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.
Example 2: NOT(A) AND B
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"
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.