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
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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
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Gain experience with the steady state analysis functionality provided by the simulation
tool PSpice.
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Get acquainted with the possibility of generating bode plots using the AC sweep mode
and the possibility to run simulations with parameters.
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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).
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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.
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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.
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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.
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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.
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