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JEE Main 2020 (2 Sep, Shift 2) · Logic Gates

Logic Gates question from JEE Main 2020 (2 Sep, Shift 2)

Q139JEE Main 2020 · 2 SEP · SHIFT 2Medium

Logic Gates

In the following digital circuit, what will be the output at ‘Z’, when the

input (A, B) are (1, 0), (0, 0), (1, 1,), (0, 1)

Figure

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Answer: (d)

  1. NAND: P=AB‾P = \overline{AB}. OR: A+BA + B. AND: P(A+B)=ABˉ+AˉBP(A + B) = A\bar{B} + \bar{A}B.
  2. Z=P+(ABˉ+AˉB)‾Z = \overline{P + (A\bar{B} + \bar{A}B)}. If P=1P = 1, Z=0Z = 0.
  3. P=1P = 1 for (1,0),(0,0),(0,1)(1,0), (0,0), (0,1), so Z = 0 there.
  4. For (1,1)(1,1): P=0P = 0 and XOR =0= 0, so Z=1Z = 1.
  5. Output: 0,0,1,00, 0, 1, 0. So the answer is (d).
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