Exclusive-OR (XOR) truth – is the output HIGH when the inputs are unequal?

Introduction / Context:
The XOR gate is widely used for parity generation, adders (sum bit), and change detection. This item verifies the canonical XOR condition in two-input form.

Given Data / Assumptions:

• Two-input XOR gate under ideal Boolean behavior.
• Active-HIGH convention for logic 1.
• No timing hazards considered.

Concept / Approach:
XOR evaluates to 1 if and only if its inputs differ. It is often read as “either A or B, but not both.” Therefore, stating that the output is HIGH when inputs are unequal is accurate.

Step-by-Step Solution:

Verification / Alternative check:
Truth table: 00→0, 01→1, 10→1, 11→0. In full adders, XOR generates the sum bit, further reinforcing the “unequal → 1” behavior.

Why Other Options Are Wrong:
“Incorrect” would describe XNOR, not XOR. The options “Only when both inputs are LOW/HIGH” refer to equality cases, which produce 0 for XOR. “Only for TTL families” confuses logic family with function; XOR behavior is universal across families.

Common Pitfalls:
Mixing XOR with inclusive OR. Inclusive OR is 1 for 01, 10, and 11; XOR excludes the 11 case, hence “exclusive.”

Final Answer:
Correct