Tektronix 2A60 Instrument Reference Book page 26

Type 2A60 Amplifier
·•
·.
~-
.
.
r
....
I"""!-,-, ~-
,,_
.
:-
-
I
-
r,--
.......
.-
---
,._
-
,__
.-·
I
-
..
..
~-
.. ~-
.,_
-
-
-
'"'I""-""
-
-
--
~
-
·.
Under-compensated Properly_ compensated
Over-compensated
Fig. 2. Probe compensation. When the probe is properly compensated, the displayed calibrator waveform will have square leading corners,
as shown in center photograph.
To properly adjust the de balance of the Type 2A60
module, proceed as follows:
1.
Set the AC-DC-GND. switch to GND.
2. Display a free-running trace (or spot, if you are not
using a time-base module).
3.
Adjust the front-panel DC BAL. adjustment until the
trace does not move as you rotate the VARIABLE control
back and forth throughout its range.
Voltage Measurements
NOTE
When making measurements, make sure there is
a common ground between the oscilloscope and
the signal source.
To measure the potential difference between two points
on a signal (such as peak-to-peak ac volts), measure the
vertical distance, in graticule divisions, between the two
points whose potential difference is desired, and multiply
by the setting of the VOL TS/DIV. switch and the attenua-
tion factor, if any, of the signal probe. Be sure the VARI-
ABLE VOL TS/DIV. control is set fully clockwise (to the
CALIBRATED position).
When the VARIABLE VOLTS/DIV. control is not in the
CALIBRATED position, the amplitude of a signal can be
determined by comparing its displayed amplitude with
the displayed amplitude of a known signal, such as the
Calibrator waveform.
To measure the de level at a grven point on a wave-
form, proceed as follows:
2
1. Set the AC-DC-GND. switch to GND. Make sure the
VARIABLE control is set fully clockwise (to the CALIBRATED
position).
2. Position a free-running trace (or the spot, if you are
not using a time-base module) so that it lies along one
of the horizontal graticule lines. This line will be used as
a zero reference line; its position in any given case will
depend upon the polarity and amplitude of the voltage
to be measured. Do not adjust the POSITION control on
the Type 2A60 module after the reference line has been
established.
3.
Set the AC-DC-GND. switch to DC. (If the position
of the trace shifts by more than
1
minor graticule division,
see Troubleshooting, "De Reference-Level Shift.")
4. Touch the probe tip to the signal source and adjust
the time-base controls to obtain a stable display.
5. Measure the distance, in graticule divisions, from the
zero reference line established in step 2 to the point on
the waveform at which the de level is desired.
6. Multiply this distance by the setting of the VOLTS/DIV.
switch and the attenuation factor, if any, of the probe.
This is the de level of the point measured.
You can reestablish your zero reference line at any
time merely by placing the AC-DC-GND. switch to GND.;
you do not need to disconnect the probe from the signal
source. If desired, you can establish a reference other
than zero by placing the AC-DC-GND. switch to DC, con-
necting the signal probe to the desired reference voltage,
and positioning the trace as described in step 2 of the
procedure.
®!