Assignment title Electronic systems design, power supplies and calculating values Assessor Date issued Final deadline Duration (approx) Four one-hour sessions over two weeks Qualification suite covered BTEC BTEC BTEC BTEC Units covered Unit 8: Electronic Circuit Design and Construction Learning aims covered Learning aim A: Know about electronic systems design Scenario You have just taken a new position as a Design Engineer at a small company that makes a variety of electrical and electronic products. Your Supervisor has given you some basic details for a new product that includes an electronic system. You have to design the electronic system and report back to her, commenting on the reasons for component choices and possible power supplies. You must also show her all the relevant calculations to prove the system is suitable, as this new product is crucial to the continued success of the company. Task 1 You will be provided with a block diagram, an example of which is shown below: Level Level Level Level 1/Level 1/Level 1/Level 1/Level 2 2 2 2 First First First First Award in Engineering Certificate in Engineering Extended Certificate in Engineering Diploma in Engineering Considering the example above, you must identify and select: appropriate input components to respond to falling temperature a processing component or components that would produce a very high amplification an output component that would give a loud audible sound appropriate passive components. You must then: © Pearson 2014 annotate the block diagram you have been given with symbols of the chosen components (within the Input, Process and Output blocks) write notes giving details as to why you chose each component, ensuring that you refer to what each component does provide in-depth information of how each of your chosen input, process and output components combine to solve the electronics problem shown in the block diagram. 1 Evidence you must produce for this task Annotated block diagram Supporting notes and further information Criteria covered by Task 1: Unit Criterion reference Select and apply appropriate input, process and output, and passive components for a circuit. 8 2A.P1 Explain reasons for the selection of electronic input, process, output and passive components. 8 2A.M1 Justify the selection of appropriate input, process and output components in a circuit design to solve a given electronics problem. 8 2A.D1 To achieve the criteria you must show that you are able to: Task 2 Part 1 Research and produce a written report on the characteristics of different types of power supplies used to power low current electronic circuits, including: zinc carbon, alkaline and NiCad batteries button cells low voltage power supply units solar cells. Part 2 The following questions are examples of problems where values relating to electronic circuits have to be calculated. You must complete the calculations given to you, using the correct units of measurement and showing all workings. 1. Use the circuit diagram below to answer questions a-e. R1 R2 a. If R1 = 360Ω and R2 = 600Ω, what is the total resistance in the circuit? b. If the supply voltage is 9V, what is the current flowing in the circuit? c. What is the potential difference across R1? d. If R1 = 20KΩ and R2 = 10KΩ, what is the total resistance in the circuit? e. If the supply voltage is 12V, what is the electrical power in the circuit? © Pearson 2014 2 2. Use the information below to answer questions a-c. For capacitors the time constant = C (in farads) x R (in Ohms) After 1 time constant a capacitor is 50 per cent charged. It takes 6 time constants for a capacitor to fully charge. a. If C = 10uF and R = 10KΩ, what is the time constant? b. If C = 100nF (or 0.0000001F) and R = 33KΩ, what is the time constant? c. How long will it take a 1nF capacitor to charge fully with a resistance of 10KΩ? 3. Power can be calculated using power = VI = I 2R = V2/R, so: a. If V = 9V and I = 13A, what is the electrical power? b. If V = 12V and R = 33KΩ, what is the electrical power? c. If the power = 100W and current = 12A, what is the resistance in the circuit? 4. Use the following circuit diagram to answer questions a-f: R1 R2 a. If R1= 10KΩ and R2=15KΩ, what is the total resistance in the circuit? b. If the supply voltage is 12V, what is the current flowing through R1? c. What is the current flowing through R2? d. If R1 and R2 are equal, what happens to the current? e. R1 and R2 = 560Ω. The supply voltage = 9V. What is the current flowing through R1? f. Evidence you must produce for this task How could you reduce the current flowing through R2 by half? Written report (Part 1) Accurate electronic circuit calculations using correct units of measurement and showing workings (Part 2) Criteria covered by Task 2: To achieve the criteria you must show that you are able to: Describe the characteristics of power supplies and carry out simple and complex calculations using units of current, resistance, voltage and power in electronic circuits. © Pearson 2014 Unit Criterion reference 8 2A.P2 3 Sources of information Textbooks Clarke, S. et al. (2012) BTEC First in Engineering Student Book, Harlow: Pearson Education, 978 1 44690 243 1. Sedra, A.S. and Smith, K.C.A. (1997) Microelectronic Circuits, 4th Edition, Oxford: Oxford University Press, 978 0 19511 690 8. Tooley, M. (2006) Electronic Circuits: Fundamentals and Applications, 3rd Edition, Oxford: Newnes, 978 0 75066 923 8. Tooley, M. (2010) BTEC First Engineering, 2nd Edition, Oxford: Newnes, 978 1 85617 685 9. Wallis, S. et al. (2010) BTEC First Engineering, London: Hodder Education, 978 1 44411 052 4. Websites www.bbc.co.uk/schools/gcsebitesize/design/electronics/componentsrev1.shtml www.technologystudent.com/elec1/elecex.htm www.bbc.co.uk/bitesize/higher/physics/elect/resistors/revision/1/ www.harfordemcomm.org/files/ohms_law.pdf Note to assessors We are committed to ensuring that teachers/tutors and learners have a choice of resources to support their teaching and study. We would encourage them to use relevant resources for your local area such as local employers, newspapers and council websites. Resources from various publishers are available to support delivery and training for all Pearson and BTEC qualifications so that learners and teachers/tutors can select those that best suit their needs. Above are some examples of textbooks and websites. Further useful resources may be found at www.edexcel.com/resources. If you have not achieved the Level 2 criteria, your work will be assessed to determine if the following Level 1 criteria have been met. To achieve the criteria you must show that you are able to: Unit Criterion reference Describe the function and characteristics of electronic input, process, output and passive components. 8 1A.1 Carry out simple calculations using units of current, resistance, voltage and power. 8 1A.2 © Pearson 2014 4

Download
# Unit 8: Electronic Circuit Design and Construction