ITPEC FE Subject A April 2026 Question 17

Topic: Hardware

Which of the following is the appropriate circuit with two (2) inputs and one (1) output where the output X is 0 only when the two (2) inputs A and B are both 1?

a)AND circuitb)NAND circuitc)OR circuitd)XOR circuit

Explanation

NAND circuit — its output is 0 only in the row where both inputs are 1.

NAND is AND followed by NOT:

A	B	X
0	0	1
0	1	1
1	0	1
1	1	0

Answer (b)

Why not others:

•(a) AND circuit — outputs 1 when both inputs are 1, the inverse of what is asked
•(c) OR circuit — outputs 0 only when both inputs are 0
•(d) XOR circuit — outputs 0 whenever the inputs are equal, so also for 0 and 0

Key rule: Turn the wording into truth-table rows and match the gate: a single 0 at inputs 1, 1 is NAND, a single 0 at inputs 0, 0 is OR.

Hardware · AI-written, may contain errors

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