ECT4701/101/0/2014 Tutorial letter 101/0/2014 Electronics IV (Theory) ECT4701 Year Module Department of Electrical and Mining Engineering IMPORTANT INFORMATION: This tutorial letter contains important information about your module. CONTENTS Page 1 INTRODUCTION...........................................................................................................................3 2 PURPOSE OF AND OUTCOMES FOR THE MODULE ...............................................................3 2.1 Purpose ........................................................................................................................................3 2.2 Outcomes .....................................................................................................................................3 3 LECTURER(S) AND CONTACT DETAILS ...................................................................................3 3.1 Lecturer(s).....................................................................................................................................3 3.2 Department ...................................................................................................................................3 3.3 University ......................................................................................................................................4 4 MODULE-RELATED RESOURCES .............................................................................................4 4.1 Prescribed books ..........................................................................................................................4 4.2 Recommended books ...................................................................................................................4 4.3 Electronic Reserves (e-Reserves) .................................................................................................4 5 STUDENT SUPPORT SERVICES FOR THE MODULE ...............................................................4 6 MODULE-SPECIFIC STUDY PLAN .............................................................................................4 7 MODULE PRACTICAL WORK AND WORK-INTEGRATED LEARNING...................................10 8 ASSESSMENT ...........................................................................................................................10 8.1 Assessment plan .........................................................................................................................10 8.2 General assignment numbers .....................................................................................................10 8.2.1 Unique assignment numbers .......................................................................................................11 8.2.2 Due dates for assignments ..........................................................................................................11 8.3 Submission of assignments .........................................................................................................11 8.4 Assignments ...............................................................................................................................12 9 OTHER ASSESSMENT METHODS ...........................................................................................22 10 EXAMINATION ...........................................................................................................................22 11 FREQUENTLY ASKED QUESTIONS.........................................................................................22 12 SOURCES CONSULTED ...........................................................................................................22 13 CONCLUSION ............................................................................................................................22 14 ADDENDUM ...............................................................................................................................22 2 ECT4701/101 1 INTRODUCTION Dear Student Welcome to the subject Electronics IV (Theory) (ECT4701) at UNISA. This tutorial letter serves as a guideline to this subject. It provides you with general administrative information as well as specific information about the subject. Read it carefully and keep it safe for future reference. We trust that you will enjoy this course. 2 PURPOSE OF AND OUTCOMES FOR THE MODULE 2.1 Purpose On successfully completing this module, the learners will be able to: Fully understand the electives, thus identify various electronic circuits, analyse and design electronic components within various applications, identify various photovoltaic applications, design various stand-alone photovoltaic systems, and apply extensive faultfinding and repair 2.2 Outcomes The learners will be able to: Practice and manage electrical engineering activities and applications at the level expected of a professional technologist ( engineering ). 3 LECTURER(S) AND CONTACT DETAILS 3.1 Lecturer(s) Your Lecturer for Electronics IV is Mr M Joubert. You can contact Mr Joubert for any theoretical questions at the following number: Tel nr : (016) 985 5718 e-mail: martinj@vut.ac.za Contact Times : Mondays to Fridays 18h00 to 21h00 3.2 Department Department of Electrical and Mining Engineering: electrical&mining@unisa.ac.za 3 3.3 University If you need to contact the University about matters not related to the content of this module, please consult the publication My studies @ Unisa that you received with your study material. This brochure contains information on how to contact the University (e.g. to whom you can write for different queries, important telephone and fax numbers, addresses and details of the times certain facilities are open).Always have your student number at hand when you contact the University. 4 MODULE-RELATED RESOURCES 4.1 Prescribed books Solar Electricity-second Edition 2005 by Markvart .John Wiley & Son. ISBN: 0- 471-94161-1 or newest edition. 4.2 ANALOGUE ELECTRONIC DESIGN PRINCIPLES – NICO J. OOSTHUYSEN Recommended books There are no recommended books for this module. 4.3 Electronic Reserves (e-Reserves) There are no electronic reserves for this module. 5 STUDENT SUPPORT SERVICES FOR THE MODULE Important information appears in your my Studies @ Unisa brochure. 6 MODULE-SPECIFIC STUDY PLAN Use your my Studies @ Unisa brochure for general time management and planning skills. CRITICAL CROSS-FIELD OUTCOMES This module will address the following critical cross-field outcomes. CCFO (x) Assessment criteria Problem solving: critical & creative thinking (x) All Group work / Team ship (x) All 4 ECT4701/101 Manage & organize / Self-responsibility (x) All Research (x) All Communication (x) All Responsibility towards environment (x) All Interrelated systems / not in isolation (x) All Societal / economic outcomes (x) All MODULE CONTENT Topic Unit 1 RESISTORS CAPACITORS SO/ AC AND 1.1 Learner Activity General [P05] Recognise the generally used E12 range 1.2 Resistors [P07] Describe the different type of wattage in use 1.3 Capacitors [P08] State the different capacitor values 1.4 Working voltage [P08] Describe working voltage 1.5 Nearest available value [P09] Explain nearest available value 1.6 Colour codes for resistors and capacitors [P09] Recognise resistor and capacitor colour coding Prefixes [P13] BIASING 1.7 State the different prefixes 2.1 Getting started [P16] Recognise how to get started Explain how to get proper biasing 2.2 The first design [P25] Design a single stage amplifier 5 2.3 Capacitor behaviour in amplifiers [P26] Identify coupling capacitors Recognise capacitor behaviour within an amplifier circuit Identify amplitude-frequency response within an amplifier circuit Understand input and output impedance 2.4 Capacitor calculations [P34] Calculate capacitor values within an amplifier circuit BIASING 2.5 More about input impedance [P35] 2.6 Another design example [P35] 2.7 Typical voltage gain [P37] 2.8 Some improvements [P37] 2.9 Design example of a stabilized case [P44] Design a single stage amplifier with stabilisedbiasing 2.10 Another design example [P47] 2.11 New Q-Point with external load [P49] Consider Q-point shift with external load change 2.12 Analysis [P56] Analyse different biased amplifier circuits 2.13 Transistor specification [P60] 3.1 ADVANCED BIASING Introduction [P63] Review previous chapter 3.2 Input impedance [P67] Use new method to determine input impedance 3.3 Design example [P69] 3.4 Advanced design example [P71] Design more advanced amplifiers ADVANCE BIASING 6 3.5 Special biasing 01 [P75] 3.6 Special biasing 02 [P77] ECT4701/101 3.7 Choice of amplifier parameters [P78] 3.8 The bootstrap stage [P83] Design the bootstrap stage 3.9 Electronic buffer [P96] Design an electronic buffer 3.10 Node graphs [P100] Draw node graphs for various designs 3.11 Electronic laboratory procedure [P102] Explain laboratory procedures 3.12 Polarity of capacitors [P104] EXERCISES 4.1 THE TRANSISTOR 5.1 AS A SWITCH 5.2 Do exercise numbers 1 – 23 [P107] Introduction to switching circuits [P118] Introduce switching circuits Various design examples [P125] Design various switching circuits 5.3 Transistor characteristics [P127] Explain transistor characteristics 5.4 Switching speed [P128] Describe transistor switching speed 5.5 Inductive load [P131] Describe inductive loads THE COMPACT DISK 12.3 The Compact Disk [P164] MEASUREMETNS 22.1 Impedance matching [P253] 22.2 Measuring voltage gain of amplifier [P254] 22.3 Measuring Beta of transistor [P254] 22.4 Measuring input impedance [P256] 7 22.5 Measuring output impedance [P257] 22.6 Measuring hie of transistor [P258] 22.7 Measuring hoe of transistor [P258] 22.8 Measuring low cut off frequency [P259] 22.9 Measuring high cut off frequency [P259] Topic SO/AC Learner Activity Unit 2 ELECTRICITY THE SUN FROM 1.1 SOLAR RADIATION 2.1 Why we need photovoltaic [P01] Introduction [P06] The aim of this section is to determine the solar energy available to photovoltaic systems 2.2 Energy from the sun [P07] Understand the nature of solar radiation at different locations on the earth Describe the apparent daily and yearly motion of the sun Show how the amount of solar radiation falling on photovoltaic panels can be determined by measured data 3.1 Introduction [P24] The aim of this section is to explain how solar cells work and how they are manufactured SOLAR CELLS What are solar cells? [P25] 3.2 How solar cells works [P26] 3.3 Analyse the structure of a solar cell Silicon solar cell technology [P46] 3.4 Explain the power output from a cell in terms of the incident energy flux and the electronic structure of the semiconductor 8 ECT4701/101 Evaluate the cell performance by using its currentvoltage characteristic Assess the operation of practical devices and limits imposed on their performance 3.5 Thin-film solar cells [P62] Identify the technological steps which are used in the manufacture of solar cells 4.1 Introduction [P81] The aim of this section is to survey the structure operation and design of photovoltaic systems Structures of a photovoltaic system [P83] 4.2 PHOTOVOLTAIC SYSTEM ENGINEERING 4.3 Understand the structure of a photovoltaic system, its subsystems and the concept of sizing The photovoltaic generator [P85] Analyse the operation of the photovoltaic generator in terms of modules and their electrical characteristics 4.4 Energy storage [P93] Examine the battery operation in photovoltaic systems 4.5 Power conditioning and control [P98] Evaluate the role of power conditioning and control elements 4.6 Sizing photovoltaic systems [P110] Size a simple system using the radiation power supply and load power requirements 4.7 5.1 Photovoltaic-Diesel [P120] hybrid energy system Introduction [P138] The aim of this section is to introduce the most common applications for solar electricity Name a wide range of applications for photovoltaic APPLICATION Explain the basic features of each application Understand why photovoltaic is a suitable option in 9 each case 5.2 Economics of PV installation [P142] Assess the economic viability of a PV installation 7 5.3 Rural electrification [P155] 5.4 Water pumping [P163] MODULE PRACTICAL WORK AND WORK-INTEGRATED LEARNING The practical part of this module will be covered in the module ECTPRA4. 8 ASSESSMENT 8.1 Assessment plan You will find your assignments for this subject in this Tutorial Letter. Assignment 1, 2 and 3 are compulsory and all assignments will be used in the calculation of your year mark. Please send the completed assignments to UNISA before the closing dates stated in this section. Assignment 1 must be completed on a mark reading sheet. The mark for Electronics IV (Theory) (ECT4701) is calculated as follows: The year mark contributes to 20%. The examination mark contributes to 80% The year mark is based on all the assignment marks obtained and their contribution towards the final year mark are as shown in the table below: ASSIGNMENT NUMBER 1 (Compulsory) 10% 2 (Compulsory) 45% 3 (Compulsory) 45% TOTAL 8.2 CONTRIBUTION TOWARDS YEAR MARK = 100 % General assignment numbers Assignments are numbered consecutively per module, starting from 01. 10 ECT4701/101 8.2.1 Unique assignment numbers Assignment 1: Assignment 2: Assignment 3: 543257 543280 543289 8.2.2 Due dates for assignments THE CUT-OFF SUBMISSION DATES FOR THE ASSIGNMENTS ARE : Assignment 1: 21 May 2014 Assignment 2: 18 July 2014 Assignment 3: 5 September 2014 8.3 Submission of assignments ALL ASSIGNMENTS (submitted) HAVE TO BE ATTEMPTED!!!!!!! THE SUBMISSION OF AN EMPTY ASSIGNMENT COVER IS UNACCEPTABLE. IT IS VERY IMPORTANT TO CONSIDER THE FOLLOWING POINTS : NO LATE ASSIGNMENT SUBMISSIONS WILL BE ACCEPTED. KEEP A CLEAR COPY OF THE ASSIGNMENT FOR YOUR OWN REFERENCE. THIS IS IMPORTANT, AS ASSIGNMENTS DO GET LOST. SUBMISSIONS OF ASSIGNMENTS MUST BE IN ACCORDANCE WITH “MY STUDIES @ UNISA”. Please note that model answers for the assignments will be dispatched to all students within 1 week of the closing date of the assignment. This implies that you cannot submit your assignment later than the stipulated submission date. For detailed information and requirements as far as assignments are concerned, see the brochure my Studies @ Unisa that you received with your study material. To submit an assignment via myUnisa: Go to myUnisa. Log in with your student number and password. Select the module. Click on assignments in the menu on the left-hand side of the screen. Click on the assignment number you wish to submit. Follow the instructions. 11 8.4 Assignments THE CUT-OFF SUBMISSION DATES FOR THE ASSIGNMENTS ARE : Assignment 1: (Compulsory) 21 May 2014 Assignment 2: (Compulsory) 18 July 2014 Assignment 3: (Compulsory) 5 September 2014 ASSIGNMENT 1 To be completed on mark reading sheet 1. A common-emitter amplifier has very high input impedance, high voltage gain, and high current gain. 1) true 2) false 2. A high input impedance amplifier could be a Darlington pair. 1) true 2) false 3. A common-collector amplifier is also known as an emitter follower. 1) true 2) false 4. The total voltage gain, expressed as a ratio, of a multistage amplifier is the sum of the individual voltage gains. 1) true 2) false 5. The best selection for a high input impedance amplifier is a: 1) low gain common-emitter 2) common-base 3) common-collector 4) high gain common-emitter 12 ECT4701/101 6. The characteristic that is not of a common-base amplifier is: 1) high input impedance 2) current gain of 1 3) medium voltage gain 4) high output impedance 7. The characteristic that is not of an emitter-follower is: 1) voltage gain of 1 2) low input impedance 3) low output impedance 4) medium current gain 8. The best choice for a very high power amplifier is a(n): 1) common-collector 2) common-base 3) common-emitter 4) emitter-follower 9. Refer to Figure 6-1. The value of VC is: 1) 20 V 2) 10 V 3) 5 V 4) 0 V 13 10. Refer to Figure 6-1. If an emitter-bypass capacitor was added, the voltage gain: 1) would not change 2) would decrease 3) would increase 4) would decrease to zero 11. Refer to Figure 6-1. If R2 opened, VCE would be: 1) 0 V 2) 20 V 3) 10 V 4) 4.8 V 12. Refer to Figure 6-1. If R2 opened, the value of IC would be: 1) 6 mA 2) 6.67 mA 3) 8 mA 4) 10 mA 13. Refer to Figure 6-1. If RC opened, VE would: 1) increase 2) decrease 3) remain the same 4) be undetermined 14. Refer to Figure 6-1. If the emitter collector shorted, the voltage VC would be: 1) 0 V 2) 20 V 3) 16.67 V 4) 3.33 V 14 ECT4701/101 15. Refer to Figure 6-1. If the collector opened internally, the voltage on the collector would: 1) increase 2) decrease 3) remain the same 4) be undetermined 16. Refer to Figure 6-1. If VE = 0, the trouble might be that: 1) RE is open 2) RC is open 3) R2 is open 4) R1 is open 17. Refer to Figure 6-2. When checking this amplifier, Vout was below normal. The trouble might be: 1) an open C3 2) an open C4 3) C4 is shorted 4) C1 is open 18. Refer to Figure 6-2. If VB2 was higher than normal. The problem, if any, could be: 1) C3 is shorted 15 2) R3 is open 3) BE1 is open 4) C2 is open 19. Refer to Figure 6-2. In servicing this amplifier Vout was found less than normal. The problem could be caused by: 1) an open C3 2) an open C2 3) an open base-emitter of Q2 4) a shorted C2 20. Refer to Figure 6-2. The output signal from the first stage of this amplifier is 0 V. The trouble could be caused by: 1) an open C4 2) an open C2 3) an open base-emitter of Q2 4) a shorted C4 16 ECT4701/101 ASSIGNMENT 2 Question 1 Amplifier design method 1.1 Give a detailed discussion on the effect of the load resistor R (load) on the design approach when needed to design a common emitter class-A-amplifier. (10) 1.2 Simple two resister biasing amplifiers have a dependence on the beta value of the transistor. Discuss in detail how to overcome the problem of beta dependence. (10) 1.3 Explain in detail how to measure the beta value of a transistor using an amp meter and voltmeter. (10) Question 2 Practical design 2.1 Design component values for a common emitter class-A amplifier given in figure 1. Take the effect of R load into consideration by getting Q-point in the center for I collector of 2 mA. R load is 2K7 ohms, Take h fe = 100, hie = 2000 ohms, the voltage gain is 10 and the power supply is 20 volts. (20) + Vcc C3 R3 R1 R5 C1 C2 R2 R4 RL Figure 1 2.2 Draw the node graphs for the design in 2.1 if the input is 10 mV peak to peak. (10) 17 Question 3 3.1 Mathematical Analysing The class A amplifier in figure 2 has a sine wave input of 1 kHz with a 0,5 peak to peak amplitude. Analyse the circuit and draw the node graphs on scale from point A to J, show all calculations. (20) H 2k7 39 k A + 20 V C2 J D B E C1 10 k + 8k2 180 R F vg 820 R C3 G Figure 2 Class A- amplifier design 3.2 Will the amplifier work in practice? State your answer as yes or no. If your answer is no, redesign the amplifier so that the amplifier will work properly. If your answer is yes motivate. (10) Question 4 +5V +5V =1 0 0 L o g icg a te 4 k 7 3 9 0R L E D Figure 3: Driving an LED with a PNP transistor so that the LED grounded. The disadvantage of the circuit in figure 3 is that the “logic” output is reversed. An “ON” signal from the gate keeps the LED off, and an “OFF” signal from the gate will illuminate the LED. Design a circuit to correct this by using and extra transistor. (10) Total = 100 18 ECT4701/101 ASSIGNMENT 3 Question 1 Refer to Photovoltaic’s and answer the following questions. 1.1. What subsystems of a PV system can you name? (4) 1.2. What are the main categories of PV systems? (2) 1.3. How do the current and voltage of a module depend on the operating conditions? (2) 1.4. How many cells usually comprise a module? How are the cells connected and why? (2) 1.5. What is the role of a bypass diode? (2) 1.6. What are mismatch losses and how can they be reduced? (2) 1.7. What is the temporal pattern of battery operation in a PV system? (2) 1.8. Why is it a good maintenance practice to overcharge the battery at the end of winter? (2) 1.9. Is it true to say that the operational capacity of a battery in a PV system can be significantly higher than the manufacturer’s specifications? (2) 1.10. What are the disadvantages of operating battery storage as a seasonal buffer? (2) 1.11. What is the role of the blocking diode? Is it always necessary? (2) 1.12. How can a PV system operate without electronic control and what disadvantages does this system design have? (2) 1.13. What types of charge regulators are used in PV systems? (2) 1.14. Which inverter would you use in a stand-alone domestic system? (2) 1.15. Which control element would you use to ensure maximum power extraction from PV generator? (2) 1.16. Why is accurate sizing of PV installations important? (3) [35] Question 2 Photovoltaic design 2.1 Refer to a city in Europe latitude 20° north. You must design a PV system and no tables for the radiation are available. Show how to design without the irradiance tables by stating the tilt angle and solar hour for the following: 2.1.1 The highest irradiation over the whole year. (3) 19 2.1.2 The highest irradiation during winter months (3) 2.1.3The highest irradiation during summer months (3) 2.2 Refer to the data in table 1 and determine the angle of inclination and the solar hour to be recommended in order to maximize the input to a photovoltaic (PV) system for the following conditions: 2.2.1 The highest energy incident on the inclined panels over the whole year. (3) 2.2.2 The month and highest energy during the winter months at 30°. (3) 2.2.3 The month highest energy during the summer months at 30°. (3) 2.2.4 The worst month of the year at 30°. (2) 2.2.5 The best month of the year at 30°. (2) Table 1 Solar radiation for Pretoria RSA 20 ECT4701/101 Question 3 Explain with the aid of sketches how to plot the characteristic curve of a photovoltaic panel practically. Show how to calculate the maximum power point, maximum power ratio and the fill factor and explain the meaning of each. (10) Question 4 Design and size a photovoltaic system for a streetlamp at Pretoria latitude 25°44’south by considering table 1 for the following electrical load: 1 * 100watt 12 V streetlamp operating 10 hour every day. The use of a maximum power point tracker contributes 20% more energy transfer to the system. Available are 50 W, 12 volt panels. 4.1 Sketches the power flow block diagram for the system. (3) 4.2 Calculate the total daily load for the streetlight in kWh/day a seen by the PV including the losses of the system. (4) 4.3 From table 1 determine the tilt angle that will maximise the mean average of the year. (3) 4.4 From table 1 determine the solar hour for the tilt angle in 4.3. (3) 4.5 Calculate the size and number of solar panels for this tilt angle. (4) 4.6 Calculate the (SF) safety factor of the panels. (3) Question 5 Refer to question 4. If a set of batteries needed to be added to the system, design and size the batteries for the following conditions: Assume 2 days of storages in a battery with an efficiency of 80% and the batteries should not be discharge to less than 50% of its capacity and the deficit annually is zero. Available are 95 Ah, 12V batteries. (10) Total 100 21 9 OTHER ASSESSMENT METHODS None 10 EXAMINATION Use your my Studies @ Unisa brochure for general examination guidelines and examination preparation guidelines. 11 FREQUENTLY ASKED QUESTIONS The my Studies @ Unisa brochure contains an A-Z guide of the most relevant study information. 12 SOURCES CONSULTED None 13 CONCLUSION Please ensure that you have all the tutorial letters and prescribed book available before starting with your studies. 14 None 22 ADDENDUM