1
1 The diagram shows the symbol for a logic gate.
The truth table for this logic gate is shown in the table.
input X input Y output Z
0 0 0
0 1 0
1 0 0
1 1 1
State the name of this logic gate. .. [1]
[Total: 1]
2
2
(a) A student designs the circuit shown in the diagram.
Complete the truth table for this circuit in the table.
A B C D E
0 0 1 Text
0
0 1 0 0
1 0 0
1 1 0
[3]
(b) A single logic gate can be used to produce output E in the circuit shown in (a) with the inputs
A and B shown in the table in (a).
State the name of this logic gate. .
[1]
[Total: 4]
3 An arrangement of logic gates A, B and C is shown in the diagram. The arrangement has two inputs,
X and Y and two outputs P and Q.
3
Output P of logic gate B has logic state 1 (high).
(a) Determine the logic states of the two inputs of logic gate B.
upper input = ..............................................
lower input = .............................................. [1]
(b) Determine and explain the logic state of output Q.
logic state of Q = ...............................................................................................................
explanation........................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
........................................................................................................................................... [3]
[Total: 4]
4 State how the behaviour of an AND gate differs from that of an OR gate.
..................................................................................................................................................
.................................................................................................................................................. [1]
[Total: 1]
5 Describe how a digital signal differs from an analogue signal. You may draw a diagram.
..................................................................................................................................................
..................................................................................................................................................
.................................................................................................................................................. [2]
[Total: 2]
4
6 Complete the truth table for a NAND gate.
input 1 input 2 output
0 0
0 1
1 0
1 1
[Total: 1]
7 In the appropriate box, draw the symbol for an AND gate and the symbol for an OR gate.
AND gate OR gate
[1]
[Total: 1]
8 The circuit shown in the diagram contains two different types of gate, labelled X and Y.
The table shows a partially completed truth table for this circuit.
input intermediate point output
A B C D E
0 0 0 0
0 1 1 0
5
1 0 1 0
1 1 1 1
(a) From the truth table, deduce the name of logic gate Y.
Ring your answer from the list.
AND NAND NOR NOT OR
[1]
(b) Complete the truth table.
[2]
[Total: 3]
9 State the name of the logic gate with the symbol shown in the diagram.
.................................................................................................................................................. [1]
[Total: 1]
6
10 The diagram shows a digital circuit.
Complete the truth table for this circuit for all possible combinations of input.
A B C D E
1 1
1 0
1 0
0 0
[4]
[Total: 4]
11 State the name of the logic gate with this truth table.
input output
0 1
1 0
.................................................................................................................................................. [1]
[Total: 1]
12 A student is designing a digital electronic circuit. The diagram shows her partly completed design.
7
(a) The table is a truth table.
Complete the columns in this truth table to show the values for input B in the circuit.
Input A Input B Point C Point D Output O
1 0 0 1
0 0 0 1
1 0 1 0
0 1 0 0
[2]
(b) The column O in the truth table shows the desired output values for the circuit.
On the diagram, complete the circuit to achieve these output values. Label any gate used.
[2]
[Total: 4]
