project overview
Design a combinational logic circuit that has three inputs and seven outputs. As the inputs (X, Y, and Z) count from 000 to 111, the seven outputs (a) through (g) will generate the logic required to display your date of birth on a seven-segment display. The date of birth will be displayed in the MM-DD-YY format.
truth table
The purpose of the truth table is to check your circuit by substituting the values into the multi sim program.
we have columns a through g because the value of each row contains the values needed to control the output of the leds. the use of x as a variable is to make it what ever you need it to be so that it is easier to create the truth table. K maps are a pictorial method used to minimize Boolean expressions without having to use Boolean algebra theorems and equation manipulations. the expressions are in Sum of Products form. i arrived at the mid terms by k mapping. i used k mapping instead because its easier. i have so many expressions for each letter a through g.
multi-sim implementation
I had a fairly easy circuit to create the hardest one to create was A. I was lucky and 2 of them were always on. in multi sim i used a bus so it would be easier to create my circuit and it made it look much neater and less complicated. i used 4 types of gates to create the circuit they were 1 74ls00p, 2 74ls04p, 1 74ls08p,1 74ls32p. i used nand gate to create one of my paths. it required less materials to construct. it contained less gates than i would of if i would of used a regular and and or gate. this is important because it saves materials time and money. the difference between common cathode and common anode is cathode needs to be grounded and anode needs to be powered. i'm using a common cathode. the purpose of the resistor is so that the circuit will work with out them the lights flash or dont turn on.
bread boarding
This was my first attempt at the bread board that proved to be wrong and i was forced to start over again
This in the correct board at the finished a working state
this is showing how i used s1 s2 and s3 multiple times by plugging them in on the bread board its self
Bill of materials
74ls00p=1
74ls04p=2
74ls08p=1
74ls32p=1
wires=52
74ls04p=2
74ls08p=1
74ls32p=1
wires=52
description / bread boarding experience
first i had to create 7 truth tables. each one represented a number of my birthday. after the truth tables were created i then proceeded to create the combinational circuit on multi sim. i succeeded the first time but with out using a nand or a nor gate. so i went back and added one and changed the values of the wires to negative so they would come out the same i didnt know at the time that this was incorrect. i proceeded to breadboard the entire circuit. when i was finished i had done it correctly but not knowing that my multi sim was wrong it was all incorrect so i went back fixed my multi sim circuit and completed my bread-boarding.
Reflection
n this project i learned that i have become a lot better at bread boarding. Also i learned to pay attention to detail and how much a nand gate can mess up things if your not careful. Next time i will make sure to check my circuit carefully when adding a new piece so that i dont proceed to bread board twice because of a simple mistake. a question that i have about the project is CAN WE USE these skill to creatE a clock.