Lab # 9
Full Adder and Half Adder
Adrian Brown
11/5/98
Abdul Habibala
Introduction . Abstract . Procedure . Results . Conclusion
The purpose of this lab is to become familiar with the Half Adder and the Full Adder.We will be simulating the Adders using the B^2 logic programme, and also using proto-board with the chips available to us. The truth table for each circuit is known and will be used to comfirm the results.
The Adders are used to add binary digits together, resulting in an sum bit and a carry bit. The half Adder adds two binary digits while full adders can add multi digit numbers. adders produce a sum and a carry digit as their out put. A full adder consist of two hafl adders
To design this circuit we needed the Proto Board the AND chip the OR chip and the NOT chip.
The proto board
The AND chip
7408
The OR chip
7432
The NOT chip
7404
First we simulated the half adder circuit using the followng schematic and truth table
Half Adder using an exclusive or gate and an AND gate
Half Adder using AND and OR gates and inverters
A | B | sum | carry |
0 | 0 | 0 | 0 |
0 | 1 | 1 | 0 |
1 | 0 | 1 | 0 |
1 | 1 | 0 | 1 |
Truth Table for the half adder.
we then simulated the circuit on both b^2 logic and on the proto board.
We then simulated the full adder using the schematic and truth table.
for the first and second half of the adder we substitued using the AND and OR arrangement shown above
A | B | carry in | sum | carry out |
0 | 0 | 0 | 0 | 0 |
0 | 0 | 1 | 1 | 0 |
0 | 1 | 0 | 1 | 0 |
0 | 1 | 1 | 0 | 1 |
1 | 0 | 0 | 1 | 0 |
1 | 0 | 1 | 0 | 1 |
1 | 1 | 0 | 0 | 1 |
1 | 1 | 1 | 1 | 1 |
Full Adder truth Table
We then simulated using B^2 logic andthe protoboard.
A | B | sum | carry | results |
0 | 0 | 0 | 0 | yes |
0 | 1 | 1 | 0 | yes |
1 | 0 | 1 | 0 | yes |
1 | 1 | 0 | 1 | yes |
Results for half adder
A | B | carry in | sum | carry out | results |
0 | 0 | 0 | 0 | 0 | yes |
0 | 0 | 1 | 1 | 0 | yes |
0 | 1 | 0 | 1 | 0 | yes |
0 | 1 | 1 | 0 | 1 | yes |
1 | 0 | 0 | 1 | 0 | yes |
1 | 0 | 1 | 0 | 1 | yes |
1 | 1 | 0 | 0 | 1 | yes |
1 | 1 | 1 | 1 | 1 | yes |
Results for full Adder
The simulation on the B^2 logic programme worked well. We comfirmed all the sum and carry bits using this programme. However simulating the circuit on the proto board was not successful. This was due to the faulty proto boards.