## Q: D-Flip-flop using MUX

Q- Can we implement the D-Flip-flop using MUX? Ans: Yes, we can. As we can derive a D FF from D latch by following circuit: So we implement the above circuit to get D ff from MUX as: The following D FF is a falling edged or negative edged Flip-flop. And we can implement the rising edge […]

## QUESTIONS: Flip flops/Latch

Q-What is the difference between LATCH & FLIP-Flop? Ans:  We can easily find the answer after going through the theory given: Latches are level sensitive while flip-flops are edge sensitive devices Hence latches faces problems like glitches in the output while no such problem occurs in flip-flops. As we can see from different circuits given […]

## Q10: Implement ALU using MUX & ADDER

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           […]

## 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 […]