Combination Circuit

Question 1

1. Given the input waveforms for A, B and C. Draw the output waveform X for the OR gate for Figure 1 [4]

Figure 1

2. Given the logic function 

•  Implement the logic circuit for the expression: [3]
•  Construct its truth table [3]
•  Redraw the circuit using NOR gates only [10]

3. Simplify the following expressions using K-Maps

•  F(A,B,C,D) = ∑_m(0,1,2,3,6,8,9,12,14,15) [5]
•  F(A,B,C,D) = ∑_m(0,1,3,6,9,11,12,13) +∑_d(4,10) [5]

4. Given the logic circuit shown in Figure 2.

•  Determine the output expression for the circuit [2]
•  Simplify expression in i. above using laws of Boolean Algebra. [2] 

Figure 1

5. Write SOP for the Boolean Expression F = (A+B)(C+D)E [2]

6. Simplify the following expressions using laws of Boolean Algebra. Express your answer in SOP form [4]

7. Design full Subtractor. Implement the circuit using NAND gates only. [10]

8. Obtain the truth table for a combinational circuit that accepts a 3- bit ‘number and generates an output binary number equal to the square of the input number. [10]

9. Design a logic circuit that has three inputs, A, B, and C, and whose output will be HIGH only when a majority of the inputs are HIGH. [10]

10. Design a parity generator for a 4-bit word for an odd parity machine. [5]

11. Design a circuit that converts a 4-bit gray code to 8421BCD [20]