Castleford Campus Edexcel Centre 38210 School of Engineering and Motor Vehicle QCF LEVEL 4: HNC DIPLOMA Assignment Brief Programme Details Edexcel Programme No(s) This student ML041 Programme Titles HNC Diploma Electrical Engineering Unit Details Unit No Unit Title Level 66 ELECTRICAL, ELECTRONIC AND DIGITAL PRINCIPLES 5 Assignment Details Original Author John D Siviter No. Title Assessor Audit Ref Michael Schonborn HEED001A 1 Use of complex notation in RLC circuits analysis IV Ref This assignment should be completed within 3 weeks Student Details Issue Date Hand in Date Actual Hand in Date 11/01/16 01/02/16 Name Statement I certify that the work carried out in this assignment is my own Signature Criteria Achieved 1.1 1.2 M1 D1 D3 1
ASSIGNMENT No: TITLE Outcome Be able to apply complex notation in the analysis of single phase circuits To complete this assignment successfully, at least all of the pass criteria must be achieved. To obtain a pass grade on the complete unit, all pass criteria from all assignments from the unit must be achieved. Criteria 1.1 Solve problems involving LCR circuits 1.2 Evaluate the effects on circuit performance of changes in values of impedances Achieved To obtain a merit for the full unit, all merit criteria from all assignments from the unit must be completed successfully in addition to all of the pass criteria from all assignments from the unit. Criteria Contextualisation Achieved M1 Identify and apply strategies to find appropriate solutions By exploring interrelationship of R,L C and resonance in Q4 To obtain a distinction for the full unit, all the distinction criteria and all the merit criteria from all assignments from the unit must be completed successfully in addition to all of the pass criteria from all assignments from the unit. Criteria Contextualisation Achieved D1 Use critical reflection to evaluate own work and justify valid conclusions Draw up a conclusion of other applications of RLC circuits in Q5 with examples D3 Demonstrate convergent/lateral/ creative thinking Define dynamic resistance and derive dynamic resistance of Q2 (b). Calculate the value of dynamic resistance of Q2 (b). NOTE: Your work should be set out neatly and logically and should be well presented. You should always show all calculations and add explanation where necessary. Don t just submit a mass of figures! 2
Scenario You are working for a design laboratory. You are tasked with the design of filters and oscillators as a building blocks for various circuits. You need to investigate the impact of resistances in an RLC circuit and calculate resonant frequencies. You will have to make use of imaginary numbers. Clearly present your findings in a report format. This assignment brief must be handed in with the completed assignment (In your answers you must draw the circuit topologies where required, and you must show each step of calculations. It will not be sufficient to just show the final answer without clear evidence of calculations) Answer Q1 and Q2 to achieve 1.1 Q1. a) A series RLC circuit has a resistance of 20Ω, an inductance of 200mH and capacitance of 1µF. If supply voltage is 12<0⁰V at 100Hz then determine the following Inductive reactance Capacitive reactance Total circuit impedance in rectangular and polar forms Resonant frequency The current at resonance. 3 b) A series RLC circuit has a resonant frequency of 50Hz, a resistance of 30Ω and, an inductance of 400mH and supply voltage of 24V at 50Hz. Determine the circuit impedance and the Q-factor Q2. a) A circuit consists of three components in parallel, a resistor of 2kΩ, an inductor of 0.4mH and a capacitor of 47pF. Provided that supply voltage is 20<0⁰ at 50 Hz determine Inductive reactance Capacitive reactance Circuit impedance in rectangular and polar forms The resonant frequency The circuit impedance at resonance with rectangular and polar forms if possible, if not then why not? Current taken at resonance by the circuit.
b) A circuit has a coil of 200Ω resistance and inductance 50mH in parallel with a capacitor of 0.2µF. Provided that supply voltage is 20<0⁰ at 60 Hz, determine Inductive reactance Capacitive reactance Circuit impedance in rectangular and polar forms Resonant frequency Q-factor Answer Q3 to achieve 1.2 Q3 The circuit below an RLC circuit (Band pass filter) consisting of an inductor, a capacitor and a resistor in series. By considering the table below find out the impedance and resonant frequency at the given values of components. L (mh) C (µf) R Z f0 8.3mH 4.7µF 100Ω 8.3mH 4.7µF 10Ω 8.3 mh 2.2µF 10Ω V = 20V at 50Hz. Once you have found different values of resonance, comment on how does the change in impedance affects the natural frequency (resonant frequency) of the circuit. 4
Answer Q4 to achieve M1. Q4 In Q3 (1.2) Does change in resistance only change the resonant frequency of the circuit? In your own words explain what is the function of resistance in an RLC circuit? How would you describe current at resonance (justify your answer with equation of current at resonance). How does Q-factor affect the selectivity and the bandwidth in a Band pass filter? Answer Q5 to achieve D1. Q5 You have seen one of the applications of RLC circuit as Band pass filter (Q3 1.2). Describe some of the major applications of RLC circuits? You must justify your answers with some explanation and examples. Answer Q6 to achieve D3 Q6. Define dynamic resistance, for Q2 (b) you need to work out the dynamic resistance of the circuit. Calculate what is the dynamic resistance of the circuit? 5