This document provides instructions for an experiment using an oscilloscope. The objectives are to learn how to use an oscilloscope and signal generator to measure voltage signals. It includes pre-lab questions about voltmeters, cathode rays and waveforms. The procedure describes how to measure peak-to-peak voltage and period of a sine wave using the oscilloscope. It also describes how to observe Lissajous figures by connecting the signal generator to both the vertical and horizontal inputs in X-Y mode. Potential problems like tilted, blurred or asynchronous traces are discussed.

1. Prepared By
Saumya Ranjan Behura
Department of MechatronicsDepartment of Mechatronics

2. ContentsContents
1.1. ObjectivesObjectives
2.2. Pre-lab QuestionsPre-lab Questions
3.3. Introduction & ApparatusIntroduction & Apparatus
4.4. Procedure & ExperimentProcedure & Experiment
5.5. ProblemsProblems

3. 1.1. ObjectivesObjectives
 Learn how to handle the features of anLearn how to handle the features of an
oscilloscopeoscilloscope
 Teach yourself the functions of a signalTeach yourself the functions of a signal
generatorgenerator
 Measure the electric quantities of sineMeasure the electric quantities of sine
voltage signalsvoltage signals
 ObserveObserve Lissajous figures (optional)Lissajous figures (optional)

4. 2.2. Pre-lab QuestionsPre-lab Questions
 What does a voltmeter do?What does a voltmeter do?
 What is a cathode ray?What is a cathode ray?
 What will happen when an electron beamWhat will happen when an electron beam
is moving in electric fields?is moving in electric fields?
 Can you classify several typicalCan you classify several typical
waveforms?waveforms?

5. 2.2. Pre-lab QuestionsPre-lab Questions
 What does a voltmeter do?What does a voltmeter do?
 Voltmeters: measure the electrical potential
difference between two points in an electric circuit.
 Do you know the other instruments which also can be
used to determine the voltage ?
Analog voltmeters A digital voltmeter

6.  What is a cathode ray?What is a cathode ray?
2.2. Pre-lab QuestionsPre-lab Questions
The deflections of the beam are visible if viewed closely with very low ambient light
level.
Cathode rays: streams of electrons observed in evacuated
glass tubes that are equipped with a cathode (negative
electrode) and an anode (positive electrode).
 Anode Rays?
HolesHoles
Anode raysAnode rays
Cathode raysCathode rays

7.  Electron beams moving in electric fields?Electron beams moving in electric fields?
2.2. Pre-lab QuestionsPre-lab Questions
d
vz
y
z
vz
vy v
y
 Can you find out the vertical displacement y ?

8.  Can you classify several typicalCan you classify several typical
waveforms?waveforms?
2.2. Pre-lab QuestionsPre-lab Questions

9.  OSCILLOSCOPEOSCILLOSCOPE – The most commonly used instrument– The most commonly used instrument
3.3. Introduction & ApparatusIntroduction & Apparatus
Cathode ray tube
Z-axis
Vert. system
Y-axis
Horiz. system
X-axis

10.  The Screen of the CRTThe Screen of the CRT
3.3. Introduction & ApparatusIntroduction & Apparatus
Vy
VOLTS
(Y-axis)
Vertical axis
Horizontal axis
(X-axis)
TIME
t
Graticule
Signal

11.  CRTCRT – The heart of the oscilloscope– The heart of the oscilloscope
Cathode ray tubeCathode ray tube
Fluorescent
screen
Electron
beam
Vert. plates
Y-deflection
Focusing
Coil
Intensity
grid
Zero
signal
Vy Vx
Cathode
Electron gun
Horiz. plates
X-deflection

12. The Time Base Generator and The TriggerThe Time Base Generator and The Trigger
TxTx
Vy
SLOPE+
TRIG.
LEVEL
Y-axis
Periodic
signal
Vx
t
X-axis
Ramp
signal

13. OscilloscopeOscilloscope
 Operating principleOperating principle

14. OscilloscopeOscilloscope
 Operating principleOperating principle
y



=
=



∝∝
∝∝∝
yDV
xDT
VEy
tVEx
yp
x
yy
xx
Vy
Vx
t
x

15.  Get acquainted with the CRTGet acquainted with the CRT
Screen
Brightness
POWER switch
TRACE ROTATION control
FOCUS control
INTENSITY control
Definition
Slope
On/Off
Graticule Trace
OscilloscopeOscilloscope

16.  Get acquainted with theGet acquainted with the Vertical systemVertical system
POSITION control
Useless for X-Y
POSITION control
For CH2(Y)
VOLTS / DIV switches
With calibrated steps
VARIABLE controls
For continuous tuning
VERT MODE select switch
AC-GND-DC Input
coupling switches
CH1(X) jack
X-Axis input for X-Y
CH2(Y) jack
OscilloscopeOscilloscope

17.  Get acquainted with theGet acquainted with the Horizontal systemHorizontal system
POSITION control
Left or right
LEVEL control
Triggering point
SEC / DIV switch
With calibrated steps
HORIZ MODE select switch
AUTO always sweeping
NORM stop triggering for
zero signal
VARIABLE control
For continuous tuning
TRIG SOURCE switch
Only use one CH
X-Y mode operation
CH1(X) → X-Axis signal
OscilloscopeOscilloscope
SLOPE switch

18. Function Generator & Unknown SourceFunction Generator & Unknown Source
 Function GeneratorFunction Generator
 Unknown SourceUnknown Source

19. 4.4. Procedure & ExperimentProcedure & Experiment
 CAUTIONCAUTION
 HANDLE THE SCOPE WITH CARE. DO NOT CARRY ITHANDLE THE SCOPE WITH CARE. DO NOT CARRY IT
AROUND. TURN THE KNOBS GENTLY.AROUND. TURN THE KNOBS GENTLY.
 DO NOT LEAVE THE INTENSITY HIGHER THANDO NOT LEAVE THE INTENSITY HIGHER THAN
NECESSARY IN CASE OF DAMAGING THE SCREEN.NECESSARY IN CASE OF DAMAGING THE SCREEN.
 Basic operations of the oscilloscopeBasic operations of the oscilloscope
 Peak-to-Peak Voltage MeasurementPeak-to-Peak Voltage Measurement
 Period MeasurementPeriod Measurement
 Lissajous Figures (Optional)Lissajous Figures (Optional)

20.  Basic operations of the oscilloscopeBasic operations of the oscilloscope
4.4. Procedure & ExperimentProcedure & Experiment
Make sure the output of the YB1601 function generator
is attached to the CH1(X) input of the YB43020B
oscilloscope.
1. Turn on the POWER to the oscilloscope.
2. Set the FOCUS and INTENSITY control halfway.
3. Set the VERT. MODE setting to CH1(X).
4. Set HORIZ. trigger MODE to AUTO, the trigger LEVEL to the
center of range, the TRIG. SOURCE to CH1(X) identical with
the VET. MODE setting so that a stationary voltage curve can
be easily displayed.
5. Set the SEC/DIV switch to 0.1 ms/DIV.
6. Set the VOLTS/DIV switch for CH1(X) to 0.5 V/DIV.

21. 4.4. Procedure & ExperimentProcedure & Experiment
7. Se the VARIABLE controls rotated fully counterclockwise
to the CAL positions, respectively.
8. Turn on the POWER to the function generator.
9. Select a sine waveform FUNCTION, set the frequency
f = 1000 Hz. Adjust the AMPL control to zero.
9. Adjust the FOCUS and INTENSITY control to produce a
not too bright but clear line.
10.Adjust the vertical POSITION control for CH1(X) of the
oscilloscope until the trace is exactly on the center line of
the vertical display.
11.Adjust the AMPL control of the signal generator, and
watch.

22.  Peak-to-Peak Voltage MeasurementPeak-to-Peak Voltage Measurement
4.4. Procedure & ExperimentProcedure & Experiment
cm6.4divisions46
cm/V1DIV/V1
==
==
=−
.Y
D
YDV
y
ypp
Snap to grid
Vertical scaleY

23.  Period MeasurementPeriod Measurement
4.4. Procedure & ExperimentProcedure & Experiment
cm4.4divisions44
cm/ms2.0DIV/ms2.0
==
==
=
.X
D
XDT
x
x
Snap to grid
Horizontal scale
X

24.  Lissajous Figures (Optional)Lissajous Figures (Optional)
4.4. Procedure & ExperimentProcedure & Experiment



+=
=
)2sin(
)2sin(
δπ
π
tfAV
tfAV
yyy
xxx
A Lissajous curve depicts the composition of simple harmonic motions in
mutually perpendicular (X-Y) directions, produced by transverse electric
forces exerting on an election moving along the Z-axis direction, which
can be described by parametric equations:
It can be done on an oscilloscope in X-Y mode.
Vy
CH2(Y)
CH1(X)
Vx
Whenever a stationary pattern is achieved, the frequency ratio fx / fy of the
horizontal input to the vertical input is equal to the ratio Ny / Nx of the
number of vertical to horizontal points of tangency to a rectangle that
encloses the pattern, i.e., fx / fy is rational .
x
y
y
x
N
N
f
f
=

25.  Unknown frequency MeasurementUnknown frequency Measurement
4.4. Procedure & ExperimentProcedure & Experiment
1. Connect the unknown sine voltage source to the CH2(Y) input
of the scope.
2. Turn on the POWER to the unknown source.
3. Set the horizontal sweep SEC/DIV switch at the position X-Y .
4. Use the COARSE and FINE control to adjust the frequency of
the function generator patiently in order that the stationary
patterns with ratio Ny / Nx = 1, 2, 2/3 are displayed on the
screen, respectively.
5. Record the frequency reading fx from the function generator,
draw the sketch map, and calculate the unknown frequency,
respectively.

26.  Tilted & Blurred TracesTilted & Blurred Traces
5.5. ProblemsProblems
Have a check

27.  Synchronous & Asynchronous TracesSynchronous & Asynchronous Traces
5.5. ProblemsProblems
Have a check

28.  An interesting problem:An interesting problem:
The oscilloscope is in good condition, butThe oscilloscope is in good condition, but
no trace appears on the screen, why?no trace appears on the screen, why?
((There are more thanThere are more than 22 answersanswers !!))
5.5. ProblemsProblems