ITPEC FE Morning October 2019 Question 24

Source exam: ITPEC FE Morning October 2019Topic: Basic Theory & Math

ITPEC FE Morning October 2019 — Question 24 of 80

NAND-only circuit conversion — replace AND, OR, NOT with NAND gates.

Original circuit: F = NOT(A·B + C)

Step-by-step using De Morgan's law:

  • NOT(A·B + C) = NOT(A·B) · NOT(C)

NAND equivalents:
- NOT(X) = NAND(X, X)

- AND(X, Y) = NAND(NAND(X,Y), NAND(X,Y))

Exam strategy: When visual parsing of gate diagrams is uncertain, build a truth table for the original function and test each option with sample inputs (e.g., A=1, B=1, C=0 → F=0).

Answer: (b)

Key rule: Any logic circuit can be built using only NAND gates. Use De Morgan's law to decompose, then map each NOT/AND/OR to its NAND equivalent.

AI-generated — may contain errors

The original exam layout is preserved in the image so diagrams, formulas, tables, and code remain accurate.

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