1. i
CANDIDATE’S DECLARATION
I hereby declare that the work which is being presented in this minor project entitled as
“Generate 5 Volt DC And Control Seven Segment LED Display” in partial fulfillment of the
requirements for the award of the degree of B. Tech in EI&CE, Rajasthan Technical
University, Kota submitted in the department of EI&CE, Govt. Engineering College, Ajmer
is an authentic record of my work carried out by me in session 2014-15 under the supervision
& guidance of Mrs. Kajal Bhadel (Assistant Professor) in the department of EI&CE, Govt.
Engineering College Ajmer.
The matter embodied in this project has not been submitted by me anywhere else for
the award of any other degree or diploma.
Dated: / 01 /2015 Veni Dan (11EI60)
Place: Ajmer Sunil Kumar (12EI80D)
CERTIFICATE
This is Certify to that the above statement made by the candidate is correct to the best of my
knowledge & belief.
Kajal Bhadel Mr. H.S. Mewara Mr. Ajay Dadhich
(Project Guide) (Project Coordinator) (Head of Department)
Dated: / 01 / 2015
Place: Ajmer

2. ii
ABSTRACT
In this project we required 5 volt supply for inputs of BCD so we use here a step – down
transformer is rating is 12 volt secondary winding output than we use bridge rectifier circuit
for convert AC voltage into DC voltage and then we use 7805 voltage regulator to regulate
the voltage and gave fix 5 volt supply.
To convert the BCD (binary coded decimal) input to corresponding binary input and display
on seven segments LED display by using 74LS48 IC and display 0 to 9 on cathode 7-
segment led display. Seven segment displays are two types (a) common anode seven segment
display and (b) common cathode seven segment display. We use at common cathode display
because we have 74ls48 BCD decoder. If we have 74LS47 decoder then we use here as
decoder is 74LS47.

3. iii
ACKNOWLEDGEMENT
We wish to take this opportunity to express our deep sense of gratitude and sincere thanks to.
Mrs. Kajal Bhadel ( Assistant professor , Electronics & Instrumentation Engineering), who
provided us their valuable guidance and much needed experience which give us a way to the
success of our project.
We are also thankful to Mr. H. S. Mewara (Project Coordinator, EIC), who provided us
every possible facility in carrying out the project smoothly and successfully and also to our
other respected faculties and other staff members who directly or indirectly helped us during
the course of the project.
Our thanks to Mr. Ajay Dadhich (Project Guide), who not only suggest us at every step of
our project but also provided us the necessary information regarding the project.
Veni Dan (11EI60)
Sunil Kumar (12EI80D)

4. iv
PREFACE
Today the world swiftly changing, there are multiple challenges faced by us. Surly it is the
knowledge through technology, which makes us to overcome them. The project report, which
is an integral part of four years engineering program provides a platform to the entire student
to augment their technical study through practical revelation. It is the time, which is
effectively used by students to enhance their interaction with technical atmosphere. The
project stage-I is obligatory as per university course outline. This report is based on work
done and theory gained during analysis of the topic. The report basically introduces working
of project in detail.
Generate fix 5 volt DC supply use as BCD inputs to seven segment LED Display is one of the
applications of electronics to increase the facilities of life. It is facilitates the operation of
voltage regulators around the electronics lab. It provides a system that is simple to understand
and also to operate, a system that would be cheaper and affordable. It adds more comfort to
everyday living by removing the inconvenience of having to move around to operate a fan
regulator.

5. v
CONTENTS
CHAPTER TITLE PAGE
NO. NO.
CERTIFICATE i
ABSTRACT ii
ACKNOWLEDGEMENT iii
PREFACE iv
CONTENTS v
FIGURE INDEX vii
TABLE INDEX viii
1. INTRODUCTION 1
1.1 Introduction 1
2. CIRCUIT DESCRIPTION 2
2.1 Circuit Connection 2
2.2 Working Of The Circuit 2
2.2.1 Step 1 Step - Down Transformer 2
2.2.2 Step 2 Rectification Process 2
2.2.3 Step 3 Voltage Regulator 3
2.2.4 Step 4 BCD Inputs Switches 3
2.2.5 Step 5 BCD To Seven Segment Decoder 3
3 COMPONENT DESCRIPTION 5
3.1 Components Requirements
4. SEVEN SEGMENTAL DISPLAY 6
4.1 Introduction 6
4.2 Types Of 7-Segment LED Digital Display 7
4.2.1 The Common Cathode Display (CCD) 7
4.2.2 The Common Anode Display (CAD) 7
4.3 Seven-Segment Display Format 8
4.4 Truth Table for7-Segment Display 8
5. BINARY CODED DECIMAL 9
5.1 Introduction 9
5.2 BCD To 7-Segment Decoder Or Driver 9
5.3 Logic Diagram Of IC 74LS48 11
5.4 Circuit Of BCD To 7 – Segment Display System 12
6. COMPONENTS DESCRIPTION 13
6.1 Transformer 13
6.2 Resistor 13

6. vi
6.3 LED (Light Emitting Diode) 14
6.4 Capacitor 14
6.5 Semi – Conductor Diode 15
CONCLUSIONS 17
BIBLIOGRAPHY 18

7. vii
FIGURE INDEX
FIGURE TITLE PAGE NO.
2.1 Full Circuit diagram of seven segment decoder 2
2.2(a) pins of 7805 voltage regulator
2.2(b) Internal circuit configuration of 7805 voltage regulator 3
2.3 decoderconfigurations with common cathode seven segment 4
4.1 Seven Segmental LED Display 6
4.2 Common Cathode And Common Anode 7-Segment Display 7
4.3 7-Segments Display Format 8
4.4 Seven-Segments Display Elements for all Numbers 8
5.1 IC's SN54/74LS48 And Pin Description 10
5.2(a) Logic Diagram Of IC 74LS48 11
5.2(b) Block Diagram Of IC 74LS48 11
5.3 Block Diagram of BCD To 7- Segment Display 12
5.4 Circuit Diagram of BCD To 7- Segment Display 12
6.1 BCD To 7- Segment Display 13
6.2 (a) Fix CarbonResistor 14
6.2(b) Variable Resistor 14
6.3 Blue, Red and Green LED 14
6.4 Capacitor 15
6.5 Semi-Conductor Diode 16

8. viii
TABLE INDEX
TABLE TITLE PAGE NO.
3.1 Components Description 5
4.1 Truth Table for a 7-segment display 8
5.1 Binary To BCD Convert 9