Start here

TYPES OF TRANSISTORS AND HOW THEY WORK

Revision

Listening

Speaking

4. Work in pairs. Make dialogues, discuss what transistors actually do. Use all the necessary information from the previous task and pictures in Fig. 3.2 to help you.

5. Listen to the text and explain the difference between old style machines and modern electronic devices. What was great about old-style machines?

6. Do this multiple-choice test to revise the already learned stuff from Units 1-2 and find out how transistors are made. There may be several correct answers for one statement.

Transistors are made from silicon and…

1) Silicon is …

a) an insulator;

b) a conductor;

c) a metal;

d) a semiconductor.

2) Intrinsic semiconductors…

a) conduct electricity;

b) don’t conduct electricity;

c) conduct electricity when they are treated with impurities.

3) Extrinsic semiconductors are…

a) doped;

b) pure;

c) n-type and p-type.

4) The process of introducing impurities into a semiconductor is called…

a) impuriting;

b) doping;

c) impurity generating.

5) Extrinsic semiconductors…

a) conduct electricity;

b) do not conduct electricity;

6) N-type semiconductors have extra…

a) positive charges;

b) electrons;

c) negative charges;

d) holes.

7) P-type semiconductors have extra…

a) negative charges;

b) positive charges;

c) electrons;

d) holes.

8) A diode is a…

a) p-n junction;

b) p-n-p junction;

c) n-p-n junction.

9) Diodes are …

a) omnidirectional;

b) bidirectional;

c) multidirectional;

d) unidirectional.

1. Work in small groups. Study the diagrams in Fig. 3.3 and discuss the questions below.

Fig. 3.3. NPN and PNP transistors and their schematic symbols.

1) What types of transistors are depicted in the diagrams?

2) What is their construction?

3) How do you think they work?

4) Why are there diode electronic symbols in Fig. 3.3 b)?

5) What is the difference between these types of transistors?

Дата добавления: 2014-11-29