Experiment No 02:

7-Segment LED Display

Title

7 Segment LED Display

Aim

To design of logical circuit for display of decimal number on 7-segment LED display.

Learning Outcomes

At the end of this experiment students are able to

LO1: Explain 7-segment LED display technology.

LO2: Construct truth table of 7-segment LED display to display decimal numbers.

LO3: Design combinational logic circuit using logic gates (Decoder for 7-segment LED display)

LO4: Elaborate applications of 7-segment LED display

Apparatus

Software implementation: Use of any digital circuit simulator or use online simulator www.falstad.com/circuit/

Hardware implementation: 7-segment LED display, logic gates AND, OR, EXOR, NOT gate ICs

Theory

Click following link to read theory of 7 segment LED display:

https://drive.google.com/file/d/1yeC-2wCnaACQOw6EOGxKG10WEEqgFApV/view?usp=sharing

7 Segment LED Display.pdf

Design Steps:

Step 1: The first step of the design involves analysis of the common cathode 7-segment display. A 7-segment display consists of an arrangement of LEDs in an ‘H’ form. A truth table is constructed with the combination of inputs for each decimal number.

Step 2: The second step involves constructing the truth table listing the 7 display input signals, decimal number and corresponding 4 digit binary numbers.

Step 4: The final step involves drawing a combinational logic circuit for each output signal. Once the task was accomplished, a combinational logic circuit can be drawn using 4 inputs (A,B,C,D)and a 7- segment display (a,b,c,d,e,f,g) as output.

Step 5: Simulate the circuit on falstad.com/circuit and upload its link.

Truth Table:

For common cathode type BCD to seven segment decoder:

Design of K-Map

Combinational Logic Circuit:

Here design to activate "a" is given. Students should draw remaining circuit

Simulation Circuit:

To simulate above circuit, you can use any software with digital logic elements.

Use following website for design https://www.falstad.com/circuit/circuitjs.html

Here one such online simulator is given in following link with total simulation of decoder for 7 segment display

http://tinyurl.com/y2pazda2

By changing inputs, check respective output

Students should design decoder in same online circuit software and have to paste link in following google give in question and answer:

Questions and Answers:

Simulate decoder for 7 segment display using https://www.falstad.com/circuit/circuitjs.html this software and upload link in following google form.

It also have questions and answers in quiz form which will be counted for your grades

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