Boolean Logic · 5 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 9% of your exam marks.
Truth tables and Boolean expressions from circuit diagrams appear in every paper. 4 to 6 marks.
Sometimes a question gives the circuit and asks for the Boolean expression. The method is the mirror image of section 8.
Method. (1) Label each gate's output left to right. (2) Write the expression for each labelled output in terms of the inputs feeding it. (3) Substitute into the final output's expression so that everything is expressed in terms of the original inputs.