10/2/2012
Arab Academy for Science ,
Technology and Maritime
Transport
Electronics
EC 331
Dr. Mohamed Hassan
Course Assessment
• * In-class exams:
•
7th week exam
•
12th week exam
40%
25%
15%
• *Tutorial exams and activities: 10%
• (5%with 7th week exam + 5%with 12th week exam)
•
• * All term activity : 10% (with final)
or), Absence in Lecs & Secs (and-or),
(and-or)
• Progress within term (and –or)
Bonuses in Lecs only,
• Dr. evaluation (and-or) and Extra projects-research.
• Final exam:
40%
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10/2/2012
Rules and educational hints (very important)
• You can view your marks and answer book in all exams any time according
to model answer (viewed in Dr or TAs office hours).
•
25% of any sheet will not be solved intentionally ….they will left for your
home works OR class activities OR exams in sections OR exams of 7th and
12th.
• You have all wrights to ask about the 25% of previous point in TAs office
hours and not in the day of exam and get the true solution but in condition
of trying and working before asking.
• We will construct list contains each student name, Id and email for each
class. Each student will be responsible for checking his mail 2 times a week
during the term for any upgrades related to our subject.
• Dr is not responsible for error mail- junk- or not giving mails. Dr will send
material to each class and contact specific student if any matter happens
during the term.
• Any problem just contact Dr.
mhabdazeem@hotmail.com
• Bonus marks are allowed through good participation in lectures and good
p j
outside projects.
• Students that have lower than 26/50 by end of week 14 will be advised to
make (w). (Dr. will send advise through the mail by end of week 14).
• You have to get the lectures with you each time (printed or on PDAs) to
follow up.
• You have to be prepared for tutorials activities each time (calculatorpapers-pen……
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10/2/2012
TEXT BOOKS:
BOOKS:
• C.J.Savant, M.S.Rooden, G.L.Carpenter, ”Electronic Design”,
Addison Wesley
• Martin
M ti Rodan
R d
and
d Gordon
G d
C
Carpenter,
t
" Electronic
El t i Design:
D i
f
from
concept to reality“
REFERENCE BOOKS:
BOOKS:
Sedra & Smith, Microelectronic Circuits, 5th edition, 2004.
Boylestad, Nashelsky, Electronic Devices&circuit theory, Prentice
Hall, 2005
•
•
Course Contents
•Semiconductor Physics:
St d i semiconductors
Studying
i
d t
materials,
t i l Extrinsic
E t i i materials
t i l and
d
semiconductor diodes.
• P-N junction diode:
Theory of operation, Built-in potential, Forward and reverse
connections, P-N junction as a circuit element, special diods
and P-N jjunction diode Applications.
pp
• BJT and MOSFET:
Bipolar Junction Transistor (BJT) and Field Effect Transistor
(FET) Electronic amplifiers and switches
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Materials Types
1. INSULATORS
• An INSULATOR is any material that inhibits
(stops) the flow of electrons (electricity).
• An insulator is any material with 5 to 8 free
electrons in the outer ring. Because, atoms
with 5 to 8 electrons in the outer ring are held
(bound) tightly to the atom,
atom they CANNOT be
easily moved to another atom nor make room
for more electrons.
• Insulator material includes glass, rubber, and
plastic
Materials Types
2. CONDUCTORS
•A
A CONDUCTOR is any material that easily
allows electrons (electricity) to flow.
•A CONDUCTOR has 1 to 3 free electrons in
the outer ring. Because atoms with 1 to 3
electrons in the outer ring are held (bound)
loosely to the atom, they can easily move to
another atom or make room for more electrons.
•Conductor material includes copper and gold
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Materials Types
3. SEMICONDUCTORS
•Any
Any material with exactly 4 free electrons in
the
outer
orbit
are
called
SEMICONDUCTORS.
•A semiconductor is neither a conductor or
insulator.
• Semiconductor material includes carbon,
carbon
silicon, and germanium.
•These materials are be used in the
manufacturer of diodes, transistors, and
integrated circuit chips.
Extrinsic Materials: n-Type and p
p--Type
The characteristic of semiconductor can be altered byy
adding impurity through doping process (extrinsic
material)
Two type:
1) N-type
2) P-type
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Extrinsic Materials : n-Type
•
•
•
•
N-type is created by
introducing impurity elements
that have five valence
electrons (pentavalent)
ex: antimony, arsenic,
phosphorus.
Note that four covalent bonds
are still present, however there
is additional fifth electron due
to impurity atom.
The remaining electron is free
to move within the newly
formed n-type material.
Diffused impurities with five
valence electrons are called
donor atoms.
Antimony impurity
in n-type material
Extrinsic Materials : p-Type
•
•
•
•
P-type is created by doping
with impurity atoms having
three valence electrons –
(boron gallium,
(borongallium indium)
Note that there are
insufficient number of
electrons to complete
covalent bonds resulting a
hole
This hole is readyy to accept
p
a free electron
The diffused impurities with
three valence electrons are
called acceptor atoms.
Boron impurity in
p-type material
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Majority and Minority Carriers
•
•
In an n-type material - electron is called majority
carrier and hole the minority carrier
In a p
p-type
type material – hole is majority carrier and
electron is the minority carrier
Semiconductor Diode
•
•
•
•
Diode is formed by bringing these two material together p- and n-type.
Holes diffuse from the p side to the n side, leaving behind negatively
charged immobile negative ions.
Electrons diffuse from the n side to the p side, leaving behind positively
charged immobile positive ions.
Electrons and holes at joined region will combine, resulting in a lack of
carriers in the region near the junction (depletion region)
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Reverse--Bias Condition (VD < 0V)
Reverse
Reverse-biased p-n junction
Reverse--Bias Condition (VD < 0V)
Reverse
•
•
•
•
The number of positive ions in the depletion region of n-type
will increase due to large number of free electrons drawn to
the positive potential.
The number of negative ions will increase in p-type resulting
widening of depletion region.
This region established great barrier for the majority carriers
to overcome, resulting Imajority = 0
A very small amount of reverse current does flow, due to
minority
i i carriers
i
diff i
diffusing
f
from
the
h (p/n)
( / ) regions
i
i
into
the
h
depletion region and drifting across the junction.
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Forward--Bias Condition (VD > 0V)
Forward
Forward-biased p-n junction
Forward--Bias Condition (VD = 0V)
Forward
• A semiconductor diode is forward-biased when the
p-type
yp and p
positive voltage
g and n-type
yp
association p
and negative voltage has been established.
• The application of forward-bias potential will pressure
the electrons in n-type and hole in p-type to
recombine with ions near the boundary and reduce
the width of depletion region
• The reduction in width of depletion region has
resulted in a heavy majority flow across the junction
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