Q- Implement a basic ALU which performs the operations of logical AND, logical OR, ADD, SUBRACT depending on the values of S1 & S0 Ans: We need to use an ADDER, AND gate, OR gate and some MUXes to implement the above function. We select the functions using the two variables S0 & S1 as: S1 […]

# Tag: Multiplexers

## Q9: Implement 4to1 MUX using 2to1 MUX

Q- Can we implement 4 to 1 MUX using (a) three 2 to 1 MUX (b) only two 2 to 1 MUX and a OR gate & NOT gate? Ans: (a) We can implement 4 to 1 MUX from 2 to 1 MUX as shown below: (b) We have already implemented 8 to 1 MUX using […]

## Q8: Implement function using MUX & ADDER

Q- Design and implement the following logical functions with a combinational circuit (with A and B being 4-bit numbers): S1 S0 Output 0 0 A OR B 0 1 A AND B 1 0 A’ 1 1 A XOR B Ans: The following circuit would give the required outputs:

## Q7: Implement function using MUX & ADDER

Q- Design and implement the following with a combinational circuit (with A and B being 4-bit numbers): S2 S1 S0 Output 0 0 0 2A 0 0 1 A plus B 0 1 0 A plus B’ 0 1 1 A minus 1 1 0 0 2A + 1 1 0 1 A plus B […]

## Q6: Implement function using MUX & ADDER

Q- Design and implement the following with a combinational circuit (with A and B being 4-bit numbers): S1 S0 Output 0 0 A plus B 0 1 left shift A 1 0 A plus B plus 1 1 1 2A + 1 Ans: We need one 4-bit parallel ADDER and MUX to implement the above. As […]

## Q4: Debug error in MUX

Q- Find out the situation when the following circuit of MUX 2 to 1 would not work as expected and how can we eliminate the error. Ans: When we have the static values at the inputs circuit would work fine but when ever there is a transition in the value of Select pin we have a situation […]

## Q: Implement LOGIC GATES using MUX

Q- Using 2 to 1 MUX implement the following 2-input gates: (a) OR (b) AND (c) NOR (d) NAND (e) XOR (f) XNOR (g) NOT. Ans: To implement the above for every gate, either we can derive the different gates using the logic (the truth table) or the procedure to implement any function with MUX (discussed […]

## Q2: Implement the function using MUX

To implement the function F(A, B, C, D)= Σ (1, 2, 5, 7, 9, 14) using MUX using different variable as selection variable. Let’s now take the variable A for input lines and B, C & D for selection lines. N=4 so MUX is 2 N-1= 23 = 8 to 1 So min terms with A in compliment form are 0 […]

## Q: Implement function using MUX

e.g. To implement the function F(A, B, C)= Σ (1, 2, 5, 7) using MUX using different variable as selection variable. Let’s now take the variable B for input lines and A & C for selection lines. The min terms with B in compliment form are 0, 1, 4, 5 and the min terms with B in un-complimented form are […]

## Q: Boolean function Implementation using MUXes

Q-How to implement any Boolean function using MUX? Ans: While implementing any function using MUX, if we have N variables in the function then we take (N-1) variables on the selection lines and 1 variable is used for inputs of MUX. As we have N-1 variables on selection lines we need to have 2 N-1 to 1 […]