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MHT CET · Physics · Semiconductors

To obtain the truth-table shown, from the following logic circuit, the gate \(\mathrm{G}\) should be

\(\begin{array}{|l|l|l|}\hline \mathrm{A} & \mathrm{B} & \mathrm{Y} 0 & 0 & 1 0 & 1 & 0 1 & 0 & 1 1 & 1 & 1 \\\hline\end{array}\)

  1. A AND
  2. B NAND
  3. C OR
  4. D NOR
Verified Solution

Answer & Solution

Correct Answer

(D) NOR

Step-by-step Solution

Detailed explanation


The truth table for given configuration is as shown below.
\(\begin{array}{|c|c|c|c|c|}
\hline Case & \mathbf{A} & \mathbf{B} & \mathbf{C} & \mathbf{A}+\mathbf{C}=\mathrm{Y} \\
\hline I & 0 & 0 & \mathrm{C}_1 & 0+\mathrm{C}_1=1 \\
\hline II & 0 & 1 & \mathrm{C}_2 & 0+\mathrm{C}_2=0 \\
\hline III & 1 & 0 & \mathrm{C}_3 & 1+\mathrm{C}_3=1 \\
\hline IV & 1 & 1 & \mathrm{C}_4 & 1+\mathrm{C}_4=1 \\
\hline
\end{array}\)
Considering case (I), in order to have output \(\mathrm{Y})\) as \(1, \mathrm{C}_1\) has to be 1 . For input values, \(\mathrm{A}=0\) and \(\mathrm{B}=0\), if \(\mathrm{C}_1\) is to be high, the gate \(\mathrm{G}\) could be either NAND or NOR.
Considering case (II), in order to have output (Y) as \(0, C_2\) has to be 0 . For input values, \(\mathrm{A}=0\) and \(\mathrm{B}=1\). If \(\mathrm{C}_2\) is to be 0 , the gate must be NOR.