Question

1. write a truth table using this symbol: -->

2. write the inputs for the truth table to the left of the --> and write the outputs for the truth table to the right of the -->

3. write the compliment, or NOT using '

As an example:

The truth table for AND is written this way:

A B --> A AND B

0 0 --> 0

0 1 --> 0

1 0 --> 0

1 1 --> 1

or this way:

A B --> A AND B

a' b' --> 0

a' b --> 0

a b' --> 0

a b --> 1

As another example:

For a 3 input, 2 output truth table, the truth table is written this way:

A B C --> X Y

0 0 0 --> 0 0

0 0 1 --> 1 0

0 1 0 --> 1 0

0 1 1 --> 0 1

1 0 0 --> 1 0

1 0 1 --> 0 1

1 1 0 --> 0 1

1 1 1 --> 1 1

A particular kind of multiplexer known as a 2 to 1 multiplexer is made with and two AND gates, and one OR gate has the following sum of products:

C = (A •S) +(B• S)

where inputs A and B are selected with the selector S.

(Optional: You can look at a diagram and read a description of the multiplexer in the textbook, Appendix B, Page B-17)

Part a) Write the truth table for the multiplexer.

Part b) Explain in English what the purpose of the S value is in the multiplexer -- how does S relate to the A value and B value of the multiplexer? Write your explanation in 4 sentences or less.

Answer 1

a) The truth table of multiplexer is as follow:

S A B -> C

0 0 0 -> 0

0 0 1 -> 0

0 1  0 -> 1

0 1 1 -> 1

1 0 0 -> 0

1 0 1 -> 1

1 1  0 -> 0

1 1 1 -> 1

b) As it can be seen through the truth table that output is not depending on the inputs i.e A and B but it is depending on the selector  i.e S.

So, the purpose of the S is to select that which input is to be pass through the multiplexer as when S is 0 it is allowing the A and when S is 1 it is allowing B to pass through multiplexer.

I hope I am solve to solve your problem, if yes then do give a thumbs up . It really helps :)