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EEL1 – No. 4 (PSpice) University of Applied Sciences Hamburg DEPARTMENT OF ELECTRICAL ENGINEERING Group No : Laboratory for Instrumentation and Measurement L1: in charge of the report Date: Test No. 4 (PSpice) Professor: Assistant A2: 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 EEL1Lab4.doc Prof. ............................................................... -1Dahlkemper 15.12.2009 EEL1 – No. 4 (PSpice) Important • • • • • • • • First page of report: fill out the first page of the corresponding test. Don’t forget to specify the exact group number, e.g. IE2.1, IE2.2 Leave a left-margin of at least 3 cm on the sheets. Write on one side of the sheet only. Don’t put the sheets into plastic folders. At the end: bring all sheets into an order and number them consecutively. Circuits must contain all quantities used for analysis, together with the corresponding „reference arrows“. All PSpice-plots must have a title/figure caption. Objectives • Gain experience with the steady state analysis functionality provided by the simulation tool PSpice. • Get acquainted with the possibility of generating bode plots using the AC sweep mode and the possibility to run simulations with parameters. • Understand the filter characteristics of an RC high-pass and low-pass filter and of an RLC series and parallel circuit. 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 Develop the formulas for the transfer function, amplitude response and phase response of the RC high-pass filter shown in fig. 1 as function of f and calculate the cutoff-frequency. Preparation for exercise 2: RC low-pass filter Calculate the cutoff frequency of the low-pass filter shown in fig. 2 for the 3 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 in fig. 3. Preparation for exercise 4: RLC parallel circuit Determine the Quality factor of the RLC circuit shown in fig. 4 (without the internal resistance Ri of the voltage source) for the different values of the resistance R (1 Ω, 2 Ω, 4 Ω). EEL1Lab4.doc -2- Dahlkemper 15.12.2009 EEL1 – No. 4 (PSpice) Exercise 1: RC high-pass filter Simulate the frequency response of the RC high-pass shown in Fig. 1 both as linear plot and as logarithmic Bode plot. Follow the steps described below. Fig. 1: RC high-pass filter 1. Open schematics and draw the circuit of figure 1 including the labels. Store the file with the name EEL1SpiceLab2_1.sch in the directory C:\PSpice\ or in your home directory. 2. According to your pre-calculated cutoff-frequency select the appropriate settings for the start and end frequency and run the simulation. 3. Add traces for the amplitude response and phase response in degree as function of the frequency f as lin-lin plot. Mark the 1/√2 point of the amplitude response and the 45° degree point of the phase response. 4. Activate the Log commands function by selecting File→ Log Commands, save the file as Bode.cmd. Add a second window and add traces for the amplitude response as Bode plot. Deactivate Log commands by re-selecting the menu item File→ Log Commands. 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. EEL1Lab4.doc -3- Dahlkemper 15.12.2009 EEL1 – No. 4 (PSpice) Exercise 2: RC low-pass filter Analyze the amplitude response of the low-pass filter shown in Fig. 2 for different values of R and C. Fig. 2: RC low-pass filter with parameter R 1. Save the exercise 1 file as EEL1SpiceLab2_2.sch and exchange the capacitor and the resistor as shown in figure 2. Remember to save the file again after having done the changes. 2. Add the element PARAMETERS and define a parameter named Rpara with the value 1. Make the value of R depend from the parameter Rpara. Define the values 500 Ω, 1 kΩ and 2 kΩ for the parameter Rpara and select the parametric settings as described in figure 2. Run the simulation. 3. Recall the Bode plot diagram by selecting the menu item File→Run Commands and loading the file Bode.cmd. 4. Determine the cutoff-frequencies by approximating a straight line to each curve and mark each cutoff frequency. 5. Compare the pre-calculated cutoff-frequencies with the frequencies obtained in 4. EEL1Lab4.doc -4- Dahlkemper 15.12.2009 EEL1 – No. 4 (PSpice) Exercise 3: RLC series circuit Simulate the RLC series circuit fed by a linear voltage source and determine the output voltage in resonance for different values of the resistance. Analyze the voltage across the components of the series circuit using trace expressions. Fig. 3: RLC series circuit 1. Save the exercise 2 file as EEL1SpiceLab2_3.sch and modify the circuit as shown in figure 3. Remember to save the file again after having done the changes. 2. Run the simulation and visualize the ratio of Uout and U0 as lin-log plot, e.g. by recalling the Bode.cmd and modifying the Y-axis scaling. 3. Apply the Trace→Cursor→Minimum function to determine and mark the minimum values of the amplitude response. Set up the equations to determine these minimum values. 4. Open a second plot in the same window and analyze the voltage across the capacitor using the trace functions. 5. Describe the behavior of the voltage across the capacitor for low frequencies, resonance and high frequencies. What is remarkable in the range of the resonance for low resistances R. Find analogies to explain this with examples that have nothing to do with electrical engineering. 6. Compare the pre-calculated values of the resonance frequency with the values obtained in 3. EEL1Lab4.doc -5- Dahlkemper 15.12.2009 EEL1 – No. 4 (PSpice) Exercise 4: RLC parallel circuit Simulate the amplitude response of the RLC parallel circuit and analyze 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. Don’t forget to save the file again after having done 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 resistor for resonance and the according current through L at resonance. 4. Set up a table to determine for each value of R at the 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 through the dissipated power. Compare the reactive power in L and C at resonance frequency. Discuss why either the reactive power in C or L is considered for the calculation of the quality factor and not both of them. 5. Compare the pre-calculated values of the quality factor with the simulated ones. EEL1Lab4.doc -6- Dahlkemper 15.12.2009