Tektronix 2221 User Manual

П
Basic
Applications
--
2221
Operators
GROUND
REFERENCED DC
VOLTAGE
NOTE
100
30
NEGATIVE
REFERENCE
LINE
Either
channel
input
connector
may
be used for
the
signal input . Use the VERTICAL MODE switches to
select the
appropriate
channel
for
display
.
VERTICAL
DEFLECTION
1. Apply the signal to be measured to the selected
channel
input and
obtain
a
NON
-
STORE
display
.
А
n
П
П
27
POSITIVE
REFERENCE LINE
2. Ensure
that the VOLTS /
DIV
Variable control is in
the
calibrated
detent
and
determine the
polarity
of
the
volt
age to be measured as follows :
Ol 5mg
MEASURE POSITIVE
AMPLITUDE
А
OR
NEGATIVE AMPLITUDE
©
το
Θ
4998-31
a . Set the AC - GND - DC switch to GND and verti
cally position the baseline trace to the center
horizontal
graticule
line
.
Figure
6-2 .
Ground
referenced
voltage measurement .
b . Set the
AC - GND - DC
switch to DC .
If the
waveform moves above the center line of the crt ,
the voltage is
positive . If the
waveform
moves
below the
center
line
of the
crt ,
the
voltage is
negative
.
ence fine , the
VOLTS / DIV
switch is set to
2 V , and a
10X
scale
-
factor
-
switching
probe
is
used
.
Substituting the given values into the formula :
Voltage
= 4.6 divisions X ( +1 ) X 2 V / div = + 9.2 V
3. Set
the AC -
GND - DC
switch
to
GND and
position
the
baseline trace to a
convenient
reference line .
For
example ,
if the voltage
to be
measured
is positive ,
position the
baseline
trace to
the
bottom
graticule line . If
a
negative
voltage is to be measured , position the baseline trace to
the top
graticule
line .
ALGEBRAIC
ADDITION
9
no
ย
1
9
n
1
П
4. Set the
AC - GND - DC
switch to
DC .
Measure the
divisions
of
vertical
deflection
between
the
reference
line
and the
desired
point on the
waveform ( see
Figure 6-2 ) .
With the
VERTICAL
MODE
switches in the
ADD
posi
tion , the
waveform
displayed
represents the
algebraic sum
of the signals applied to the Channel 1 and Channel 2
input connectors ( CH 1 + CH 2 ) . If the Channel 2 INVERT
switch is pressed in , the resulting waveform is the
difference of the signals applied to the Channel 1 and
Channel 2
input
connectors (
CH 1
CH 2 ) .
The total
deflection
factor in the
ADD
mode is
equal to the
deflection
factor
indicated by
either VOLTS / DIV
switch
( when both
VOLTS
/
DIV
switches are set
to the
same
deflection factor ) . A
common
use for
the ADD
mode is to
provide a dc
offset for a
signal riding on top
of a dc level .
5.
Calculate the
voltage
, using
the
following
formula :
Voltage
Vertical VOLTS / DIV
Distance
X
Polarity
Х Switch
( Divisions )
( + or - )
Setting
NOTE
The following general precautions should be observed
when using the ADD mode :
The
attenuation
factor
of
the
probe
being
used must
be
included if it is
not a
10X
scale
-
factor
-
switching
probe .
a . Do
not
exceed the
input
voltage
rating of the
oscilloscope
.
o
EXAMPLE : The
vertical distance
measured is 4.6
divi
sions ( see Figure 6-2 ) . The waveform is above the refer
b . Do
not
apply
signals that
exceed
the
equivalent
of about eight
times the VOLTS
/ DIV switch
set
O
6-5

Tektronix 2221 Specifications

General

Brand	Tektronix
Model	2221
Category	Test Equipment
Language	English