Truth Tables - All Possible Combinations
Part of Logic Gates — GCSE Computer Science
This key facts covers Truth Tables - All Possible Combinations within Logic Gates for GCSE Computer Science. Revise Logic Gates in Boolean Logic for GCSE Computer Science with 15 exam-style questions and 20 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 6 of 8 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 8
Practice
15 questions
Recall
20 flashcards
Truth Tables - All Possible Combinations
A truth table shows the output for EVERY possible combination of inputs. With 2 inputs, there are 4 possible combinations (2² = 4).
| AND Gate Truth Table | OR Gate Truth Table | NOT Gate Truth Table | |||||
|---|---|---|---|---|---|---|---|
| A | B | Q (A AND B) | A | B | Q (A OR B) | A | Q (NOT A) |
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 0 | 1 | 0 | 0 | 1 | 1 | 1 | 0 |
| 1 | 0 | 0 | 1 | 0 | 1 | ||
| 1 | 1 | 1 | 1 | 1 | 1 | ||
AND Gate: Only ONE row outputs 1 (the last row: 1,1 → 1). All need to be true!
OR Gate: Only ONE row outputs 0 (the first row: 0,0 → 0). At least one needed!
NOT Gate: Just FLIPS the bit - 0 becomes 1, 1 becomes 0