2024 SST Electronics Prelims QP

Page 1 of 26 [Turn over SECONDARY 4 PRELIMINARY EXAMINATION ELECTRONICS 6063/01 14 August 2024 (Wednesday) 2 hours CANDIDATE NAME CLASS INDEX NUMBER READ THESE INSTRUCTIONS FIRST Do not turn over the page until you are told to do so. Write your name, class, and index number in the spaces provided above. Write in dark blue or black ink pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, and glue or correction fluid/tape. Sections A and B Answer all the questions. Write your answers in the spaces provided on the question paper. Approved electronic calculators are allowed for use in this paper. The number of marks is given in brackets [ ] at the end of each question or part question. The total mark for this paper is 100. This document consists of 26 printed pages including the cover page FOR EXAMINERS’ USE Section A / 40 Section B / 60 TOTAL / 100

Page 2 of 26 [Turn over RESISTOR COLOUR CODE 1st Colour Band 1st Digit 2nd Colour Band 2nd Digit 3rd Colour Band Multiplier 4th Colour Band Tolerance Black 0 Black 0 Black 0 Gold ±5% Brown 1 Brown 1 Brown 1 Red ±2% Red 2 Red 2 Red 2 Orange 3 Orange 3 Orange 3 Yellow 4 Yellow 4 Yellow 4 Green 5 Green 5 Green 5 Blue 6 Blue 6 Blue 6 Violet 7 Violet 7 Violet 7 Grey 8 Grey 8 Silver 0.01 White 9 White 9 Gold 0.1 STANDARD VALUES FOR RESISTORS (E24 SERIES) 1.0 1.1 1.2 1.3 1.5 1.6 1.8 2.0 2.2 2.4 2.7 3.0 3.3 3.6 3.9 4.3 4.7 5.1 5.6 6.2 6.8 7.5 8.2 9.1 and multiples of ten

Page 3 of 26 [Turn over Table on Boolean algebra

Page 4 of 26 [Turn over Section A Answer all questions in this section. 1 Complete Table 1.1 The first row has been completed for you. [5] Component name Component symbol Fixed resistor SPDT switch Microphone Table 1.1 [Total: 5 marks]

Page 5 of 26 [Turn over 2 The maximum current through a 75 Ω resistor is 80 mA. (a) Write down the colour code of a 75 Ω resistor with 5% tolerance. [2] (b) Calculate the maximum power that the resistor will dissipate. [2] (c) Suggest a suitable power rating for the resistor. Resistors with power ratings of 0.25 W, 0.5 W, 1 W and 2 W are available. [1] ............................................................................................................................. [Total: 5 marks] ………………… ….. ………………… ….. ………………… ….. ………………… …..

Page 6 of 26 [Turn over 3 (a) Fig. 3.1 shows the currents entering and leaving three circuit nodes. Fig. 3.1 Complete Table 3.1. [3] Current Value I1 I2 I3 Table 3.1

Page 7 of 26 [Turn over (b) Fig. 3.2 shows a circuit with two voltage sources. The direction of current through each resistor is indicated with an arrow in Fig. 3.2. Fig. 3.2 Complete Table 3.2. [2] Voltage Value V1 V2 Table 3.2 [Total: 5 marks]

Page 8 of 26 [Turn over 4 A rectangular signal has the following characteristics: • Frequency = 200 Hz • Duty cycle = 40% • Low level voltage = 0 V • High level voltage = 5 V (a) On Fig. 4.1, draw the waveform of the rectangular signal when connected to a digital oscilloscope. The oscilloscope uses the following settings: • horizontal scale: 1 ms / div • vertical scale: 2 V / div [3] Fig. 4.1 (b) A rectangular signal is periodic. Explain what is meant by a periodic signal. [1] ........................................................................................................................ ........................................................................................................................ [Total: 4 marks]

Page 9 of 26 [Turn over 5 Fig. 5.1 shows two capacitors, X and Y. Capacitor X Capacitor Y Fig. 5.1 (a) Write down the capacitance of capacitor X. [1] ............................................................................................................................. (b) Capacitor Y has a capacitance of 2200 µF. Besides their capacitance values, state another difference between capacitors X and Y. [1] ............................................................................................................................. ............................................................................................................................. [Total: 2 marks]

Page 10 of 26 [Turn over 6 Fig. 6.1 shows an incomplete circuit diagram of a full-wave rectifier. Fig. 6.1 (a) Complete Fig. 6.1 by drawing four diodes. [2] (b) State the property of diodes that a full-wave rectifier makes use of. [1] ............................................................................................................................. (c) Fig. 6.2 shows how the input voltage varies with time. Complete Fig. 6.3 to show how the output voltage varies with time. [2] Use the ideal diode model. Fig. 6.2 Fig. 6.3 [Total: 5 marks]