lOMoARcPSD|14906348
Lab, Report 2
Electric Circuits (University of Ontario Institute of Technology)
StuDocu is not sponsored or endorsed by any college or university
Downloaded by ???? Tasman (yahaaay2020@gmail.com)
lOMoARcPSD|14906348
Lab 2 Report:
The various experiments in this lab explore further on how to use the equipment found in
the laboratory to find values such as resistance, voltage, and current in different types of circuits
such as series and parallel. In this lab we also use laws like Ohm’s law and Kirchhoff’s law to
find the values asked for which can later be compared with the values found using the
equipment.
The purpose of this lab is to use Kirchhoff’s voltage and current laws to find the voltage
and current at the resistors in the circuits. The lab also gives more practice in using nodal
analysis to find the voltage at specific nodes in the given circuit. This lab will also allow us to
learn how to create the given circuit diagrams on the breadboard so we can find the values that
are necessary. Being able to do this will help in confirming the values which were calculated
using Kirchhoff’s laws.
Components and Instruments used:







MultiSim : used in pre-lab to get currents and voltages
Resistor kit : contains the resistors used to create circuits on breadboard
XK 150 kit breadboard : used to create the circuit and connect wires to find values
Agilent power supply : voltage source
Agilent digital multi meter : measures circuit current in resistors
BNC to Alligator Clips
Resistors: 4.7 kohm, 200 ohm (instead of 470 ohm), 10 kohm
Procedure:
1. Created Figure 2.3 circuit on breadboard using 4.7 kohm resistor and connected it to the
Agilent power supply +25 V connector.
2. Connected digital multi meter to the circuit and measured the current at 4.7 kohm resistor
by opening the circuit and putting the DMM in series to the resistor.
3. The voltage was supplied from 0.5 V to 4.5 V in steps of 1 V and the values were put into
Table 2.3.
4. A graph was created on Excel using these values.
5. The 4.7 kohm resistor was replaced with a 200 ohm resistor and connect like in step 1.
The current was varied from 2 mA to 18 mA in steps of 4mA and reported into Table 2.4.
6. A graph was created using Excel for these values.
Verification of Kirchhoff’s Laws:
1. Created a new series circuit like Figure 2.4 on breadboard consisting of resistors 20
kohm, 4.7 kohm, 10 kohm and the voltage across each resistor was found using the DMM
and reported into Table 2.5.
2. The same resistors were then connected in parallel and the current into each resistor was
measured using the DMM and reported into Table 2.6.
*** Did not get to part consisting of Table 2.7 & Table 2.8.
Downloaded by ???? Tasman (yahaaay2020@gmail.com)
lOMoARcPSD|14906348
Pre-Lab Results:
2.2.1:
1)
1.
a. RED RED GREEN  2.2MΩ
b. BROWN RED BLACK  12Ω
c. ORANGE YELLOW WHITE34000000000Ω
2.
a. 2.7kΩ  red violet red
b. 470kΩ yellow violet yellow
c. 10MΩ brown black violet
2.2.2:
1) & 3) look at pre-lab attached for calculations
2)
VARIABLE
I1
I2
I3
VR1
VR2
VR3
VR4
VR5
CALCULATED
2.5042A
1.6848A
1.6012A
5.0084V
8.194V
13.8237V
1.6012V
7.91856V
SIMULATED
2.588mA
1.757mA
1.747mA
1.692V
8.308V
0.049 V
1.742V
8.258V
%ERROR
3.2
4.1
8.34
196
1.37
28
8.08
4.11
CALCULATED
10V
16.8903V
29.3548V
0.001425A
0.001689A
0.00377A
0.01A
0.00624A
SIMULATED
10V
1.742V
0.049V
0.00208A
0.00699A
0.035211A
0.011678A
0.002463A
%ERROR
0
8.6
5.98
31.4
75.8
89.29
9.0
15.3
4)
VARIABLE
VA
VB
VC
IR1
IR2
IR3
IR4
IR5
Downloaded by ???? Tasman (yahaaay2020@gmail.com)
lOMoARcPSD|14906348
Results:
Tables:
2.3.1 : Voltage and Current Sources and Measurements
Table 2.3:
Voltage
(volts)
Current
(m-amps)
0.5
1.5
2.5
3.5
4.5
0.107
0.321
0.535
0.749
0.963
Table 2.4: Voltage and Current in a Resistor
Current
(m-amps)
Voltage
(volts)
2
6
10
14
18
0.303
1.102
1.904
2.706
3.512
2.3.2: Verification of Kirchhoff’s Laws
Table 2.5: Voltage and Current in a Resistor
Element
R1
R2
R3
Voltage
(volts)
5.774
1.363
2.856
Supply
Voltage
10V
Table 2.6: Voltage and Current in a Resistor
Element
R1
R2
R3
Current
(mA)
Got 0 as value
not sure ***
2.142
0.338
Downloaded by ???? Tasman (yahaaay2020@gmail.com)
Supply
Current
50
lOMoARcPSD|14906348
Graphs:
Voltage VS Current Table 2-3
1.2
Current (mA)
1
0.8
0.6
0.4
0.2
0
0
0.5
1
1.5
2
2.5
3
3.5
4
Voltage (V)
Current (mA)
Voltage VS Current Table 2-4
20
18
16
14
12
10
8
6
4
2
0
0
0.5
1
1.5
2
2.5
3
3.5
4
Voltage (V)
Downloaded by ???? Tasman (yahaaay2020@gmail.com)
4.5
5
lOMoARcPSD|14906348
Analysis:
1. Ohm’s law : Voltage = Current( I ) * Resistance ( R )
Lab tasks 2.3.1 and 2.3.2 can show Ohm’s Law by:
2.3.1:
Current: comparing to values in table 2.3
R = 4.7 kohm = 4700 ohm V1=0.5V V2=1.5V V3=2.5V V4=3.5V V5=4.5V
V1 = R*I1
V2= R*I2
V3= R*I3
V4= R*I4
V5= R*I5
Calculated
0.107
0.321
0.535
0.749
0.963
I1 = V1/R = 0.5/4700 = 0.106382mA
I2 = V2/R = 1.5/4700 = 0.319148 mA
I3 = V3/R = 2.5/4700 = 0.531914 mA
I4 = V4/R = 3.5/4700 = 0.74468 mA
I5= V5/R = 4.5/4700 = 0.957446 mA
&
Simulated
0.106
0.319
0.5319
0.744
0.95744
% difference between methods
0.938
0.5786
0.5784
0.6697
0.5790
Voltage: comparing to values in table 2.4
R = 200 ohm I1=2mA I2=6mA I3=10mA I4=14mA I5=18mA
V1 = R*I1 = 0.4 V
V2= R*I2 = 1.2 V
V3= R*I3 = 2 V
V4= R*I4 = 2.8 V
V5= R*I5 = 3.6 V
Calculated
0.303
1.102
1.904
2.706
3.512
&
Simulated
0.4
1.2
2.0
2.8
3.6
% difference between methods
27.59
8.51
4.918
3.41
2.47
2. The % error calculated does not fall within the required tolerance as specified by the
tolerance band on the resistors this could be because some values maybe not have been
found correctly using multisim giving numbers which could be wrong.
Downloaded by ???? Tasman (yahaaay2020@gmail.com)
lOMoARcPSD|14906348
3. We didn’t get a chance to build the circuit in 2.3.2, so I’ll be basing this analysis from my
estimation. Kirchhoff’s Laws are his voltage law and his current law. Kirchhoff’s voltage
law states that the sum of voltage around every closed loop equals zero. Kirchhoff’s
current law states that at every node the sum of all current entering a node must equal
zero. If we had done the measurements we could have verified our results using KVL and
KCL because they would have given us the theoretical values of our measurements. If we
had done the experiment, we would’ve seen that the sum of all voltage in each loop
would be 0 and at each node the amount of current going into the node would equal the
amount of current coming out of the node because the node can’t hold current otherwise
it would break the circuit.
4. You would want to use an oscilloscope over a DMM if you want to measure voltage in a
lot of detail. An oscilloscope can plot two voltages at the same time. This allows you to
compare the two voltages and how they affect the circuit. An oscilloscope can also
measure how the voltage is changing over time. A DMM only measures the average
voltage level. You would also use an oscilloscope if you wanted to plot the waveforms
against time.
5.
Some difficulties that we had with the lab was that we found it difficult to operate the
machines. We would have to constantly call the TA over to our table and ask her to show
us what to do and that took up a lot of the time. The appendix is very confusing in their
explanations. I think that having links to short YouTube videos that shows how each
device works would be very helpful. Another minor difficulty we had was getting used to
the breadboard. We had trouble figuring out whether our resistors were connected and
whether they were in series or in parallel with each other. One thing about this lab is that
we ran out of time and did not get a chance to build the final circuit.
Summary:
In this lab we have learnt how to use the laboratory equipment correctly and how to use
them to find the values for specific quantities such as voltage and current in this lab. Some errors
in this lab could be the way the circuit was made on the bread board. Also looking back at the
prelab another error could be when calculating the values and using multisim to confirm the
values. Some difficulties faced at the beginning of the lab was not being sure if we were
connecting the equipment correctly to the circuit on the bread board and changing the settings on
the DMM. In concluding this lab has given us a better understanding of how to use the
equipment for upcoming labs and gave us more practice on using Ohm’s Law, Kirchhoff’s Law
and Nodal Analysis for parallel and series circuits.
Downloaded by ???? Tasman (yahaaay2020@gmail.com)