This document discusses electronics and was prepared by Vijay Balu Raskar. It contains 7 chapters on topics in electronics including introduction to electronics, semiconductor theory, semiconductor diodes, rectifiers filters and regulators, bipolar junction transistors, field effect transistors, and integrated circuits. The chapter on semiconductor theory defines semiconductors and discusses intrinsic and extrinsic semiconductors. It explains conduction in intrinsic semiconductors and how doping can increase conductivity in extrinsic semiconductors.

1. Subject Title :
Electronics
Prepared by,
Vijay Balu Raskar
Mr. Vijay Balu Raskar
RASKAR
(BE)Electrical Engineer
Electronics is the branch of engineering. Electonics derived
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from Greek word ‘Elektron and Electron Mechanics’
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2. Subject Title : Electronics
Prepared by , Mr. Vijay Balu Raskar vijayraskar2003@yahoo.co.in / vijay.raskar1986@gmail.com
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ELECTRONICS
S. NO NAME OF CHAPTER MARKS
1 Introduction to electronics 04
2 Semiconductor Theory 10
3 Semiconductor Diode 20
4 Rectifiers Filters and Regulators 20
5 Bipolar Junction Transistor 30
6 Field Effect Transistors 10
7 Integrated Circuits 06
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3. Subject Title : Electronics
Prepared by , Mr. Vijay Balu Raskar vijayraskar2003@yahoo.co.in / vijay.raskar1986@gmail.com
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1. Introduction to electronics
Chapter number one is under construction.
Refer other chapters because of importance.
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4. Subject Title : Electronics
Prepared by , Mr. Vijay Balu Raskar vijayraskar2003@yahoo.co.in / vijay.raskar1986@gmail.com
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2. Semiconductor Theory
Q.1 Define semiconductor.
Ans:- The material whose electrical conductivity lies between those of
conductors and insulators and hence negative temperature coefficient
of resistance are known as semiconductors.
Q.2 Write a short note on semiconductor.
Ans:- They are classified as,
There are two types of semiconductor,
1) Intrinsic semiconductor and
2) Extrinsic semiconductor a) P-type and b) N-type
Explanation:-
 The material whose electrical conductivity lies between those of
conductors and insulators and hence negative temperature
coefficient of resistance are known as semiconductors.
 Semiconductors have low conductivity of order of 10 7 s/m.
 They have low resistivity of the order of 10 1 to 10 2 ohm-m.
 There is low forbidden energy gap (Eg = 1eV).
 Resistance of semiconductor material decreases with increase in
temperature.
 They have moderate concentration of free electrons.
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5. Subject Title : Electronics
Prepared by , Mr. Vijay Balu Raskar vijayraskar2003@yahoo.co.in / vijay.raskar1986@gmail.com
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 At room temperature, they act as a moderate conductor of
electricity.
1) Intrinsic Semiconductor:-
 A semiconductor in an extremely pure form is known as
intrinsic semiconductor.
 An intrinsic semiconductor also called an undoped
semiconductor or i-type semiconductor.
 Intrinsic Semiconductor has a negligible conductivity at room
temperature.
 Semiconductor material with larger impurity concentrations
(Example silicon and germanium)
 The current which will flow in an intrinsic semiconductor
consists of both electron and hole current.
 In intrinsic semiconductors the number of
excited electrons and the number of holes are equal: n = p.
Conduction in Intrinsic Semiconductor:-
 Current conduction is takes place by electron and holes.
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6. Subject Title : Electronics
Prepared by , Mr. Vijay Balu Raskar vijayraskar2003@yahoo.co.in / vijay.raskar1986@gmail.com
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 The free electrons are generated due to the breaking up of some
covalent bonds by thermal energy.
 The electron experiences the force towards the positive terminal
of the battery.
 The holes experience the force towards the negative terminal of
the battery.
 Random motion of electrons and holes occur a net movement
called drift.
 This random motion is not contributing to any electric current.
 The free electron drifts towards the positive terminal of the
battery and holes towards the negative.
 This moment of charge carriers constitute the electric current.
 Electron flows from negative to positive terminal of the battery.
 Current flows from positive terminal to negative terminal of the
battery.
 The total current inside the semiconductor crystal is the sum of
electric currents due to the free electrons and holes.
 When the flow of charge carriers is due to an applied voltage the
resultant current is called a drift current.
 Diffusion current is also exit by the difference of carrier
concentration from one region to another.
 The current which will flow in an intrinsic semiconductor
consists of both electron and hole current.
2) Extrinsic Semiconductor:-
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7. Subject Title : Electronics
Prepared by , Mr. Vijay Balu Raskar vijayraskar2003@yahoo.co.in / vijay.raskar1986@gmail.com
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 Electrical conductivity have to be increased by adding a certain
amount of desired impurity atoms to intrinsic semiconductor is
called as extrinsic semiconductor.
 The process of deliberately adding or diffusing impurity atoms to
the intrinsic semiconductor crystal is called doping.

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