ECE 480: SENIOR DESIGN LABORATORY
DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING
MICHIGAN STATE UNIVERSITY
I.
TITLE: Lab I - Introduction to the Oscilloscope, Function Generator,
Digital Multimeter and Power Supply
II.
PURPOSE: The oscilloscope, function generator and digital multimeter
are the basic tools in the measurement and testing of circuits. This lab
introduces the first time operation of these instruments along with the
use of a compensated probe.
The concepts covered are:
1.
equivalent circuits of the oscilloscope inputs, function generator
output and digital multimeter inputs;
2.
the use of a balanced bridge to compensate for the stray
capacitance of a measuring cable and the equivalent impedance
of the oscilloscope;
3.
accuracy of components and instruments.
The laboratory techniques covered are:
1.
voltage amplitude and time measurement with an oscilloscope;
2.
a procedure for compensating an oscilloscope probe;
3.
procedures for setting up multiple DC supplies.
III.
BACKGROUND MATERIAL:
A)
The Oscilloscope
The oscilloscope used in this course is a two channel digital
storage oscilloscope that allows the observation of low frequency
repetitive signals and transients over a wide range of frequencies. In this
lab and the following labs we will be covering most of the available
features.
The oscilloscope, or scope for short, is divided into five blocks: the
Display Block, the Vertical Amplifier Block, the Sweep Block, the Trigger
Block and the Storage Block. The Display Block consists of the cathoderay tube (CRT) and associated controls. The CRT is a device which
provides a visual display of a voltage. This voltage is applied to the scope
at the Vertical Amplifier Block. The scope creates a CRT display by
capturing and overlaying successive windows of time. These windows
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
1
begin at the same trigger point on the voltage being examined and end
at a specific increment of time. The trigger point is controlled by the
Trigger Block and the time increment is controlled by the Sweep Block.
The Storage Block allows us to save the wave form for future reference
or hard-copy.
In measuring any circuit we will need to connect the measuring
instrument to our circuit. This changes the original circuit by connecting
the equivalent circuit of the instrument into the circuit. We will always
need to know what the equivalent circuit of the instrument is, so that we
can either neglect loading effects or include loading effects in the
calculations of the circuit's response. The equivalent circuit for the A and
B input terminals are shown in Figs. 1-3 for the three settings of the
AC/DC and GND buttons. This is the load seen by our circuits.
In the DC position the measured signal is Directly Coupled to the
vertical amplifier and we see displayed the actual wave form. In the AC
position, a blocking capacitor is inserted in series with the measured
signal. This blocks any dc signal in steady-state and we see displayed
only the time varying component of our measured signal. This is useful
for measuring transistor amplifier circuits where the time varying signal
is very small compared to the dc level. In these cases displaying the
actual wave form makes it difficult to see the characteristics of the time
varying signal. In the GND position the load seen by our circuit is an
open circuit but the vertical amplifier, internal to the scope, sees a short
and displays 0 volts. This feature is useful for setting a reference line.
Figure 1. DC position
Figure 2. AC position
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2
Figure 3. GND position
B)
The Function Generator
The function generator is a precision source of sine, triangle,
positive and negative ramp, haversine, square, positive pulse and
negative pulse wave forms plus dc voltage. The frequency of the wave
forms is manually and remotely variable from 100:Hz to 50MHz.
The equivalent circuit for the OUTPUT terminal is shown in Fig.
4.
C)
Probes
Figure 4. Generator
In some instances we may wish to measure a voltage which
exceeds the input rating of the oscilloscope (approximately 400 volts). To
do this we can attenuate the signal with a simple resistive voltage
divider, measure the voltage and solve for the actual voltage. However,
stray capacitance may distort our measurement. It will be shown that it
is possible to compensate for stray capacitance and measure the true
attenuated voltage.
The resistive voltage divider of Fig. 5 would simply multiply the
input signal by a factor of y = R2/(R1+R2) independent of frequency if it
were not for the stray capacitance C2 which shunts R2. The capacitance
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
3
C2 represents the parallel combination of the input capacitance of the
oscilloscope and the stray capacitance of the probe's cable.
Figure 5. Divider with stray cap.
Using Thevenin's theorem, the circuit of Fig. 5 is replaced by its
equivalent in Fig. 6 where RTH = R15R2. For a step input of VP volts for
VTH we have that,
VO = VP [1 - e
-t/RTHC2
]
(1)
Solving for t, we find that
t = RTH C2 ln [VP /(VP - VO)]
(2)
The rise time of a signal (tr) is the time required for the signal to go from
10% (at time t1) to 90% (at time t2) of its final value, that is, tr = t2 - t1.
Therefore,
t2 = RTH C2 ln [VP /(VP - 0.9VP)]
(3)
t1 = RTH C2 ln [VP /(VP - 0.1VP)]
(4)
Solving for the rise time, we find that
tr = 2.197 RTH C2
(5)
Figure 6. Thevenin equivalent circuit
If R1 = 9MS, R2 = 1MS and C2 = 30pF then the rise time for a step
input is 59:seconds. If the input is a square wave then half the period
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4
should be much greater than 59:sec, say 590:sec, so as not to be
noticeable on the scope. Then the frequency of the input voltage would
be less than 1/1180: = 847Hz. This is a severe limitation.
Figure 7. Compensated attenuator
It is possible to compensate this attenuator such that the
attenuation is independent of frequency by adding a capacitor in parallel
with R1 as shown in Fig. 7. To explain the operation of this circuit,
consider the capacitive voltage divider of Fig. 8. If a voltage VS is applied,
I1 flows through C1 and C2 such that
then
and
q1 = * I1 dt
(6)
VS = (q1/C1) + (q1/C2)
(7)
= q1 (C1+C2)/C1C2
(8)
Va = q1/C2 = VS C1/(C1+C2).
(9)
Likewise, consider the resistive voltage divider of Fig. 8 where
Vb = VS R2 /(R1+R2)
(10)
Figure 8. Cap. and res. attenuator
If Va and Vb are the same voltage then the difference between these two
node voltages is zero. Any element can be connected between these two
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5
points without affecting the voltage because no current will flow. This is
the concept of a balanced bridge. In Fig. 7, the element between points
a and b is a short circuit. Setting Eqns. 9 and 10 equal, we find the
condition needed for compensation is
R1 C1 = R2 C2.
(11)
If R1 = 9MS, R2 = 1MS and C2 = 30pF then C1 = 3.33pF and VO =
VS /10.
What happens if Eqn. 11 is not satisfied? For a step input, the
voltage across the capacitors must change rapidly. This will require a
very large current of short duration. So we can neglect the currents in R1
and R2 at t = 0+ and VO is basically determined by the capacitive voltage
divider. In steady-state the capacitors are open circuits and VO is
determined by the resistive voltage divider. If
x = C1 /(C1+C2) > R2 /(R1+R2) = y
(12)
then there will be an overshoot on the response at 0+. Solving Eqn. 12 we
find that R1 C1 > R2 C2. This is called over-compensation and is illustrated
in Fig. 9. Likewise for R1 C1 < R2 C2 we find an undershoot on VO at t = 0+
and this is called under-compensation. This is shown in Fig. 10.
Figure 9. Over-compensated
Figure 10. Under-compensated
The probe used in lab is shown in Fig. 11. R1 = 9MS, C1 = 14pF,
and C3 is effectively the parallel combination of the capacitance of the
coax cable (.10pF/foot of cable) and a variable capacitor. The probe also
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
6
has a switch for connecting a resistance of 470S to ground. This makes
a voltage divider that is very small and effectively applies zero volts to
the scope input. This allows the user to display the zero volt reference
while holding the probe.
Although we started out with trying to measure large voltages by
using a voltage divider, it is desirable to use this compensated divider in
any application where the loading effects of the cable and the oscilloscope
are significant. The only limit would be the smallest voltage scale of the
oscilloscope. For the PM3365 this is 2mV/div. For at least a 1 division
display with an attenuation of 10, the measured voltage would need to
be greater than 10 x 2mV = 20mV.
It is important to note that the PM3365 senses whether the X10
probe is connected and correctly displays the proper volts per division.
Most other scopes do not do this and the user must make this correction.
Figure 11. Probe schematic
BECAUSE THERE IS A 9MS RESISTOR INSIDE THE SCOPE PROBE
YOU SHOULD NEVER USE THE SCOPE PROBE ON THE FUNCTION
GENERATOR. THIS WILL FORM A VERY LARGE VOLTAGE
DIVIDER.
D)
Accuracy
The scope has a horizontal and vertical accuracy of ±3 % for both the
analog and digital readings. The digital multimeter’s accuracy is
different on each scale. But if the maximum number of digits are
displayed, it is better than ±0.02%.
IV.
EQUIPMENT REQUIRED:
1
1
1
1
1
Philips PM3365 Digital Storage Oscilloscope
Philips PM5193 Programmable Synthesizer/Function Generator
HP 34401 A or Fluke 8840A Digital Multimeter
HP E3630 A Triple Output Power Supply
Philips PM8926/59 10:1 Passive Probes
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7
V.
PARTS REQUIRED:
1
1
1
BNC-BNC cable
BNC-to-Banana cable
Small screwdriver
VI.
LABORATORY PROCEDURE:
A)
First Time Operation of the PM3365 Oscilloscope
1.
Before actually turning on the oscilloscope, there are a few controls you
can preset to facilitate the startup procedure. On the right side there are
two columns of 4 round knobs. The outermost column are labeled Y POS,
Y POS, X POS and TRIG LEVEL. These knobs should be pointing
straight up. The other column of knobs are labeled VAR, VAR, VAR and
HOLD OFF. These knobs should be turned fully clockwise and pointing
to CAL, CAL, CAL and MIN, respectively.
2.
Press in the POWER switch found in the upper left corner. If the trace
that appears is extremely bright, turn the INTENS control counterclockwise.
CAUTION: If the cathode ray tube (CRT) is left with an extremely bright
dot or trace for a very long time, the fluorescent screen may be permanently
damaged. If a measurement requires high brightness, be certain to turn
down the INTEN control immediately afterward.
3.
Turn the INTENS control to adjust the brightness to the desired level.
4.
Turn the FOCUS control for a sharp trace.
B)
The PM5193 Programmable Synthesizer/Function Generator
1.
The laboratory function generator is a precision source of sine, triangle,
positive and negative ramp, haversine, square, positive pulse and
negative pulse wave forms plus dc voltage.
2.
Press the POWER switch found in the lower left corner to the on
position. Sometimes an ERR3 display comes up during power up. This
indicates a low back up battery. We won’t be saving our settings so this
isn’t critical to our work. Just press any button and it should clear itself.
C)
Wave form Measurement
1.
Coaxial cable is the most common method of connecting an oscilloscope
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
8
to signal sources and equipment having output connectors. The outer
conductor of the cable shields the central signal conductor from hum and
noise pickup. These cables are usually fitted with a BNC on each end.
Connect a BNC-to-BNC cable from the OUTPUT of the function
generator found on the lower right side to the A input terminal of the
scope found in the lower center. Our first task will be to generate a
voltage equal to 4 + 5 sin (2B 1000 t).
2.
Press the button with the sinewave. This is the upper left button in the
set of nine buttons under WAVE FORM. A red light should be on. This
indicates that we have selected this particular wave form.
3.
We next need to set the frequency of the wave form. This is done with the
START button. This is the upper left button in the set of six buttons
under FREQUENCY. Again a red light will indicate your selection. The
value is entered with the number key pad on the right side. Press 1 0 0
0. This value will appear on the left most display. Press ENTER which
is found on the lower right side. The frequency is now selected to be 1000
Hz.
4.
The parameters of our wave form are set with the LEVEL buttons. Push
the button labeled Vpp. This is the peak-to-peak value of the wave form
selected. Enter a value of 10. (This is done by selecting the number with
the key pad followed by enter.) You now have generated a voltage with
the expression 5 sin (2B 1000 t).
5.
To add a dc offset onto our wave form, we need to select LEVEL button
Vdc. Enter a value of 4. We now have a voltage of 4 + 5 sin (2B 1000 t).
6.
If you make a mistake or want to change any of the above settings, just
repeat the specific step.
7.
A wave form should appear on your scope screen. If not ask your lab
instructor for help.
8.
The wave form on the screen may appear small or crowded. This is
because of the setting selected by the scope during power-up. We will
learn shortly how to change this. However we can quickly re-set the
scope so that it will try to make our wave form easier to view by pressing
the green AUTO SET button on the scope. Do this.
9.
The scope has two different modes of operation. These are called analog
and digital. In the analog mode the wave form is very smooth and
continuous. In the digital mode the wave form is being sampled and
displayed and may appear jagged on the screen.
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
9
Many digitizing scopes have phantom results displayed due to the
capture process. Although digitizing scopes are pretty good, there is no
substitute for seeing the actual waveform to truly verify the
measurement wave shape is correct. However, digitizing scopes are great
for wave form calculations and storage. The Philips PM3365 is one of the
rare (and very expensive) scopes that allows you to see both with the
same instrument.
Many employers expect engineers to be able to use analog scopes for
advanced measurement. This is why we are using an analog /digital
scope in ECE 480.
Press the white DIGITAL MEMORY button on the scope. You will see
these two modes. Place the display back in the analog mode.
10.
The top number found in the menu window is the value for each of the
vertical divisions. These are the large squares of the screen grid.
Counting the number of these divisions from the highest to lowest point
of your sine wave and multiplying this times the setting displayed in the
menu window is the peak-to-peak value of your sine wave. This may be
difficult depending on where your wave form is on the screen.
11.
We can set and/or place the zero volt reference of the input. This is done
by first pressing the GND button. There are two such buttons. The top
one is for the A input and the second one two rows down is for the B
input. Press the A input GND. This is zero voltage reference for this
channel. Rotate the Y POS for this channel and place this line in the
center of the screen. Now press the A input GND button again.
Calculate the measured peak-to-peak value of your sine wave using the
setting of the scope, that is, the voltage per division times the number of
divisions. Record this, and all data that follows, as indicated in the Lab
Report. If your calculated peak-to-peak voltage is not what was set in
part 4, ask your instructor for help.
12.
Press the A input AC/DC button. Now you should be in the DC mode.
Your wave form still has a zero reference at the center line of the screen.
Calculate the dc level of your wave form. If this is not what was set in
part 5, ask your instructor for help.
What is the purpose of the AC/DC button? (Answer this and all
questions in a complete sentence in the Lab Report.)
13.
The other number in the menu window is value of the horizontal
divisions. Count the number of divisions per cycle and calculate the
period of your sine wave. The frequency of your sine wave is the
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
10
reciprocal of the period. Calculate the frequency. If this is not the same
as set in part 3, ask your instructor for help.
14.
What function does the AC OFF perform on the function generator?
What advantage do you see in this feature?
Restore the wave form to that in part 13.
15.
The PM 3365 can also perform wave form measurement. Place the scope
in the digital mode. Press the right most white button on the screen bezel
so that the words: CURSORS SETTINGS SHIFT and TEXT-OFF
appear.
Press the CURSORS button, then the CONTROL button. CURSOR
CONTROL should appear. The measurement cursors are the small
cursors. They float as necessary but are bounded on the left and right by
the large cursors. By moving the large cursors you can force an automatic
measurement on a wave form. To have the greatest degree of freedom we
need to move the cursors to the extreme right and left position. Play with
this feature and leave the large cursors at the extreme right and left
position. Press RETURN twice.
Press the CURSORS button. A new menu appears on the bottom of the
screen. Press the CALC button. A new menu appears. We can select the
measurement of amplitude or time. Select TIME. Again a new menu
appears. Select FREQ. The frequency of your sine wave should now
appear in the upper portion of the screen. Record the value displayed in
the Lab Report. If the measurement is constantly changing, this may be
due to noise in the lab. There is a LOCK located in the center column of
buttons and one row from the bottom. If you press it don’t forget to press
it again to take new measurements.
Now press RETURN and this time select AMPL. Record the peak-topeak in the Lab Report. Also measure the MEAN (average) and RMS
values.
16.
At the time of manufacturing, the scope supported two printers. These
are no longer available. We will use a digital camera in the future to
record wave forms.
17.
Do not turn off or change the settings of the function generator.
D)
Digital Multimeter
1.
If your lab bench has Fluke 8840A Digital Multimeter proceed to Section
E).
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11
If your lab bench has an HP 34401A Digital Multimeter proceed with the
following steps.
Turn On the multimeter by pressing the button on the lower left corner.
The display should show mVDC. If not, press the DC V button.
Disconnect the function generator from the scope without changing the
setting on the function generator. Obtain a BNC-to-Banana cable and
connect the function generator to the HP 34401A Digital Multimeter
with the red banana connector inserted into the right most HI input and
the black (ground) banana connector into the right most LO input.
2.
If the DC value is way off from the expected value, toggle the AC OFF
button on the function generator. Sometimes powering up the multimeter
charges up the blocking capacitor and this will help clear it. Turning the
multimeter on and off should have the same effect. This is common in
digitizing equipment and that is why having a true reading with the
analog scope can help resolve these phantom results.
Record the value of the DC voltage displayed on the multimeter in the
Lab Report.
This may be off by several hundred millivolts from what was set on the
function generator. This is due to the fact that the DC offset tolerance is
several hundred millivolts. If this is critical to an application we an null
this by adjusting the dc level on the function generator.
3.
Press the AC V button. Record the RMS value of the mutimeter in the
Lab Report.
The values measured in steps 2 and 3 are much more accurate than
readings we can get off of the scope and this is why we have the meter.
4.
Calculate the RMS value by dividing the value set peak-to-peak on the
function generator by 2 times the square root of 2 which equals 2.828.
How does this compare to the measured value in part 3?
5.
Proceed to Section F).
E)
Fluke 8840A Multimeter
1.
If your lab bench has a Fluke 8840A Digital Multimeter proceed with the
following steps.
Turn On the multimeter by pressing the button on the lower right
corner. The display should show mVDC. If not, press the V DC button.
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
12
Disconnect the function generator from the scope without changing the
setting on the function generator. Obtain a BNC-to-Banana cable and
connect the function generator to the Fluke Digital Multimeter with the
red banana connector inserted into the left most HI input and the black
(ground) banana connector into the left most LO input.
2.
Record the value of the DC voltage displayed on the multimeter in the
Lab Report.
This may be off by several hundred millivolts from what was set on the
function generator. This is due to the fact that the DC offset tolerance is
several hundred millivolts. If this is critical to an application we an null
this by adjusting the dc level on the function generator.
3.
Press the V AC button. Record the RMS value of the multimeter in the
Lab Report.
The values measured in steps 2 and 3 are much more accurate than
readings we can get off of the scope and this is why we have the meter.
4.
Calculate the RMS value by dividing the value set peak-to-peak on the
function generator by 2 times the square root of 2 which equals 2.828.
How does this compare to the measured value in part 3?
Proceed to Section F).
F)
Probe Compensation and Use
1.
Locate a scope probe. Hold the base such that the set screw of the
adjustment capacitance trimmer is face up. Connect the probe to the A
input connector such that the set screw is still face up. Pull back on the
probe flange to expose the hook on the tip of the probe and attach to the
CAL 1.2V connector.
2.
Press the AUTO SET button. Measuring the peak-to-peak value of this
wave form would be easier if we could enlarge the picture on the screen.
The setting of the vertical voltages per division can be changed by the
user with the rocker switch marked A. Push on one end and then the
other and watch what happens on the screen. Set the value to 0.2 Volts
(per division).
Now measure the peak-to-peak value of this by counting divisions on the
screen and record this value. How does this compare with the value
stamped on the scope?
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
13
3.
CAUTION: Excessive turning of the adjustment trimmer screw will
permanently damage the probe. The replacement cost of one probe is
approximately $100.
With a small screwdriver, adjust the set screw of the capacitance
correction trimmer of the probe no more than a 1/8 turn in either
direction to display an under-compensated wave form (rounded edges).
Make a rough sketch of this wave form in the Lab Report indicating
maximums, minimums and levels.
4.
Adjust the probe to display an over-compensated wave form (edges with
peaks). Make a rough sketch of this wave form in the Lab Report
indicating maximums, minimums and levels.
5.
Adjust the probe so that the wave form is a correctly compensated square
wave.
6.
Determine the DC (average) value and period by counting divisions.
Record and determine the frequency of this calibration signal.
7.
Measure the average (mean) value and frequency using the digital mode
of the scope.
8.
Because there is a 9MS resistor inside the scope probe you should never
use the scope probe on the function generator. This will form a very large
voltage divider.
9.
Disconnect the probe from the scope.
G)
HP-E3630A Triple Output Lab Bench DC Power Supply
1.
Got to a lab bench with an HP-E3630A power supply.
In using integrated circuits, it is often necessary to supply positive and
negative voltages to operate the chip. Suppose we need to supply +15
VDC and !15 VDC. We will use the Lab Bench Power Supply to do this.
This power supply has 3 adjustable DC voltages as indicated in Fig. 12.
With no external connections to the HP-E3630A Triple Output Lab
Bench DC Power Supply, turn it On by pressing the button in the lower
left corner and press the +20V button in the set labeled METER. The
display should be lit and indicate the voltage and current of the 0 to +20
V supply. Check that the Tracking Ratio knob in the upper right
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
14
corner is pointing to Fixed. Adjust the ±20 V knob in the upper right
side such that the displayed voltage is about 15. The current should be
reading 0.00 since we have nothing connected to the +20V terminals.
Figure 12. Lab Bench Power Supply equivalent circuit
2.
The power supply has a built in current limiter to protect its internal
electronics and our circuits from damage. This is the maximum current
we can get from this voltage source. For this power supply it is NOT
adjustable. So great care must be taken when building circuits. Check you
wiring before you turn on the power supply.
Obtain a red banana wire from the racks on the wall. Connect the wire
from the +20V terminal to the COM terminal. The voltage displayed is
the voltage at the terminals which should be around zero. The current
coming out of our power supply and through our wire is displayed under
AMPS. When we try to exceed the maximum allowed current an
OVERLOAD light comes on for that supply. (If this happens when we
build and test any circuit, something is seriously wrong.)
Record the value of AMPS displayed in the Lab Report.
3.
REMOVE THE RED BANANA WIRE from the terminal of the power
supply.
Press the -20V button in the set labeled METER. The display indicates
the voltage and current of the -20 V to 0 supply. The meter should read
about -15 because we have the Tracking Ratio invoked. By this we mean
that the ratio of these two voltages is one in magnitude.
To illustrate this, adjust the ±20 V knob in the upper right side such that
the displayed voltage is about -12. Press the +20V button in the set
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
15
labeled METER. The displayed voltage is now about 12.
Measure the short circuit current and record in the Lab Report. Remove
the short circuit from the -20V supply.
4.
Set the +6 V supply to 5 V. Measure the short circuit current for the + 6
volt supply and record in the Lab Report. Remove the short circuit.
5.
Adjust the ±20 V knob in the upper right side such that the displayed
voltage is again about 15. We now have a +5 V, +15 V and !15 V battery
available. Record in the Lab Report the actual values displayed for the
+5 V, +15 V and !15 V settings.
6.
Using the digital voltmeter, measure the +5 V, +15 V and !15 V
terminals. Record in the Lab Report. Again note that the digital volt
meter is more accurate than the settings on the supply.
It is good practice to build your circuit without power applied. If the
value of the supply voltage is critical you may want to use the lab digital
voltmeter.
H)
Clean up
Please return all wires to the racks from which they were taken. Turn off
all equipment. Assemble your lab report, staple it and hand it in to your
instructor. Please read and sign the Code of Ethics Declaration on the
cover.
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
16
Lab Report
Lab I - Introduction to the Oscilloscope, Function Generator,
Digital Multimeter and Power Supply
Name: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Partner: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Date: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lab Section Number
..............................................
Lab Station Number
..............................................
Code of Ethics Declaration
All of the attached work was performed by our lab group as listed above. We did
not obtain any information or data from any other group in this lab.
Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
17
VI-C11
Voltage per division =
Number of divisions =
Measured Voltage Peak-to-Peak =
VI-C-12
Number of divisions =
Measured DC (average) Voltage =
..........................................................
..........................................................
..........................................................
..........................................................
VI-C-13
Seconds per division =
Number of divisions =
Measured Period =
Measured Frequency =
VI-C-14
..........................................................
..........................................................
..........................................................
..........................................................
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
18
VI-C-15
FREQ =
VPP =
VMEAN =
VRMS =
VI-D/E-2
VDC = VMEAN =
VI-D/E-3
VRMS =
VI-D/E-4
VRMS (calculated) =
..........................................................
..........................................................
VI-F-2
Voltage per division =
Number of divisions =
Measured Voltage Peak-to-Peak =
Value stamped on Scope =
..........................................................
..........................................................
..........................................................
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
19
VI-F-3
Sketch of undercompensated probe below
VI-F-4
Sketch of overcompensated probe below
VI-F-6
Voltage per division =
Number of divisions =
Measured dc Voltage =
Seconds per division =
Number of divisions for one period =
Measured Period =
Calculated Frequency = _________
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
20
VI-F-7
Measured Mean (DC) Voltage =
Measured Frequency =
VI-G-2
Maximum current of the + 20 V supply =
AMPS
Maximum current of the - 20 V supply =
AMPS
Maximum current of the + 6 V supply =
AMPS
VI-G-3
VI-G-4
VI-G-5
Voltage displayed on the + 6 V supply =
Voltage displayed on the + 20 V supply =
Voltage displayed on the - 20 V supply =
VI-G-6
Measured Voltage of the + 6 V supply =
Measured Voltage of the + 20 V supply =
Measured Voltage of the - 20 V supply =
Copyright © 2007 by Gregory M. Wierzba. All rights reserved.
21