# show how a larger MUX can be built using only the two 74LS153 ICS.

#### riteshaukhojee

Joined Jun 21, 2022
4
n someone pls help me with these 2 questions. im new to electronics and where was a lab on this . all the designs i saw have not gates but we were not given those. here are the questions, i also attached the lab

Q1. If you are provided with two such ICs, show how a larger MUX can be built using only the two 74LS153 ICS.

Q2. Hence, build a circuit using only two 74LS153 ICs, a LED and an appropriate resistor at the output, to implement the Sum output of a Full Adder. Draw the circuit of the FA using the available Multiplexers. Show the pin out diagram. Draw the truth table and details your observations with respect to the operation of the FA implemented using MUX.

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#### Ian0

Joined Aug 7, 2020
5,503
I’ll not comment on Q1, because it doesn’t define what is meant by “a larger mix”.

For Q2, start by drawing a truth table Of what outputs are required depending on the two inputs. Hint: the A and B inputs are your logic inputs.
Then work out how to connect the “c” inputs to give the required logic outputs on the “Y” pins

#### riteshaukhojee

Joined Jun 21, 2022
4
I’ll not comment on Q1, because it doesn’t define what is meant by “a larger mix”.

For Q2, start by drawing a truth table Of what outputs are required depending on the two inputs. Hint: the A and B inputs are your logic inputs.
Then work out how to connect the “c” inputs to give the required logic outputs on the “Y” pins
Yes I did that
For sum, I got c,c',c' and c
But how do I input c' if I have no not gates?

#### Ian0

Joined Aug 7, 2020
5,503
Yes I did that
For sum, I got c,c',c' and c
But how do I input c' if I have no not gates?
But suppose you did have a NOT gate, where would you connect its input?

#### riteshaukhojee

Joined Jun 21, 2022
4
But suppose you did have a NOT gate, where would you connect its input?
Switch? I'm not sure

I also found a circuit

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#### Ian0

Joined Aug 7, 2020
5,503
Switch? I'm not sure
If so, then you can invert it just by moving the switch to the other position, so why would you need a NOT gate?
but do you ever need to change the logic level?

I also found a circuit
That would seem to answer Q1

#### riteshaukhojee

Joined Jun 21, 2022
4
If so, then you can invert it just by moving the switch to the other position, so why would you need a NOT gate?
but do you ever need to change the logic level?

That would seem to answer Q1
If so, then you can invert it just by moving the switch to the other position, so why would you need a NOT gate?
but do you ever need to change the logic level?

That would seem to answer Q1
Yeah now I understood. So we invert the input that the mux is giving as output(c)

#### dl324

Joined Mar 30, 2015
14,678
Smaller image to reduce file size:

You should learn how to do screen captures so we don't have to deal with glare and moire patterns.

Does larger mean more inputs? Were you provided with logic gates?