XOR — IEEE double curve vs IEC `=1` — logic gate symbols
exam standardwhy the qualifier is `=1` and not `⊕`
Answer
output column 0110
Why this example is worth doing
The IEC qualifier for XOR is =1, meaning exactly one input is true — which is the correct reading for two inputs but diverges for more, because a multi-input XOR is odd-parity rather than exactly-one. The page is explicit that =1 on a three-input rectangle means one-hot, not parity, and that odd-parity needs the 2k+1 qualifier. This is a genuine trap in reading European schematics and it is almost never mentioned in introductory material.
Try your own input in the Logic gate symbols. Every gate in both symbol standards, side by side, on a printable one-page chart.
How the answer is reached
Truth table
| # | A | B | A ⊕ B |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 1 | 0 | 1 | 1 |
| 2 | 1 | 0 | 1 |
| 3 | 1 | 1 | 0 |