Question

How many NAND gates are required to form an AND gate?

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

Answer: (B)

Two NAND gates arranged as shown, would give an AND gate.

Here output from first NAND gate is $\overline{A.B}$

This, as input, is again fed to a NAND gate, giving

$\overline{\overline{A.B}.\overline{A.B}}=\overline{\overline{A.B}}+\overline{\overline{A.B}}=A.B$