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ADDER
-Jadhav Avinash J.
-2K13E11
- SavitriBai Phule Pune University
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ADDER MEANS???
 An adder is a digital circuit that performs addition of
numbers.
 In processor it is used to calculate addresses, table
indices, and similar operations.
 It can be constructed for many numerical
representations, such as binary-coded decimal or
excess-3,the most common adders operate on
binary numbers.
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TYPES OF ADDERS???
 Half Adder
 Full Adder
 Ripple Adder
 Look ahead carry unit
 Carry-save adders
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4.
HALF ADDER
The half adder adds two single
binary digits A and B.
It has two outputs, sum (S) and
carry (C).
Sum = AB’+A’B.
Carry=A*B.
For half-adder design,
an XOR gate & an AND gate
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5.
TRUTH TABLE
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FULL ADDER
A combinational circuit that adds 3 input bits to generate a
Sum bit and a Carry bit
Where X,Y,Z are inputs and C & S are outputs.
Sum= X+Y+Z.
Cout= XY’+YZ’+ZX’.
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7.
TRUTH TABLE
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X Y Z S C
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 0

8.
RIPPLE CARRY ADDER
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It is possible to create a logical circuit using multiple full
adders to add
N-bit numbers.
Each full adder inputs a Cin, which is the Cout of the
previous adder.
This kind of adder is called a ripple-carry adder, since
each carry bit "ripples" to the next full adder.

9.
LOOK AHEAD CARRY UNIT
 By combining multiple carry lookahead adders even
larger adders can be created.
 This can be used at multiple levels to make even
larger adders.
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Any QUESTIONS???