Lab # 9

Full Adder and Half Adder

Adrian Brown

11/5/98

Abdul Habibala

 

Content

Introduction . Abstract . Procedure . Results . Conclusion

 

 

<<< Introduction. >>>

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.

 

<<< Abstact. >>>

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

 

 

<<< Procedure. >>>

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.

 

<<< Results >>>

 

 

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

 

<<<Conclusion>>>

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.

 

 

 

 

 

 

 

 

 

Adrian Brown

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