Warm up

DIODE

UNIT 2

Review

Vocabulary

Listening

4. Listen to the text and do the tasks below.

5. Study the energy band structures of intrinsic and extrinsic semiconductors in Fig. 1.5.

Fig. 1.5. Energy band structures of undoped (pure) and doped (n-type, p-type) semiconductors.

6. Make a comparative table of an N-type and a P-type semiconductor. Use the information in the previous tasks.

Types of extrinsic semiconductors

N-type semiconductor	P-type semiconductor
Majority charge carriers
Minority charge carriers
Group of the impurity atoms in the periodic table of elements
Impurities are called
Extra energy level
Fermi level lies in between

7. Use the example of a word map in Fig. 1.6 to make your own word maps of the following words:

1) semiconductor

2) doping

3) impurity

4) hole

5) electron

6) conductivity

7) crystal

The Plan of a Word Map:

1) Vocabulary word

2) Sentence or phrase from the text

3) The matching dictionary definition

4) Synonym

5) Antonym

6) Other forms of the word

7) Your association, example or sketch

8) Your own sentence

Fig. 1.6. Word map

8. Make a concept map on the topic: “Semiconductors.”

A concept map is a visual organizer that can enrich your understanding of a new concept. It is a way to display how your mind "sees" a particular topic. Using a graphic organizer, think about the concept in several ways. By constructing a concept map, you reflect on what you know and what you don't know.

There are several ways to construct concept maps. Most include the following steps:

1) Model how to identify the major ideas or concepts.

2) Organize the ideas into categories. Your organization may change as you continue to read and add more information.

3) Use lines or arrows on the map to represent how ideas are connected to one another. Limit the amount of information on the map to avoid frustration.

4) Share and reflect on how you made the connections between concepts.

5) Use the concept map to summarize what was read.

Fig. 2.1. Diodes

Contents

Ø What is a Diode?

Ø Creating a P-N Junction.

Ø Types of Diodes.

Ø Diode Applications.

1. WHAT IS A DIODE?

1. Revise your vocabulary on the topic: “Semiconductors” with the word association game.

Procedure:

The students associate the teacher’s chosen word: “Semiconductor”. Ask all the students to stand up. The first player will say any word associated with the chosen one. This continues from player to player. If a student says a disassociated word, repeats a word or is too slow to answer, he is out and has to sit down. The winner is the last person left standing. All associated words must be written on the blackboard.

2. Revise the verb “To be” and the concept of semiconductors making your own sentences.

Procedure:

You will need a ball, but a screwed up piece of paper is fine. The teacher throws the ball to one student and says a sentence such as: “Silicon and germanium are semiconductor materials.” The student must reply with a sentence on this topic using the verb “to be”. When answered the ball is thrown to the next student, who continues. The teacher says the last sentence: “Semiconductors are widely used in Diodes”.

3. Answer the following questions:

How much do you know about diodes?

Have you ever heard about diodes?

What do you think they are?

How do they work?

Дата добавления: 2014-11-29