Question

To get an OR gate from a NAND gate, we need

• A. Only two NAND gates
• B. Two NOT gates obtained from NAND gates and one NAND gate
• C. Four NAND gates and two AND gates obtained from NAND gates
• D. None of the above

Answer 1

Answer: (B)

Two NOT gates obtained from NAND gates and one NAND gate

To obtain OR gate from NAND gates we need to NOT gates obtained from NAND gates and one NAND gate as figure.
Boolean expression $Y=\overline{A.B.}=\overline{A}+\overline{B}$
$=A+B,$ $OR$ gate