ENG 220/250 Lab Report Requirements
Version 0.8 -- 08/13/2018
I. General Requirements
The length of a lab report must not exceed 10 typewritten pages. This
includes any and all attachments included in the report.
The font size used in the body of the report must not exceed 12 pts.
The lab report must be submitted as a single document file with all of
the required attachments included.
[Refer to Exhibit #1]
Reports submitted electronically must be in the Adobe PDF format.
For any videos submitted (online students only):
They must have a minimum video resolution of 480p.
The maximum length for any video submitted must not exceed 5
minutes.
Due to their large file size, the video files must not be sent as
email attachments.
They can be uploaded to cloud storage (Dropbox, Google Drive, One
Drive, etc.). The link to the video file can then be submitted
via email.
II. Required Attachments
MultiSim simulation screenshots
The only simulation software that can be used for any lab
assignments in this course is MultiSim.
[Refer to Exhibit #2]
The simulation(s) shown on the lab report must show the same
types of measuring instruments that were used to perform the lab.
[Refer to Exhibit #3]
The illustration(s) included in the lab report must be actual
screenshots of the circuit simulation.
[Refer to Exhibit #4]
All screenshots of circuit simulations included in the report
must show the values being measured.
[Refer to Exhibit #5]
The screenshot(s) must be included in the body of the report.
They must be properly labelled and referenced in the lab report.
Printouts from MultiSim are not acceptable.
[Refer to Exhibit #6]
Raw Data
A copy of the original hand-written data sheet that you used to
record the data must be included in the lab report.
[Refer to Exhibit #7]
If the data is recorded on the lab assignment sheet, include only
the portion of the assignment sheet that you wrote your data on.
[Refer to Exhibit #8]
III. Lab Report Requirements
Equipment Documentation
The lab reports must include the make, model, and serial number
of lab equipment used in performing the lab. The equipment
includes
● Multimeters
● Capacitance and inductance testers
● Oscilloscopes
● Function generators
● Power Supplies
[Refer to Exhibit #9]
Lab Procedure
The lab procedure that you used must be documented in the report
as a step-by-step process. Bullet points or numbers must be used
to identify each step.
[Refer to Exhibit #10]
Data
Data must be shown in tabular format and all headings must be
clearly labelled along with the proper units of measurement.
[Refer to Exhibit #11]
No more than 2 to 4 decimal places are required for the showing
of data values. The use of engineering notation and/or metric
units of measurement is strongly recommended.
[Refer to Exhibit #12]
Showing ca.
ENG 220250 Lab Report Requirements Version 0.8 -- 0813201.docx
1. ENG 220/250 Lab Report Requirements
Version 0.8 -- 08/13/2018
I. General Requirements
The length of a lab report must not exceed 10 typewritten pages.
This
includes any and all attachments included in the report.
The font size used in the body of the report must not exceed 12
pts.
The lab report must be submitted as a single document file with
all of
the required attachments included.
[Refer to Exhibit #1]
Reports submitted electronically must be in the Adobe PDF
format.
For any videos submitted (online students only):
2. They must have a minimum video resolution of 480p.
The maximum length for any video submitted must not exceed 5
minutes.
Due to their large file size, the video files must not be sent as
email attachments.
They can be uploaded to cloud storage (Dropbox, Google Drive,
One
Drive, etc.). The link to the video file can then be submitted
via email.
II. Required Attachments
MultiSim simulation screenshots
The only simulation software that can be used for any lab
assignments in this course is MultiSim.
[Refer to Exhibit #2]
3. The simulation(s) shown on the lab report must show the same
types of measuring instruments that were used to perform the
lab.
[Refer to Exhibit #3]
The illustration(s) included in the lab report must be actual
screenshots of the circuit simulation.
[Refer to Exhibit #4]
All screenshots of circuit simulations included in the report
must show the values being measured.
[Refer to Exhibit #5]
The screenshot(s) must be included in the body of the report.
They must be properly labelled and referenced in the lab report.
Printouts from MultiSim are not acceptable.
4. [Refer to Exhibit #6]
Raw Data
A copy of the original hand-written data sheet that you used to
record the data must be included in the lab report.
[Refer to Exhibit #7]
If the data is recorded on the lab assignment sheet, include only
the portion of the assignment sheet that you wrote your data on.
[Refer to Exhibit #8]
III. Lab Report Requirements
5. Equipment Documentation
The lab reports must include the make, model, and serial
number
of lab equipment used in performing the lab. The equipment
includes
● Multimeters
● Capacitance and inductance testers
● Oscilloscopes
● Function generators
● Power Supplies
[Refer to Exhibit #9]
Lab Procedure
The lab procedure that you used must be documented in the
report
as a step-by-step process. Bullet points or numbers must be used
to identify each step.
[Refer to Exhibit #10]
6. Data
Data must be shown in tabular format and all headings must be
clearly labelled along with the proper units of measurement.
[Refer to Exhibit #11]
No more than 2 to 4 decimal places are required for the showing
of data values. The use of engineering notation and/or metric
units of measurement is strongly recommended.
[Refer to Exhibit #12]
Showing calculations is not necessary in the lab report.
However,
you can show the formulas that you used for the lab report.
[Refer to Exhibit #13]
All graphs must be clearly identified, labelled, and referenced
7. in the lab report’s narrative.
[Refer to Exhibit #14]
The use of photographs is allowed only if they are clearly
labelled, described, and referenced in the lab’s narrative.
[Refer to Exhibit #15]
The data gathered in performing the lab must be accurate. If the
data presented in the lab report data is not accurate, no credit
will be given for lab all.
If the data presented in the lab report is not within 10% of the
theoretical or simulated values, the lab report must include an
explanation for any discrepancies.
IV. Lab Practices
Only discrete test instruments are allowed to be used in
performing the labs. The use of ELVIS or any other simulation
8. type of hardware/software simulator which is similar is strictly
prohibited.
[Refer to Exhibit #16]
On each report the differences between the measured and
nominal
values of resistors, capacitors, and inductors used in the lab
must be documented.
[Refer to Exhibit #17]
Use of the proper test equipment is required. While digital
multimeters are easy to use, they are not accurate for measuring
at frequencies higher than 1 kHz or measuring non-sinusoidal
waveforms.
[Refer to the attached example lab report]
Examples
9. Exhibit #1: Wrong File Format, Multiple Files Submitted
Exhibit #2: Wrong Software Circuit Simulator Used Instead of
Multisim
Exhibit #3: The instruments used to perform the lab are not the
same
as those used in the simulation.
10. This part of a lab required an oscilloscope to measure voltages.
Not
only are the wrong instruments used but also the wrong voltages
are
displayed in the simulation.
Exhibit #4: An example of a MultiSim screenshot that can be
used in a
lab report.
Exhibit #5: A MultiSim simulation with no measured values
displayed.
Exhibit #6: An example of a MultiSim printout which is NOT
acceptable
to include in a lab report.
11. Exhibit #7: Example of a raw data sheet which can be attached
to a
lab report.
12. Exhibit #8: Unnecessary portions of the lab assignment sheet
were attached to
this lab report.
Exhibit #9: An example of a good materials list.
Exhibit #1O: Procedures Examples
Example of a poorly formatted lab procedure
An example of a properly formatted lab procedure
13. Exhibit #11: Data Table Examples
Examples of well formatted data tables
This is not a data table
14. Exhibit #12: Data table values shown with too many decimal
places
Exhibit 13: Unneeded calculations shown
Exhibit #14: A properly labelled graph
15. Exhibit #15: Pictures with no labelling or identification
Exhibit #16: Examples of Discrete Electrical Instruments
Digital Multimeter DC Power Supply
16. Function Generator
Oscilloscope
Exhibit 17: A table showing the nominal and measured
component values
Experiment 1
Introduction to DC Circuits
Lab #1 ENG 250-001
Name: Date:
Introduction to DC Circuits
17. Basic Circuit Definitions and Concepts
The concepts and definitions outlined here are extremely
important for understanding how to construct and
analyze electric and electronic circuits.
In general, an electric circuit consists of a group of components
such as batteries, lamps, switches and motors
connected together, in some pattern, by conducting wires.
Circuits that contain semiconductor devices such as
transistors and diodes, or thermionic devices such as vacuum
tubes, are called electronic circuits. A DC circuit
is an electric or electronic circuit in which the electric current
through every component is constant in time. All
of the points where a given circuit connects to devices that are
not considered to be part of the circuit itself are
called terminals of the circuit.
Current (we use the symbol I ) is the rate as which charge flows
past a given point in a circuit. It is measured in
units of Amperes. One Ampere (or Amp for short) is one
Coulomb of charge passing a given point along the
circuit in one second. I = Q / T
A single loop circuit is one that consists of two or more
components connected together in series (one after the
other) to form a single closed path. The current in a single loop
circuit will always have the same magnitude at
all points around the loop, otherwise charge would build up or
disappear somewhere which, by the law of
conservation of charge, cannot happen.
Multi-loop circuits contain nodes, points where the current can
divide up and take alternate paths, or where
currents can merge. Any circuit path between two nodes is
called a branch. The sum of all branch currents
18. arriving at a node must always equal the sum of all branch
currents leaving the same node. This is called
Kirchoff’s Node Law. Two or more circuit branches that
connect together through the same pair of nodes are
said to be connected in parallel.
Potential difference, also known as voltage, (using the symbol
V ) is the work required per unit of charge to
move charge from one point in a circuit to another. It is
measured in Volts. One Volt is one Joule of work per
Coulomb of charge moved. When a potential difference is
negative, it is often referred to as a potential drop.
The sum of potential differences along any closed path within a
DC circuit is always zero. This principle is
known as Kirchoff’s Loop Law.
Power (using the symbol P) is the rate at which energy is
transferred to or from a portion of the circuit. It is
usually measured in Watts or Joules per second. The amount of
power delivered to or from a circuit component
is equal to the product of the current through the component and
the potential difference across it.
Some components in a DC circuit will absorb energy and
transform it to mechanical energy or to heat, or store
it as chemical potential energy, while other components will
supply energy to the circuit. Rechargeable batteries
can perform either of these functions, depending upon whether
they are being recharged or discharged at the
time. When the potential is lower at the point where current
exits from a component than at the point where it
entered, power is being removed from the circuit by the
component. But if the potential is higher at the point
where the current exits, then that component is acting as a
power source, delivering power to the circuit.
19. Tariq Karroameh 6110
Experiment 1
Introduction to DC Circuits
Resistance (symbol = R) is a property of energy absorbing
electrical devices that convert electrical energy into
heat. Often the current, I, through the device is directly
proportional to the potential drop, V, across it. The
relation V = IR is known as Ohm's Law, and a device satisfying
this linear relationship is called a resistor.
Resistance is measured in Ohms. A one-Ohm resistor carries a
current of one Amp if there is a potential drop of
one Volt across its terminals.
The Digital Multimeter
The digital multimeter (DMM for short) is a multifunction
instrument that can be used to measure Voltage,
Current or Resistance, depending upon which function is
selected and how it is connected to the circuit. A large
rotary switch on the face of the DMM sets the range of the
instrument as well as selecting the quantity to be
measured. The decimal point in the DMM’s digital display will
move automatically, as you change ranges, but
you need to be aware of the units implied on each particular
range of the instrument. Please Note: One of the
test leads must be plugged into a different jack on the meter
when it is used to measure Current, than the jack
used when measuring Voltage or Resistance. One lead is always
connected to the COM jack.
20. To measure the potential difference between any two points in a
circuit, first select an appropriate DC Voltage
range, plug the test leads into the COM and V/: jacks, and then
connect the test leads to the appropriate circuit
points. There is also a switch near the top to select DC versus
AC.
To measure the current in a single loop circuit or in a particular
branch of a multi-loop circuit, select an
appropriate DC Current range, plug the test leads into the COM
and A terminals, break the loop or circuit
branch, and connect the DMM leads across the break, to
complete the circuit. Note: To measure the current in a
circuit branch, the DMM must always be connected in series
with the components that make up that branch.
To measure the resistance of a device, you must remove it from
the circuit and connect it directly across the
DMM test leads, plugged into the COM and V/: jacks. Switch
the DMM to one of the resistance ranges.
Attempting to use the DMM as an Ohmmeter (to measure the
resistance of a component) while the component
is connected in a circuit will generally lead to erroneous results,
and it may permanently damage the meter as
well.
The Power Supplies
There are several power supplies in your trainer kit. On the left
side of the breadboards are jacks for the
following power supplies: A variable DC supply from +1.25 V
to 20 V; A variable DC supply from –1.25 V to
–20 V; A fixed AC supply at 15 V and 30 V; A ground jack; and
fixed +5 V, +12 V and –12 V jacks. In most
labs you will be using the +5 V DC fixed supply.
21. On the top of the kit are a series of knobs that control what is
called a function generator. With these knobs you
can create a varying voltage supply with variable frequency and
shape. The function generator will be discussed
in a later lab.
The Breadboard
Permanent circuits are usually constructed by soldering the
components to a fiberglass circuit board that is
constructed with metal “traces” that interconnect all of the
components, completing the circuit. These
permanent circuits are inexpensive to construct, easy to test and
reliable, but difficult to modify or experiment
with. For experimentation with new or modified circuits, the
best strategy is to build the circuit with a
“breadboard” and jumper wires. This is an ideal way to make
temporary but fairly reliable electrical
Experiment 1
Introduction to DC Circuits
connections and keep things spaced out to avoid accidental
short circuits (connections where you don't want
them).
The layout of connection points on the breadboard is designed
for dual-in-line package integrated circuits,
which you will be using in a few weeks, but it's useful in
working with discrete component circuits as well. The
narrower strips on the breadboard are called bus strips; they
have two long lines of connection points and all the
22. points in one line are connected together under the board.
Typically you'll connect the +5 Volt output of the
power supply to one bus line and the power supply common
(ground) output to another bus line; then wires
plugged into the bus lines at any point can conveniently connect
power to your circuit. The wider breadboard
strips with a groove down the middle are wired quite
differently: Groups of 5 connection points running
perpendicular to the length of the board on each side of the
center groove are connected together. This allows an
integrated circuit to be plugged in straddling the groove with
four available connection points to each pin of the
integrated circuit. ( See a copy of layout at the end of your lab.)
Resistors
Carbon-film resistors obey Ohm's law quite accurately and come
in a broad range of resistance values: from 10
Ohms to 22 Mega ohms. (“Meg” means million). They carry a
color-code to make it easy to identify their
resistance value.
The color of the first color band (closest to one end) represents
the first decimal digit of the resistance value.
The next band is the second decimal digit. The third band
represents the number of zeroes that must be added
behind the two digits to represent the resistance as an integer.
0: Black 5: Green
1: Brown 6: Blue
2: Red 7: Violet
3: Orange 8: Gray
4: Yellow 9: White
23. There is also a fourth color band that gives you the tolerance of
the resistor. The tolerance tells you how close
the color code resistance is to the actual resistance. The
following table shows the colors of the fourth band and
the corresponding tolerances:
Brown 1 %
Gold 5 %
Silver 10 %
None 20 %
Experimental Procedures
1. Using a DMM check the output voltages available from your
power supply and record them.
(Notice that you may connect the DMM leads to the power
supply either way and that the DMM gives you a
minus sign on its display when the potential is lower at the V/:
terminal than at the COM terminal. Use the DC
Volt range that gives you the greatest number of significant
figures.)
1 505 v
Experiment 1
Introduction to DC Circuits
24. 2. Select three different resistors from the front of the class,
record their color codes from lowest to highest
using the above table, and record the nominal value. Measure
the resistance of each resistor with the DMM's
ohmmeter function and compare the measured values with the
nominal (approximate) color-code values. Adjust
the range to get the largest number of significant figures.
Color Code Nominal Value Measured Value
a. ________________________ ________________________
________________________
b. ________________________ ________________________
________________________
c. ________________________ ________________________
________________________
3. Construct a series circuit using the 1.5 Volt power supply and
tow of your lowest resistor. Calculate the
current in this circuit. Draw a schematic of your circuit with the
polarity and insert an ammeter to show how
you connect your meter in the circuit.
I cal =
25. Measure the current using your DMM as an ammeter (start on
the 200 milliamp DC Amp scale). Change the
range until you get the largest number of significant figures.
Record your value.
I Meas =
4. Repeat part 3 using all three resistors in series. Draw a
schematic with the polarity, calculate and measure
voltage drop across each resistor. Insert the ammeter at
different points in the circuit loop to confirm that the
current is the same everywhere around a single-loop circuit.
V1 cal =
V2 cal =
V3 cal =
I meas =
5. Construct a circuit with two highest value resistors in
parallel. Predict and then measure the current in each
branch of the circuit. Draw a schematic of your circuit and
insert an ammeter to show how you connect your
meter in the circuit. Is Kirchoff’s node law obeyed? Can you
think of a reason that it might not seem to be
obeyed exactly? (Hint: Use one DMM to measure the voltage
drop across the terminals of the other DMM.)
I1 meas = I2 meas =
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I 02 5 1000N 987 A
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Iir 03425 47 1161
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amp
Experiment 1
Introduction to DC Circuits
6. Add the third resistor in series with that parallel pair. Draw a
schematic of your circuit and insert an ammeter
to show how you connect your meter in the circuit. Predict and
then measure the voltage drop across each
resistor in this circuit. Do the results make sense?
I1 meas = I2 meas = I3 meas =
27. 7. Using Multisim, build each of the circuits and verify your
data for each of the steps (3-6.).
Measured Value Simulated Value
Step 3. I Meas =______ ____________________
Step 4. V1 Meas =_______ ________________________
V2 Meas =_______ ________________________
V 3Meas =_______ ________________________
I Meas =_______ ________________________
Step 5. I1 meas =_______ ________________________
I2 meas =________ ________________________
V Meas =________ ________________________
Step 6. I1 meas =_______ ________________________
I2 meas =________ ________________________
I3 meas =________ ________________________
Did you find your measured and simulated value to be
different?
28. Explain why.
182h47
1.497
dgero ookton.edu
1. Title Page
Not all lab reports have title pages, but if your instructor wants
one, it would be a single
page that states:
The title of the experiment.
Your name and the names of any lab partners.
Your instructor's name.
The date the lab was performed or the date the report was
submitted.
2. Title
The title says what you did. It should be brief (aim for ten
words or less) and describe the
main point of the experiment or investigation. An example of a
title would be: "Effects of
Ultraviolet Light on Borax Crystal Growth Rate". If you can,
29. begin your title using a
keyword rather than an article like 'The' or 'A'.
3. Introduction / Purpose
Usually the Introduction is one paragraph that explains the
objectives or purpose of the
lab. In one sentence, state the hypothesis. Sometimes an
introduction may contain
background information, briefly summarize how the experiment
was performed, state the
findings of the experiment, and list the conclusions of the
investigation. Even if you don't
write a whole introduction, you need to state the purpose of the
experiment, or why you
did it. This would be where you state your hypothesis.
4. Materials
List everything needed to complete your experiment.
5. Methods
Describe the steps you completed during your investigation.
This is your procedure. Be
sufficiently detailed that anyone could read this section and
duplicate your experiment.
Write it as if you were giving direction for someone else to do
the lab. It may be helpful
to provide a Figure to diagram your experimental setup.
6. Data
30. Numerical data obtained from your procedure usually is
presented as a table. Data
encompasses what you recorded when you conducted the
experiment. It's just the facts,
not any interpretation of what they mean.
7. Results
Describe in words what the data means. Sometimes the Results
section is combined with
the Discussion (Results & Discussion).
8. Discussion or Analysis
The Data section contains numbers. The Analysis section
contains any calculations you
made based on those numbers. This is where you interpret the
data and determine
whether or not a hypothesis was accepted. This is also where
you would discuss any
mistakes you might have made while conducting the
investigation. You may wish to
describe ways the study might have been improved.
9. Conclusions
Most of the time the conclusion is a single paragraph that sums
up what happened in the
experiment, whether your hypothesis was accepted or rejected,
and what this means.
10. Figures & Graphs
31. Graphs and figures must both be labeled with a descriptive title.
Label the axes on a
graph, being sure to include units of measurement. The
independent variable is on the X-
axis. The dependent variable (the one you are measuring) is on
the Y-axis. Be sure to
refer to figures and graphs in the text of your report. The first
figure is Figure 1, the
second figure is Figure 2, etc.
11. References
If your research was based on someone else's work or if you
cited facts that require
documentation, then you should list these references.
Experiment 1
Introduction to DC Circuits
Lab #1 ENG 250-001
Name: Date:
32. Introduction to DC Circuits
Basic Circuit Definitions and Concepts
The concepts and definitions outlined here are extremely
important for understanding how to construct and
analyze electric and electronic circuits.
In general, an electric circuit consists of a group of components
such as batteries, lamps, switches and motors
connected together, in some pattern, by conducting wires.
Circuits that contain semiconductor devices such as
transistors and diodes, or thermionic devices such as vacuum
tubes, are called electronic circuits. A DC circuit
is an electric or electronic circuit in which the electric current
through every component is constant in time. All
of the points where a given circuit connects to devices that are
not considered to be part of the circuit itself are
called terminals of the circuit.
Current (we use the symbol I ) is the rate as which charge flows
past a given point in a circuit. It is measured in
units of Amperes. One Ampere (or Amp for short) is one
Coulomb of charge passing a given point along the
33. circuit in one second. I = Q / T
A single loop circuit is one that consists of two or more
components connected together in series (one after the
other) to form a single closed path. The current in a single loop
circuit will always have the same magnitude at
all points around the loop, otherwise charge would build up or
disappear somewhere which, by the law of
conservation of charge, cannot happen.
Multi-loop circuits contain nodes, points where the current can
divide up and take alternate paths, or where
currents can merge. Any circuit path between two nodes is
called a branch. The sum of all branch currents
arriving at a node must always equal the sum of all branch
currents leaving the same node. This is called
Kirchoff’s Node Law. Two or more circuit branches that
connect together through the same pair of nodes are
said to be connected in parallel.
Potential difference, also known as voltage, (using the symbol
V ) is the work required per unit of charge to
move charge from one point in a circuit to another. It is
measured in Volts. One Volt is one Joule of work per
34. Coulomb of charge moved. When a potential difference is
negative, it is often referred to as a potential drop.
The sum of potential differences along any closed path within a
DC circuit is always zero. This principle is
known as Kirchoff’s Loop Law.
Power (using the symbol P) is the rate at which energy is
transferred to or from a portion of the circuit. It is
usually measured in Watts or Joules per second. The amount of
power delivered to or from a circuit component
is equal to the product of the current through the component and
the potential difference across it.
Some components in a DC circuit will absorb energy and
transform it to mechanical energy or to heat, or store
it as chemical potential energy, while other components will
supply energy to the circuit. Rechargeable batteries
can perform either of these functions, depending upon whether
they are being recharged or discharged at the
time. When the potential is lower at the point where current
exits from a component than at the point where it
entered, power is being removed from the circuit by the
component. But if the potential is higher at the point
where the current exits, then that component is acting as a
power source, delivering power to the circuit.
35. Experiment 1
Introduction to DC Circuits
Resistance (symbol = R) is a property of energy absorbing
electrical devices that convert electrical energy into
heat. Often the current, I, through the device is directly
proportional to the potential drop, V, across it. The
relation V = IR is known as Ohm's Law, and a device satisfying
this linear relationship is called a resistor.
Resistance is measured in Ohms. A one-Ohm resistor carries a
current of one Amp if there is a potential drop of
one Volt across its terminals.
The Digital Multimeter
The digital multimeter (DMM for short) is a multifunction
instrument that can be used to measure Voltage,
Current or Resistance, depending upon which function is
selected and how it is connected to the circuit. A large
rotary switch on the face of the DMM sets the range of the
36. instrument as well as selecting the quantity to be
measured. The decimal point in the DMM’s digital display will
move automatically, as you change ranges, but
you need to be aware of the units implied on each particular
range of the instrument. Please Note: One of the
test leads must be plugged into a different jack on the meter
when it is used to measure Current, than the jack
used when measuring Voltage or Resistance. One lead is always
connected to the COM jack.
To measure the potential difference between any two points in a
circuit, first select an appropriate DC Voltage
connect the test leads to the appropriate circuit
points. There is also a switch near the top to select DC versus
AC.
To measure the current in a single loop circuit or in a particular
branch of a multi-loop circuit, select an
appropriate DC Current range, plug the test leads into the COM
and A terminals, break the loop or circuit
branch, and connect the DMM leads across the break, to
complete the circuit. Note: To measure the current in a
circuit branch, the DMM must always be connected in series
with the components that make up that branch.
37. To measure the resistance of a device, you must remove it from
the circuit and connect it directly across the
the DMM to one of the resistance ranges.
Attempting to use the DMM as an Ohmmeter (to measure the
resistance of a component) while the component
is connected in a circuit will generally lead to erroneous results,
and it may permanently damage the meter as
well.
The Power Supplies
There are several power supplies in your trainer kit. On the left
side of the breadboards are jacks for the
following power supplies: A variable DC supply from +1.25 V
to 20 V; A variable DC supply from –1.25 V to
–20 V; A fixed AC supply at 15 V and 30 V; A ground jack; and
fixed +5 V, +12 V and –12 V jacks. In most
labs you will be using the +5 V DC fixed supply.
On the top of the kit are a series of knobs that control what is
called a function generator. With these knobs you
can create a varying voltage supply with variable frequency and
38. shape. The function generator will be discussed
in a later lab.
The Breadboard
Permanent circuits are usually constructed by soldering the
components to a fiberglass circuit board that is
constructed with metal “traces” that interconnect all of the
components, completing the circuit. These
permanent circuits are inexpensive to construct, easy to test and
reliable, but difficult to modify or experiment
with. For experimentation with new or modified circuits, the
best strategy is to build the circuit with a
“breadboard” and jumper wires. This is an ideal way to make
temporary but fairly reliable electrical
Experiment 1
Introduction to DC Circuits
connections and keep things spaced out to avoid accidental
short circuits (connections where you don't want
them).
39. The layout of connection points on the breadboard is designed
for dual-in-line package integrated circuits,
which you will be using in a few weeks, but it's useful in
working with discrete component circuits as well. The
narrower strips on the breadboard are called bus strips; they
have two long lines of connection points and all the
points in one line are connected together under the board.
Typically you'll connect the +5 Volt output of the
power supply to one bus line and the power supply common
(ground) output to another bus line; then wires
plugged into the bus lines at any point can conveniently connect
power to your circuit. The wider breadboard
strips with a groove down the middle are wired quite
differently: Groups of 5 connection points running
perpendicular to the length of the board on each side of the
center groove are connected together. This allows an
integrated circuit to be plugged in straddling the groove with
four available connection points to each pin of the
integrated circuit. ( See a copy of layout at the end of your lab.)
Resistors
Carbon-film resistors obey Ohm's law quite accurately and come
in a broad range of resistance values: from 10
40. Ohms to 22 Mega ohms. (“Meg” means million). They carry a
color-code to make it easy to identify their
resistance value.
The color of the first color band (closest to one end) represents
the first decimal digit of the resistance value.
The next band is the second decimal digit. The third band
represents the number of zeroes that must be added
behind the two digits to represent the resistance as an integer.
0: Black 5: Green
1: Brown 6: Blue
2: Red 7: Violet
3: Orange 8: Gray
4: Yellow 9: White
There is also a fourth color band that gives you the tolerance of
the resistor. The tolerance tells you how close
the color code resistance is to the actual resistance. The
following table shows the colors of the fourth band and
the corresponding tolerances:
41. Brown 1 %
Gold 5 %
Silver 10 %
None 20 %
Experimental Procedures
1. Using a DMM check the output voltages available from your
power supply and record them.
(Notice that you may connect the DMM leads to the power
supply either way and that the DMM gives you a
terminal than at the COM terminal. Use the DC
Volt range that gives you the greatest number of significant
figures.)
Experiment 1
Introduction to DC Circuits
42. 2. Select three different resistors from the front of the class,
record their color codes from lowest to highest
using the above table, and record the nominal value. Measure
the resistance of each resistor with the DMM's
ohmmeter function and compare the measured values with the
nominal (approximate) color-code values. Adjust
the range to get the largest number of significant figures.
Color Code Nominal Value Measured Value
a. ________________________ ________________________
________________________
b. ________________________ ________________________
________________________
c. ________________________ ________________________
________________________
3. Construct a series circuit using the 1.5 Volt power supply and
tow of your lowest resistor. Calculate the
current in this circuit. Draw a schematic of your circuit with the
polarity and insert an ammeter to show how
you connect your meter in the circuit.
43. I cal =
Measure the current using your DMM as an ammeter (start on
the 200 milliamp DC Amp scale). Change the
range until you get the largest number of significant figures.
Record your value.
I Meas =
4. Repeat part 3 using all three resistors in series. Draw a
schematic with the polarity, calculate and measure
voltage drop across each resistor. Insert the ammeter at
different points in the circuit loop to confirm that the
current is the same everywhere around a single-loop circuit.
V1 cal =
V2 cal =
44. V3 cal =
I meas =
5. Construct a circuit with two highest value resistors in
parallel. Predict and then measure the current in each
branch of the circuit. Draw a schematic of your circuit and
insert an ammeter to show how you connect your
meter in the circuit. Is Kirchoff’s node law obeyed? Can you
think of a reason that it might not seem to be
obeyed exactly? (Hint: Use one DMM to measure the voltage
drop across the terminals of the other DMM.)
I1 meas = I2 meas =
Experiment 1
Introduction to DC Circuits
6. Add the third resistor in series with that parallel pair. Draw a
schematic of your circuit and insert an ammeter
to show how you connect your meter in the circuit. Predict and
then measure the voltage drop across each
45. resistor in this circuit. Do the results make sense?
I1 meas = I2 meas = I3 meas =
7. Using Multisim, build each of the circuits and verify your
data for each of the steps (3-6.).
Measured Value Simulated Value
Step 3. I Meas =______ ____________________
Step 4. V1 Meas =_______ ________________________
V2 Meas =_______ ________________________
V 3Meas =_______ ________________________
46. I Meas =_______ ________________________
Step 5. I1 meas =_______ ________________________
I2 meas =________ ________________________
V Meas =________ ________________________
Step 6. I1 meas =_______ ________________________
I2 meas =________ ________________________
I3 meas =________ ________________________
Did you find your measured and simulated value to be
different?
Explain why.