Transistors-Basics

1. TRANSISTORS
“The building blocks of
electronics world”

2. This session will help you to
understand the,
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

3. 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

4. The first transistor
In 1947, John
Bardeen and
Walter Brattain
deviced - the first
"point contact"
transistor.

5. Moore’s Law
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.

6. Transistor Definition
 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
transistor.

7. Bipolar Junction Transistors (BJT’s)
 The term bipolar refers to the use of both
holes and electrons as charge carriers in the
transistor structure
 There are two types of BJTs, the NPN and
PNP

8. Basic construction

9. Regions of a transistor
 A transistor has three regions namely,
 Emitter- heavily doped
 Base- lightly doped
 Collector- moderately doped

10. Transistor symbols Transistor
symbols

11. Transistor operation
force – voltage/current
water flow – current
- amplification

12. Transistor biasing
 The base-emitter (BE) junction is forward biased
 The base-collector (BC) junction is reverse biased.
IE=IB+IC

13. Operating regions of BJT
Cut off region
Linear region
Saturation region

14. Types of transistor
 BJT - Bipolar Junction Transistor
 UJT- Unipolar Junction Transistor
 FET - Field Effect Transistor
 MOS - Metal Oxide Semiconductor

15. Transistor applications
Transistor as a switch
When used as an electronic switch, the transistor is
normally operated alternately in cut-off and saturation
regions.

16. Transistor as amplifier
 Due to the small changes in
base current the collector
current will mimic the input
with greater amplitude

17. Future of Transistors




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Molecular electronics
Carbon nanotube transistors
Nano inspiration wire transistors
Quantum computing
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

18. What’s new in transistor
technology?
3D Transistor made using
Tri-Gate transistors on its 22nm logic
technology.
Advantage of Tri-Gate Transistors
·More than 50% power reduction at
constant performance.
·37% performance increase at low voltage
·Improved performance and efficiency.