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]
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]
