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09 - Boolean Expressions and Diagrams

 1. Read the definition of a LOGIC CIRCUIT and decide whether it is true or false 
A logic circuit is a combination of logic gates.

  FALSE

  TRUE

 2. In a statement like this: (A+B) . (C + D) - what do the brackets mean?
booleanstatement_AND.png

  It doesn't mean anything

  The brackets mean that the expression inside them is processed LAST

  That the brackets are done first (just like BODMAS rules in maths)

  The brackets are there for aesthetic and artistic effect

 3. What is the boolean expression for this circuit? …. 
Note: that the '.' is an AND gate and a + refers to an OR gate
booleanexpressions1.png

  A AND B

  (A+B) . (C + D)

  (A+B)+(C.D)

  NOT Y = AB

 4. What is the boolean expression for this circuit? …..
booleanexpressions2.png

  None of the above

  (A+B) . NOT C

  (A + B) AND (NOT C)

  NOT C (A+B+C)

 5. The boolean expression for this circuit is: (AB + C)D
booleanexpressions3.png

  False

  True

 6. What is the boolean expression for this circuit? …….
booleanexpressions4.png

  (A + B) AND (NOT C)

  (AB + C)D

  None of the above

  (A.B).C.D

 7. Look at the image below and the output shown for this circuit. Is it correct? (Yes: True or No: False)
booleanexpressions5.png

  TRUE

  FALSE

 8. Which output of the two shown outputs is INCORRECT?
booleanexpressions6.png

  They are both incorrect

  The first one (the one at the top) is incorrect

  Actually, they are both correct

  The second one (near the bottom)

 9. What would the boolean expression be for the output C?
booleanstatement_twooutputs.png

  C = A AND C

  C = S AND B

  A = A AND B

  C = A AND B

 10. Write the boolean expression for this particular logic diagram (note that you can use brackets to denote an 'AND') 
Don't forget that a + is an OR gate and a . (or brackets) is an AND gate.
booleanstatement_question10.png

  C(D) + A

  A + C (D)

  A(BD) + C

  (AB + C)D


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