“The building blocks of
This session will help you to
1.Evolution of transistor
2.Importance of transistor
3.Definition & transistor types
4.Transistor symbol & operation
5.Advantages of transistor
6.Latest in transistor technology
History of transistors
In 1906, an American inventor and physicist,
Lee De Forest, made the vacuum tube triode
or audion as he called it.
Used in radios
Used in early computers
The first transistor
In 1947, John
deviced - the first
It’s an observation made by Gordon E. Moore, in
which he predicted that the number of transistors,
inside an Integrated Circuit, could
be doubled every 24 months.
At the density that also
minimized the cost of a transistor.
Transistor is an electronic device made
of three layers of semiconductor
material that can act as an insulator
and a conductor.
The three layered transistor is also
known as the bipolar junction
Bipolar Junction Transistors (BJT’s)
The term bipolar refers to the use of both
holes and electrons as charge carriers in the
There are two types of BJTs, the NPN and
force – voltage/current
water flow – current
The base-emitter (BE) junction is forward biased
The base-collector (BC) junction is reverse biased.
Operating regions of BJT
Cut off region
Types of transistor
BJT - Bipolar Junction Transistor
UJT- Unipolar Junction Transistor
FET - Field Effect Transistor
MOS - Metal Oxide Semiconductor
Transistor as a switch
When used as an electronic switch, the transistor is
normally operated alternately in cut-off and saturation
Transistor as amplifier
Due to the small changes in
base current the collector
current will mimic the input
with greater amplitude
Future of Transistors
Carbon nanotube transistors
Nano inspiration wire transistors
CMOS devices will add functionality to CMOS nonvolatile memory, opto-electronics, sensing….
CMOS technology will address new markets
macroelectronics, bio-medical devices, …
Biology may provide for new technologies bottom-up
assembly, human intelligence
What’s new in transistor
3D Transistor made using
Tri-Gate transistors on its 22nm logic
Advantage of Tri-Gate Transistors
·More than 50% power reduction at
·37% performance increase at low voltage
·Improved performance and efficiency.
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