The output from NAND gate having inputs A and B given below will be,

Solution

Physics sir · 3 steps

A NAND gate gives 0 only when both inputs are 1, so just hunt for the intervals where A and B are both high.

1. NAND rule. NAND is AND followed by NOT, so Y = A · B̅. The output is 0 only when A = 1 and B = 1 together. In every other case it is 1.
2. Read the inputs. The dashed lines split time into intervals. Read A and B in each one, then apply the rule.

   Interval	A	B	Y = A · B̅
   before 1st line	1	1	0
   1st to 2nd	0	0	1
   2nd to 3rd	0	1	1
   3rd to 4th	1	0	1
   4th to 5th	1	1	0
   5th to 6th	0	0	1
   6th to 7th	0	1	1

3. So. The output is low at the start, high for three intervals, low for one interval, then high to the end. Only waveform (b) has this shape.

The idea to keep. For NAND, find only the intervals where all inputs are 1 and mark the output 0 there. Everywhere else the output is 1. That one scan settles any timing-diagram question.

Answer from the NTA final answer key. Solution by PrepWiser.