This presentation summarizes a summer training project on 7-segment displays completed at ARMbedded Electronics Pvt. Ltd. ARMbedded is an embedded design company registered under the Indian Companies Act of 1956. The presentation covers an introduction to LEDs and how they work, the different types of 7-segment displays, and how to drive a 7-segment display using switches or a 4511 IC. It explains that 7-segment displays are useful for displaying numeric digits in devices and discusses applications of 7-segment displays.

1. S.K.CHAUDHARY EDUCATIONAL TRUST’S
SHANKARA INSTITUTE OF TECHNOLOGY
KUKAS, JAIPUR
PRESENTED BY:
SHRUTI NARAYAN
B.TECH. 4TH YEAR
12ESIEC051
SESSION (2015-2016)
ARMBEDDED ELECTROICS PVT.LTD.
A SUMMER TRAINING PRESENTATION ON
7-SEGMENT DISPLAY
PRESENTED TO:
MR. RAJESH KANWADIA
(ASSISTANT PROF.)
MS. SHWETAAGARWAL
(ASSISTANT PROF.)
E.C.E. DEPARTMENT 1

2. ARMbedded Electronics Pvt.Ltd. is an Embedded design
house. It is registered under company act. 1956 and ISO
9001:2008 Certified Company. The Company undertake
various projects related to industrial automation, domestic
applications and higher end biomedical applications designed
on Embedded System Design, Embedded Wireless,VLSI,
MATLAB.
It provides an environment which equips an
engineer/student to use the practical knowledge gained during
the training period, fully in the technical field. It also
undertake training for corporate in all the respective domains.
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4.  INTRODUCTION
 INTRODUCTION TO LEDs
 LED WORKING
 TYPES OF SSD
 DRIVING A 7-SEGMENT DISPLAY USING A SWITCH
 DRIVING A 7-SEGMENT DISPLAY USING 4511 IC
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5.  A seven-segment display (SSD), or seven-segment
indicator, is a form of electronic display device for
displaying decimal numerals.
 The Seven segment display consists of seven LEDs
arranged in a rectangular fashion.
 Each of the seven LEDs is called a segment.
 Each segment is labelled from “a” to “g” and decimal
point by “dp”.
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 By forward biasing, the LED glow and desired
character pattern or number is displayed.

7. Decimal Digits 0-9
Select Alpha Characters
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8.  The main element needed to manufacture a seven
segment display are LEDs, so we must have review of
LEDs.
 A light emitting diode (LED) is essentially a PN
junction opto-semiconductor device that emits a light
by electroluminescence, in the UV, visible or infrared
regions of the electromagnetic spectrum when operated
in a forward biased direction.
 LEDs convert electrical energy into light energy .
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10.  LED works on the principle of electroluminescence.
 Electroluminescence (EL) is an optical
phenomenon and electrical phenomenon in which a
material emits light in response to the passage of
an electric current through it or to a strong electric
field.
 Electroluminescence is the result of radiative
recombination.
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11. Excitation
Electron excited by the forward
biased voltage
Hole is in valance
band
Normally the recombination takes place between
transition of electrons between the bottom of the
conduction band and the top of the valance band
(band exterma).
The emission of light is therefore;
hc/ = Ec-Ev = Eg(only direct band gap allows
radiative transition)
E
k
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12.  Under forward bias – majority
carriers from both sides of the
junction can cross the depletion
region and entering the material at the
other side.
 These diffused carriers recombine
with the majority carriers at other
side.
 The recombination causes light to be
emitted
 Such process is termed radiative
recombination.
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P-n
junction
Electrical
Contacts

13. For LED which emit visible light, the band gap of the materials
that we use must be in the region of visible wavelength = 390-
770nm. This coincides with the energy value of 3.18eV- 1.61eV
which corresponds to colours as stated below:
Violet ~ 3.17eV
Blue ~ 2.73eV
Green ~ 2.52eV
Yellow ~ 2.15eV
Orange ~ 2.08eV
Red ~ 1.62eV
The band gap, Eg
that the
semiconductor
must posses to
emit each light
Colour of an
LED should
emits
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15.  The SSD common pin is generally used to identify which
type of 7-segment display it is. As each LED has two
connecting pins, one called the “Anode” and the other
called the “Cathode”, there are therefore two types of LED
7-segment display called: Common Cathode (CC)
and Common Anode(CA).
 The difference between the two displays, as their name
suggests, is that the common cathode has all the cathodes of
the 7-segments connected directly together and the common
anode has all the anodes of the 7-segments connected
together and is illuminated as follows.
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20.  The segments of a common anode display can be
illuminated using the switches.
 In this a LOW condition is required to activate the LED
segments on this common anode display.
eg: illuminate the decimal number “4” on the display, the
switches b, c, f and g would be closed to light the
corresponding LED segments.
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22.  7-segment Displays are usually driven by a special type of
integrated circuit (IC) like CMOS 4511. This 7-segment
display driver is able to illuminate both common anode or
common cathode displays.
 This BCD-to-7 segment driver takes a four-bit BCD
input and has outputs that will pass current through the
segments to display the decimal digit.
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As Seven segment display provides a
convenient way to display decimal
numbers in digital form, it is helpful in
general purpose devices and reduces the
complexity of data delivered.
It is used in many devices of our day to
day life, like in traffic signals, watches,
cd/dvd players etc.

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 https://en.m.wikipedia.org/wiki/Seven_segment_di
splay
 https://www.electronics-tutorials.ws/blog/7-
segment-display-tutorial.html
 https://en.m.wikipedia.org/wiki/Light_emitting_di
ode
 https://www.electronicsblog.org/seven-segment-
display-everything-you-need-to-know-about/
 https://www.instructables.com/id/Seven-
Segment-Display-Tutorial/

25. Thanks
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