This document provides an overview of transistors. It defines a transistor as an electronic device made of semiconductor material that can act as a conductor or insulator. The first transistor was invented in 1947 by Bardeen and Brattain. Transistors are essential components in modern technology and have improved according to Moore's Law, doubling in capability every two years. Transistors come in various types like BJT, FET, and MOSFET and are used as switches or amplifiers in applications like computers and electronics. New transistor technologies include 3D transistors and carbon nanotube transistors.

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Seminar
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TRANSISTORS

2. Content
 What is a Transistor?
 Evolution of transistor
 Importance of transistor
 Definition & transistor types
 Transistor symbol & operation
 Advantages of transistor
 Latest in transistor technology
 References

3. What is a Transistor?
 Semiconductors: ability to change
from conductor to insulator
 Can either allow current or prohibit
current to flow
 Useful as a switch, but also as an
amplifier
 Essential part of many technological
advances

4. 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

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

6. 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.

7. 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.

8. 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

9. Basic construction

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

11. Transistor symbols Transistor
symbols

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

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

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

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

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

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

18. Future of Transistors
 Molecular electronics
 Carbon nanotube transistors
 Nano inspiration wire transistors
 Quantum computing
 CMOS devices will add functionality to CMOS non-
volatile 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

19. 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.

20. References
 www.google.com
 www.wikipedia.com
 www.studymafia.org
 www.pptplanet.com

21. Thanks