COMPUTER SCIENCE AND ENGINEERING
COMPUTER ORGANIZATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Sum of Half Adder
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Difference of Half Subtractor
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Difference of Full Subtractor
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None of the above
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Detailed explanation-1: -Explanation: The sum and difference output of a full adder and a full subtractor are same. If A, B and C are the input of a full adder and a full subtractor then the output will be given by (A XOR B XOR C), respectively.
Detailed explanation-2: -We can also express the full adder circuit construction in Boolean expression. For the case of SUM, We first XOR the A and B input then we again XOR the output with Carry in. So, the Sum is (A XOR B) XOR C. We can also express it with (A ⊕ B)
Detailed explanation-3: -When designed from truth-tables and K-maps, a full subtractor is very similar to a full adder, but it contains two inverters that a full adder does not. When configured to subtract, an adder/subtractor circuit adds a single inverter (in the form of an XOR gate) to one input of a full adder module.
Detailed explanation-4: -By comparing the adder and subtractor circuits and truth tables, we can observe that the output D in the full subtractor is exactly same as the output S of the full adder. And the only difference is that input variable A is complemented in the full subtractor.