Preview

02 - Truth Tables and Logic Circuits

 1. The concept may be confusing at first but all digital circuits are created using a combination of logic _______________ 
Learning note: Electronic gates require a power supply.
Gate INPUTS are driven by voltages having two nominal values, e.g. 0V and 5V representing logic 0 and logic 1 respectively.
The OUTPUT of a gate provides two nominal values of voltage only, e.g. 0V and 5V representing logic 0 and logic 1 respectively. In general, there is only one output to a logic gate except in some special cases.
There is always a time delay between an input being applied and the output responding.

  gates

  bulbs

  mates

  CPUs

 2. Digital systems are said to be constructed by using logic gates. These gates are the AND, OR, NOT, NAND, NOR, EXOR and EXNOR gates.
allgates.png

  FALSE

  TRUE

 3. The functionality of each gate can be described using a ________________ 
The structure used to represent the boolean expression 
of a logic gate function is commonly called a ___________.

A logic gate ____________shows each possible input combination
to the gate or circuit with the resultant output depending upon
the combination of these input(s).

  logic gate correlation

  truth table

  binary expression

  boolean multiplication law

 4. The following gate is an '_______' gate.
andgate.gif

  NOT

  AND

  NAND

  OR

 5. The following gate is an '_______' gate.
orgate.gif

  NOT

  AND

  OR

  NAND

 6. The following gate is an '_______' gate.
notgate.gif

  OR

  NOT

  NAND

  AND

 7. The AND gate is an electrical circuit that gives an output of ____ only if all of its inputs are also _____.

  1

  2

  3

  0

 8. The OR gate is an electrical circuit that gives an output of a 1 if_______________ of its inputs are a 1.

  none

  all

  at least one

  at least two

 9. The NOT gate is an electrical circuit that produces an _______ version of the input as the output. (e.g. a 1 will be a 0)

  negative

  converted

  inverted

  positive

 10. If the input into a NOT gate is a 0 the output will also be a 0.

  FALSE

  TRUE

 11. A truth table can show the operations (with inputs and outputs) of any given gates. The following shows the truth table for the ________ 
2 Input truth table for an ____gate
======================
A      B      Output
------------------------
0       0            0
0       1            0                                   1       0            0       
1       1            1

  NOT Gate - because the output is always the inversion (opposite) of what is in A or B

  Or Gate because when either A or B inputs are 1 the output is 1

  And Gate because both inputs (A and B) need to be 1 in order for the output to be 1

  This truth table is incorrect and doesn't describe any gate

 12. If the input is 0 and it goes through a NOT gate, the output would also be 0

  FALSE

  TRUE

 13. To get an output of 1 using an AND gate, it would be necessary to have a 1 and a 1 (two ones)

  FALSE

  TRUE

 14. An OR gate would produce an output of 1 if the input is 0 and 0.

  TRUE

  FALSE

 15. It is the OR gate that is shaped like a triangle.

  TRUE

  FALSE


Report an error