[Semester 1] Introduction to Logic

Question 1

What do logic gates do?

Answer 1

Logic gates represent Boolean functions, i.e. they can be either true or false.

Question 2

An AND gate can be represented by this equation…

Answer 2

X = A · B

Question 3

An OR gate can be represented by this equation…

Answer 3

X = A + B

Question 4

True or false: A XOR gate is true if all inputs are true

Answer 4

False! A XOR gate is true if at least one input is true, but false if all or none of the inputs are true.

Question 5

A XOR gate can be represented by this equation…

Answer 5

X = A ⊕ B

Question 6

Negation

Answer 6

The opposite of the original gate, e.g. a NAND gate is always true unless all inputs are true.
Negation is indicated by a circle on the logic gate, or in equations, a line above the letter of the gate, like this: Ā

Question 7

A XNOR gate can be represented by this equation…

Answer 7

X = A ⊙ B

Question 8

True or false: A NOR gate has three inputs, A = 0, B = 0 and C = 0. The output value is 1.

Answer 8

True! NOR gates are only true if all inputs are false.

Question 9

Why is electricity important in a logic circuit?

Answer 9

As the current flows through the circuit, it uses the logic gates to make logical decisions.