ECE 101
Introduction to Electrical and Computer
Engineering
Laboratory and Experiment Guide
GEORGE MASON UNIVERSITY
ELECTRICAL AND COMPUTER ENGINEERING
LABORATORY RULES
1.
There will be NO FOOD OR DRINKS in the laboratory at any time. Students will be held
liable for any damage to equipment resulting from abuse of this rule.
2.
Students are not allowed in the laboratories without a Lab Instructor or Lab Monitor
present, unless signed in with the Lab Manager. Open lab times for make-up or project
work will be posted. When a Teaching Assistant is holding office hours, he/she is also
monitoring an open lab which any student may use.
3.
If you suspect a problem with the equipment, notify the TA or Room Monitor. Then,
either leave a note on it with a brief description of the problem/symptoms, or bring the
equipment to the Lab Manager, Room ENGR 3916.
4.
Handle equipment with care. Equipment out for repair means less available for your use.
5.
YOU are responsible for leaving your workstation clean and in good condition when you
leave. Failure to do this will negatively impact your final lab grade.
Before leaving:
a)
Hang up all test leads neatly under appropriate connector combination.
b)
Tidy workstation.
c)
Throw away all trash.
d)
TURN OFF equipment and lab table SWITCHES.
This is a non-smoking university. This building has NO designated smoking areas
so you must go outdoors if you choose to smoke.
ELECTRONICS SAFETY
Exercise of good judgment and knowledge will ensure you a safe laboratory experience.
Do not defeat any safety device such as a fuse or circuit breaker, by shorting across it or
by using a higher amperage fuse than that specified by the manufacturer.
Avoid direct contact with any voltage source. Do not wear rings, watches, bracelets, or
dangling necklaces while working on equipment. Do not grasp any exposed metal in your
circuit when the power is on.
Keep hands dry. Water and perspiration increase conductivity. Wear shoes with
insulating soles. Measure voltages with one hand held behind you or in your pocket.
Avoid eye injury when cutting off excessive wire lengths. Point the wires downward
toward your table top so the cut pieces cannot fly toward your eyes or another
person’s.
Shut off the power when connecting components or test equipment to a circuit. Double
check your wiring before you apply power.
Make sure your circuit is properly grounded. Beware of a possible floating ground. It is a
good idea to connect all grounds together before applying power.
To prevent power terminals from shorting, keep the leads coming from those terminals
apart.
1.
2.
3.
4.
Your exercise of common sense, safety precautions and knowledge will help you avoid
the dangers of electricity. The amount of current required to become lethal depends
upon:
The person involved and state of health
Area of the body involved
Length of time the shock is received and
Type of electrical current.
Severe electrical shock will cause burns and/or paralysis. A small current passing through
the chest can kill. With even minor electrical shock, some people react by going into
traumatic shock.
In case of accident, turn off power immediately and call 911. If you suspect someone is touching a
"live" wire, do not touch them. Use something non-conductive to push, rather than pull, them
away from the wire. An injured person should be kept lying down until medical personnel arrive,
and should be kept warm to help prevent traumatic shock.Be sure nothing is done to cause
further injury.
GEORGE MASON UNIVERSITY
ELECTRICAL AND COMPUTER ENGINNERING LAB TIPS
1) Instruction manuals for the laboratory equipment may be checked out from the lab
manager in room 3916. It is essential that you become familiar with the correct way to
use the basic equipment in your first lab course. Wire cutters/strippers are available for
sale or you will need to bring your own.
2) Twenty-two gauge wires (22AWG) is the best size to use with the trainers and solder less
breadboards. Solid wire only, never stranded, is used for the trainers. There are spools
of wire cabled to the back shelf. You will need to cut some and strip the insulation at
both ends. Keep jumper wires short. Strive for a neat and logical layout. This will make
troubleshooting easier and successful circuits more likely.
Strip no more than approximately 3/8 inch of insulation from your jumper wires.
Exposed wire increases the risk of short circuits.
3) Using more than one color of wire will help you debug your circuits. Normally RED and
BLACK are reserved for power and ground.
4) Probe tips should not be inserted into the solder less breadboard. Wrap a wire around
your probe hook tip twice for stability and insert the other end into the connector
block. Alligator clips on the equipment leads also need a wrapped wire for connection
to the trainers and breadboards.
5) Always ground your probe, but keep the ground wire short. Use the method of wire
wrapping described in the previous tip to attach to the alligator clip of the probe
ground wire.
6) For any potentiometers (such as most multi-turn) which require adjusting, a trimpot tool
is available for purchase from room ENGR 3916. It is included in appropriate kits.
7) Most of the chips used in your lab are not overly static sensitive. However, you should
observe some precautions when handling them. If you were issued a tube, it protects
the chips from static charges, and is sturdy enough to provide protection to the
delicate, metal pin legs.
8) Keep your chips away from magnets, motors and high temperatures. Don't leave them in
your car in the sun or extreme cold. They do best in the moderate temperatures most
humans prefer.
LAB TIPS CONTINUED
9) Bent pins may be gently straightened with fingernails or needle nose pliers. If the pins
break, you will need to purchase a new IC.
10) A small, narrow-blade, flathead screwdriver is useful in removing chips from
breadboards. Using a side-to-side rocking motion as you insert the blade under the chip,
keep a finger lightly on top of the chip to prevent it suddenly popping up on one end,
bending the pins.
11) To locate pin 1 on an integrated circuit (IC, chip), look for one of the following:
A Semicircle at one end, often cut
into the end of the chip – with this
at the top, pin1 is at the left half
circle. Sometimes there is one
whole circle.
A tiny spot in the corner of the
chip beside pin1 – There may or
may not be other marks on the
chip.
Always count pins from pin 1 around the chip so that the last pin is straight across from
pin 1. Common chip sizes are 8 pin, 14, 16, 18, 20, 24, 28, and 40 pin. Your TTL ICs
(Transistor-Transistor Logic Integrated Circuits) will be in dual inline packages (DIP).
12) Chip leads are slightly flared to help hold them in printed circuit boards while being
soldered. You will need to reduce the flare to allow them to be inserted into the
breadboard. Use a pair of needle nose pliers or press the leads against a table top while
rotating the body of the chip towards the lead points to reduce the lead angle of all
evenly. Don't bend too far; there is no easy correction.
Laboratory Report Format
I.
Cover Page
a)
b)
c)
d)
II.
Course Number
Experiment Number and Title
Your Name
The Date of Submission
Objectives
State the objective and what you are trying to prove. This should be general and is
intended for a reader with moderate background knowledge.
III.
Theoretical Background
Provide enough mathematical or theoretical background to understand how the
experiment works. List the principle and equations if any.
IV.
Materials and Equipment
List all the equipment used for each lab.
V.
Circuit diagram
Use proper symbols of all the components and construct a relevant circuit diagram for
every lab experiment in this lab.
VI.
Laboratory Data
This section is for your collected data, along with any plots, tables, or illustrations.
VII.
Theoretical Data
Include any data that you can predict using mathematical models/calculations and
laws.
VIII.
Comments and Conclusions
Discuss what went as expected and what did not. Compare your theoretical and
laboratory values. Are they the same? Why or why not?
Make sure that all of the questions in the lab manual are answered completely.
Be creative. Think of this as a technical report that you are submitting to your boss at
work. Try to explain as much as possible, yet be concise. Remember that this report
should be targeted to an audience with mid-level expertise. Anyone with some
background knowledge in the subject should be able to understand it.
ECE 101 Lab Manual
Table of Contents
Fall 2015
Laboratory
Experiment
1.
Laboratory Fundamentals
2.
DC Circuits
3.
A Simple Communication System
4.
Introduction to the Oscilloscope
5.
Simple Filtering
6.
Transistor Fundamentals
7.
The Transistor as an Amplifier
8.
Combinational Logic
9.
Smart Buttons (extra credit)
Student
TA Signature
Signature
Laboratory 1
Laboratory Fundamentals
Note: This lab is designed to introduce you to the use of the multi-meter to
measure resistance, voltage and current as well as teach the color codes on
resistors.
Resistor Color Codes
There are usually four stripes on the body of the resistor. The first three
stripes give the value of the resistor, and the last stripe gives the tolerance. The
value of the colors is as follows:
Color
Black
Brown
Red
Orange
Yellow
Green
Blue
Violet
Grey
White
First three Stripes
Value
Color
0
Gold
1
Silver
2
3
4
5
6
7
8
9
Fourth Stripe
Tolerance
±5%
±10%
The first three stripes give the value of resistance in Ω (ohms) according to
the formula:
A B × 10C
Where A is the first stripe's value, B is the second stripe's value and C is
the third stripe's value. For example, for the following resistor color code:
Brown-Black-Red-Gold
Reading the values off of the color code chart, A=1, B=0, C=2. Therefore the value of
the resistor in ohms is 10 × 102 = 1000 = 1KΩ and the tolerance is ± 5% due to the gold
stripe. So this resistor will have a resistance in the range of ± 5% of 1,000Ω, which
corresponds to a resistance value between 995 Ω-1005 Ω.
A second resistor may have the color codes as follows:
Yellow-Violet-Orange-Silver
Reading the values off of the color chart, A = 4, B = 7, and C = 3. Therefore the
value of the resistor in ohms is 47×103 = 47,000 = 47KΩ and the tolerance is ± 10%,
due to the silver stripe.
Part 1) Resistor Measurement
Locate all of the resistors from your kit. Locate the power button of the
multi-meter and turn it on. Take two banana to alligator plug wires (one red and one
black) and connect the red wire's banana end to the hole marked Ω (usually a red
hole) on the multi-meter, and the black wire's banana end to the hole marked
"Ground" or "Common" (usually a black hole) on the multi-meter. Connect the
alligator ends of these wires to the wires coming from a resistor. When using an
auto-ranging multi-meter, the value of the resistance should come up as soon as the
wires are connected. For those multi-meters with manual ranging, you will have to
adjust the range such that the value with the most significant digits as possible is
shown on the LCD display. For this lab, measure each of the resistors in the kit
noting down for each resistor the color code on the resistor, the value that the color
code indicates, and the measured value of the resistor as seen on the multi-meter.
Complete the table below with these values.
Color code based Measured value
value of the
of the resistor
resistor
Tolerance Calculated resistance Is the measured resistance value
value
range of resistor
within the designated tolerance
(xΩ-yΩ)
limits?
Part 2) Voltage Measurement
In an electrical circuit, voltages and currents can be measured and reflect
the flow of electrons through electrically conducting materials. A voltage occurs
whenever there is a surplus of electrons at one point of the circuit relative to
another. A non­zero voltage can occur only between two points in a circuit that
are NOT connected via an ideal conductor. One says, a voltage can only drop
across a resistor. To equalize this imbalance, electrons flow through the resistor
and give rise to electric currents. A voltage is introduced into an electrical circuit
via a voltage source such as a battery. Voltages are measured in volts (V) and
currents are measured in amperes (A).
Set up the simple circuit illustrated in figure 1.1. Use R1=1 kΩ resistor and use
the power supply (voltage source) to set V1=10 V. Locate the power button of the
multi-meter and turn it on. Take two banana to alligator plug wires (one red and
one black) and connect the banana ends respectively to the black and red
terminals of the multi-meter marked by a V (for Voltage). Select the appropriate
range of measurement by choosing the next higher value of your supplied voltage
(source). Connect the alligator ends in parallel to the two terminals of the resistor
in the circuit. If you are using a trainer, use two wires to connect each of them on
the same column of each end of the device you are measuring and connect the
alligator plugs of t he m ultimeter to the loose ends of the wires. Read the
voltage value observed across the resistor R1 from the LCD screen. What is
the value?
Figure 1.1. Simple circuit used to measure voltage, current and resistance
Supply Voltage
Vr (Voltage caross the resistor)
Part 3) Current Measurement
Use the same circuit illustrated in figure 1.1. Locate the power button of the
multi-meter and turn it on. Take two banana to alligator plug wires (one red and
one black) and connect the banana ends respectively to the black and red
terminals of the multi-meter marked by “A” (for amperes) or “I” (for current).
Select the appropriate range of measurement by choosing the next higher value
to get a value on the display. Connect the alligator ends in series to the device you
want to measure. Read the value of the current I1 from the LCD screen. What is
the value?
Supply Voltage-Vs
Measured Current-Ia
Lab Report
Prepare a detailed lab report. Each student must turn in their own report to
the teaching assistant not later than the beginning of the next lab. Your report
should be in narrative form. Include diagrams and plots as required as well as
responses to any questions asked.
Laboratory 2
DC Circuits
•
•
•
The relationship between voltages and currents in any circuit obeys three
simple rules that we will study in the experiments below. The three rules are:
Ohm's law
Kirchhoff's current law (KCL)
Kirchhoff's voltage law (KVL)
Ohm's law states that the current through a resistor is proportional to the voltage
across the resistor and inversely proportional to the resistance of the resistor. This is
often expressed via the simple formula:
I = V/R or V=IR or R=V/I
Where I denotes the current through the resistor, R denotes the resistor's
resistance, and V denotes the voltage across the resistor.
Figure 2.1: Ohm's law predicts the relationship between current and voltage for a
resistor.
Kirchhoff's current law ( K C L ) states that any current flowing into a node must also
flow out again. Hence, it implies that currents cannot be stored in "regular" circuit
elements. The most common application of this law occurs in the case when a circuit
branches as shown below.
Figure 2.2: The current I1 equals I2 + I3
Kirchhoff's voltage law (KVL) states that the sum of all voltages in a circuit mesh
must equal zero. This is simply a consequence of our earlier observation that a
voltage can exist only across resistive elements. To illustrate consider the figure
below:
Figure 2.3: Kirchhoff s voltage law implies that V1 equals V2
Preparation
Read the background material above and the information that you learned in
Laboratory 1. Anticipate the results of the experiments below.
Experiments
The following experiments are intended to teach you to use a multimeter for
measuring voltages, currents, and resistances.
1. Ohm's Law:
a) Find the 1 K.Ω Resistors in your kit and wire up the circuit in Figure 2.4 on the trainer
station. Use the adjustable voltage source on the trainer. Note that the multimeter
(denoted as ammeter in the figure) used to measure current flowing through the
resistor is connected in series to the resistor while the multimeter (denoted as
voltmeter in the figure) that measures voltage is connected in parallel to the resistor.
b) Adjust the voltage source such that the voltage V across the resistor changes in
increments of 2 V between 2 V and 20 V. For each voltage, record the current I. Also,
compute the ratio of voltage and current (V/I) for each measurement.
c) Repeat this experiment for the 5.1KΩ resistor in your kit.
d) Draw plots/graphs that show voltage (on the x-axis) versus current (on the y­ axis)
for both resistors.
e) For a given resistor, what is the relationship between voltage and current?
f) How does the ratio of voltage and current relate to the value of the resistor used in the
circuit?
g) Does this experiment verify Ohm’s law? Explain
Figure 2.4: Circuit for Experiment 1
2. Kirchhoff' s Voltage Law:
a) Find a 1 K.Ω resistor and a 5.1 K.Ω resistor in your kit and use them as resistor R1and
R2, respectively, in the circuit shown in Figure 2.5. For obvious reasons, the two
resistors are said to be connected in series.
b) Measure the current I in the circuit, and the voltages V1 and V2 across resistors R1
and R2, respectively.
c) Replace the 1 K.Ω resistor with the second 5.1 K.Ω resistor and repeat the
measurements.
d) How does the sum of V1 and V2 relate to the source voltage?
e) How can that relationship be explained by Kirchhoff’s Voltage Law.
f) What are the ratios V1/I and V2/I equal to?
g) If you wanted to replace the series connection of R1 and R2 by a single resistor, such that
the current I is unchanged, what value would that resistor need to be?
Figure 2.5: Circuit for Experiment 2
3. Kirchhoff’s Current Law:
a) Find the 1 kΩ resistor and the 5.1 k Ω resistor in your kit and use them as resistor R1 and
R2 respectively, in the circuit in figure 2.6. These two resistors are said to be connected
in parallel.
b) Measure the currents I, I1 and I2 in the circuit. Also measure the voltage V. You will have
to move your multi-meter around to take all these measurements.
c) Replace the 1 KΩ resistor with the second 5.1 KΩ resistor and repeat the measurements.
d) How does the sum of I1 and I2 relate to the current I?
e) How can that relationship be explained by Kirchhoff’s Current Law?
f) What are the products I1 R1 and I2R2 equal to respectively?
g) If you wanted to replace the parallel connection of R1 and R2 by a single resistor, such
that the current I is unchanged, what value would that resistor need to be? Calculate
using Ohm’s law
Figure 2.6: Circuit for Experiment 3
Lab Report
Prepare a detailed lab report. Each student must turn in their own report to
the teaching assistant not later than the beginning of the next lab. Your report
should be in narrative form. Include diagrams and plots as required as well as
responses to any questions asked.
Laboratory 3
A Simple Communication System
Preparation
•
•
Review class notes on "Encoding in Binary Format".
Design an encoding table for mapping the 26 characters in the alphabet plus space (
), comma (,), and period (.) into a binary representation. You could simply use 7 bit
or 8 bit ASCII encoding but there are more efficient forms of encoding for this
limited set of characters. You will have to bring a sheet to the lab that clearly shows
the encoding you designed. It must be clear enough to be interpreted by another
person!
Experiments
1. Light emitting diode (LED)
• Connect a 1kΩ resistor and the red LED in series to the adjustable voltage source.
Make sure that the input voltage supply is initially set at 0V
• Vary the input voltage between 1.2V and 5V and measure the current through the
diode and the voltage across the diode. Record also if the diode is lit or not. Vary the
voltage in steps of 0.1 V between 1.2 V and 2 V, and in steps of 0.5 V between 2 V
and 5 V.
• Turn the LED around and repeat the previous measurements.
• Summarize your measurements in two graphs that show voltage across the diode
versus current through the diode for each of the two possible orientations of the
diode. Indicate on your graph the range of currents and voltages for which the diode
was lit.
2. Telegraph
• Add a switch in series with your resistor and diode (LED). The diode should be
oriented such that it lights up when you push the button on your switch. You may
have to experiment a little with the switch to determine how to connect it.
• Build a second identical circuit using your second (differently colored) diode. Test
your circuits and verify that the diodes light up when you push the corresponding
buttons.
• You will be given a short message for transmission. Encode that message using the
code you designed in preparation for the lab. The message and the binary
representation should be part of your lab report.
• Transmit that message to your lab partner. Illuminate the red diode to transmit a
"1" and light up the other diode to send a "0".
• Your lab partner should record the received binary message and decode it with the
help of the encoding table you prepared.
• Repeat the experiment with reversed roles.
Lab Report
Your lab report should accurately reflect the experiments conducted in this lab.
It should be in narrative form. The following should be included, referred to, and
explained in your narrative:
•
•
•
•
•
•
Diagrams of the circuits you wired up
Graphs for the first experiment
Your encoding table
Your lab partner's encoding table
The message you transmitted, both in text and binary form
The message you received, in binary and text form
Be sure to write a section that summarizes your findings, insights, observations,
and conclusions. Your report forms the basis for your grade in this lab.
Preparation
Laboratory 4
Introduction to oscilloscope
Read the following document on the Introduction to Oscilloscopes:
https://ece.gmu.edu/sites/ece/files/student-resource/7911/oscilloscope-manual.pdf
•
•
•
•
•
•
•
•
Be sure that you understand the following terms:
sine wave
square wave
amplitude
period
frequency
phase
trigger
probe
Experiments:
1. Using the Oscilloscope
a) Build a simple circuit in which you connect the function generator (your voltage
source) to a 1 KΩ resistor.
b) Set the function generator to produce sine waves of frequency 1 KHz and amplitude
2 Volts (Vp).
c) Display the voltage across the resistor on the oscilloscope. Be sure to record all
relevant settings of the control knobs.
d) Increase and decrease the amplitude of the signal and describe the effect on the
trace displayed on the oscilloscope.
e) Increase and decrease the frequency of the signal and describe the effect on the
trace displayed on the oscilloscope.
f) On graph paper, plot a trace you observed. Be sure to include the grid lines on the
oscilloscopes. Accurately label your plot by indicating amplitudes and times
corresponding to the grid lines.
g) Explain how you can determine the frequency of the sine wave from the plot you
recorded.
h) Repeat the last two assignments for a sinusoid of frequency 100 KHz.
i) Repeat steps b-h for a square waveform.
2. AC signals and diodes
a) Add a diode (LED) in series to your circuit from the first experiment.
b) Set the function generator to produce a sine wave of frequency 1 KHz and amplitude
5 Volts (Vp).
c) Is your LED lit? What if you turn it around? Explain!
d) Display the voltage across the resistor on the oscilloscope. Plot the trace on graph
paper. Accurately label your plot.
e) Explain the shape of the signal you observe.
f) What happens if you reduce the amplitude (Vp) of the sine wave to 1 Volt?
g) What would you expect to observe in terms of how the LEDs behave if you repeated
steps a-c if the sine wave frequency was adjusted to be 2Hz?
Lab Report
Your lab report should accurately reflect the experiments conducted in this lab. It
should be in narrative form. The following should be included, referred to, and
explained in your narrative:
• Diagrams of all circuits you set up
• The procedure you used to display signals on the oscilloscope
• The required plots of signals
• Answers to questions asked above
Be sure to write a section that summarizes your findings, insights, observations, and
conclusions. Your report forms the basis for your grade in this lab.
Laboratory 5
Simple Filtering
Preparation:
Read the following document on the Introduction to Oscilloscopes:
https://ece.gmu.edu/sites/ece/files/student-resource/7911/oscilloscope-manual.pdf
Experiments:
1. Frequency Response of a Low Pass Filter
a)
b)
c)
d)
e)
f)
g)
The last three parts of this experiment can be done after the lab while you are
preparing your report.
Build a simple circuit in which you connect the function generator (your voltage
source) to the series of a 51 KΩ resistor R and a 0.001µF capacitor C.
Set the function generator to produce sine waves of amplitude 1 Volts (Vp). Set the
frequency initially to 3 KHz.
Display the voltage across the capacitor and the input voltage on the oscilloscope.
Please note: Connect the positive of the oscilloscope to the positive of the function
generator and negative to the negative of the function generator.
On graph paper, plot a trace of the signals you observed. Be sure to record all
relevant settings of the control knobs.
Set the amplitude of the input signal to 1 Volt (Vp) and record the voltage observed
across the capacitor for each of the following input frequencies: 10 Hz, 100 Hz, 500
Hz, 1 KHz, 2 KHz, 3 KHz, 4 KHz, 5 KHz, 10 KHz, 20 KHz, and 100 KHz.
Draw a graph that shows frequency on the x-axis and voltage observed across the
capacitor on the y-axis.
Calculate the values for H(f) for each value of the frequency f given in step (d) using
the following formula:
H (f) =
1
�1+(2𝜋𝜋𝜋𝜋)2
Where R and C are the values of the resistor and capacitor, respectively.
h) Prepare a plot of the values you calculated in the previous step with H(f) on the yaxis and frequency on the x-axis.
i) Compare the two graphs you obtained in steps (e) and (g)
j) What is the value of 1/(2πRC) and what role does that value play in your graphs?
Fig 4-1: Low pass filter-sine wave input
2. Passing a Square Wave through a Low Pass Filter
a) Use the same circuit as in the previous experiment. Set the function generator to
produce square waves of amplitude 1 Volt (Vp).
b) Record the waveform of the voltage across the capacitor when the input frequency is
100 Hz.
c) Record the waveform of the voltage across the capacitor when the input frequency
is 3 KHz.
d) What can you say about the difference in the waveforms that you observed in steps
b) and c)?
e) What could be one practical application of this observation?
Fig 4-2: Low pass filter square wave input
3. Rectifier
a) Set up the circuit in the diagram below.
b) Set the function generator to produce a sine wave of frequency 3 KHz and amplitude
3 Volts (Vp).
c) Display the voltage across the capacitor C1 and the voltage across the resistor R1.
Plot these voltages on a graph paper.
d) Repeat s t e p s a - c for a frequency of 30 KHz.
e) Explain the shape of the signals you observe in each case (there will be 4 graphs in
total)
f) Suggest a practical use for a circuit like this. Think of a voltage source with a
frequency of 60 Hz.
Figure 4.3: Half-Wave Rectifier Circuit
Lab Report
Your lab report should accurately reflect the experiments conducted in this lab. It
should be in narrative form. The following should be included, referred to, and
explained in your narrative:
•
•
•
•
•
Diagrams of all circuits you set up
The required plots of signals
An interpretation of your results and plots, i.e., describe what y o u r results mean.
Answers to questions asked above.
Be sure to write a section that summarizes your findings, insights, observations, and
conclusions. Your report forms the basis for your grade in this lab.
Laboratory 6
Transistor Fundamentals
Experiments:
In this experiment, we investigate the electrical characteristics of a bipolar
Junction transistor (BJT). In the subsequent experiments, we will see the use of a
transistor as a digital switch and as an amplifier.
A transistor is an element with three terminals – For BJT type transistors, the
terminals are called collector, emitter and base. In the circuits that we investigate,
we consider the voltage between base and emitter (Vbe) as the input, and the
voltage between collector and emitter (Vce) as the output. Between base and
emitter there is fundamentally a diode. Hence, just as with a diode the input voltage
determines the current flowing into the base of the transistor (see lab 2). Thus, we
could also consider the current into the base as the input signal.
As you will see, the input voltage can be used to control the resistance of the
transistor, i.e., by adjusting the voltage between base and emitter we can control
the current flowing into the collector. Furthermore, small changes in the input
voltage (or input current) lead to large changes in the collector current.
1.
The Transistor as a Switch
a) Set up the circuit shown below.
b) Vary the input voltage Vbe (by adjusting the resistor) between 0 V and 0.75 V.
c) You can use increments of 100 mV from 0V to 500 mVfor Vbe and then increments of
50 mV from 500 mV to 750 mV.
d) For each input voltage, measure the output voltage Vce across the 5k Ohm resistor
e) Draw a graph with Vbe on the x-axis and Vce on the y-axis.
f) Explain how the transistor acts as an electrically controlled switch in this circuit.
Hint: Remember our discussions on digital technology and associate a binary 1 with
a high (5 V) voltage level and a binary 0 with a low (0 V) voltage .
Figure 5 . 2 : Circuit diagram showing transistor used as a switch.
Vbe(mV)
Vce(mV)
0
100
200
300
400
500
550
600
650
700
750
2.
Electrical Characteristics of a Transistor
a) Set up the circuit in the diagram below. You will have to use the constant 5 Volt
supply and the adjustable 1kΩ resistor to set the voltage Vbe· You will also have to
use the adjustable (1.2V-20V) voltage supply to set the voltage Vce. These values will
have to be set in the next steps.
b) Adjust the 1kΩ resistor such that the voltage between base and emitter (Vbe) takes
on values between 550 mV and 750 mV in increments of 50 mV.
c) For each of these voltages Vbe, vary the voltage Vce between collector and emitter
from 1 V to 10 V in increments of 1 V. For each combination of Vbe and Vce measure
and record the current lc flowing into the collector.
d) Plot the results of your measurements in one graph which shows the collector
current Ic (y-axis) versus the voltage Vce (x-axis) for each of the different voltages Vbe·
There will be a total of 5 curves within the same graph.
e) In your report, explain how these curves show what was said about the Transistor in
the introduction above.
Figure 5.1: Circuit diagram for measuring transistor characteristics.
Lab Data:
Vce (V)
Ic (mA)
Vbe=550mV
Vbe=600mV
Vbe=650mV
Vbe=700mV
Vbe=750mV
1
2
3
4
5
6
7
8
9
10
Lab Report
Your lab report should accurately reflect the experiments conducted in this lab. It
should be in narrative form. The following should be included, referred to, and
explained in your narrative:
•
•
•
•
Diagrams of all circuits you set up,
The required plots,
An interpretation of your results and plots, i.e., describe what your results mean,
Answers to questions asked above.
Be sure to write a section that summarizes your findings, insights, observations, and
conclusions. Your report forms the basis for your grade in this lab.
Laboratory 7
Transistor as an Amplifier
Experiment:
In this experiment, we exploit the electrical characteristics of a bipolar junction
transistor (BJT) to construct a simple amplifier.
The Transistor as an Amplifier
a) Set up the circuit in the diagram below. Use the constant 12 Volt supply and the
adjustable 1 k Ω resistor to set the voltage Vbe to approximately 0.6 V.
b) Use the function generator for the input voltage. Use a sinusoidal input of frequency
10 KHz and set the amplitude to the smallest possible value. I.e., turn the amplitude
knob all the way to the left.
c) On the oscilloscope, use two probes to display the input voltage and the output
voltage on the same screen. Record the waveforms you observe.
d) Measure the amplitude of the input voltage (Vp-p) and the output voltage (Vp-p).
e) Vary the input voltage carefully and observe the effect on the output voltage.
f) In particular, observe the ratio of the amplitudes of output and input voltage.
g) At what input voltage does the shape of the output waveform begin to change?
Record the waveform you are observing.
h) Replace the 2kΩ resistor with a 5kΩ resistor and repeat the experiments above.
i) In your report, answer the following questions
j) Please graph your input and output waveforms.
•
In what way do the values of the resistors that are connected to the collector and
the emitter, respectively affect the ratio of output voltage and input voltage?
Figure 6.1: Circuit diagram for a simple amplifier.
Lab Report
Your lab report should accurately reflect the experiments conducted in this lab. It
should be in narrative form. The following should be included, referred to, and
explain in your narrative:
•
•
•
•
Diagrams of all circuits you set up,
The required plots,
An interpretation of your results and plots, i.e., describe what your results mean,
Answers to questions asked above.
Be sure to write a section that summarizes your findings, insights, observations, and
conclusions. Your report forms the basis for your grade in this lab.
Preparation:
Laboratory 8
Combinational Logic
Read lecture notes on combinational logic.
Experiments
1. Digital Logic Chips
Take each of the two chips, 74LS08 and 74LS86, that you received and connect them as
follows:
a)
• Connect the pin immediately to the right of the notch in the casing to +5 V
• Connect the pin diagonally across from the first one to ground,
• Connect the top two pins to the left of the notch to two different DIP switches on the
trainer
• Connect the third pin from the top to the left of the notch to an LED.
b)
c)
d)
For each of the four possible combinations of the two DIP switches, record if the LED is lit.
Summarize your findings in a truth table. You will need to create a truth table for each chip
Which logic function does each of these chips achieve?
2. Half Adder
a) Set up the logic circuit in the diagram below. Do not forget to connect the supply voltage p i n
VCC to the power supply (5V) and the ground pin to ground!
b) Use DIP switches for the inputs A and B, and LEDs for the outputs Sum and Carry.
c) Determine the truth table for this circuit.
d) Describe the function of this circuit, i.e., explain why it is called a half adder.
Figure 7.1: Half Adder
3. 2-Bit Full Adder
a) Set up the logic circuit in the diagram below. Each box labeled "Half Adder" contains the circuit
from the previous diagram.
b) Use DIP switches for the inputs A1, A2, B1, and B2, and LEDs for the outputs S1 S 2, and Carry.
c) Create the truth table for this circuit.
d) Describe the function of this circuit, i.e., explain why it is called a 2-bit adder.
Figure 7 . 2: 2-Bit Full Adder
Lab Report
Your lab report should accurately reflect the experiments conducted in this lab. It should be in
narrative form. The following should be included, referred to, and explained in your narrative:
•
•
•
•
Diagrams of all circuits you set up
The required plots
An interpretation of your results and plots, i.e., describe what your results mean
Answers to questions asked above.
Be sure to write a section that summarizes your findings, insights, observations, and conclusions.
Your report forms the basis for your grade in this lab.
Laboratory 9
Smart Buttons
Preparation:
Read class notes on combinational and sequential logic.
Experiments:
a)
b)
c)
d)
e)
Part 1) Smart Button
Set up the smart button circuit provided in the logic diagram given below in figure 9.1. Make sure to
connect all the S and R inputs to high (i.e. 5V) so that they have no effect on the operation of your
circuit.
Upon the first push of the button switch, LED1 lights up.
After the second push, LED1 goes off and LED2 turns on
Another push illuminates both the LEDs
The fourth push causes both LEDs to turn off.
Verify that the above functionality is achieved by demonstrating the circuit to the lab instructor
D1
S
S
D2
Q1
Q2
LED1 on
trainer
CP1
Q1
LED2 on
trainer
CP2
Q2
Push button
switch
R
R
Figure 9.1 Smart button circuit
Part 2) Jeopardy Button
a) Set up the Jeopardy Button circuit as shown in figure 9.2 below. (make sure to connect the set inputs
to high i.e. 5V)
b) Experiment and verify its operation.
c) Explain how two players can use this circuit to play jeopardy
d) How can this circuit be reset to be used again by the two players?
Lab Report
Your lab report should accurately reflect the experiments conducted in this lab. It should be in
narrative form. The following should be included, referred to, and explained in your narrative:
• Diagrams of all circuits you set up
• The procedure you used to display signals on the oscilloscope
• The required plots of signals
• Answers to questions
Be sure to write a section that summarizes your findings, insights, observations, and
conclusions. Your report forms the basis for your grade in this lab.
LED1 on
trainer
D1
Push button
switch
CP1
(
S
Q
1
Q1
Q2
R)
LED2 on
trainer
D2
Push button
switch
S
Q
1
Q2
Q2
CP2
(
R)
Push button
switch
Figure 9.2 Jeopardy Button Circuit
APPENDIX A
Data Pages
74LS02
74LS08
74LS74
SN54/74LS02
QUAD 2-INPUT NOR GATE
QUAD 2-INPUT NOR GATE
VCC
14
1
LOW POWER SCHOTTKY
13
2
12
11
3
4
10
5
9
6
8
J SUFFIX
CERAMIC
CASE 63208
7
GND
14
1
N SUFFIX
PLASTIC
CASE 646-06
14
1
D SUFFIX
SOIC
14
1
CASE 751A-02
ORDERING INFORMATION
SN54LSXXJ
SN74LSXXN
SN74LSXXD
Ceramic
Plastic
SOIC
GUARANTEED OPERATING RANGES
Min
Typ
Max
Unit
VCC
Symbol
Supply Voltage
Parameter
54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
TA
Operating Ambient Temperature Range
54
74
–55
0
25
25
125
70
°C
IOH
Output Current — High
54, 74
– 0.4
mA
IOL
Output Current — Low
54
74
4.0
8.0
mA
FAST AND LS TTL DATA
5-1
SN54/74LS02
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Min
Parameter
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
VIK
Input Clamp Diode Voltage
VOH
Output HIGH Voltage
VOL
Output LOW Voltage
Typ
2.0
54
Unit
V
Guaranteed Input HIGH Voltage for
All Inputs
V
Guaranteed Input LOW Voltage for
All Inputs
V
VCC = MIN, IIN = – 18 mA
0.7
74
0.8
– 0.65
– 1.5
Test Conditions
54
2.5
3.5
V
74
2.7
3.5
V
VCC = MIN, IOH = MAX, VIN = VIH
or VIL per Truth Table
54, 74
0.25
0.4
V
IOL = 4.0 mA
74
0.35
0.5
V
IOL = 8.0 mA
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
20
µA
VCC = MAX, VIN = 2.7 V
0.1
mA
VCC = MAX, VIN = 7.0 V
– 0.4
mA
VCC = MAX, VIN = 0.4 V
–100
mA
VCC = MAX
Power Supply Current
Total, Output HIGH
3.2
mA
VCC = MAX
Total, Output LOW
5.4
IIH
Input HIGH Current
IIL
Input LOW Current
IOS
Short Circuit Current (Note 1)
ICC
Max
–20
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS (TA = 25°C)
Limits
Symbol
Parameter
Min
Typ
Max
Unit
Test Conditions
VCC = 5.0 V
CL = 15 pF
tPLH
Turn-Off Delay, Input to Output
10
15
ns
tPHL
Turn-On Delay, Input to Output
10
15
ns
FAST AND LS TTL DATA
5-2
SN54/74LS08
QUAD 2-INPUT AND GATE
QUAD 2-INPUT AND GATE
VCC
14
1
LOW POWER SCHOTTKY
13
2
12
11
3
4
10
5
9
6
8
J SUFFIX
CERAMIC
CASE 63208
7
GND
14
1
N SUFFIX
PLASTIC
CASE 646-06
14
1
D SUFFIX
SOIC
14
1
CASE 751A-02
ORDERING INFORMATION
SN54LSXXJ
SN74LSXXN
SN74LSXXD
Ceramic
Plastic
SOIC
GUARANTEED OPERATING RANGES
Min
Typ
Max
Unit
VCC
Symbol
Supply Voltage
Parameter
54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
TA
Operating Ambient Temperature Range
54
74
–55
0
25
25
125
70
°C
IOH
Output Current — High
54, 74
– 0.4
mA
IOL
Output Current — Low
54
74
4.0
8.0
mA
FAST AND LS TTL DATA
5-1
SN54/74LS08
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Min
Parameter
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
VIK
Input Clamp Diode Voltage
VOH
Output HIGH Voltage
VOL
Output LOW Voltage
Typ
2.0
54
Unit
V
Guaranteed Input HIGH Voltage for
All Inputs
V
Guaranteed Input LOW Voltage for
All Inputs
V
VCC = MIN, IIN = – 18 mA
0.7
74
0.8
– 0.65
– 1.5
Test Conditions
54
2.5
3.5
V
74
2.7
3.5
V
VCC = MIN, IOH = MAX, VIN = VIH
or VIL per Truth Table
54, 74
0.25
0.4
V
IOL = 4.0 mA
74
0.35
0.5
V
IOL = 8.0 mA
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
20
µA
VCC = MAX, VIN = 2.7 V
0.1
mA
VCC = MAX, VIN = 7.0 V
– 0.4
mA
VCC = MAX, VIN = 0.4 V
– 100
mA
VCC = MAX
Power Supply Current
Total, Output HIGH
4.8
mA
VCC = MAX
Total, Output LOW
8.8
IIH
Input HIGH Current
IIL
Input LOW Current
IOS
Short Circuit Current (Note 1)
ICC
Max
–20
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS (TA = 25°C)
Limits
Symbol
Parameter
Min
Typ
Max
Unit
Test Conditions
VCC = 5.0 V
CL = 15 pF
tPLH
Turn-Off Delay, Input to Output
8.0
15
ns
tPHL
Turn-On Delay, Input to Output
10
20
ns
FAST AND LS TTL DATA
5-2
SN54/74LS74A
DUAL D-TYPE POSITIVE EDGETRIGGERED FLIP-FLOP
The SN54 / 74LS74A dual edge-triggered flip-flop utilizes Schottky TTL circuitry to produce high speed D-type flip-flops. Each flip-flop has individual
clear and set inputs, and also complementary Q and Q outputs.
Information at input D is transferred to the Q output on the positive-going
edge of the clock pulse. Clock triggering occurs at a voltage level of the clock
pulse and is not directly related to the transition time of the positive-going
pulse. When the clock input is at either the HIGH or the LOW level, the D input
signal has no effect.
DUAL D-TYPE POSITIVE
EDGE-TRIGGERED FLIP-FLOP
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
CASE 632-08
LOGIC DIAGRAM (Each Flip-Flop)
14
1
SET (SD)
4 (10)
Q
5 (9)
CLEAR (CD)
1 (13)
CLOCK
3 (11)
N SUFFIX
PLASTIC
CASE 646-06
14
Q
6 (8)
1
D
2 (12)
D SUFFIX
SOIC
14
CASE 751A-02
1
ORDERING INFORMATION
SN54LSXXJ
SN74LSXXN
SN74LSXXD
MODE SELECT — TRUTH TABLE
INPUTS
OPERATING MODE
SD
SD
Ceramic
Plastic
SOIC
OUTPUTS
D
Q
Q
L
H
X
H
L
Set
H
L
X
L
H
Reset (Clear)
L
L
X
H
H
*Undetermined
h
H
H
H
L
Load “1” (Set)
l
H
H
L
H
Load
“0”
(Reset)
* Both outputs will be HIGH while both SD and CD are LOW, but the output states are unpredictable
if SD and CD go HIGH simultaneously. If the levels at the set and clear are near VIL maximum then
we cannot guarantee to meet the minimum level for VOH.
H, h = HIGH Voltage Level
L, I = LOW Voltage Level
X = Don’t Care
i, h (q) = Lower case letters indicate the state of the referenced input (or output) one set-up time
prior to the HIGH to LOW clock transition.
LOGIC SYMBOL
4
10
2
D SD Q
3
CP
5
12
D SD Q
11
CP
6
CD Q
13
1
VCC = PIN 14
GND = PIN 7
FAST AND LS TTL DATA
5-1
CD Q
9
8
SN54/74LS74A
GUARANTEED OPERATING RANGES
Min
Typ
Max
Unit
VCC
Symbol
Supply Voltage
Parameter
54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
TA
Operating Ambient Temperature Range
54
74
–55
0
25
25
125
70
°C
IOH
Output Current — High
54, 74
– 0.4
mA
IOL
Output Current — Low
54
74
4.0
8.0
mA
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
VIK
Input Clamp Diode Voltage
V OH
VOL
IIH
Min
Parameter
Output HIGH Voltage
Typ
Max
2.0
54
0.7
74
0.8
– 0.65
– 1.5
Unit
V
Guaranteed Input HIGH Voltage for
All Inputs
V
Guaranteed Input LOW Voltage for
All Inputs
V
VCC = MIN, IIN = – 18 mA
54
2.5
3.5
V
74
2.7
3.5
V
VCC = MIN, IOH = MAX, VIN = VIH
or VIL per Truth Table
0.25
0.4
V
IOL = 4.0 mA
74
0.35
0.5
V
IOL = 8.0 mA
20
40
µA
VCC = MAX, VIN = 2.7 V
mA
VCC = MAX, VIN = 7.0 V
– 0.4
– 0.8
mA
VCC = MAX, VIN = 0.4 V
–100
mA
VCC = MAX
8.0
mA
VCC = MAX
Input High Current
Data, Clock
Set, Clear
Data, Clock
Set, Clear
0.1
0.2
Input LOW Current
Data, Clock
Set, Clear
IOS
Output Short Circuit Current (Note 1)
ICC
Power Supply Current
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
54, 74
Output LOW Voltage
IIL
Test Conditions
–20
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS (TA = 25°C, VCC = 5.0 V)
Limits
Symbol
Parameter
fMAX
Maximum Clock Frequency
tPLH
tPHL
Clock, Clear, Set to Output
Min
Typ
25
33
13
Max
Unit
MHz
25
Test Conditions
Figure 1
ns
Figure 1
25
40
ns
Max
Unit
VCC = 5.0 V
CL = 15 pF
AC SETUP REQUIREMENTS (TA = 25°C)
Limits
Symbol
Parameter
Min
Typ
Test Conditions
tW (H)
Clock
25
ns
Figure 1
tW (L)
Clear, Set
25
ns
Figure 2
Data Setup Time — HIGH
LOW
20
ns
ts
20
ns
th
Hold Time
5.0
ns
Figure 1
FAST AND LS TTL DATA
5-2
Figure 1
VCC = 5.0 V
SN54/74LS74A
AC WAVEFORMS
1.3 V
D*
1.3 V
th(H)
th(L)
ts(L)
ts(H)
tW(H)
tW(L)
1.3 V
1.3 V
CP
tPHL
1
fMAX
Q
tPLH
1.3 V
1.3 V
tPHL
tPLH
1.3 V
1.3 V
Q
*The shaded areas indicate when the input is permitted to change for predictable output performance.
Figure 1. Clock to Output Delays, Data
Set-Up and Hold Times, Clock Pulse Width
tW
SET
1.3 V
1.3 V
tW
CLEAR
1.3 V
1.3 V
tPLH
tPHL
1.3 V
1.3 V
Q
tPHL
tPLH
Q
1.3 V
1.3 V
Figure 2. Set and Clear to Output Delays,
Set and Clear Pulse Widths
FAST AND LS TTL DATA
5-3
SN54/74LS86
QUAD 2-INPUT
EXCLUSIVE OR GATE
QUAD 2-INPUT
EXCLUSIVE OR GATE
LOW POWER SCHOTTKY
VCC
14
13
12
11
10
9
8
J SUFFIX
CERAMIC
CASE 63208
1
2
3
4
5
6
7
14
1
GND
14
TRUTH TABLE
IN
N SUFFIX
PLASTIC
CASE 646-06
1
OUT
A
B
Z
L
L
H
H
L
H
L
H
L
H
H
L
D SUFFIX
SOIC
14
1
CASE 751A-02
ORDERING INFORMATION
SN54LSXXJ
SN74LSXXN
SN74LSXXD
Ceramic
Plastic
SOIC
GUARANTEED OPERATING RANGES
Symbol
Parameter
Min
Typ
Max
Unit
VCC
Supply Voltage
54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
TA
Operating Ambient Temperature Range
54
74
–55
0
25
25
125
70
°C
IOH
Output Current — High
54, 74
– 0.4
mA
IOL
Output Current — Low
54
74
4.0
8.0
mA
FAST AND LS TTL DATA
5-1
SN54/
74LS
86
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Min
Parameter
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
VIK
Input Clamp Diode Voltage
VOH
Output HIGH Voltage
VOL
Output LOW Voltage
IIH
Input HIGH Current
IIL
Input LOW Current
IOS
Short Circuit Current (Note 1)
ICC
Power Supply Current
Typ
Max
2.0
54
0.7
74
0.8
– 0.65
– 1.5
Unit
Test Conditions
V
Guaranteed Input HIGH Voltage for
All Inputs
V
Guaranteed Input LOW Voltage for
All Inputs
V
VCC = MIN, IIN = – 18 mA
54
2.5
3.5
V
74
2.7
3.5
V
VCC = MIN, IOH = MAX, VIN = VIH
or VIL per Truth Table
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
54, 74
0.25
0.4
V
IOL = 4.0 mA
74
0.35
0.5
V
IOL = 8.0 mA
40
µA
VCC = MAX, VIN = 2.7 V
0.2
mA
VCC = MAX, VIN = 7.0 V
– 0.8
mA
VCC = MAX, VIN = 0.4 V
–100
mA
VCC = MAX
10
mA
VCC = MAX
Typ
Max
Unit
–20
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS (TA = 25°C)
Limits
Symbol
Min
Parameter
tPLH
tPHL
Propagation Delay,
Other Input LOW
12
10
23
17
ns
tPLH
tPHL
Propagation Delay,
Other Input HIGH
20
13
30
22
ns
FAST
AND LS
TTL
DATA 52
Test Conditions
VCC = 5.0 V
CL = 15 pF