Half Adder / Full Adder / Half Subtractor / Full Subtractor:
AIM: To realize
- Half Adder
- Full Adder
- Half Subtractor
- Full Subtractor
- To realize the adder and subtractor circuits using basic gates and universal gates
- To realize full adder using two half adders
- To realize a full subtractor using two half subtractors
- IC 7400
- IC 7408
- IC 7486
- IC 7432
- Patch Cords & IC Trainer Kit
A combinational logic circuit that performs the addition of two data bits, A and B, is called a half-adder. Addition will result in two output bits; one of which is the sum bit,
S, and the other is the carry bit, C.
|A||B||S = A ⊕ B||C = AB|
HALF ADDER USING NAND
HALF ADDER USING NOR
The half-adder does not take the carry bit from its previous stage into account.
This carry bit from its previous stage is called carry-in bit. A combinational logic circuit that
adds two data bits, A and B, and a carry-in bit, Cin , is called a full-adder.
|A||B||C||S =A ⊕ B||C = AB + BC + AC|
FULL ADDER USING NAND
FULL ADDER USING NOR
Subtracting a single-bit binary value B from another A (i.e. A -B ) produces
a difference bit D and a borrow out bit B-out. This operation is called half subtraction and the
circuit to realize it is called a half subtractor.
|A||B||D = A ⊕ B||B = AB|
HALF SUBTRACTOR USING NAND
HALF SUBTRACTOR USING NOR
Subtracting two single-bit binary values, B, Cin from a single-bit value A
produces a difference bit D and a borrow out Br bit. This is called full subtraction.
|A||B||C||D =A ⊕ B ⊕ C||B = AB + BC + AC|
FULL SUBTRACTOR USING NAND
FULL SUBTRACTOR USING NOR