Question

What is the output Y in the following circuit when all the three inputs A, B, C are first $0$ and then $1$ ?

• A. $1,1$
• B. $0,1$
• C. $0,0$
• D. $1,0$

Answer 1

The correct option is D $1,0$


Here the gate P is a logic symbol of AND gate and Q is a NAND gate.
So, the output of P is $Y_p=A.B$ and the output of Q is
$Y=\overline{Y_p}.C$
When, $A=0,B=0,C=0$
$\Rightarrow Y_p=0,Y=$ $\overline{0.0}$$=1$

When, $A=1,B=1,C=1$
$\Rightarrow Y_p=1,Y=$ $\overline{1.1}$$=0$