Topic: Transistor

1. Presented by:
Mohammad Babor
Em@il : rajshekh21@gmail.com
Green University Of Bangladesh

2. 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.

3. Let we know about this topics.
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

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. Basic construction

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

9. Transistor symbols Transistor
symbols

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

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

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

13. The bipolar junction transistor(BJT)
 A bipolar junction transistor (bipolar transistor or BJT) is a
type of transistor that uses both electron and hole charge
carriers. In contrast, unipolar transistors, such as field-effect
transistors, only use one kind of charge carrier. For their
operation, BJTs use two junctions between two semiconductor
types, n-type and p-type.
 BJTs are manufactured in two types, NPN and PNP, and are
available as individual components, or fabricated in integrated
circuits, often in large numbers. The basic function of a BJT is to
amplify current. This allows BJTs to be used as amplifiers or
switches, giving them wide applicability in electronic
equipment, including, computers, televisions, mobile phones,
audio amplifiers, industrial control, and radio transmitters.

14. 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

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

16. The Unijunction Transistor(UJT)
The Unijunction Transistor or UJT for short, is
another solid state three terminal device that can
be used in gate pulse, timing circuits and trigger
generator applications to switch and control either
thyristors and triacs for AC power control type
applications. Like diodes, unijunction transistors
are constructed from separate P-type and N-type
semiconductor materials forming a single (hence
its name Uni-Junction) PN-junction within the
main conducting N-type channel of the device.

18. The field-effect transistor (FET)
 The field-effect transistor (FET) is a transistor that uses
an electric field to control the shape and hence the
electrical conductivity of a channel of one type of charge carrier
in asemiconductor material. FETs are also known as unipolar
transistors as they involve single-carrier-type operation. The
FET has several forms, but all have high inputimpedance. While
the conductivity of a non-FET transistor is regulated by the input
current (the emitter to base current) and so has a low input
impedance, a FET's conductivity is regulated by a voltage applied
to a terminal (the gate) which is insulated from the device. The
applied gate voltage imposes an electric field into the device,
which in turn attracts or repels charge carriers to or from the
region between a source terminal and a drain terminal. The
density of charge carriers in turn influences the conductivity
between the source and drain.

20. Metal Oxide Semiconductor(MOS)
 The metal–oxide–semiconductor field-effect
transistor (MOSFET, MOS-FET, or MOS FET) is a type
of transistor used for amplifying or switching
electronic signals.
 Short for Metal Oxide Semiconductor, MOS is a
method of creating transistors. MOS consists of three
layers, a metal conductor, insulating silicon layer, and
a semiconductor silicon layer.

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

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

24. Transistor as a Switch
Transistors are commonly used in digital circuits as
electronic switches which can be either in an "on" or
"off" state, both for high-power applications such
as switched-mode power supplies and for low-power
applications such as logic gates. Important parameters
for this application include the current switched, the
voltage handled, and the switching speed, characterised
by the rise and fall times.

26. 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

27. 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.

28. THANK YOU EVERYBODY