Практическое занятие 13. Фильтры

Lesson 1 3. Filters

 

1. Read and learn the words:

 

filter - фильтр

bypass - шунт

choke - дроссель

high-pass - высокопроходной

low-pass - низкопроходной

to oppose - оказывать сопротивление

on the other hand - с другой стороны

choke coil - дроссельная катушка

bypass coil - шунтовая катушка

bypass condenser - шунтирующий конденсатор

high-pass filter - фильтр верхних частот

low-pass filter - фильтр низких частот

opposing coils - противодействующие витки

opposed current – противоток

Read and translate the text.  

Filters

This filter is used to separate direct current from alternating current. It consists of a capacitor and a choke coil. Direct current cannot flow through the capacitor since its insulators oppose the flow of direct current. Therefore, it flows through the choke coil. Its windings easily pass direct current through them. Alternating current, on the other hand, passes through the capacitor, since it cannot easily pass through the choke coil. In this way the direct and the alternating currents are separated.

I. A high-pass filter is used to pass high frequencies and to prevent the flow of low frequencies. It consists of a condenser and an inductance coil. The condenser passes currents of high frequencies and opposes the flow of low frequency currents. Low frequencies must be returned to the source and the inductance coil is used for a bypass.

II. A low-pass filter is used to pass low frequencies and to prevent the flow of high frequencies. It consists of an inductance coil and a condenser. The inductance coil passes low frequencies and opposes the flow of high frequencies. To return the high frequencies back to the source, a condenser is used for a bypass. Its capacity opposes the flow of low frequencies through it.

 

Complete the sentences using the correct variant

 

1. A filter is used in order

a) to separate d.c. from a.c.

b) to transfer energy from the primary to the secondary.

c) to separate low frequencies from high frequencies.

 

2. A filter consists of

a) a resistor and a transformer.

b) a choke coil and a capacitor.

c) an inductance coil and a capacitor.

 

3. Direct current easily passes

a) through a choke coil.

b) through a capacitor.

 

4. Alternating current easily passes

a) through a capacitor.

b) through a choke coil.

 

5. A low-pass filter is used

a) to pass high frequencies and to prevent the flow of low frequencies.

b) to pass low frequencies and to prevent the flow of high frequencies.

 

6. In a low-pass filter

a) a capacitor is used as a bypass.

b) an inductance coil is used as a bypass.

 

7. In a high-pass filter

a) an inductance coil is used as a bypass.

b) a capacitor is used as a bypass.

 

4. Complete these sentences using on the other hand. Follow the model

 

Model: Direct current passes through the choke coil of a filter; alternating

current, on the other hand, passes through the capacitor.

1. A low-pass filter is used to pass low frequencies..........

2. In a high-pass filter an inductance coil is used as a bypass....

3. A high-pass filter is used to prevent the flow of low frequencies..........

4. Alternating current passes through a capacitor..........

 

5. Answer the following questions:

 

1. What is a filter used for?

2. What does a filter consist of?

3. What is the function of a low-pass filter?

4. What is the function of a high-pass filter?

5. What is the difference between a low-pass filter and a high-pass filter?

6. What elements are used as a bypass?

7. What is the function of a choke coil?

8. What is the function of an inductance coil?

 

Draw schemes of a choke input filter and a capacity input filter. Describe the schemes and the function of the filters.

Практическое занятие 14. Электронные лампы

Lesson 1 4. Electron Tubes

 

1. Read and learn the words:

tube - электронная лампа

bulb - баллон

grid - сетка

screen - экран

to contain -  вмещать

to collect -  собирать

to emit - излучать

to suppress - глушить, подавлять

control circuit - контрольная цепь

control grid - управляющая сетка

screen grid - экранирующая сетка

screen grid tube - экранированная лампа

suppressor grid - защитная сетка

counter flow - противоток

oscillatory circuit - колебательный контур