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Title and header
Title describes report contents appropriately, adequately, and concisely
Author information complete (full name, affiliations)
Related information complete (course name, date, etc.)
Formatting centered, top of page
Abstract
State background and objectives
Summarize lab procedures and results
Provide conclusion
Standalone, clear, complete, and concise
Introduction
Give background and opening information
Provide the significance of the lab (why we care about this lab)
Present the purpose and objectives of the lab
Describe the object/system being tested
Provide necessary theoretical fundamentals (equations)
Does not contain results
Instruments
Explain major device(s) or sensor(s) used in this lab
Lab procedures
Overview of the approach
Describe the overall procedure logically, clearly and concisely
Gives enough details to allow for replication of procedure
All measurement instruments are accurately presented
Describe instrument calibration and/or validation
Describe and explain all variables in the lab
Describe the variables that will be controlled, and how they respond
State assumptions
Self developed, not copy paste lab handout
Results and discussions
Present the results clearly
Present the data appropriately (figures and/or tables)
Give quantitative discussions of the results
Provide uncertainty analysis to the results
Explain sources and magnitudes of experimental uncertainties
Clearly state the findings from the lab
Discuss the limitations of the findings and provide recommendations
Conclusions
Summarize the lab (what has been done)
Summarize major findings, reflecting the lab objectives
Summarize major issues, and recommendations
References
All references given in appropriate format
References are listed in the order of their appearance in the report
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Acknowledgements
37 Acknowledge the institutes and persons who help you to complete the lab
General formatting, wrting styles, organization, and lab attendance
38 Appropriate headings and formatting at all levels
39 Use course template (margin, font sizes, double column, justified,
single spacing, indented, etc.)
40 Cite all references
41 Correct figure and table caption format
42 Figures and tables in appropriate size and font size
43 Graphs with correct markings, legends, labels, etc.
44 Cite all figures and tables, in appropriate format
45 Grammar and spelling correct
46 Attending lab session
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Laboratory 2
A
LAB REPORT BY USING FLUID MEASUREMENTS
NAME: Mustafa Munshi
Department of Mechanical Engineering
University of South Carolina
Columbia, SC29208
ABSTRACT
Engineering is a branch of applied science in
which already known ideas, facts and models are
used to construct something. So to have practical
knowledge about the theory studied in the
classroom is essential. Fluid measurement is the
determination of the flow rate, velocity and
pressure of the liquid flowing in a vessel. The
practical knowledge about the fluid
measurements helps the students in their future
study as well as in their professional life. In this
lab, the students are made familiar with the
experiments in which they had to take various
measurements such as flow rate, pressure and
power of the pump. In this experiment students
also learnt to determine the coefficient of the
discharge. The measurements were taken by
closing valve in different sets. Pump power and
flow rate dropped when the valve was closed,
but pressure surged.
INTRODUCTION
Fluid flow measurements are required in a wide
range of applications, from the regulation of drug
delivery in ventilators to the control of fuel flow
in engine management systems. There are many
things you need to consider while doing fluid lab
such as, the flow velocity, mass flow rate, and
volumetric flow rate, not paying attention to
them clearly might lead to wrong data. The need
of the knowledge about the fluid measurements
is very high. The goal of this lab was to provide
students practical learning experience taking
fluid measurements. Learners need to take
different types of measurements by having the
actual number of the flow by gathering it in a
bottle for specific time, and some data need to
be taken from the computer like the fluid
pressure, fluid flow and the power of the pump.
Objectives:
Using fluid systems with wet differential
pressure to measure the pressure in a
system.
Measuring the system’s flow rates by
using fluids in venturi’s meter and
paddle wheel.
Observing some reactions that can
happen in a fluid system that are linked
to slow flow rates, and some are also
due to a decrease in the system
pressure. They also affect the power of a
pump
The figure below shows the general
arrangements of the flow system consisting
pump, flow meter pressure gauge and piping
system.
conditions are applied and those conditions are
the system having high velocity and in
association with a decrease in pressure.
2
The water is pumped up by a pump and the
pressure in the gauge is taken for each section:
pump, flow meter, and venturi meter. The actual
flow rate is taken by collecting water in reservoir
for a specific time period.
Venturi Meter
What is the venturi meter? We use to it measure
instrument that is some people name it as a
meter, that is used to measure the flow of a fluid
through a pipe. It basically works on the principle
of Bernoulli's Theorem. The pressure of a fluid
flowing through a tiny cross section decreases
quickly, causing the flow velocity to rise. There
are some points where you have high level of
pressure and low velocity that will be
transformed to a low level of pressure and high
level of velocity, when it reached that point, it
will go back to having the first process. The
venturi meter has a maximum output when two
The theoretical flow can be determined by using
the expression:
Qtheoretical = MA2√ 2 g / ρ( p1− p2)
And the actual flow is calculated by,
Qactual = Cd MA2√ 2 g / ρ( p1− p2)
Where M = velocity of approach factor =
1
1
√
2
8.82
A2 =
1−
1−(
)
2
A1
17.6
√
2
( )
= 1.033
Cd = coefficient of discharge = Qactual/Qtheoretical
P1 = pressure at section 1 in venturi tube
P2 = pressure at section 2 in venturi tube
A1 = cross-section area of section 1
=π*0.01762/4= 0.000243m2
A2 = cross-section area of section 2 = π*0.00882/4
= 0.000061m2
Efficiency of the pump =
∆ p∗Q
∗100 %
P
Where Δp = differential pressure of the pump
Q = actual flow rate
collected by time period with valve fully
open.
4. The obtained value of actual flow rate is
entered into Labview. The labview was
started and set and given time to
stabilize.
5. After the readings were taken, the valve
was slightly closed to lower the power of
the pump by ≈ 1W and the steps from
1-5 were repeated.
6. Again the valve was closed slightly to
lower the power by 0.5W-0.6W and the
steps from 1-5 were repeated.
P = wattage of the pump
Instruments and apparatus required:
Venturi meter
Pump:
The pump is required to pump the
water through the pipe system.
Differential pressure gauge:
The differential pressure gauge is
used to take measurements of pressure
at various section of pump, flow meter
and venturi meter.
Laptop computer with Labview:
It gives the reading of the flow
meter, pressure gauge, pump power in
digital form.
Results and conclusions:
The data or readings obtained from the
experiment are shown in the table below:
Opening of
valve
Fully
open
15.45
Slightly
closed
to lower
power
by ≈
1w
14.8
Slightly
closed to
lower
power
by ≈
0.5W
14.5
2.48
2.166
2.113
2.46
2.20
2.11
2.48
2.16
2.01
Procedures:
1. Initially the labview was set up and the
sensors were calibrated. This process
needs to start again each time the valve
is locked .
2. Then, the pump was turned on and
wattage was required.
3. The manual flow of the fluid was
measured by collecting the fluid over a
short period of time in a graduated
cylinder by dividing the volume of water
Pump
power(W)
Actual flow
rate(gpm)
Paddle wheel
flow
rate(gpm)
Venturi meter
flow
rate(gpm)
1.36
1.64
0.23
1.01
1.78
0.247
1.92
1.81
From the above experiments it is seen that as
the valve is closed, there is fluctuation in the
value of the power flow rate, pressure. There is
arrow that starts increasing in the differential
pressure while having flow rate and the power of
the pump to start increasing. This happens
because as the flow decreases the velocity of the
fluid increases resulting in the increase in
pressure. Also, the coefficient of discharge for
different flow is calculated and its value was
found to be 0.775, 0.389, 0.366 for fully open
valve, slightly open valve to lower power by 1W,
and slightly open valve to further lower the
power by 0.5W respectively. The efficiency of the
pump for different flow rate is calculated and
mean value is found to be 11.42 percentage. This
unknown shown as error seems to be occurred
by having wrong data(1).
It seems like the error is between paddle wheel,
venturi, and the actual flow that affected their
rates. Moreover, the date that relates the flow
rate and differential pressure in the below graph.
The error encountered might be due to the
incorrect reading taken, incorrectly graduated
cylinder or loss of water during collection. Also
the sensors might not have been properly
calibrated.
Differential pressure(in psi)
2.500
2.000
1.500
Pump DP
1.000
Valve DP
0.500
0.000
Venturi
tube DP
2.480
2.166
Actual flow rate
2.113
2.500
Differential pressure(in psi)
0.076
2.000
1.500
Pump DP
1.000
Valve DP
0.500
0.000
Venturi tube
DP
2.460
2.200
2.110
Paddle wheel flow rate
2.500
Differential pressure(in psi)
Venturi tube
differential
pressure(psi)
Valve
differential
pressure(psi)
Pump
differential
pressure(psi)
2.000
1.500
Pump DP
Valve DP
Venturi tube DP
1.000
0.500
0.000
2.480
2.160
2.010
Venturi meter flow rate
The calculation table is given below:
References:
Conclusions:
In conclusion, the experiment was informative
and useful for Mechanical engineering students,
and in lecture notes and experiencing the
problem in real world made it more clear. From
the above experiments. students were able to
measure the flow rate, pressure in the venturi
meter and paddle wheel flow meter. Students
were also able to see the effect of closure of
valve on the pressure and flow rate. By having
the above experiment, students should be fully
understanding the fluid measurements and its
tool
Acknowledgement:
I would like to express my sincere gratitude to
Mechanical Engineering Department, University
of South Carolina for arranging a lab class which
helped the students to become familiar with the
venturi meter set up. I would like to thank my
professor Mr.Xue for guiding and teaching us
through out the lab period. I would also like to
thank professor’s assistant Mr.Xu for helping and
guiding us.
Limjuco, R. P., Glover, F. F. G., & Mendez,
I. M. (2012). Low-Cost Venturi Meter:
Understanding Bernoulli’s Equation rough A
Demonstration.
Adeniyi, A. A., & Komolafe, O. D. (2014).
Performance Analysis of an Experimental
Centrifugal Pump. Nigerian Journal of
Technology, 33(2), 149-155.
EMCH361
Mechanical Engineering Lab I
Lab #3
Spring 2021
1
Notice: Quiz 2
Quiz content: Lecture #3 and #4
•
•
•
•
Distribution
Probability
Confidence interval
Confidence level
It is your responsibility to use reliable computer and
internet to take your quiz in Blackboard.
You are responsible for the any failures induced by your
computer and internet!
2
Assignment (TA)
Lab date
Report due date
Lab 1: LabView
(Puja Chowdhury,
email: pujac@email.sc.edu)
Week of Sept 20
No report
Lab 2: Fluid
(Lei Xu,
email: leix@email.sc.edu)
Week of Sept 27
Oct 6 (Wednesday)
Lab 3: Motion
(Lei Xu,
Email: leix@email.sc.edu)
Week of Oct 11
Oct 20 (Wednesday)
Lab 4: Hardness measurement
(Deb Mandal,
Email: dmandal@email.sc.edu)
Week of Oct 25
Nov 3, (Wednesday)
Lab 5:Strain gauge and strain
measurement
(Deb Mandal,
Email: dmandal@email.sc.edu)
Week of Nov 8
Nov 22 (Monday)
3
Submission (deadline: Oct 15)
• Please submit your proposal to Bb, one per team
• Files must be named in the format of
“Proposal_LastName1_LastName2_LastName3”
• Failing to follow the formatting requirement will
result in point deduction from project grade
4
5
Lab 3 Motion measurements
Step pulley spindle
Pulley
Platter
Tension (T)
Falling mass
m
a
mg (g= 9.80665 m/s2)
6
Actual pictures for the experimental set up
7
Actual pictures for the experimental set up
8
Major properties of ultrasound:
Sound speed depends on the medium in
which it propagates.
1
=
2
the speed of sound in the air is about 340
meters per second (m/s). That in water is
about 1530 m/s and that in iron as high as
about 5,850 m/s.
wiki
9
Data Acquirement
10
Data Acquirement
11
EMCH361
END of Lab #3
12
Motion Lab Introduction
Course: EMCH 361
Professors: Lingyu Yu, Xingjian Xue
TA: Lei Xu
TA Email: leix@email.sc.edu
Objectives
We will be conducting experiments on motion measurements in a system
with a rotating disc connected to a mass by a string. The objectives of this lab
are to:
• Learn linear motion measurement using ultrasonic position/proximity
sensor
• Learn rotational motion measurement using optical decoder sensor
• Learn how to determine acceleration from displacement measurements
through 2nd order curve fitting
• Understand the relations between rotational and linear motions in terms of
accelerations (verify a = r × α), and how mass affects the linear and
rotational motions (acceleration)
Equipment
• ToughSonic TSPC-30
ultrasonic distance sensor
• US Digital E7P optical kit
encoder
• Motion fixture
• Weights
• Laptop computer with
LabVIEW (for data
acquisition)
Handout:
Displacement
Equations
Calibration Procedure (Only need to do once)
• Make sure the switches for the DAQ and sensors are on
• Open SignalExpress
• Click: Add Step, Acquire Signals, DAQmx, Analog Input, Voltage,
find channel on DAQ(ai0-3), hit run
• For calibration you’ll need the linear equation y = mx + b
• Find value(mV) at weight bottom (measure the height),
• Find value (mV) when the weight is back at the top and measure the
height. Find the slope m (meter/V). x is your read voltage, solve b.
• This equation translates Voltage to meters.
• With your y=mx + b equation, find custom scaling -> create new
-> linear -> name -> put in m and b. (This sets up the voltage)
• Find Add step -> counter input -> angular position -> set
pulse/rev to 720, units to radians.
Experiment Procedure
• Coil the string so that the hanger is at the highest position and hold it.
• Hit record, both voltage and angular, and let go of the disk as you hit
ok. Hit record again when the hanger reaches the bottom.
• Open your data under the logs, on the bottom left of the program.
• Open both voltage and angular and export to excel.
• Select data, scatter diagram, trendline, 2nd order polynomial, display
equation. Save File and share.
• Change the falling mass and repeat the experiment.
Examples of linear and angular motion
Results and analysis
• Graph the linear and angular positions w.r.t. time at 3 selected falling masses, respectively
• Use 2nd order curve fitting to derive the linear and angular displacements as functions of time for all masses,
respectively
• Determine the linear and angular acceleration for all curves
• Compare the experimental accelerations with the theoretical values and give the error in %. How do you think
of your experimental measurements? What could be the possible reasons for error?
Analysis Cont.
• Example linear acceleration error:
• Do the linear and angular accelerations satisfy the theoretical relation?
• • Graph the linear and angular acceleration w.r.t. masses, and discuss how mass affects the acceleration
• (Note: in this lab, you will process and conclude with large amount of data. Using Tables to present your data or
results is an effective means. You need to design your own table to present your data or results.)
EMCH 361 – Mechanical Engineering Lab I
Lab 7: Motion Measurements
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Objectives
We will be conducting experiments on motion measurements in a system with a rotating disc
connected to a mass by a string. The objectives of this lab are to:
Learn linear motion measurement using ultrasonic position/proximity sensor
Learn rotational motion measurement using optical decoder sensor
Learn how to determine acceleration from displacement measurements through 2 nd order
curve fitting
Understand the relations between rotational and linear motions in terms of accelerations,
and how mass affects the linear and rotational motions (acceleration)
Introduction
When all the particles of a rigid body move along paths which are equidistant from a fixed plane,
the body is said to undergo planar motion. In general, planar motions can be categorized into
linear (or called translational) motion, rotational motion, or combined. Rotational motion occurs
if every particle in the rigid body moves about a fixed axis.
sh
Th
The motion in which all particles in the rigid body move through the same distance is defined as
translational motion. It can be rectilinear or curvilinear. Only the former will be discussed in this
lab. Such a motion can be described by the position of the rigid body as a function of time. Using
equations of motion, the displacement for motions with constant acceleration a is given as:
1
x x0 v0t at 2
(1)
2
with x0 and v0 being the initial displacement and velocity. In the limit of very small times, the
acceleration is the derivative the velocity w.r.t. time while the velocity is the derivative of the
displacement w.r.t. time. Hence, the relation between acceleration (a) and displacement (x) is:
d 2x
(2)
a 2
dt
Similarly, angular displacement is the measure of the angle the rigid object rotates at a certain
amount of time. It can be in radians, degrees or revolutions. For motions with constant
acceleration in the limit of very small times, the angular acceleration is the derivative the angular
velocity w.r.t. time while the angular velocity is the derivative of the angular displacement w.r.t.
time. Hence, the relation between angular acceleration (α) and displacement (θ) is:
d 2
(3)
2
dt
In the rotational motion, the angular quantities (acceleration, velocity, and displacement) are the
same for every point in the body. Hence tangential quantities are often used to describe rotational
motion as well. Given θ as the angular displacement in radians at a given amount of time, the arc
length s that being passed by a point at radius r can be determined as
s r
(4)
1
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Such a relation also applies to the velocity and acceleration. For example, the tangential
acceleration a and angular acceleration α is:
a r
(5)
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Equipment
In the motion lab, you will study the dynamic behaviors of a rotating disk driven by a falling
mass. Schematic drawing and the actual lab setup are shown in Figure 1 below.
Figure 1 Schematic of a rotating disk driven by a falling mass used for linear and rotational motion
measurements
Th
Actual laboratory setup of the disk and falling mass is
shown in Figure 2. The box on the ground is the
ultrasonic sensor for measuring the height of the falling
mass. The weight is attached by a string to a pulley on
the main platter. In this picture, the main platter is
sitting on top of the auxiliary platter. It is instrumented
with the decoder sensor for measuring the angular
position of the platter.
Figure 2 Picture of the actual setup of
motion lab
sh
Equipment
ToughSonic TSPC-30 ultrasonic distance sensor
US Digital E7P optical kit encoder
Motion fixture
Weights
Laptop computer with LabVIEW (for data acquisition)
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Procedure
You are going to graph the weight’s position (height) vs. time and the disk’s position (radians)
vs. time for variations in mass. For varying the mass, you’re going to need at least three levels of
this variable. Then each graph will have three curves. Please be aware that SI units shall be
used during the graphing and subsequent analysis, while the immediate outputs from the
measuring sensors might be in English units. Hence conversion is needed from inches to meters.
Example of data recording table is shown in Table 1. Parts specifications are given in Table 2.
It is recommended that you start with the main platter on the rotary apparatus and a mass of 50300 grams on the falling weight. Remember that the mass of the hanger is 50 grams. The
properties of the platters are on page 2 of the instruction manual for rotary apparatus.
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Using second order polynomial curve fitting, you will be able to determine the linear and
rotational positions (displacements) as a function of time. From there, you can find the
corresponding linear and angular accelerations. Figure 1 gives the examples of linear and angular
motions from the measurements.
After deriving the accelerations, you will need to verify if you are getting the relationship
between angular and linear acceleration in this system, as described in Eq. (4), where r is the
radius of the pulley attached to the string, α is the linear acceleration of the falling mass, and α is
the angular acceleration of the rotating disk.
You will also need to study the effect of falling weight on the accelerations by graphing the
relations between the acceleration and the mass.
Report General Guideline
•
•
sh
•
•
Abstract – a standalone summary of the whole report
Introduction – Overall (what is being reported here? why measuring positions in motion
systems? how in general linear and angular positions are measured? etc.)
Theory – linear and angular position measurement devices
• Explain the ultrasonic distance sensor used in this lab
• Explain the encoder sensor used in this lab
Methods – your measurement methods and analysis methods
• Explain how the 2nd order curve fitting method
• Explain how to determine acceleration through displacement function
Lab Procedures
Results and analysis
• Graph the linear and angular positions w.r.t. time at 3 selected masses,
respectively
• Use 2nd order curve fitting to derive the linear and angular displacements as
functions of time for all masses, respectively
• Determine the linear and angular acceleration for all curves
• Compare the experimental accelerations with the theoretical values, and give the
error in %. How do you think of your experimental measurements? What could be
the possible reasons for error?
Th
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•
•
•
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•
•
Do the linear and angular accelerations satisfy the theoretical relation?
Graph the linear and angular acceleration w.r.t. masses, and discuss how mass
affects the acceleration
(Note: in this lab, you will process and conclude with large amount of data. Using
Tables to present your data or results is an effective means. You need to design your
own table to present your data or results.)
Discussion and conclusions
Have all the objectives of this lab been met?
Are you able to prove some theories? Any errors or discrepancy? What could be
the possible reasons?
Any other discussion that you think necessary
Acknowledgement
Reference
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Figure 2 Examples of linear and angular motions from the laboratory measurements. Using Excel, 2nd order
curve fitting gives the position functions by which accelerations can be derived.
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Table 1 Example of data recording table used by students in lab. You need to test three different mass values
to see how mass affects the accelerations.
Table 2 Parts specifications
Mass
Dimension
Moment of Inertia
Main platter
991 grams
Radius=12.7 cm
7.50x10-3 kgm2
Auxiliary platter
894 grams
Radius=12.7 cm
7.22x10-3 kgm2
Steel bar
690 grams
L22.2cmxW5.1 cm
2.98x10-3 kgm2
Steel ring
701 grams
OR=6.4cm; IR=5.4cm
2.46x10-3 kgm2
Step pulley spindle
negligible
Radii=1.50 cm
negligible
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Component
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Appendix A
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Appendix B
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EMCH361 Mechanical Engineering Laboratory I, Fall 2019
Laboratory 2
ELECTICAL MEASUREMENTS
William E. Davidson
Department of Mechanical Engineering
University of South Carolina
Columbia, SC 29208
The RMS (root mean square), also known as the
quadratic mean, is a statistical measure of the
magnitude of a varying quantity. It is especially
relevant when the function is alternating between
positive and negative values. The equation to find
the RMS is:
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ABSTRACT
The objective of this experiment is to analyze
Kirchhoff’s current and voltage law, as well as ohms law,
while at the same time learning how to use oscilloscope
and multimeter equipment and quantifying common
waveforms. Different resistors were tested and measuring
the voltage and resistance of a circuit allowed to use ohm’s
law to find that the current of the circuit was 1.48 mA. The
potential difference across the circuit nodes were measured
to be 13.488 V and proved Kirchhoff’s law that the input
voltage of 13.44 V was equal to the output voltage. The
difference in voltage input/output can be attributed to
certain variables present during measuring. Two
wavelengths were examined, and their RMS values were
calculated to be 0.2828 V and 0.413 V.
Oscilloscope - is used to display and analyze the
waveform of electronic signals. A digital multimeter is
a tool used to measure electrical values, primarily
voltage, current, and resistance.
Signal generator - a device that can produce various
patterns of voltage at a variety of frequencies and
amplitudes.
Voltage divider circuit - a passive linear circuit that
produces and output voltage that is a fraction of its
input voltage.
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INTRODUCTION
Regarding voltage, current, and resistance in
electrical circuits there exists fundamental laws that
can be studied and used to accurately predict the
way in these three factors affect each other. One of
which is Kirchhoff’s law, which is broken down into
two parts, Kirchhoff’s voltage law and current law.
Kirchhoff’s current law uses the same guidelines as
the conservation of energy, stating that the sum of
the current entering a node in a circuit is the same
as the current leaving the circuit, resulting in a net
sum of zero. Very similar to this law is Kirchhoff’s
voltage law, which states that the sum of the voltage
entering a circuit is equal to the voltage leaving the
circuit, so when all the voltages across the various
nodes are added together the result should be equal
to the voltage entering the circuit.
Ohm’s law is another fundamental law that
denotes the relationship between voltage, current,
and resistance. This law states that in a circuit,
voltage is equal to the current multiplied by the
resistance.
Resistors value can be identified by the different
colored band’s around the resistor. Each specific
color is directly correlated to a specific resistance
value.
In this lab, one will use various physical
measurements of the resistance, current, voltage,
wavelength, and frequency of an electrical circuit
and compare them to the theoretical values given by
the various laws to determine their effectiveness and
uncertainty. These fundamental laws are essential to
creating many different technologies that are used
throughout people’s daily lives and it is important to
understand the theories and practicalities behind
them.
INSTRUMENTS
To complete this lab, one will need an oscilloscope,
digital multimeter, signal generator, voltage divider
current, wall circuit adapter, and assorted resistors.
1
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A wall circuit adapter - converts AC to DC current, or
vice versa.
Assorted resistors - resistors of varying resistance
values.
Frequency
Amplitude
RMS
Value
Wavelength 1 33.9 Hz
400 mV
0.2828 V
Wavelength 2 47.9 Hz
584 mV
0.413 V
Table 3 shows the frequency, amplitude, and calculated
rms values from two different wavelengths.
From the values shown on the oscilloscope, the
RMS values were calculated to be 032828 V for
wavelength 1 and 0.413 V for wavelength 2. RMS is
important to calculate because it is used to compare both
alternating and direct currents (or voltage). Any possible
errors in the calculations for the RMS value from this
experiment would be that the wavelength amplitude
values were estimated when measured.
CONCLUSIONS
During this experiment, the total measured
potential difference of the voltage divider circuit
(13.488 V) was found to be higher than that of the
total voltage entering the circuit (13.44 V). This
difference can be attributed partly to the uncertainty
in the measurements provided by the equipment.
This led to error propagation and the resulting
calculations results became higher than the actual
value. This could also have been due to certain
physical variables present such as temperature or
temperature. If one ignores the propagation error,
the sum of the input and output potential difference
equal each other, this proves Kirchhoff’s law. Ohms
law was used to calculate the current, which was
1.47 mA, and the RMS for wavelength 1 was 0.2828
V and wavelength 2 RMS was 0.413 V.
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LAB PROCEDURES
To perform this lab, the first step it to measure
and record the resistance of the five resistors with an
equal indicated value. After this one must measure and
record the resistance of the resistors in the voltage divider
circuit, which will be used to calculate the voltages
between each resistor for a known input voltage. Then
the potential differences will be measured and compared
to the calculated theoretical values. Choosing one resistor
in the voltage divider circuit at random, measure the
resistance and voltage across the resistor five different
times, this value will be used to evaluate the errors
contained in the current measurements. After completing
this step, proceed to utilize the oscilloscope to display
and record the frequency and amplitude of two different
unique signals that will be produced from the signal
generator.
Table 3
RESULTS AND DISCUSSIONS
Table 1
Mean Resistance Theoretical Resistance
Value
Value
22.1 ohm
22.0 ohm
Table 1 represents the mean measured resistance value
of five resistors and their theoretical resistance value.
When the five different resistors where measured
the there were varying measurements for the actual
resistance, with the lowest being 22.0 ohm and the
highest being 22.2 ohm. With the percent tolerance of the
resistors being .1% (0.11 ohm), it is concluded that the
probability of an out of tolerance resistor is 20%.
REFERENCES
Alwazzan, Mohammad. “Hardness.” EMCH 361. University of
South Carolina, Columbia, October 9, 2019.
. Zhao, Yueyang. “Electrical Measurements Lab.” EMCH 361.
University of South Carolina, Columbia, October 9, 2019.
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Table 2
Measured
Theoretical
Potential
Resistance
Resistance
Difference
Value
Value
(across resistor)
R1 1.79 Kohm
1.8 Kohm
2.678 0.04 V
R2 0.467 Kohm 0.470 ohm
0.7 0.04 V
R3 6.76 Kohm
6.8 Kohm
11.11 0.04 V
Table 2 shows the measured and theoretical resistance
values found from the resistors along with the potential
difference across each resistor in the voltage divider
circuit.
Based on the theoretical resistance values of the
resistors and the total voltage entering the circuit (13.44
V) the current was calculated to be 1.48 mA. The total
voltage potential difference sum across the resistors
combined equaled 13.48 V, which proves Kirchhoff’s law.
There were possible variables in effect that may have
occurred while measuring resulting in a slightly higher
output voltage than the input voltage of 13.44 V.
2
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