Week 3 - Logic Gates 1

Question 1

What is the function of a NOT gate?

Answer 1

The NOT gate inverts the input signal

Question 2

What is the function of the AND gate?

Answer 2

The AND gate typically takes between 2 and 8 inputs. Any logic low gives a logic low.

Question 3

What is the function of the OR gate?

Answer 3

The OR gate takes more than 2 inputs. Any logic high gives a logic high.

Question 4

What is the function of a NAND gate?

Answer 4

A NAND gate is an AND gate with an inverted output. Any low gives a high.

Question 5

What is the function of the NOR gate?

Answer 5

The NOR gate is just the OR gate with an inverted output. Any high gives a low.

Question 6

What is the function of the XOR gate?

Answer 6

The XOR gate is like the OR gate but when both or all inputs are logic high then the output is logic low. Essentially, matching inputs gives a logic low and differing inputs give a logic high.

Question 7

What is a multiplexer composed of and what is the purpose of a multiplexor?

Answer 7

A multiplexer is composed of a decoder and a selector. The purpose of a multiplexer is to act as a switch with the output of the multiplexer being determined by the ‘select’ signal.

Question 8

What is the difference between a half-adder and a full-adder?

Answer 8

A half-adder will perform bit addition but with no input for a carry bit. It has a sum and carry output.

A full-adder will perform bit addition along with a carry input.