Dld

1. LAB PRACTICAL # O7
OBJECT:
Design a full adder circuit which provide sum and carry in their output.
Tools:
Circuit maker.
Theory:
The full adder is same as half adder which provide sum and carry ,and difference and borrow in
their output the only difference is that in half adder the two inputs are required whereas in full
adder the three inputs are used.
Blockdiagram:
TRUTH TABLE:
A B C SUM CARRY
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
LOGICAL DIAGRAM:
SUM=A’B’C+A’BC’+AB’C’+ABC
CARRY =A’BC+AB’C+ABC’+ABC
A
B
C
Sum
carry

2. TRUTH TABLE:
A B C DIFFERENCE BORROW
0 0 0 0 0
0 0 1 1 1
0 1 0 1 1
0 1 1 0 1
1 0 0 1 0
1 0 1 0 0
1 1 0 0 0
1 1 1 1 1
LOGICALEXPRESSION:
DIFFERENCE=A’B’C+A’BC’+AB’C’+ABC
BORROW=A’C+A’B+BC