Department of Electrical, Electronics, and computer Engineering
Laboratory Experiment 3: Seven-Segment Decoder Design
Assignment 1
NAME: KAULINGE M.S
STUDENT NO: 219378751
INTRODUCTION
 The purpose of this experiment is to design and experimentally verify the operation of a
seven-segment decoder using basic logic gates and the use of Karnaugh maps .The primary
goal is to create a digital logic circuit that can convert binary inputs into the corresponding
decimal digits and display them on a seven-segment display. This experiment will provide
hands-on experience in digital logic design and validation through practical implementation
and testing
OBJECTIVES
 Design a digital logic circuit that can decode binary inputs into decimal digits suitable for
display on a seven-segment display.
 Create a truth table that maps binary input combinations to the segments of the seven-segment
display using MultiSim.
 Derive simplified Boolean expressions for each segment's control signal based on the truth
table.
 Implement the logic circuit on a breadboard using basic logic gates (AND, OR, NOT).
 Test the functionality of the decoder by verifying that the correct segments of the sevensegment display illuminate for various binary inputs.
TRUTH TABLE
Boolean expressions
a = F1 (A, B, C, D) = ∑m (0, 2, 3, 5, 7, 8, 9)
b = F2 (A, B, C, D) = ∑m (0, 1, 2, 3, 4, 7, 8, 9)
c = F3 (A, B, C, D) = ∑m (0, 1, 3, 4, 5, 6, 7, 8, 9)
d = F4 (A, B, C, D) = ∑m (0, 2, 3, 5, 6, 8)
e = F5 (A, B, C, D) = ∑m (0, 2, 6, 8)
f = F6 (A, B, C, D) = ∑m (0, 4, 5, 6, 8, 9)
g = F7 (A, B, C, D) = ∑m (2, 3, 4, 5, 6, 8, 9)
K-Map Simplification
Calculation of the resistance for the appropriate resistor of the design
Red common cathode segment display
 Forward voltage=3.00V
 Current =0.04A
The voltage supplies.
Voltage= 5V
R=V/I
= (5-3.00)/0.04
=50 ohm
Logic circuit diagram for the simplified expressions
1. Select Start » All Programs » Applications » National Instruments » Circuit Design Suite
0.1 » Multisim 14. A blank file opens on the workspace called Circuit 1.
2. Select File » Save As to display a standard Windows Save dialog. Name and save the file in
your Z drive.
3. Select Place » Component to display the Select a Component browser. Select the group
Indicators in the Group menu, and the Hex_display Family. Navigate to the 7-segment LED
display as shown below and click OK. The component appears as a “ghost” on the cursor.
4. Place the remaining components in the workspace. The LED is in the Diode Group. The
voltage sources are in the Sources Group; Power sources family and Signal voltage sources
family. The resistors are in the Basic Group. The integrated circuits are in the TTL Group.
The pushbutton is in the Electromechanical Group; Momentary switches family. Note: as this
is a digital circuit, you should use DGND as ground. For analog circuits use the GROUND
component.
5. You can adjust the properties of the components, such as the frequency of the square wave,
double clicking on them. Right-click the mouse. A wire appears, attached to your cursor.
Click on a pin on the second component to finish the connection. Multisim automatically
places the wire, which conveniently snaps to an appropriate configuration. You can also
control the flow of the wire by clicking on points as you move the mouse. Each click “fixes”
the wire to that point.
7. Select Simulate»Run or press the Run button in the simulation toolbar to simulate the
circuit. As the circuit simulates the 7-segment display counts up and the LED flashes at the
end of each count cycle. The pushbutton is an interactive component. Look what happens
when it is pressed.
8. Save and close the circuit.
CONCLUSION
 In conclusion, this laboratory exercise allowed us to design, simulate, and implement a
seven-segment decoder circuit. By following a systematic design process and conducting
experiments, we successfully achieved the objective of creating a functional decoder. The
exercise provided valuable hands-on experience in digital logic design and practical
electronics