Exam 3 Review Questions (with Answers)

There will be ONLY one online exam including both lectures and labs on Tuesday, July 09, 2024 at 9:00 AM. This is a online exam via Canvas/Zoom.

Review

Exam 3 covers topics after the lab 4 and is NOT comprehensive.

Overall, Exam 3 may include material from the following sources:

• Handouts
• Labs 5 and 6
• This review

Questions

1. What component is shown below?
   
   
   
   Answer:

   An OR gate.

   
   

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2. What component is shown below?
   
   
   
   Answer:

   An AND gate.

   
   

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3. What component is shown below?
   
   
   
   Answer:

   A NOT gate.

   
   

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4. Draw the circuit corresponding to the following sum-of-products equation, where !A refers to the negation of variable A, and so on:

   		R = !A!B + AB
   		

   Answer:

   
   
   

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5. Consider the following sum-of-products equation:

   R = !ABC + ABC + A!B!C
   

   Using the above equation, do the following:

   • Write it as a truth table:
     
     Answer:

     
   
   
   • Simplify it using boolean algebra:
     
     Answer:

     
   
   
   • Simplify it using a Karnaugh map:
     
     Answer:

     
     R = A!B!C + BC
   
   

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6. Consider the truth table augmented with don't cares, shown below:
   
   

   A	B	C	D	U
   0	0	0	0	1
   0	0	0	1	X
   0	0	1	0	0
   0	0	1	1	1
   0	1	0	0	X
   0	1	0	1	1
   0	1	1	0	0
   0	1	1	1	X
   1	0	0	0	1
   1	0	0	1	0
   1	0	1	0	X
   1	0	1	1	0
   1	1	0	0	1
   1	1	0	1	0
   1	1	1	0	X
   1	1	1	1	0

   Using the above truth table, write out the following:

   1. The unoptimized sum-of-products equation, skipping over don't cares
      Answer:

      			U = !A!B!C!D + !A!BCD + !AB!CD + A!B!C!D + AB!C!D
      			

      
      
   2. A Karnaugh map, along with boxes which exploit don't cares where appropriate.
   Answer:
   
   
   
   3. An optimized sum-of-products equation, derived from the Karnaugh map created in the previous step.
      Answer:

                    U = !C!D + !AD
                   

      
      

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7. Consider the truth table augmented with don't cares, shown below:
   
   

   A	B	C	D	Output
   0	0	0	0	0
   0	0	0	1	0
   0	0	1	0	X
   0	0	1	1	X
   0	1	0	0	0
   0	1	0	1	0
   0	1	1	0	1
   0	1	1	1	1
   1	0	0	0	X
   1	0	0	1	0
   1	0	1	0	1
   1	0	1	1	X
   1	1	0	0	1
   1	1	0	1	0
   1	1	1	0	X
   1	1	1	1	1

   Using a K-map, derive an optimized equivalent sum-of-products equation that exploits don't cares where appropriate.

   Answer:

   
   
   

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