Logic circuits

According to De Morgan's laws, which expression is equal to NOT(A AND B)?

  1. A(NOT A) AND (NOT B)
  2. B(NOT A) OR (NOT B)
  3. CA OR B
Show answer and explanation

Answer: B. (NOT A) OR (NOT B)

De Morgan's laws state NOT(A AND B) = (NOT A) OR (NOT B) and NOT(A OR B) = (NOT A) AND (NOT B). When the negation is distributed inside the parentheses, AND and OR swap. Using these laws, one can show that any logic circuit can be built from NAND gates alone, or from NOR gates alone.

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