Adding two single bits using logic Which type of logic gate directly produces the sum output when adding two one-bit operands (ignoring the carry)?

Introduction / Context:
Binary addition of two single bits (A and B) produces a sum and a carry. In half adders and full adders, distinct logic functions generate these outputs. Knowing which gate corresponds to the sum output is a foundational digital design skill.

Given Data / Assumptions:

• Operands: A and B are 1-bit values.
• We are asking only about the sum output, not the carry.
• Standard gate-level realization is assumed.

Concept / Approach:
The truth table for the binary sum without carry is: A B → Sum: 00→0, 01→1, 10→1, 11→0. This exactly matches the Exclusive-OR (XOR, written Ex-OR) function. The carry-out for a half adder is A * B (AND), but that is not requested here.

Step-by-Step Solution:

Verification / Alternative check:
Construct a half adder: Sum = A XOR B, Carry = A AND B. Simulation or logic-equation derivation yields the same mapping.

Why Other Options Are Wrong:

• Ex-NOR: outputs 1 when inputs are equal (00 or 11) → not the sum.
• Ex-NAND: not a standard primitive function for addition.
• NOR: outputs 1 only when both inputs are 0.

Common Pitfalls:
Confusing the roles of XOR and AND in a half adder; remember XOR is for sum, AND for carry.

Final Answer:
Ex-OR