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
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Computer 2008
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First Television, 1930’s
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TV 1950’s
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TV 1980’s
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TV 2011
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First telephone, 1860’s
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Telephone 1950’s
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Telephone 1990’s
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Telephone 2011
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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
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-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
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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
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William Shockley (theoretician) selected Walter Brattain (experimental physicist) and John Bardeen (theoretical physicist) to create a semiconductor amplifier.
The Story of the Transistor Continued…
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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
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Highest Achievement-Nobel Prize
William Shockley, Walter Brattain and John Bardeen shared the 1956 Nobel Prize in Physics.
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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
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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.