Question 17: The output (\mathrm{Y}) of the given logic gate is similar to
the output of an/a :
(1) NAND gate
(2) NOR gate
(3) OR gate
(4) AND gate
Answer: Option (4)
Explanation:
In the given circuit, the top gate is a NAND gate with both inputs connected
to \mathrm{A}. Such a configuration works as a NOT gate.
Therefore, the output of the top gate is \overline{\mathrm{A}}.
The bottom gate is a NOR gate with both inputs connected to \mathrm{B},
which also behaves as a NOT gate.
Hence, the output of the bottom gate is \overline{\mathrm{B}}.
These two outputs, \overline{\mathrm{A}}
and \overline{\mathrm{B}}, are then applied to a NOR gate.
The output of the NOR gate is
\mathrm{Y}=\overline{\overline{\mathrm{A}}+\overline{\mathrm{B}}}Using De Morgan’s theorem,
\mathrm{Y}=\mathrm{A}\cdot \mathrm{B}This is exactly the logical expression of an AND gate.
Therefore, the output \mathrm{Y} is similar to the output of an AND gate.