Laboratory Procedures
DeVry University
College of Engineering and Information Sciences
I.
OBJECTIVES
1. To analyze a
parallel AC circuit containing a resistor (R), an inductor
(L), and a capacitor (C).
2.
To simulate
the RLC circuit and observe the circuit responses.
3.
To build the RLC circuit and measure the circuit
responses.
II. PARTS LIST
Equipment:
Function Generator
DMM (Digital Multimeter)
Parts:
1  470 ? Resistor 1  1 µF
Capacitor
1  47 mH Inductor
Software:
MultiSim
11
III. PROCEDURE
A. Theoretical Analysis
1.
Given
the R, L, & C parallel circuit in Figure
1, calculate the total equivalent admittance, Y_{T}, and the impedance,
Z_{T}, of the circuit at f = 550 Hz and 1 kHz. List the calculated
values in Table 1.
.gif">
Figure 1: Parallel
R, C, L Circuit
Frequency
Hz

L
& C Admittances in Rectangular Form

Inductor
G_{L}
 jB_{L}

Capacitor
G_{C}
+ jB_{C}

550



1000



Frequency Hz

Total
Circuit Admittance Y_{T}

Rectangular
Form
G_{T}
+ jB_{T}

Magnitude

Angle

550




1000




Frequency Hz

Total
Circuit Impedance Z_{T}

Rectangular
Form
R_{T}
+ jX_{T}

Magnitude

Angle

550




1000




Table 1 – Calculated RLC Admittance
and Impedance Values
2.
Calculate
and record the following quantities:
Frequency
Hz

I_{R} (RMS). A

I_{C} (RMS), A

I_{L} (RMS). A

Magnitude

Angle

Magnitude

Angle

Magnitude

Angle

550







1000







Frequency
Hz

{I_{R}
+ I_{C} + I_{L} }= I_{S} (RMS), A

I_{S}
= V * Y_{T}

Rectangular Form

Magnitude

Angle

Magnitude

Angle

550






1000






Table
2 – Calculated RLC Component Current Values
Does the sum of the magnitudes of the three currents I_{R}, I_{C,} and
I_{L}, in the table above, equal
the current, I_{S}, calculated directly in the last column?
(YES
or NO)
Explain why your
answer is what it is.
3.
Calculate
the power dissipated by the parallel resistor and the power supplied by the
source:
Frequency Hz

P_{R},
W

P_{S},
W

550



1000



Table 3 – Calculated RLC
Resistor Power Dissipation
B. Multisim Simulation and Circuit
Calculations
1. Launch MultiSim and build the circuit
schematic shown in Figure 2.Include
the AC Power source and the DMMs.
2. Set both DMMs, XMM1 thru’ XMM4, to read AC
measurements and Current, I. See fig. 2 below.
.jpg">
Figure 2: MultiSim RLC Parallel Circuit with Instrumentation
3. Activate the simulation and record the current
readings for both frequencies:
Frequency
Hz

I_{S}
(RMS), A

I_{R}
(RMS), A

I_{C}
(RMS), A

I_{L}
(RMS), A

550





1000





Table 4 – Current
Measurements Simulation Results
4. Do the current values in Table 4 agree with
those obtained in Tables, 2, 3, & 4 of Part A? (Circle your answer)
YES NO
5. Remove the DMMs and attach the wattmeter as
shown below:
.jpg">
Figure 3  AC Power Measurement
6. Record the measurement from the wattmeter.
Frequency
Hz

Source Power, P_{S}
(Watts)

Power Factor

550



1000



Table 5  Power Measurement
Readings
7. Do values
in the Tables 6 and 2 agree?
(Circle your answer)
YES NO
If there is any disagreement investigate the source of
error and report your findings below:
C. Construction of a Parallel R, L, C Circuit and
Measurement of Circuit Characteristics
1. Construct the circuit in Figure 1.
2. Set the function generator voltage to2.5V RMS and the frequency value to 550 Hz.
3. Turn the circuit on.
4. Record the
current reading.
I_{S} = _____________ (A)
5. Is this the same as the simulated and
calculated value? ________ (YES or NO)
6. Measure and
record the branch currents:
I_{R} = ________ (A)
I_{C}= ________(A) I_{L
}= ________(A)
Are the current readings
the same as your calculated and simulated values?
(Circle your answer)
YES NO
If you answered NO, explain why you think they
differ.
7.
Repeat Steps 2 through 6 with the frequency
generator set to output at 1000 Hz.
I_{S} = ______________(A)
I_{R} = ________ (A)
I_{C}= ________(A) I_{L
}= ________(A)
Are the current readings
the same as your calculated and simulated values?
(Circle
your answer)
YES NO
If you answered NO, explain why you think they
differ.
IV. TROUBLESHOOTING
Describe any problems encountered and how those problems were solved.
Laboratory Report Cover Sheet
DeVry University
College of Engineering and Information Sciences
Course Number:ECET210
Professor:
Laboratory Number:
4
Laboratory Title:Analysis
of AC Parallel RLC Circuit using Simulation and Construction
Submittal Date:Click here to enter a date.
Objectives:
Results:
Conclusions:
Team:







Name


Program


Signature








Name


Program


Signature








Name


Program


Signature

Observations/Measurements:
III. A. 1. RLC Circuit
Calculated Impedance and Admittance Values:
Frequency
Hz

Susceptance,
Siemens

Inductive,
B_{L}

Capacitive,
B_{C}

550



1000



Frequency Hz

Total
Circuit AC Admittance, Y_{T}

Complex
Notation

Magnitude

Angle

550




1000




Frequency Hz

Total
Circuit AC Impedance, Z_{T}

Complex
Notation

Magnitude

Angle

550




1000




III. A. 2. RLC Circuit Calculated Current Values:
Frequency
Hz

I_{R} (RMS). A

I_{C} (RMS), A

I_{L} (RMS). A

Magnitude

Angle

Magnitude

Angle

Magnitude

Angle

550







1000







Frequency
Hz

{I_{R}
+ I_{C} + I_{L} }= I_{S} (RMS), A

I_{S}
= V * Y_{T}

Complex Form

Magnitude

Angle

Magnitude

Angle

550






1000






Match? Yes _____ No ______
Explanation:
III A. 3. RLC
Circuit Calculated Power Dissipation:
Frequency Hz

P_{R},
W

P_{S},
W

550



1000



III. B. 3. RLC
Circuit Simulation Results:
Frequency
Hz

I_{S}
(RMS), A

I_{R}
(RMS), A

I_{C}
(RMS), A

I_{L}
(RMS), A

550





1000





III. B. 4.
Simulation Values Match Calculated Values:
Match? Yes
_____ No ______
III. B. 6. RLC
Circuit Simulated Power Measurement:
Frequency
Hz

Source Power, P_{S}
(Watts)

Power Factor

550



1000



III. B. 7.
Simulation Values Match Calculated Values:
Match? Yes
_____ No ______
Explain any mismatch:
III. C. 4. RLC
Circuit Measured Current at 550 Hz:
I_{S} = _____________ (A)
III. C. 5.
Value Matches Calculated and Simulated Values:
Match? Yes
_____ No ______
III. C. 6. RL
Circuit Measured Currents:
I_{R} = ________(A) I_{C
}= ________(A) I_{L}= ________(A)
Match? Yes
_____ No ______
Explain any mismatch:
III. C. 7. RLC
Circuit Measured Current at 1000 Hz:
I_{S} = _____________ (A)
I_{R} = ________(A) I_{C
}= ________(A) I_{L}= ________(A)
Match? Yes _____
No ______
Explain any mismatch:
Questions:
1.
.gif">Construct a Phasor Diagram to represent the source current and the branch
currents, I_{R}, I_{C,} and I_{L} through the resistor,
capacitor, and the inductor. The diagram does not need to be drawn to scale.
However, the values of the items represented must be included in the diagram.
2.
Did
you notice any interesting feature in the lab exercise with regard to the two
different frequencies chosen for the experiment?
3. In the Multisim simulation, change the
frequency of the source to be between 725Hz to 735 Hz (in increments of 2 Hz)
and record the inductor and the capacitor currents.
Frequency,
Hz

I_{R},_{
}mA

I_{C},
mA

I_{L},
mA

725




727




729




731




733




735




What do you notice from the readings?
Grade:
Deliverable

Points
Available

Points
Achieved

Laboratory Cover Sheet

8


Working Circuit(s)/Program(s)

8


Observations/Measurements

6


Questions

8


Total
Points

30



Comments:
