected in series in order a) to increase the current capacity.

b) to increase the voltage output.

a) cells are connected in series. b) cells are connected in parallel.

5. In order to increase the current ca­pacity

6. Answer the following questions:

1. What is a cell used for?

2. What does a cell consist of?

3. What is the function of the terminals?

4. In what way are cells connected in order to increase the voltage output?

5. In what way are cells connected in order to increase the current capacity?

6. In what way are the terminals of series cells connected?

7. In what case does a cell stop operating?

8. What should be done in case it stops operating?

7. Solve these problems:

1. Suppose that you have four electric cells. The current capacity of each cell equals 1.5 amp, the voltage output equals 2 V.

equals

a) Connect the cells in series. In what way should it be done?

b) Connect the battery to a circuit whose resistance value 15 ohms. What is the value of current in the circuit?

2. Suppose that you have three cells of the same value.

a) Connect them in parallel. In what way should it be done?

b) Connect the second battery to the same circuit: what will it result in?j

Suppose that one of the cells stops operating. What should be done in this case?

1.

2.

capacitor	[ka'paesita]	конденсатор
insulator	['insjuleita]	изолятор
frequency	['fri:kwansi]	частота
distance	['distans]	расстояние
advantage	[ad'vaxitidj]	преимущество
disadvantage		недостаток
plate		анод (лампы)
part	[pa:t]	часть
to apply	[a'plai]	прилагать, применять
to move	[mu:v]	двигать(ся)
to prevent		предотвращать
reason		причина
for this reason		по этой причине
besides		кроме того
provided that		при условии что

a. paper insulators _________________________

air insulators _________________________

electrolyte capacitors _________________________

advantages of electrolyte capacitors___________________________

disadvantages of air insulators

b. cells under test

capacitors in common use nowadays _________________________

radio sets under test

PC in common use nowadays

с a radioman

radio work

radio parts

telephone and radio work___________________________________

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vantage is that they change their capacity when the temperature changes. They can operate without achange only at temperatures not lower than -40 С Common troubles in capacitors are an open and a short. A capacitor stops operating and does not store energy in case it has a trouble. A ca­pacitor with a trouble should be substituted by anew one. Complete these sentences using the correct variant: 1. A capacitor is used a) to supply voltage. b) to increase the voltage output. c) to store energy.

3. Translate into Russian. Mind provided that.

1. A circuit operates well provided that it does not have any trouble.

2. The bulb lights provided that the circuit is connected to the cell.

3. A cell supplies energy provided that its electrodes are of different matj rials.

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A capacitor is one of the main elements of a circuit. It is used Ц store electric energy. A capacitor stores electric energy provided that j voltage source is applied to it.

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Fig. 8

Fig. 9

The main parts of a capacitor are metal plates and insulators. ТЫ function of insulators is to isolate the metal plates and in this way t<J prevent a short.

In the diagram one can see two common types of capacitors in usJ nowadays: a fixed capacitor and a variable one. The plates of a fixeJ capacitor cannot be moved; for this reason its capacity does not change The plates of a variable capacitor move; its capacity changes. ТЫ greater the distance between the plates, the less is the capacity of a ca[ pacitor. Variable capacitors are commonly used by radiomen; theil function is to vary the frequency in the circuit. Fixed capacitors ar^ used in telephone and radio work.

Fixed capacitors have insulators produced of paper, ceramics an^ other materials; variable capacitors have air insulators. Paper capacitors are commonly used in radio and electronics; their advantage is theij high capacity: it may be higher than 1,000 picofarad.

Besides, electrolyte capacitors are highly in use. They also have a very high capacity: it varies from 0.5 to 2,000 microfarad. Their disadf

2. The main parts of a capacitor are

3.The function of insulators is

4. The capacity of a capacitor de­pends on

5. The capacity of a fixed capacitor

6. The plates of a variable capaci­tor

7. In order to charge a capacitor a voltage source is applied

8. The greater the distance between the plates,

a) insulators only.

b) metal plates only.

c) metal plates and insulators be­tween them.

a) to store energy.

b) to isolate the metal plates.

c) to prevent a short between the metal plates.

a) the size of the plates.

b) the distance between the plates.

c) the material of the insulators.

a) is constant.

b) is varied.

a) can be moved.

b) cannot be moved.

a) to the metal plates.

b) to the insulators.

a) the greater is the capacity of a capacitor.

b) the less is the capacity.

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