2. Teaching Methodology Detailing
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Lecture
No.
Topic Books Page No.
1. Evolution of Electronics
Impact of Electronics in Industry and Society
T1 Preface
2. Materials used in Electronics, Introduction to
active and Passive components, switches and
relays
3. Currents in semiconductors, P-type and N- type
semiconductors
T1 1.4 and
1.6
4. P-N junction diode: construction and working, V-I
characteristics
T1 1.7,1.8,
1.9
5. Diode as switch, Half, Full wave and Bridge
rectifier
T1 2.1, 2.2
6. Special purpose diodes: Zener diode, LED and
Photo diode and their applications
T1 3.1,3.4
T1: “Electronics Devices ” by Thomas L. Floyd, 9th Edition, Pearson
3. 1904: the simplest vacuum tube – the diode – was
invented by John Fleming.
1907: De Forest invented the triode by inserting
a third electrode between cathode and anode.
Evolution of Electronics
Vacuum tubes
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7. heralded as a "Giant Brain" by the press
thousand times faster than electro-mechanical computer
17,468 vacuum tubes, 7200 crystal diodes, 1,500 relays,
70,000 resistors, 10,000 capacitors, 6,000 manual
switches, and approximately 5,000,000 hand-soldered
joints.
consumed 150 kW
Input was possible from an IBM card reader
100 kHz clock
Several tubes burned out almost every day, leaving it
non-functional
about half the time.
ENIAC computer
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8. The vacuum tube was a bulky and fragile device which consumed a
significant power.
1947: Shockley, Bardeen, and Brattain at Bell Labs invented the first
transistor.
The first transistor was a “point contact transistor.” The modern
transistor is a junction transistor, and it is monolithic (in the same
semiconductor piece).
The first transistor
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9. The bipolar transistor continues to be an important device
both as
a discrete device and as part of Integrated Circuits (IC).
However, in digital circuits such as processors and
memory, the MOS (Metal Oxide Semiconductor) field-
effect transistor has surpassed the bipolar transistor
because of the high integration density and low power
consumption it offers.
1930: patent filed by Lilienfeld for field-effect transistor (FET).
1958: Jack Kilby (Texas Instruments) demonstrated the first
integrated circuit (bipolar transistor, resistor, capacitor)
fabricated on a single piece of germanium.
The rest is history!
Semiconductor technology
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16. Difference between active & Passive
components
1.Active devices inject power to the circuit, whereas
passive devices are incapable of supplying any energy.
2. Active devices are capable of providing power gain,
and passive devices are incapable of providing power
gain.
3.Active devices can control the current (energy) flow
within the circuit, whereas passive device cannot
control it.
4. An external power is required to start basic operation
of an active device where no extra power is used for
passive device.
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17. Introduction to semiconductor physics
parameter Conductor Semi
conductor
insulator
No. of valance
electrons
3 or less than 3 4 5 or more
than 5
conductivity high medium negligible
Semi Conductor Types
Intrinsic Extrinsic
P type N type
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25. Forward and reverse currents
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1
nkT
qV
S
D
D
e
I
I
Ideal Diode Equation
Where,
ID and VD are the diode current and voltage, respectively
q is the charge on the electron
n is the ideality factor: n = 1 for indirect semiconductors (Si, Ge, etc.)
n = 2 for direct semiconductors (GaAs , InP, etc.)
k is Boltzmann’s constant
T is temperature in Kelvin
kT/q is also known as Vth, the thermal voltage. At 300K (room
temperature),kT/q = 25.9mV
26. Simplification
When VD is negative
When VD is positive
nkT
qV
S
D
D
e
I
I ~
S
D I
I
~
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34. Features:
Uses the relatively constant
reverse breakdown voltage
to produce a voltage reference.
Breakdown voltage is called
the Zener voltage, VZ
Output voltage of circuit
shown is equal to VZ despite
variations in input voltage V
A resistor is used to limit
the current in the diode
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Special Purpose Diode: Zener Diode
46. Key Points
Diodes allow current to flow in only one direction
At low temperatures semiconductors act like
insulators
At higher temperatures they begin to conduct
Doping of semiconductors leads to the production of
p-type and n-type materials
A junction between p-type and n-type
semiconductors has the properties of a diode
Silicon semiconductor diodes approximate the
behavior of ideal diodes but have a conduction
voltage of about 0.7 V
There are also a wide range of special purpose
diodes
Diodes are used in a range of applications
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