This circuit inverts input A (using NOT gate) then combines it with B using an AND gate.
| A | B | NOT A (intermediate) |
NOT(A) AND B (final output) |
| 0 | 0 | 1 | 0 |
| 0 | 1 | 1 | 1 |
| 1 | 0 | 0 | 0 |
| 1 | 1 | 0 | 0 |
NOT A column: Flips A's value (0→1, 1→0)
Final output: Only 1 when NOT(A) is 1 AND B is 1 - that's row 2 only
In plain English: Output is 1 only when "A is false AND B is true"
This key facts covers Example 2: NOT(A) AND B within Truth Tables for GCSE Computer Science. Revise Truth Tables in 3.4 Computer Systems for GCSE Computer Science with 15 exam-style questions and 15 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 6 of 11 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Truth Tables
How many rows are needed in a truth table with 2 inputs (not including the header row)?
Explain why truth tables are useful when designing or testing logic circuits.