Exercise 2. Find in the text above the English equivalents of the follow- ing word combinations

Exercise 2. Find in the text above the English equivalents of the follow- ing word combinations

1. тем не менее; 2. беспорядочное движение электронов; 3. ока- зывать сопротивление; 4. как первый, так и последний; 5. в случае, если; 6. используемый материал; 7. прохождение тока; 8. определен- ные факторы.

 

Unit 6. Inductance and mutual inductance

Vocabulary

ampere, A                   ампер (единица измерения силы тока)

to bring                       приносить

coil                              катушка, обмотка

definite                       определенный

fast                              быстрый

high-frequency           высокочастотный

to induce                     индуцировать

induced voltage          индуцированное напряжение

inductance                  индуктивность

low-frequency            низкочастотный

mutual                         взаимный

result from                  происходить в результате, быть следствием

size                              размер

terminal                      клемма; ввод, вывод

that is                          то есть

to touch                       касаться, трогать

unit                              единица

value                           значение, величина

 

Text

Any conductor has some definite value of inductance. The induct-

ance of a conductor shows how well it can provide induced voltage.

Elements of a circuit with a definite value of inductance are coils of wire called inductors. The inductance of a coil depends on its size and ma- terial. The greater the number of turns of a coil, the higher is its induct- ance. An iron core also increases the value of inductance. Coils of this type are used for low-frequency currents while coils with an air core are used for high-frequency currents.

The coils 1 and 2 are brought close together and a source of alternat- ing current is applied to coil 1. If a measuring device is connected across the terminals of coil 2 it will

be found that voltage is in- duced in this coil though the two coils do not touch. The secondary voltage, that is the voltage in coil 2, is called in- duced voltage and energy from one coil to the other transfers by induction. The coil across

which the current is applied is called the primary, that in which voltage is induced is called the secondary. The primary and the secondary coils have mutual inductance. Mutual inductance is measured in the same unit as in- ductance, that is in henries.

Thus, when a rate of change of one ampere per second in the primary coil will produce one volt in the secondary coil, the two coils have one henry of mutual inductance.

It should be taken into consideration that induction by alternating current results from the change in current, not in the current value. The faster the current changes, the higher the induced voltage.