A-LevelComputer ScienceHardware9618/12 · May/June 2024 · Q16 Marks

Describe the operation of each of the following logic gates: NAND NOR XOR OR

(a)Describe the operation of each of the following logic gates: NAND NOR XOR OR[4]
(b)Draw a logic circuit for this logic expression: X = NOT ((A AND B) OR (C AND D))[2]

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Mark scheme

Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.

[1] (a) NAND: The output is 0 when both inputs are 1, otherwise the output is 1
[1] (a) NOR: The output is 1 when both inputs are 0, otherwise the output is 0
[1] (a) XOR: The output is 1 when one of the inputs is 1 and the other input is 0, otherwise the output is 0
[1] (a) OR: The output is 0 when both inputs are 0, otherwise the output is 1
[1] (b) 1 mark for both AND gates with correct inputs
[1] (b) 1 mark for correct OR and NOT gates with correct inputs and no superfluous gates

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About this question

Topic

Hardware, A-Level Computer Science (syllabus 9618). Structured question, 6 marks.

Source

A-Level Computer Science, May/June 2024 Paper 1 Variant 2, question 1.

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