Adder ppt
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This document discusses different types of digital adders. It defines an adder as a digital circuit that performs addition of numbers. It describes half adders, full adders, ripple carry adders, and look ahead carry units. For half adders, it provides the logic equations for sum and carry outputs. For full adders, it gives the logic equations for sum and carry outputs and includes the truth table. It explains that ripple carry adders use multiple full adders in sequence to add N-bit numbers, with each carry bit "ripplying" to the next full adder.
Adder ppt
- 1. ADDER -Jadhav Avinash J. -2K13E11 - SavitriBai Phule Pune University 1
- 2. 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. 2
- 3. TYPES OF ADDERS??? Half Adder Full Adder Ripple Adder Look ahead carry unit Carry-save adders 3
- 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 4
- 6. 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’. 6
- 7. TRUTH TABLE 7 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 8 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. 9