Full Adders and Half Adders work on the same basic principle, a half adder is a method of adding two binary numbers using only the left-most bits. Half adders are fast and efficient, but they only work for binary numbers. If you want to add a decimal number, you will need a full adder. A full adder can add decimal numbers just like binary numbers, but it can also add decimal numbers in the middle bits, too
Half Adder
Half Adder is a combinational logic circuit and it is obtained by connecting one EX-OR gate and another is AND gate. The half adder circuit has two inputs which are A and B and two outputs that are Sum and Carry. The output of the EX-OR gate is the Sum that is obtained from the sum of both the one-bit numbers. that is called the Half Adder circuit.
Half Adder Circuit
Half-Adder Circuit Diagram
Truth Table Of Half Adder
Logical Expression of Half Adder
Sum (S) = A ⊕ B
Carry (C) = A . B
Full Adder
Full Adder also combinational logic circuits like half adder and it consists of two EX-OR gates, two AND gates, and one OR gate. Full Adder can adds three inputs and gives two outputs from EX-OR, AND, and OR gates. The first two inputs are A and B among three inputs and third input is carry as C-IN. According to circuit diagram the output is designed as C- Out and the normal output is designed as S that is SUM.
Full Adder Circuit
Full Adder Circuit Diagram
Truth Table Of Full Adder
Logical Expression of Full Adder
CARRY-OUT = AB + BCin + ACin
SUM = (A ⊕ B) ⊕ Cin
Difference Between Half Adder and Full Adder
Half Adder |
Full Adder |
The Half Adder is a type of combinational logic circuit that adds two of the 1-bit binary digits. It generates carry and sum of both the inputs. | The Full Adder is also a type of combinational logic that adds three of the 1-bit binary digits for performing an addition operation. It generates a sum of all three inputs along with a carry value. |
The Half Adder does not add the carry obtained from the previous addition to the next one. | The Full Adder, along with its current inputs A and B, also adds the previous carry. |
A Half Adder consists of only one AND gate and EX-OR gate. | A Full Adder consists of one OR gate and two EX-OR and AND gates. |
There are two inputs in a Half Adder- A and B. | There are a total of three inputs in a Full Adder- A. B. C-in. |
The Half Adder is good for digital measuring devices, computers, calculators, and many more. | The Full Adder comes into play in various digital processors, the addition of multiple bits, and many more. |
Here is the logical expression of Half Adder:C = A * B
S = A ⊕ B |
Here is the logical expression of Full Adder:Cout = (AB) + CinA ⊕ CinB
S =A ⊕ B ⊕ Cin |