Question 19: Semiconductors and Logic Gates

Question

$ 	ext { The given circuit works as : } $
![](https://app-content.cdn.examgoal.net/fly/@width/image/6y3zli1ml8ayqpf/30da82d4-73e5-40c5-9a1c-166e358104dd/192ee030-01ef-11f1-bb8c-db351d97a854/file-6y3zli1ml8ayqpg.png?format=png)

Accepted Answer

The circuit is composed entirely of NOR gates. A NOR gate with its inputs tied together (or receiving the same signal) acts as a NOT gate. $\$ 	ext{} $\$
If input is $A$, the output is $\overline{A+A}=\bar{A}$ $\$
$ \begin{array}{|l|l|l|l|} \hline 	ext { Input 1 } & 	ext { Input 2 } & 	ext { OR Output } & 	ext { NOR Output } \ \hline 1 & 1 & 1 & 0 \ \hline 0 & 0 & 0 & 1 \ \hline \end{array} $ $\$ 	ext{} $\$
$ \begin{array}{|l|l|l|l|l|l|} \hline \mathrm{A} & \mathrm{~B} & \mathrm{Y}_1=\overline{\mathrm{A}} & \mathrm{Y}_2=\overline{\mathrm{B}} & \mathrm{Y}_3=\overline{\mathrm{Y}_1+\mathrm{Y}_2} & \mathrm{Y}_4=\overline{\mathrm{Y}_3} \ \hline 1 & 1 & 0 & 0 & 1 & 0 \ \hline 1 & 0 & 0 & 1 & 0 & 1 \ \hline 0 & 1 & 1 & 0 & 0 & 1 \ \hline 0 & 0 & 1 & 1 & 0 & 1 \ \hline \end{array} $ $\$ 	ext{} $\$
The final expression $\mathrm{Y}=\overline{\mathrm{A} \cdot \mathrm{B}}$ is the characteristic equation for a NAND gate. $\$
Therefore, the circuit functions as a NAND gate. $\$
Hence, the correct option is (D).
![](https://app-content.cdn.examgoal.net/fly/@width/image/6y3zli1mm4l5mcq/3de7509a-79d5-4250-8b31-51f94865dddd/088ebca0-13b0-11f1-865a-8bf6aebc55a0/file-6y3zli1mm4l5mcr.png?format=png)

Answer

NOR gate

Answer

OR gate

Answer

AND gate

Answer

NAND gate

Semiconductors and Logic Gates

\text{ The given circuit works as : }

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