2.4 - Boolean Logic

Question 1

Describe the purpose of a ‘Truth Table’.

Answer 1

To show all possible combinations of inputs to a logic circuit and the corresponding output for each combination.

Question 2

How many rows are in a truth table with 3 inputs?

Answer 2

Eight rows, because 2 to the power of 3 equals 8.

Question 3

Draw or describe the symbol and logic result for an ‘AND’ gate (Conjunction).

Answer 3

The symbol is a D-shaped gate with no circle. The output is 1 (True) only when both inputs are 1; otherwise, the output is 0.

Question 4

Draw or describe the symbol and logic result for an ‘OR’ gate (Disjunction).

Answer 4

The symbol is a curved, pointed shape with no circle. The output is 1 (True) if either or both inputs are 1.

Question 5

Describe the features of a ‘NOT’ gate (Negation) symbol.

Answer 5

The symbol is a triangle with a small circle showing inversion. It has one input and one output, and the output is always the opposite of the input.