Reading. 7.Make a crossword puzzle on the topic: “Diodes

Warm up

TRANSISTOR

UNIT 3

Review

7. Make a crossword puzzle on the topic: “Diodes

Fig.3.1 A typical transistor on an electronic circuit board.

Contents

Ø What Does a Transistor Actually Do?

Ø Types of Transistors and How They Work.

Ø Transistors in Computers.

Ø Who Invented the Transistor?

1. WHAT DOES A TRANSISTOR ACTUALLY DO?

1. Study the photo in Fig. 3.1 and answer some questions:

What can you see in this photo?

What is it?

Is it an insect with three legs?

Listen to this short text and find the answer.

2. Look at the pictures in Fig. 3.2 and discuss the questions below.

a)

b)

Fig. 3.2 What does a transistor actually do?

1) What do you see in these pictures?

2) Are they related to our topic?

3) What is our topic?

4) Can these pictures help us understand what transistors actually do?

3. Read the following text and entitle the pictures a-b in Fig. 3.2.

A transistor is really simple and really complex. Let's start with the simple part. A transistor is a miniature electronic component that can do two different jobs. It can work either as an amplifier or a switch.

When it works as an amplifier, it takes in a tiny electric current at one end (an input current) and produces a much bigger electric current (an output current) at the other. In other words, it's a kind of current booster. That comes in really useful things like hearing aids, one of the first things people used transistors for. A hearing aid has a tiny microphone in it that picks up sounds from the world around you and turns them into fluctuating electric currents. These are fed into a transistor that boosts them and powers a tiny loudspeaker, so you hear a much louder version of the sounds around you.

William Shockley, one of the inventors of the transistor, once explained transistor-amplifiers to a student in a more humorous way: "If you take a bale of hay and tie it to the tail of a mule and then strike a match and set the bale of hay on fire, and if you then compare the energy expended shortly thereafter by the mule with the energy expended by yourself in the striking of the match, you will understand the concept of amplification."

Transistors can also work as switches. A tiny electric current flowing through one part of a transistor can make a much bigger current flow through another part of it. In other words, the small current switches on the larger one. This is essentially how all computer chips work. For example, a memory chip contains hundreds of millions or even billions of transistors, each of which can be switched on or off individually. Since each transistor can be in two distinct states, it can store two different numbers, zero and one. With billions of transistors, a chip can store billions of zeros and ones, and almost as many ordinary numbers and letters (or characters, as we call them).

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