Preview

04 - Logic circuit diagrams #1

 1. Recap: What does Boolean Logic mean?
Definitions
===========
#1
Boolean logic describes the states of the inputs and outputs to the 
logic gates.

#2
Boolean logic represents all values as TRUE (1) or FALSE (0).

#3
Boolean logic represents the way that George Boole depicted the CPU and 
modelled it with boole variables.

  All of the above

  Only #1

  None of the above

  #1 and #2

 2. What is a truth table?

  A truth table is a table that shows the combinations of all binary addition outcomes

  A table that will tell the truth no matter what, with regard to Binary addition

  A table showing the output from all possible combinations of input.

  A table that shows the truth about any given boole variable

 3. What logic gate does this truth table describe?
-----Inputs----Output--
A    |   B   |    Q
=======================
0    |   0   |    0 
=======================
0    |   1   |    1
=======================
1    |   0   |    1
=======================
1    |   1   |    1

  None of the above

  And Gate

  Not Gate

  Or Gate

 4. Logic gates are used to build complex logic systems, such as burglar alarms and combination locks. What are D and E in this complex logic gate?
logiccircuits_question4.gif

  D and E are inputs

  D and E are logic gates

  D and E are outputs but also inputs required to find Z

  D and E are outputs

 5. Looking at the logic gate and the truth table below, can you fill in the blank (for the question mark in the truth table)
A	B	C	D	E	Z
0	0	0	1	0	1
0	0	1	1	0	1
0	1	0	1	0	1
0	1	1	1	1	1
1	0	0	0	0	0
1	0	1	0	0	0
1	1	0	0	0	0
1	1	1	0	?	1
logiccircuits_question4.gif

  2

  3

  0

  1

 6. How is this XOR gate different from an OR gate?
logiccircuits_question6.png

  In an OR gate an input of a 1 and 1 would give a 0

  In an OR gate an input of a 1 and 1 would give a 1 not a 0

  In an OR gate an input of a 0 and 1 would give a 0

  It isn't different

 7. What output will go in the '?' in the truth table shown?
logiccircuits_question7.png

  0

  3

  2

  1

 8. If A =0 and B = 0, what is the output C?
logiccircuits_question8.png

  1,1

  0

  0,0

  1

 9. If the inputs are both 1, analyse the outputs as shown on the diagram and point out, if any, the error.
logiccircuits_question9.png

  The output after the NOT gate at the top should be a 1 because it inverts the 0 to a 1

  There are no errors. The outputs are all shown correctly

  The last output C should be a 1 and 0 (e.g. 1,0) because it has more than one input coming in

  The last output C should be 0, because a 0 and 1 give a 0.

 10. Which colour/color box is showing an incorrect output?
logiccircuits_question10.png

  The white 0 at the end should be a 1

  The yellow box should be a 1

  The red box should be a 1

  The green box should be a 0