Computational logic 1

Question 1

outcomes in computational logic

Answer 1

true or false/on or off/ 0 or 1

Question 2

What is boolean logic and how does it relate to computers?

Answer 2

boolean logic is a form of algebra in which all values are either TRUE or FALSE

it is important for computer science as it fits with the binary system using bits with a value of either 0 or 1

Question 3

transistors

Answer 3

switches that are either on or off

they transmit an electrical current when on
they don’t transmit when off

the two conditions represent true (on) or false (off)

a processor contains over 1 billion transistors

Question 4

logic gates

Answer 4

logic gates use transistors that carry out all of the calculations and execute program instructions in the processor

logic gates are represented by symbols in logic diagrams

• AND gate
• OR gate
• NOT gate

Question 5

AND gate

Answer 5

represented by half of an oblong

• two inputs (A and B)
• one output (Q)

for an output at Q there must be an input at both A AND B

Question 6

OR gate

Answer 6

represented by half an oblong that has been curved outwards to a point on the right, and curved inwards in a semicircle on the left

• two inputs (A and B)
• ouput (Q)

for an output at Q there must be an input at either one of A OR B or at both of them

Question 7

NOT gate

Answer 7

represented by a triangle with a small circle at the point

• one input (A)
• output (Q)

there is an output at Q only if there is NOT an output at A

Question 8

truth tables

Answer 8

the states of the inputs and outputs of the gates can be shown using truth tables where a 1 or 0 is used to indicate the presence or absence of an electrical current

the tables have headings of A/B/Q

e.g.
AND gate:
A    B    Q
0    0    0
0    1    0
1    0    0
1    1    1

Question 9

An AND gate has an input at A of 1 and an input at B of 0.
It is connected to a NOT gate.

What is the output of the AND gate, and the output of the NOT gate? [1]

Answer 9

the AND gate has an output of 0

the NOT gate outputs 1

Question 10

An OR gate has an input of 1 and 0.

What does it output? [1]

Answer 10

1