overview
The purpose of the circuit designed in this project is to design a circuit that will display my date of birth on a seven segment display. The date of birth will be displayed in the MMDDYY format. In the design, we have to use a common cathode seven-segment display, resistors for the bread-boarding and Karnaugh mapping to simplify the logic expression, and at least one NAND and NOR logic was required. We have to create the truth table and Karnaugh maps with simplified logic for each of the seven segments. We need to create the circuit on MultiSim to test out circuit. Finally, bread-board the circuit.
truth table
A truth table is used to show how a logic circuit responds to various combinations of inputs. The 1 represents that switch is on and the 0 represents that switch is off.
This truth table has 3 inputs that will output a number of my date of birth. The x's represent a "Don't care" condition meaning that the x can either be a zero or a one depending on your situation. There is an a through g column because in order for the seven segment timer to display a number the LED's need to 7 outputs. The seven LED's combined will display a number corresponding to my date of birth.
This truth table has 3 inputs that will output a number of my date of birth. The x's represent a "Don't care" condition meaning that the x can either be a zero or a one depending on your situation. There is an a through g column because in order for the seven segment timer to display a number the LED's need to 7 outputs. The seven LED's combined will display a number corresponding to my date of birth.
k maps & simplified logic
I took the column for each letter (a-g) and made a Karnaugh map to create the simplified logic expression for each letter.
I plugged the numbers from the truth table in the Karnaugh map by following the rules of Karnaugh mapping. My logic expression is in sum of products (SOP) form. Because, it is easier to derive from a Karnaugh map and easier to create a circuit from a SOP expression. I found the min-terms by grouping 1's.
Using K-Mapping over Boolean Algebra is a quicker and easier way to derive the logic expressions. There are seven LED's in a seven segment display and each one has its own logic expression so it can be activated when it needs to be.
I plugged the numbers from the truth table in the Karnaugh map by following the rules of Karnaugh mapping. My logic expression is in sum of products (SOP) form. Because, it is easier to derive from a Karnaugh map and easier to create a circuit from a SOP expression. I found the min-terms by grouping 1's.
Using K-Mapping over Boolean Algebra is a quicker and easier way to derive the logic expressions. There are seven LED's in a seven segment display and each one has its own logic expression so it can be activated when it needs to be.
multisim
This is the AOI(NAND) logic circuit that I created to display my date of birth. I created this circuit in MultiSim to test if my expressions were correct. This circuit was created only using two-input NOR gates.
This un-simplified circuit is created in bus form to allow the creating of the circuit to be easier. I used NOR gates (74LS02) to create this circuit. To build this circuit on a breadboard, I would need 3 NOR chips (74LS02). The NOR gates are used because they are universal gates therefore can be used for any of the basic operations. It is important to save gates and chips because it is less expensive, and the current will take less time to transfer from the beginning to the end.
All the 7 LED terminals have their own logic expression so that together they can create a number. Common Cathode has all LED grounds connected and Common Anode has all LED power connected. We are using common cathode to connect the 7 segment display to the ground and connected to the appropriate segment to power. The purpose of using resistors before the seven segment display is to limit the current going to the LED's.
This un-simplified circuit is created in bus form to allow the creating of the circuit to be easier. I used NOR gates (74LS02) to create this circuit. To build this circuit on a breadboard, I would need 3 NOR chips (74LS02). The NOR gates are used because they are universal gates therefore can be used for any of the basic operations. It is important to save gates and chips because it is less expensive, and the current will take less time to transfer from the beginning to the end.
All the 7 LED terminals have their own logic expression so that together they can create a number. Common Cathode has all LED grounds connected and Common Anode has all LED power connected. We are using common cathode to connect the 7 segment display to the ground and connected to the appropriate segment to power. The purpose of using resistors before the seven segment display is to limit the current going to the LED's.
bill of materials
This a bill of materials that lists all the materials that I uesd to make my circuit for the majority vote project. I used one breadboard with seven segment display, 41 wires, three NOR chips
Bread-boarding
This is showing the wires to the power and ground which it lighted the 7 segment display.
This is showing my X, Y, and Z inputs being connected to the NOR chips. Each segment has its own logic expression so there is 7 different circuits creating the whole circuit.
My second bread boarding experience went ok compare to my classmates. Since I had easy simplified logic expression, I made my circuit using NOR gate. After I completed my circuit, I realized that whether I used AOI or NOR I would need same amount of chips. During bread-boarding, I didn't know I could just put logic expression directly to the output.
conclusion
From this project, I learned how to put my birthday into seven segment to display. After we read and understood the problem statement, we had to create a truth table and then K-Map to simplified the logic expression for each segment of the seven segment display. Then, we created the circuit on MulitSim, and bread-boarded the circuit. What I would do differently next time is take the time to look for simple mistakes like check the chips to identify the problem. Overall I have no further questions about the concepts addressed in the problem. I understood the concepts of this project well. K-Mapping was useful to obtain the simplified logic expression. When I used the k-mapping, it was quicker, easier, and I found there was less room for mistakes. Lastly if we have one more project like this, I will definitely to better than this project.
extra credit
Need3 NOR chips
Need 4 NAND chips
Need 1 inverter, 1 OR, 1AND chip
Therefore, using AOI or NOR chips are going to be most efficient.
Therefore, using AOI or NOR chips are going to be most efficient.