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.

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First computer, 1940-1950

Computer 1960’s

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Computer 1970’s

Computer 1980’s



Computer 2008



First Television, 1930’s



TV 1950’s



TV 1980’s



TV 2011



First telephone, 1860’s



Telephone 1950’s



Telephone 1990’s



Telephone 2011



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



-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





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.



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

The Story of the Transistor Continued…



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

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The First Transistor



Highest Achievement-Nobel Prize

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



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



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.

Documents

Unit 3 Electricity & Magnetism- Transistors