logic gates o level past papers questions

General Certificate of Education Ordinary Level COMPILED BY: ABDUL MOIZ CAMBRIDGE INTERNATIONAL EXAMINATIONS

COMPUTER STUDIES 2210/1Logic Gates

Summer 2014 P1 (Q7) ………………………………………………………………………………………………………………………………. 1Specimen 2015 P1 (Q3)...................................................................................................................................2Summer 2013 P11 (Q10).................................................................................................................................3Summer 2013 P12 (Q15).................................................................................................................................4Winter 2012 P12 (Q11)...................................................................................................................................5Winter 2012 P13 (Q15)...................................................................................................................................6Summer 2012 P11 (Q12).................................................................................................................................7Summer 2012 P12 (Q10).................................................................................................................................8Winter 2011 P11 (Q14)...................................................................................................................................9Summer 2011 P11 (Q10)...............................................................................................................................10Specimen 2011 P1 (Q11)...............................................................................................................................11Specimen 2011 P1 (Q12)...............................................................................................................................12

Summer 2014 P1 (Q7)

Q. (a) Draw the logic circuit for the logic statement:

X = 1 if (L is NOT 1 AND F = 1) OR (F is NOT 1 AND A is 1)

Computer-2210 (Bit Pattern) (1) abdul.moiz99@yahoo.com

L

F X

A

[5]

(b) Complete the truth table for the above system.

L F A

Working space

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

S O L U T I O N:

(a) 1 mark per correct logic gate (accept other gate symbols)

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Specimen 2015 P1 (Q3)An alarm, Y, sends a signal (Y = 1) when certain fault conditions in a chemical process are detected. The inputs are:

The alarm, Y, returns a value of 1 if:either temperature >= 120oC AND stirrer bar is OFFor acidity > 5 AND temperature < 120oC

(a) Draw the logic circuit for the above system using these logic gates.[5]

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L F A X

0 0 0 0

0 0 1 1

0 1 0 1

0 1 1 1

1 0 0 0

1 0 1 1

1 1 0 0

1 1 1 0

Computer-2210 (Bit Pattern) (4) abdul.moiz99@yahoo.com

(b) Complete the truth table for this alarm system.[4]

A T S Y1 1 11 1 01 0 11 0 00 1 10 1 00 0 10 0 0

Summer 2013 P11 (Q10)(a) (i) Complete the truth table for the logic circuit which is made up of NAND gates only. [2]

(ii) What single logic gate has the same function as the above logic circuit? [1](b) (i) Complete the truth table for the logic circuit.

(ii) What could replace the whole logic circuit? [1]

Summer 2013 P12 (Q15)(a) Draw the logic circuit represented by the logic statement:X = 1 if (B is NOT 1 AND S is NOT 1) OR (P is NOT 1 AND S is 1)

[6]

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b) Complete the truth table for the above logic statement.[4]

Winter 2012 P12 (Q11)An alarm sounds when certain conditions occur in a nuclear reactor.The output, X, of a logic circuit that drives the alarm must have a value of 1 if:either carbon dioxide pressure too low and temperature < = 300°Cor water pressure > 10 bar and temperature > 300°CThe inputs to the system are:

(a) Draw the required logic circuit using AND, OR and NOT gates only.[5]

(b) Complete the truth table for the above system. [4]P T W X1 1 11 1 01 0 11 0 00 1 10 1 0

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0 0 10 0 0

Winter 2012 P13 (Q15)15 (a) Complete the truth table for the following logic circuit: [4]

A B C X1 1 11 1 01 0 11 0 00 1 10 1 00 0 10 0 0

(b) The above logic circuit uses AND, OR and NOT gates.Name another logic gate and complete its truth table. [3]

Name : _______________________________________________

Summer 2012 P11 (Q12)(a) (i) Complete the truth table for the following logic circuit, which is made up of

NAND gates:

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(ii) What single logic gate has the same function as the above logic circuit?[1]

b) Complete the truth table for the following logic circuit:

A B C X1 1 11 1 01 0 11 0 00 1 10 1 00 0 10 0 0

Summer 2012 P12 (Q10)(a) Complete the truth table for the following logic circuit, which is made up of NAND

gates:

A B C X1 1 11 1 01 0 11 0 00 1 10 1 0

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0 0 10 0 0

(b) Name two other types of logic gates and complete their associated truth tables:

Winter 2011 P11 (Q14)An alarm, X, gives a signal (i.e. X = 1) when a car fuel injection system gives certain fault conditions. The inputs are:

The alarm returns a value of 1 if:Either (i) pressure < 5 bar AND revs > 8000 rpmor (ii) revs <= 8000 rpm AND temp > 120 °C(a) Draw the logic circuit for the above system using these logic gates.

(b) Complete the truth table for this alarm system.

P R T X1 1 11 1 01 0 11 0 00 1 10 1 00 0 1

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0 0 0

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Summer 2011 P11 (Q10)(a) Two logic gates are the AND gate and the OR gate. Complete the truth tables for these two gates:

(b) Complete the truth table for the following logic circuit:

A B C X1 1 11 1 01 0 11 0 00 1 10 1 00 0 10 0 0

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Specimen 2011 P1 (Q11)Draw the truth table for the following logic network: [4]

A B C X1 1 11 1 01 0 11 0 00 1 10 1 00 0 10 0 0

Specimen 2011 P1 (Q12)Draw a logic network and truth table for the following logic problem:

“A sprinkler (S) is ON ifeither temperature alarm (T) is ON and cooler alarm (C) is ONor vent alarm (V) is OFF and cooler alarm (C) is ON” [9]

Working: ____________________________________________________________________

____________________________________________________________________________ [2]

Logic Network:

Truth Table:

T C V S1 1 11 1 01 0 11 0 00 1 10 1 00 0 10 0 0

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