Basic Electronics (EC21201)
MON(10:00-10:55), WED(08:00-09:55),
THURS(10:00-10:55)
Dr. Chetna Singhal (E&ECE)
Textbook
'Electronic Circuits - Analysis and Design' by
Donald A Neamen
Evaluation
Mid-sem exam
● End-sem exam
● Two class tests, one before mid- and end-sem
● Attendance is important
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https://www.iitkgp.ac.in/assets/pdf/ACADEMIC_CALENDAR_2023_24.pdf
Tutorial sessions
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One-hour per week
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Solving questions in class
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First tutorial sessions: 16-17 Aug
Some abbreviations
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PCB: Printed Circuit Board
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Plastic
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IC: Integrated Circuit
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BJT: Bipolar Junction Transistor
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MOSFET: Metal-Oxide-Semiconductor FieldEffect Transistor
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AC: Alternating current
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DC: Direct current
Background
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Electronic systems
TV
Laptop
Computer and
gadgets
Composed of electronic circuits, which include amplifiers, signal
sources, power supplies, and digital logic circuits.
Background
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Electronics
is defined as the science of the motion of charges in a gas,
vacuum, or semiconductor.
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Microelectronics
refers to integrated circuit (IC) technology, which can produce a circuit
with millions of components on a single piece of semiconductor material
History
1904: British engineer John
Ambrose Fleming invents and
patents the thermionic valve
December 1947, first transistor
demonstrated at Bell Telephone
Lab. by William Shockley, John
Bardeen, and Walter Brattain.
September 1958, Jack Kilby
of Texas Instruments
demonstrated the first
integrated circuit fabricated
in germanium
IC
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IC can contain arithmetic, logic, and memory
functions on a single semiconductor chip.
The primary example of this type of integrated
circuit is the microprocessor
Device size continues to shrink and the number
of devices fabricated on a single chip continues
to increase
Passive device
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Resistors, capacitors, inductors, transformers,
and even diodes are passive devices.
Passive devices or components do not generate
energy, but can store it or dissipate it.
Inductors and capacitors can store energy, but
they cannot deliver an average power greater
than zero over an infinite time interval.
Passive device
Ohm (Ω)
Henry (H)
Carbon, metal,
metal-oxide,
fine carbon
particles and a
non-conductive
ceramic
material
Farad (F)
two metal plates and
an insulating material
called a dielectric.
ferromagnetic
material, nickel, iron
and molybdenum.
aluminum, tantalum,
and niobium.
Active device
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DC power supplies, batteries, and ac signal
generators, are capable of supplying power.
Transistors are also considered to be active
devices, they are capable of supplying more
signal power to a load than they receive. This
phenomenon is called amplification.
The additional power in the output signal is a
result of a redistribution of ac and dc power
within the device.
Analog and Digital circuits
(a) analog signal versus time and (b) digital signal versus time
Electronic circuits that process such signals.
Semiconductor materials and Diode
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Electronic devices (transistors and diodes) are
fabricated using semiconductor materials.
Properties and characteristics of semiconductors.
A pn junction diode is a two-terminal device, with
nonlinear i–v relationship.
The analysis of circuits containing diodes is not as
straightforward as linear resistor circuits.
Semiconductor materials and properties
Silicon (most common), Gallium Arsenide (high
speed and optical devices)
● Intrinsic semiconductor
● Extrinsic semiconductor
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Intrinsic Semiconductor
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Electrons in outermost shell: valence electrons
Silicon (Si) and germanium (Ge), in group IV are
elemental semiconductors.
In contrast, gallium arsenide is a group III–V
compound semiconductor.
T = 0 K, silicon is an insulator
Electrons in lowest energy state
Electric field does not move e-
To break the covalent bond, the valence
electron must gain a minimum energy,
called bandgap energy
Energy band diagram
Insulators: Eg=3-6 eV
Semiconductors: Eg=1 eV
Conductors: large numbers of free electrons at room temperature
Two types of charged particles contribute to the current:
- the negatively charged free electron,
- the positively charged hole.
Extrinsic (doped) Semiconductor
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Electron and hole concentrations can be increased
by adding controlled amounts of certain impurities.
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Group V: phosphorus and arsenic
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The phosphorus atom is called donor impurity
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n-type semiconductor
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Group III: boron.
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The boron atom is called acceptor impurity
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Doping: when impurity is added to semiconductor
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p-type semiconductor
Extrinsic Semiconductor
Semiconductor in thermal equilibrium
Intrinsic conc.
Hole concentration
Electron conc.