(a) (i) Fig.. shows the symbol for a circuit component. Fig.. Name this component.... [] (ii) In the space below, draw the symbol for a NOT gate. (b) Fig..2 shows a digital circuit. [] C D E Fig..2 Complete the truth table for this circuit. input input output C input D output E PhysicsndMathsTutor.com [3]
(c) Suggest a modification to the circuit in Fig..2 to produce the output Z in the truth table below. It may help you to compare this truth table with the truth table in (b). input input input D output Z...... [] [Total: 6] PhysicsndMathsTutor.com
2 (a) (i) Fig.. shows the symbol for a logic gate and its truth table. output input input output Fig.. State the name of this logic gate....[] (ii) Complete the truth table for the logic gate shown in Fig..2. output input input output Fig..2 (b) Fig..3 shows the system of logic gates used to ensure the security of the strongroom of a bank. D F C E Fig..3 The strongroom door will only open when the output F is logic. Complete the table to show the logic states at,, C, D and E when the strongroom door can be opened. input input input C output D output E output F [3] [Total: 6] PhysicsndMathsTutor.com
3 Fig. 8. is a schematic diagram of an electronic circuit controlling a lamp. temperature sensor relay lamp light sensor Fig. 8. The output of the temperature sensor is high (logic ) when it detects raised temperatures. The output of the light sensor is high (logic ) when it detects raised light levels. The lamp is lit when the input to the relay is high (logic ). (a) Complete the truth table by giving the outputs of and. (b) State the conditions under which the lamp is lit. [] (c) Suggest why is connected to a relay, rather than directly to the lamp. [Total: 5] PhysicsndMathsTutor.com
4 (a) Fig.. shows the symbol for a logic gate. Fig.. (i) State the name of this gate.... [] (ii) (iii) On Fig.., label an input and an output. In the space below, draw the symbol for a NND gate. [] [] PhysicsndMathsTutor.com
(b) very low frequency alternating voltage is applied between and in the circuit shown in Fig..2. centre-zero ammeter Fig..2 On each diagram, draw a possible position of the indicator needle of the ammeter at the time in the cycle when (i) is positive and is negative, + 2 +2 (ii) there is no p.d. between and, + 2 +2 (iii) is negative and is positive. + 2 +2 [3] [Total: 6] PhysicsndMathsTutor.com
5 (a) Fig. 9. shows the symbol for a logic gate. Fig. 9. (i) State the name of this gate.... (ii) On Fig. 9., clearly label an input and an output. (b) In the space below, draw the symbol for a fuse. [] (c) Fig. 9.2 shows a circuit. 6 V Fig. 9.2 Component is not emitting light. It only emits light when the p.d. across it is greater than V. (i) change to the environment around component causes component to emit light. State the environmental change....[] PhysicsndMathsTutor.com
(ii) Explain your answer to (i).............[3] (d) The combined resistance of the two resistors shown in Fig. 9.3 is 4. Ω. 6. Ω R Calculate the resistance of resistor R. Fig. 9.3 resistance of R =... [Total: 9] PhysicsndMathsTutor.com
6 (a) Fig.. shows a digital logic circuit, not using the recognised symbols. input input ND gate D OR gate input C output E Fig.. Complete the table below to indicate the logic levels of points D and E in the circuit, when points, and C are at the logic levels indicated. represents low or off. represents high or on. C D E [3] (b) Draw the recognised symbol for an ND gate. (c) NND gate can be replaced by an ND gate and a NOT gate. Draw a diagram to show how the ND gate and the NOT gate should be connected. Label clearly the logic gates and any input or output. [] [Total: 6] PhysicsndMathsTutor.com
7 Fig.. is the symbol for a NND gate with inputs and. input input output Fig.. (a) Input and input can be set to (high) or to (low). Complete the table below to give the outputs for this NND gate. input input output (b) The two inputs of the NND gate are joined together and connected to an input C, as shown in Fig..2. [] input C output Fig..2 (i) Determine the output of this NND gate when. input C is set to, output =... 2. input C is set to. output =... [] PhysicsndMathsTutor.com
(ii) State the name of the logic gate that behaves in the same way as the NND gate in Fig..2.... [] (c) circuit combines three NND gates. The inputs to the circuit are P and Q, as shown in Fig..3. P Q R S T Fig..3 Points R, S and T in the circuit are also labelled. Input P is set to and input Q is set to. Determine the logic states ( or ) of points R, S and T. point R =... point S =... point T =... [Total: 5] PhysicsndMathsTutor.com
8 (a) (i) Fig.. shows the symbol for a logic gate. Name this logic gate. Fig..... (ii) Draw the symbol for a NOR gate. (b) (i) The two inputs of a NND gate are both low (logic level ). Write down the output state.... (ii) One input of a NND gate is low (logic level ) and the other input is high (logic level ). Write down the output state.... (c) logic gate contains a number of components. Circle one of the following that is contained in a logic gate. thermistor ansformer ansistorst ansmitter [] [Total: 5] PhysicsndMathsTutor.com