Summary Logic Gates Notes IB Computer Science

1

5 Three switches, A, B and C, each send values of 0 or 1 to a logic circuit. Value X is output from the
logic circuit.

Switch A
Switch B Logic circuit Output X
Switch C


Output X has a value of 1 depending on the following conditions:

Switch A sends value 1 AND Switch B sends value 0

OR

Switch B sends value 1 AND Switch C sends value 0

(a) Draw a logic circuit to represent the conditions above.




A




B X




C




[5]

, 2

(b) Complete the truth table for the conditions given at the start of question 5.

Working space
A B C X

0 0 0

0 0 1

0 1 0

0 1 1

1 0 0

1 0 1

1 1 0

1 1 1
[4]