Question

Input waveforms A and B as shown in Fig-I are applied to the combination of gates as shown in Fig-II. Which of the waveforms shown in Fig. (i) to (iv) correctly represents the output waveform?

• A. Fig.(i)
• B. Fig.(ii)
• C. Fig.(iii)
• D. Fig. (iv)

Answer 1

Answer: (C)

Fig.(iii)

Answer 2

Y = $\bar{A} + \bar{B}$

Ž $\begin{matrix} A & B & Y \\ 0 & 0 & 1 \\ 0 & 1 & 1 \\ 1 & 0 & 1 \\ 1 & 1 & 0 \end{matrix}$ Ž $10101010

}\begin{matrix} = 01111101 \end{matrix}$$ So, output is 'zero' when both inputs are 'one'. In all other cases output is one.