The full subtractor can be implemented using ___________a)Two XOR and an OR gatesb)Two half subtractors and an OR gatec)Two multiplexers and an AND gated)Two comparators and an AND gateCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Explanation:

Half Subtractor:
- A half subtractor is a combinational circuit that performs subtraction of two bits along with a borrow input.
- It consists of two gates - XOR gate for the difference output and an AND gate for the borrow output.

Full Subtractor:
- A full subtractor is a combinational circuit that performs subtraction of three bits: minuend, subtrahend, and borrow input.
- It consists of two half subtractors and an OR gate.
- The output of the first half subtractor is fed as input to the second half subtractor along with the borrow input.
- The outputs of the two half subtractors are then combined using an OR gate to get the final difference output and borrow output.

Implementation:
- To implement a full subtractor, we can use two half subtractors and an OR gate.
- The first half subtractor will take the minuend, subtrahend, and borrow input as inputs and produce a difference output and a borrow output.
- The second half subtractor will take the difference output from the first half subtractor, along with the borrow input, and produce the final difference output and borrow output.
- The two borrow outputs from the half subtractors are then combined using an OR gate to get the final borrow output.

Therefore, the full subtractor can be implemented using two half subtractors and an OR gate.

Answer

A full subtractor has 3 input bits and two outputs bits BORROW and DIFFERENCE. The full subtractor can be implemented using two half subtractors and an OR gate.

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