Lab equipments with figures and functions

1. 1
Lab Equipment

2. 2
Topic Slides
DC Power Supply 3-4
Digital Multimeter 5-8
Function Generator 9-12
Scope – basic controls 13-20
Scope – cursors 21-24
Scope – triggering 25-32
Scope – exploring the waveform 33-34
Scope – trace rotation and probe compensation 35-40
Scope – rise/fall time measurements 41-47
Scope – computer communication problems 48
Contents

3. 3
DC Power Supply
All three supplies share a common
terminal, which is NOT connected to
the power supply “ground”. This
terminal should normally be
connected to your circuit “ground”.
The negative 0 to 20 volt supply is proportional (by
an adjustable ratio of up to -1) to the positive supply
Vneg = (0 to –1) times Vpos
Don’t use;
connects to
chassis and
power line
gnd
DC = 0 to Vpos
DC = 0 to 6 DC = 0 to 20
+
+
+
Vpos

4. 4
DC Power Supply
DC = 0 to Vpos
DC = 0 to 6 DC = 0 to 20
+
+
+
C
B
A D
Since the COM terminal is isolated from the
power supply ground, you are not limited to using
point B for your circuit ground. If you use point
A, C, or D as your circuit ground you can use
series combinations of the three internal voltage
sources to obtain voltages higher than +20V and
lower than –20V.
Vpos

5. 5
Digital Multimeter (DMM)
Power switch
DC voltage
AC voltage
DC current
AC current
Resistance
AC = RMS value of AC part of waveform only
DC = value of DC part of waveform only
To measure TRUE RMS value of the complete waveform, press both DC and AC
Range is set
automatically

6. 6
Diode test (passes small current through diode
and measures the resulting voltage drop)
Connect the RED lead to the diode anode
and the black lead to the cathode.

7. 7
Use the RATE switch to set the speed of measurement and
the resolution of the displayed values:
F = fast speed = low resolution
M = medium speed = medium resolution
S = slow speed = high resolution

8. 8
10 AMP current input has low internal resistance
and introduces the lowest error; use this input
whenever possible
100 milliamp current input has considerable
internal resistance and may introduce
considerable error; use the 10 A input whenever
possible.
For current measurements, move the RED lead to a current input

9. 9
Function Generator
output
Select waveform
Set frequency, amplitude, and DC offset

10. 10
To enter values, press “Enter Number”, then the number keys, then “Enter”
Observe
decimal
point;
ignore the
commas

11. 11
When entering values, use
these keys to define the
units. Notice that voltage
values can be defined as
either RMS or peak-to-peak.

12. 12
If the amplitude of the waveform measured by the scope or digital
multimeter does not agree with the amplitude shown on the function
generator display, reset the output termination to “HIGH Z”
“SYS Menu”
>
“OUT TERM”
Enter
Shift >
“50 OHM ” “HIGH Z ”
> >
>
>
Enter

13. 13
Oscilloscope
Always adjust the scope to obtain as large of a
waveform as possible (to maximize accuracy)
Adjust the FOCUS and INTENSITY to obtain a clear, readable display.
When not actively observing waveforms, turn down the intensity to extend
the life of the scope screen
Function buttons

14. 14
The AUTO SET button helps the
scope find the waveform, but it
also sets the waveform signal
coupling to AC (undesirable)
After using the AUTO SET
button, reset the waveform signal
coupling to DC using the AC/DC
buttons
General Rule:
ALWAYS use
DC coupling on
the vertical
channels so that
you can observe
the complete
(AC & DC)
waveform

15. 15
The VAR controls must be in the CAL position
for the display values to be valid

16. 16
Use the X POS control to start the scope trace at the left edge of the grid

17. 17
Set the zero volt positions for ch A and ch B to
known positions on the grid, usually the center
horizontal line, by first selecting GND and then adjusting the Y POS controls

18. 18
Zero voltage
reference line set to
known point
(usually center line,
but may anywhere
you desire)
Once positioned, be
careful not to
change it.
Trace starts at first vertical
grid line
Example of Setting Zero Volt Reference

19. 19
vertical
and
horizontal
values per
division (cm)
are shown on
the display
Use these to set the
vertical (voltage) values
per division
Use this control to set the horizontal
(time) value per division

20. 20
DIGITAL MEMORY mode must be selected to be able
to use cursors and transfer waveforms to the computer

21. 21
Use function buttons to control cursors
Scope Cursors

22. 22
Cursor Positioning Buttons
Controls
lower
cursor
Controls
upper
cursor
Controls
left
cursor
Controls
right
cursor
RETURN key takes you back to the previous higher level

23. 23
Setting the Cursor Mode and Reference Channel
Use to turn cursors on/off and to select what they
display (vertical measurement = voltage or ratio;
horizontal measurement = time, phase angle, or ratio)
Voltage cursor will use either channel A or B
“voltage per division” setting, as selected.
RETURN key takes you back to
the previous higher level
cursor reference channel
Reference channel selection
available only when both channels
A and B are displayed

24. 24
Value of differences
between horizontal
(voltage) cursors
Value of difference
between vertical
(time) cursors
Frequency
computed from
inverse of time
interval (valid only
if interval is one
cycle)

25. 25
Scope Triggering
The waveform on the scope display is drawn from left to right
(repetitively), beginning at a point when one of the signals being
displayed meets a specified criteria. This criteria is defined by the
settings of the horizontal (time base) trigger controls:
Mode - the standard mode is AUTO
Source - which signal is being used to trigger the scope
Coupling - normally P-P (AC), but sometimes DC gives more control
Slope - the scope trace begins on the upward or downward slope of the wave
Level - the voltage level of the wave at which the trace begins

26. 26
Sets the trigger mode (normally set to AUTO)
Displays the trigger mode
Displays trigger slope Sets the trigger slope
Displays trigger source and coupling
Sets trigger
coupling
Sets trigger source
Adjusts the
trigger level
Horizontal
(time base)
trigger
controls

27. 27
To capture a non-repetitive waveform, set the desired
trigger conditions, select the SINGLE TRACE trigger
mode, then press RESET to “arm” the scope.
After the scope has
been “armed”, a
single trace will be
drawn when the
signal level
matches the trigger
conditions (slope
and level) you
have selected. The
trace will remain
displayed until you
press RESET or
transfer the
waveform to the
computer.
Single Trace
Operation

28. 28
Trigger level set to
zero volts and a
positive (upward)
slope
Example Waveform

29. 29
Trigger level set to
+1 volt, with a
positive slope
Zero volt reference line
Example Waveform

30. 30
Trigger level set to
–1 volts, with a
positive slope
Zero volt reference line
Example Waveform

31. 31
Trigger level set to
zero volts, with a
negative (downward)
slope
Example Waveform

32. 32
The trigger delay can be used to shift where the trigger point appears on the
screen; this allows you to observe the waveform up to 10 divisions prior to
the trigger point on repetitive waveforms.
Delayed
Trigger

33. 33
Use the X-magnification button to zoom in on part of the
waveform; the magnification factor is changed each time
you press the button.
Waveform
Zoom

34. 34
Use the Display Part rocker switch to move the display window across the
waveform image stored in the scope. (The scope stores two screen widths
of data at X1 magnification)
Move the
display
window

35. 35
Adjust to make
trace parallel
with horizontal
grid
Trace Rotation

36. 36
Scope Probe Compensation Adjustment
Connect probe
to calibration
signal
Make sure channel A and B signal coupling are set to DC

37. 37
Scope Probe Compensation Adjustment
Each probe has an
adjustment screw
that changes the
compensating
capacitor

38. 38
Scope Probe Compensation Adjustment
Adjustment capacitor value needs to be increased
until waveform is rectangular

39. 39
Scope Probe Compensation Adjustment
Adjustment capacitor value needs to be decreased
until waveform is rectangular

40. 40
Scope Probe Compensation Adjustment
Rectangular waveform with correct probe adjustment

41. 41
0%
10%
90%
100%
For rise or fall time measurements, use the 0%,
10%, 90%, and 100% lines on the scope grid
Making Rise and Fall Time Measurements on
Pulse Waveforms

42. 42
Using the vertical scale control to
set your waveform amplitude so
that it is greater than the range of
0% to 100%
Then use the var
and the Ypos
controls to line up
your waveform with
the 0% and 100%
grid lines.

43. 43
100%
90%
10%
0%
The adjusted waveform display

44. 44
Expand the waveform
horizontally using the
time base (TB) control
Set the trigger slope to
positive (upward) for rise
time measurements
Set trigger
coupling to
DC
Adjust trigger
level to the 10%
point or below
For rise time measurements

45. 45
Adjust the vertical cursors so that they pass the 10% and 90%
points on the waveform, and read off the rise time.
10%
90%

46. 46
Expand the waveform
horizontally using the
time base (TB) control
Set the trigger slope to
negative (downward) for
rise time measurements
Set trigger
coupling to
DC
Adjust trigger
level to the 90%
point or above
For fall time measurements

47. 47
Adjust the vertical cursors so that they pass the 10% and 90%
points on the waveform, and read off the fall time.
10%
90%

48. 48
Use OPTION function button to check or
correct communications settings
If scope fails to communicate with the computer:
OPTION
IEEE
IEEE-ADDR: 8 MODE: talker/listener
If you have to correct the communications settings, cycle
the scope power to reset the communications interface.