Digital Electronics

1. WELCOME TO THE PRESENTATION
ON
7-SEGMENT DECODER
Submitted to,
MD. ROBIUL ISLAM
Sr. Lecturer, Dept. Of ECE
Instirute of Science Trade &
Technology
Examiner, National University
(Professional)
Submitted by,
• ABDULLAH AL FAHIM ID. 63
• AKHINUR NAHAR SRITY ID. 53
• ISRAT FARIA EMI ID. 58
• Session: 2017 – 18
• Subject: Digital Electronics II
• Subject Code: ECE – 213
Date: July 11, 2021

2. OBJECTIVE
The purpous of this presentation is to gather understandable knowledge to
design 7-SEGMENT DECODER and combinational logic circuit to know how
does it works. To acknowledge the application and working capability of 7
SEGMENT DISPLAY DECODER.
Slide No. 01

3. DEFINITION
If we want to know about 7 Segment Decoder, we need to know about decoder
at first. Basically,
Decoder: A decoder is logic circuit that accepts a set of input that represent a
binary number and activates only the one output that corresponds to the input
number.
7-Segement Decoder: A seven-segment display is a form of electronic display
device for displaying decimal numerals that is an alternative to the more
complex dot matrix displays. Seven-segment displays are widely used in digital
clocks, electronic meters, basic calculators, and other electronic devices that
display numerical information.
Slide No. 02

4. 7-SEGMENT DECODER
PRINCIPLE
Seven-segment displays contains the arrangement of the LEDs in “Eight” (8)
passion, and a Dot (.) with a common electrode, lead (Anode or Cathode). The
purpose of arranging it in that passion is that we can make any number out of that
by switching ON and OFF the particular LED's. Here is the block diagram of the
Seven Segment LED arrangement.
A decoder is a combinational circuit that
connects the binary information from „n‟
input lines to a maximum of 2n unique
output lines. The IC7447 is a BCD to 7-
segment pattern converter. The IC7447
takes the Binary Coded Decimal (BCD) as
the input and outputs the relevant 7
segment code.
Slide No. 03

5. 7-SEGMENT DECODER LOGIC
DIAGRAM
5
Fig: Logic Circuit diagram of BCD to 7 segment Decoder.
Slide No. 04

6. 7-SEGMENT DECODER TRUTH
TABLE
6
Table: Truth table of BCD to 7 Segment Decoder
Slide No. 05

7. 7-SEGMENT DECODER IC7447 PIN DIAGRAM
7
Slide No. 06

8. 7 SEGMENT DISPLAY APPLICATIONS
8
• Digital Clock
• Motor Vehicle Odometer
• Wrist Watch
• Calculator
• Spoodometer
• Clock Radio
• Radio Frequency Indicator
Slide No. 07

9. LIMITATIONS OF 7-SEGMENT
DECODER
9
1. The circuit involves lots of logic gates and its quite complex .
2. 7 Segment decoder is only capable to display numbers 0-9 and few
alphabets
3. The appearence of the two types of display [Cathode Ray & Annode Ray]
are very similler and it causes difficulty interfacing with the controllers
Slide No. 08

10. CONCLUSION
10
• It is possible to display the decimal value of a binary number on a 7-
segment display using a BCD decoder.
• However, this method will allow displaying only digits from 0 to 9 and
letters A to F.
• The only way to display number more than 9 is to use a display that has
more than 7 segments or just using multiple 7-segment displays at once with
the corresponding BCD decoder.
Slide No. 09

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