*X025/11/01* X025/11/01 ELECTRONIC AND ELECTRICAL FUNDAMENTALS INTERMEDIATE 2 NATIONAL QUALIFICATIONS 2015 WEDNESDAY, 3 JUNE 9.00 AM 11.

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1 X05//0 NATIONAL QUALIFICATIONS 05 WEDNESDAY, JUNE 9.00 AM.0 AM ELECTRONIC AND ELECTRICAL FUNDAMENTALS INTERMEDIATE 00 marks are allocated to this paper. Answer all questions in Section A (50 marks). Answer two questions from Section B (5 marks each). In all your answers to questions requiring calculations, all working must be shown. SQA *X05//0*

2 Section A Attempt all the questions in this section (50 marks). Convert the following numbers. (a) Binary to Decimal (b) Decimal to Hexadecimal 86 0 (c) Hexadecimal to Binary AE 6 (6). Identify the pin connections for the circuit symbols shown in Figure Q(a) and Figure Q(b). (a) (b) Figure Q(a) Figure Q(b) (6). The diagrams in Figure Q show input and output waveforms to and from electronic circuits labelled X and Y. Figure Q State the full name of the function that is being performed by: (a) circuit X; (b) circuit Y. [X05//0] Page two (4)

3 4. For the circuit shown in Figure Q4: V DD = +0 V R C C V IN = 400 mv pk pk at khz R R C V OUT = V pk pk 0 V Figure Q4 (a) state the circuit configuration; (b) determine the circuit gain. () 5. Figure Q5 shows a current carrying conductor placed between magnetic poles. N S Figure Q5 (a) State what direction the force acts upon the conductor. (b) The length of conductor in the field is 0 4 m, the magnetic flux density is 0 T and a force of 6 N acts upon the conductor. Determine the current. () [Turn over [X05//0] Page three

4 6. The diagram in Figure Q6 includes a variable resistor (R V ) that can be varied between 0 kω and 50 kω. R V 0 kω V IN = 0 4 V pk pk V OUT pk pk Figure Q6 (a) State the phase relationship between input and output voltages. (b) Determine the maximum value of output voltage (pk pk). (c) Determine the maximum value of resistor that could replace the 0 kω that would enable an output voltage of 4 V (pk pk) to be achieved. (6) 7. For the circuit shown in Figure Q7: A B C Z Figure Q7 (a) determine the Boolean expression for the circuit; (b) construct the truth table; (c) use the truth table to determine an alternative Boolean expression for the circuit. 4 (8) [X05//0] Page four

5 8. For the circuit shown in Figure Q8, determine: Ω Ω 0 V 4 Ω Figure Q8 (a) the total circuit resistance; (b) the supply current; (c) the current through the Ω resistor; (d) the circuit power; (e) the energy consumed by the circuit in 0 minutes. (8) 9. A door entry system is used to open a secure area that can only be opened between 8.0 am and 5.0 pm denoted by a logic on input A. The door can be opened by two methods: when the correct code is entered via a numeric keypad denoted by a logic on input B. when an authorised swipe card is placed in the card slot denoted by a logic 0 on input C. Note that the keypad and the swipe card cannot be used at the same time to open the door. (a) Determine the logic expression for the entry system. (b) Draw the truth table for the expression. (c) Draw a logic diagram for the system using ANSI symbols. (6) [X05//0] Page five [Turn over

6 Section B Attempt any TWO questions in this section (50 marks) Each question is worth 5 marks 0 (a) Add the following binary numbers. (i) (ii) (b) State the Boolean expression and construct the truth table for the following logic gate. A B C & Figure Q0(b) (c) Using the Worksheet for Q0(c) provided, select the required logic chips and sketch the required connections on the worksheet for the circuit shown in Figure Q0(c) to function correctly. 6 B C D Z Figure Q0(c) (d) Draw, using BS symbols, the logic diagram for the following Boolean Expression and determine the truth table. Z = (R + S + T ).(S + T) 6 [X05//0] Page six

7 0. (continued) (e) The circuit shown below, Figure Q0(e)(i), has developed a fault and upon testing, the outputs shown in the truth table Figure Q0(e)(ii) were obtained. Determine which gate (input or output) is at fault and state the nature of the fault. A B C 4 TP 5 Z TP Figure Q0(e)(i) A B C TP TP Z Figure Q0(e)(ii) 6 (5) [Turn over [X05//0] Page seven

8 . (a) For the waveform shown in Figure Q(a) determine: Emf 50 V 40 V 0 V 0 V 0 V 0 0 V 0 V 0 V 40 V 50 V 0 0 ms 0 6 ms 0 90 ms ms Figure Q(a) (b) (i) the peak value of the voltage; (ii) the rms value; (iii) the period of the waveform. (i) A coil of length 5 m is moved through a magnetic field of 0 5 mt at a speed of 0 m s. Calculate the induced voltage. (ii) The same coil is now inserted in a magnetic field of mt and is connected to a supply. Determine the current flowing in the conductor if the force on the conductor is measured at 0 4 N. [X05//0] Page eight

9 . (continued) (c) For the circuit shown in Figure Q(c) determine: 0 Ω Ω 0 Ω R 0 Ω R A R R 4 R 5 R 7 A 5 Ω 5A R 6 V S Figure Q(c) (i) the supply voltage V S ; (ii) the total circuit resistance; (iii) the value of resistor R 4 ; (iv) the voltage across resistor R 6 ; (v) the value of resistor R 6. 5 (d) For the circuit shown in Figure Q(d) determine: 8 A 0 Ω 5 Ω R R A R 4 R 80 V Figure Q(d) (i) the power dissipated in the 0 Ω resistor R ; (ii) the total power dissipated in the circuit; (iii) the energy consumed, in joules, if the circuit is operated for 4 hours. (5) [Turn over [X05//0] Page nine

10 . (a) Identify the circuit shown in Figure Q(a) and identify the purpose of each of the capacitors C, C and C. 4 I C V CC V R R K5 C C I b Ideal transistor h fe = 400 R 4 V 6K8 R 4 C 6 V 0 V Figure Q(a) (b) For the circuit shown in Figure Q(a), calculate: (i) the collector current Ic; (ii) the base current I b ; (iii) the current through the resistor R ; (iv) the value of the resistor R. [X05//0] Page ten

11 . (continued) (c) For the circuit shown in Figure Q(c): 6 5 V IN R V R 50 K V OUT = 550 mv R 0 K Figure Q(c) (i) identify the circuit configuration shown in Figure Q(c); (ii) determine the gain of the circuit and the input voltage. 4 When setting up the circuit it is found that for an input of 0 V the output is not zero. (iii) What component in Figure Q(c) will allow the output to be adjusted to zero and what is this process called? (d) D Sw 0 V 50 Hz C R L V OUT Figure Q(d) Sketch the output waveform for the circuit shown in Figure Q(d) with (i) Sw open, and (ii) Sw closed. (5) [END OF QUESTION PAPER] [X05//0] Page eleven

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13 X05// NATIONAL QUALIFICATIONS 05 WEDNESDAY, JUNE 9.00 AM.0 AM ELECTRONIC AND ELECTRICAL FUNDAMENTALS INTERMEDIATE Worksheet for Q0(c) SQA *X05//*

14 Worksheet for Question 0(c) 0 V 5 V A B C D (0V) + 74 (0V) (0V) [END OF WORKSHEET] [X05//] Page two