Unit 3 Electricity & Magnetism- Transistors

Unit 3 Electricity & Magnetism-Transistors

Physics 5d.Students know the properties of transistors and

the role of transistors in electric circuits

The Story of the Transistor Bell Laboratories-originally the research

and development arm of the telephone company American Telephone and Telegraph (AT&T)

One of the first pioneering advances of Bell Labs in 1900s was the vacuum tube.

Vacuum tube-amplified faint telephone signals and high speed on-off switch.

QuickTime™ and a decompressorare needed to see this picture.

First computer, 1940-1950

Computer 1960’s

QuickTime™ and a decompressor

are needed to see this picture.

Computer 1970’s

Computer 1980’s

QuickTime™ and a decompressor

are needed to see this picture.

Computer 2008

QuickTime™ and a decompressor

are needed to see this picture.

First Television, 1930’s

QuickTime™ and a decompressor

are needed to see this picture.

TV 1950’s

QuickTime™ and a decompressor

are needed to see this picture.

TV 1980’s

QuickTime™ and a decompressor

are needed to see this picture.

TV 2011

QuickTime™ and a decompressor

are needed to see this picture.

First telephone, 1860’s

QuickTime™ and a decompressor

are needed to see this picture.

Telephone 1950’s

QuickTime™ and a decompressor

are needed to see this picture.

Telephone 1990’s

QuickTime™ and a decompressor

are needed to see this picture.

Telephone 2011

QuickTime™ and a decompressor

are needed to see this picture.

What do you notice about these gadgets over time?

They get smaller!!!!

WHY?

Because transistors replaced vacuum tubes

Why are modern radios, calculators, and computers much smaller than they were in the past? A. Modern appliances use less electricity B. Electricity has become more expensive C. Vacuum tubes replaced larger

transistors D. Transistors replaced larger vacuum

tubes

Practice

Vacuum Tubes

Before transistors came along, vacuum tubes worked as switches and amplifiers. Notice how LARGE they are!

Transistors

QuickTime™ and a decompressor

are needed to see this picture.

-Much smaller.

-Allowed technology to become more compact

-Transistors amplify electric signals/currents

Transistors So…what are they?

A semiconductor device used to amplify and switch electronic signals and power.

Are found embedded in integrated circuits (aka microchips) used in computers, mobile phones, digital appliances, etc.

Make modern radios, calculators, computers smaller than before

Microchips-in which thousands

or millions of transistors are deposited on a piece of silicon

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

Transistor

Are made out of metalloids. Why?

Transistor

Are made out of metalloids. Why?

Because they have properties of BOTH metals and non-metals

This allows them to be “altered” and manipulated to be more versatile

What makes semiconductors useful in everyday electronic devices? A. Electrons can flow at any current B. Electricity is conducted better than by

metals C. Current flow can be resisted better than

by insulators D. Conductivity can be altered by adding

other materials.

Practice

Transistor in drawingsQuickTime™ and a

decompressorare needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

William Shockley (theoretician) selected Walter Brattain (experimental physicist) and John Bardeen (theoretical physicist) to create a semiconductor amplifier.

The Story of the Transistor Continued…

QuickTime™ and a decompressor

are needed to see this picture.

They did countless tests on different samples of silicon & germanium.

In Dec. 1947, Bardeen and Brattain produced the world’s first semiconductor amplifier: the point-contact transistor

QuickTime™ and a decompressorare needed to see this picture.

The First Transistor

QuickTime™ and a decompressor

are needed to see this picture.

Highest Achievement-Nobel Prize

William Shockley, Walter Brattain and John Bardeen shared the 1956 Nobel Prize in Physics.

QuickTime™ and a decompressor

are needed to see this picture.

Practice What is the function of a transistor in an

electrical device? A. Reducing current to prevent

overheating B. Inducing a magnetic field to urn a

motor C. Controlling a large current output to

amplify an electric signal D. Storing an electrical charge that is

used as a source of power

Which electrical device is shown in the diagram?

A. CapacitorB. InductorC. ResistorD. Transistor

Practice

QuickTime™ and a decompressor

are needed to see this picture.

Activity 1 1. You will be in groups of 3

or 4 2. List 5 devices that affect

me most 3. Tell which device is

important in your life 4. Describe how your life

would change without each device

5. Then as a whole, compare & contrast each team’s list

Activity 2

Write an essay on the electronic device that most changed your life.