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EEL1 – PSpice 2 University of Applied Sciences Hamburg DEPARTMENT OF ELECTRICAL ENGINEERING Laboratory for Instrumentation and Measurement Group No : L1: in charge of the report Date: Assistant A2: PSpice 2 PC Pool Professor: Assistant A3: RC and RLC Circuit Steady State Analysis − Simulation with the Program PSpice − Report History Date Remarks Report 1 received checked result o.k. n.g. 1. Correction Term............................... Date Remarks 1. Correction received checked result o.k. n.g. 2. Correction Term............................... Last chance!! Remarks 2. Correction Date received checked result o.k. n.g. not passed back to L1................. Final decision: o.k. not passed EEL1_Lab4.doc Prof. ............................................................... -1Dahlkemper / S.Lehmann 15.12.2012 EEL1 – PSpice 2 Important • • • • • • • Complete the cover page and attach it to your report. Please do not forget to include your group number (1, 2, 3) on the cover page. Leave a left-margin of at least 3 cm and prepare your report single-sided. Please staple your reports. Do not use binders or sheet protectors. Sort and number all pages prior to submission. Circuits must contain all quantities used for analysis, together with the corresponding ‘reference arrows’. All PSpice - plots (‘probe’ graphic) must have a title field and figure caption. Objectives • Gain experience with the steady state analysis functionality provided by the simulation tool PSpice. • Become acquainted with generating bode plots using the AC sweep mode and with running simulations using parameters. • Understand the filter characteristics of an RC high-pass and low-pass filter and of RLC series and parallel circuits. Preparation Note: This homework is to be prepared as group work before the lab session starts and to be presented at the beginning of the lab session by the team leader. Preparation for exercise 1: RC high-pass filter Derive the transfer function, amplitude response and phase response of the RC high-pass filter shown in Figure 1 as functions of the frequency. Calculate the 3dB cutoff-frequency. Preparation for exercise 2: RC low-pass filter Calculate the cutoff frequency of the low-pass filter shown in Figure 2 for three different values of R (500 Ω, 1 kΩ, 2 kΩ). Preparation for exercise 3: RLC series circuit Calculate the resonance frequency of the RLC series circuit depicted in Figure 3. Preparation for exercise 4: RLC parallel circuit Determine the quality factor of the RLC circuit shown in Figure 4 (without the internal resistance Ri of the voltage source) for different values of the resistance R (1 Ω, 2 Ω, 4 Ω). EEL1_Lab4.doc -2- Dahlkemper / S.Lehmann 15.12.2012 EEL1 – PSpice 2 Exercise 1: RC high-pass filter Simulate the frequency response of the RC high-pass filter shown in Figure 1 using both a linear plot and a logarithmic Bode plot. Follow the steps described below. Fig. 1: RC high-pass filter 1. Open schematics and draw the circuit shown in Figure 1 including the labels. Save the corresponding file. 2. Set the start and end frequencies according to your pre-calculated cutoff-frequency and run the simulation. 3. Add traces for the amplitude response and phase response in degrees as functions of the frequency f (lin-lin plot). Mark the 1/√2 point of the amplitude response and the 45° degree point of the phase response. 4. Approximate the curve by two straight lines in the diagram and mark the cutofffrequency. 5. Compare the pre-calculated cutoff frequency with the results obtained in 3 and 4. EEL1_Lab4.doc -3- Dahlkemper / S.Lehmann 15.12.2012 EEL1 – PSpice 2 Exercise 2: RC low-pass filter Analyse the amplitude response of the low-pass filter shown in Figure 2 for different values of R and C. Fig. 2: RC low-pass filter with parameter R 1. Save the file from Exercise 1 under a new name and exchange the capacitor and the resistor as shown in Figure 2. Remember to save the file again after the changes. 2. Add the element PARAMETERS and define a parameter Rpara with the value 1. Establish a dependence of R on the parameter Rpara. Define the values 500 Ω, 1 kΩ and 2 kΩ for the parameter Rpara and select the parametric settings as shown in Figure 2. Run the simulation. 3. Create a Bode plot. 4. Determine the cutoff-frequencies by approximating each curve with a straight line and marking each cutoff frequency. 5. Compare the pre-calculated cutoff-frequencies with the frequencies obtained in 4. EEL1_Lab4.doc -4- Dahlkemper / S.Lehmann 15.12.2012 EEL1 – PSpice 2 Exercise 3: RLC series circuit The RLC series circuit in Figure 3 is fed by a linear voltage source. Simulate the circuit and determine the output voltage at resonance state, using different values for the resistance R. Analyse the voltages across the components of the series circuit using trace expressions. Fig. 3: RLC series circuit 1. Save the Exercise 2 file and additionally save it as a new file for Exercise 3. Modify the circuit as shown in Figure 3. Remember to save the file again after the changes. 2. Run the simulation and visualise the ratio of Uout and U0 as a lin-log plot. 3. Apply the Trace→Cursor→Minimum function to determine and mark the minimum values of the amplitude response. Derive equations to determine these minimum values. 4. Open a second plot in the same window and analyse the voltage across the capacitor using the trace functions. 5. Describe the behaviour of the voltage across the capacitor for low frequencies, resonance and high frequencies. What remarkable effect can be observed around the resonance state for small resistances R? Find analogies to explain this effect using examples that are not related to Electrical Engineering. 6. Compare the pre-calculated values of the resonance frequency with the values obtained in 3. EEL1_Lab4.doc -5- Dahlkemper / S.Lehmann 15.12.2012 EEL1 – PSpice 2 Exercise 4: RLC parallel circuit Simulate the amplitude response of the RLC parallel circuit and analyse the quality factor. Fig. 4: RLC parallel circuit at linear voltage source 1. Save the exercise 3 file as EEL1SpiceLab2_4.sch and modify the circuit as shown in Figure 3. Remember to save the file again after the changes. 2. Add a voltage marker to the Uout wire (Menu item Markers→Voltage/Level marker) and a current marker to the inductor (Menu item Markers→Current marker) and run the simulation. 3. Apply the Trace→Cursor→Minimum function to determine and mark the maximum output voltage for each resistance at resonance and the corresponding current through L at resonance. 4. Set up a table to determine for each value of R at resonance frequency the reactive power stored in L and C and the power dissipated by R. Determine the quality factor by dividing the reactive power stored in the capacitor by the dissipated power. Compare the reactive power in L and C at resonance frequency. Discuss why for the calculation of the quality factor, the reactive power in either C or L is to be considered but not both. 5. Compare the pre-calculated values of the quality factor with the simulated ones. EEL1_Lab4.doc -6- Dahlkemper / S.Lehmann 15.12.2012