A half adder is a basic digital circuit that performs addition of two binary digits and produces two outputs: a sum and a carry. It comprises an XOR gate and an AND gate. The inputs are called augend and addend, and the output sum is the XOR of the inputs while the carry is the AND of the inputs. A half adder can add only two bits and is used as a basic building block for digital addition circuits.

1. HALF ADDER
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Presented by: Rabin BK
BSc.CSIT 2nd Semester

2. Introduction to Adder
What is Half Adder?
Half Adder Logic diagram
A glimpse at the working of Half adder
Application of Half Adder
References
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3. A digital logic circuit in electronics that implements addition of 2 bits
Used to calculate addresses and table indices in the ALU and also in
other parts of the processors
Most commonly, it operate on binary numbers
Classified into two types:
 half adder and full adder
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4. It adds two binary digits
The input variables are called augend and addend bits and produces two
outputs as sum and carry following simple binary addition
The sum and carry are two outputs
For an example:
0 + 0 = 0 0
0 + 1 = 1 0
1 + 0 = 1 0
1 + 1 = 0 1
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Carry ‘C’
Sum ‘S’

5. Comprises of XOR gate and AND gate
Two input variables are A and B as augend and addend
Truth Table is:
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Augend
Addend
Output
variable
Input Output
A B S C
0 0 0 0
1 0 1 0
0 1 1 0
1 1 0 1

6. For the input variables A and B as augend and addend, the Half Adder
works as:
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Input
variable
Output
variable
SUM
CARR
Y

7. With the addition of an OR gate to combine their carry outputs, two
half adders can be combined to make a full adder
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8. References
Web reference:
 https://www.elprocus.com/half-adder-and-full-adder/
 https://upload.wikimedia.org/wikipedia/commons/thumb/9/92/Halfadder.gif/220px-
Halfadder.gif
 http://theteacher.info/index.php/programming-development-1/2-logical-operations/all-
topics/3622-an-application-of-full-adders
 https://www.google.com.np/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&ua
ct=8&ved=0ahUKEwihmqX-2pbUAhXHtI8KHa-
DF4QFggjMAE&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAdder_(electronic
s)&usg=AFQjCNFbLNz08tyf8ay0TMSApHtVnXoDGQ&sig2=5_allA9EWff09dqaizgkC
Q
 https://en.wikipedia.org/wiki/Adder_(electronics)
 http://www.lbpcentral.com/forums/showthread.php?51015-Practical-applications-for-
adder-subtraction-circuits-amp-7-bit-registers-e-t-c
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9. Queries
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