.5
MILLISEC
TIME/CM
VERTICAL
POSITIONING
Center
HORIZONTAL
POSITIONING
Center
CALIBRATOR
10
Connect
a
lead
from
the
CAL.
OUT
con
nector to
the
INPUT 1
connector. If
the
tubes
have
had time
to
warm
up,
turn
the
INTENSITY
control
clockwise
until
a
trace
is visible
on
the
screen.
Adjust
the FOCUS,
ASTIGMATISM
and
INTENSITY
controls
to
produce
a
sharp
trace
of
comfortable
brightness.
The
two
POSITIONING
controls will
move
the
trace
vertically
and
horizontally
as
nec
essary
to
position
the
display
where
you
want
it on
the
crt
screen.
Triggering Modes
If
you
have
not
had
previous experience
with
the
type
of
trigger
controls
used
on
this
oscilloscope,
the
calibrator
waveform
is
a
good
one
to practice
with.
A
few
minutes
spent
on
trying
the
triggering
modes
described
below
will be
time
well
spent
in
terms of
future
operating
convenience.
Auto
The
triggering
method
used
in
the
preceeding
example
is
the
AUTO,
(automatic)
mode
of
operation.
It
is
the
simplest
mode
of
triggering.
There
are
no front-panel
controls
to
be
adjusted
when
using
this
mode.
If
the
signal
is removed
from the
input
connector,
the
sweep
will
con
tinue,
but
at
a
reduced
repetition
rate.
This
provides
a visual
indication
that
the
signal
has
been
removed
and
the
sweep
and
triggering
circuits
are
operating.
AC
Now
try
the
AC
mode
of triggering.
Turn
the red
TRIGGER
SELECTOR
knob
to
AC.
Advance
the
TRIGGERING
LEVEL
control
clockwise
until
you
get
a
stable
trace.
There
may be
a
considerable
range
over
which
you
get
a
stable
trace.
The start
of
the
trace
will
move
up
and
down
the
edge
of
the
square
wave
over
this range.
Notice
that
the
trace
starts
on
the
up-going
part
of
the
calibrator
square
wave.
Now turn
the
black TRIGGER SELECTOR
switch
to
the
-INT
position
and readjust
the
TRIGGERING
LEVEL
control
to
get
a
stable
trace again.
Notice
now
that
the
trace
starts
on
the down-going
portion
of
the
square
wave
and
that
the
position
of
the
start
can
again
be
changed
somewhat
with
the
level
control.
DC
Turn
the
red
TRIGGER
SELECTOR
knob
to
DC.
If
necessary
adjust
the
TRIGGERING
LEVEL
control
for
stable
triggering.
Move
the
trace
vertically
on
the
screen
with
the
VERTICAL POSITIONING
control
and
note
that
triggering
occurs
at
a
vertical
level
on
the
screen
selected
by
the
LEVEL
control,
and
that
the
triggering point
changes relative
to
the
waveform
as
the
waveform
is
positioned
vertically.
This
effect
will
be
more
noticeable
if
you
look at
a
low-frequency sine
wave.
H
F Sync
The
H F SYNC
position
of
the TRIGGERING
SELECTOR
switch
is primarily
for
signals
having
a
repetition
rate
in
excess of
five
megacycles.
In
this
position
the time
base
will
trigger
poorly,
if
at
all,
on
the
calibrator
waveform.
To
stabilize
the
display
of
a
high-
frequency
signal
,
simply
advance
the
STABILITY
control
clockwise
until
a
stable
trace
is obtained.
The
LEVEL
control
is
not
used
in the
H
F
SYNC
mode.
FUNCTIONS OF CONTROLS
AND
CONNECTORS
CRT
Controls
FOCUS
INTENSITY
Control
to
adjust
the
beam
for
maximum
sharpness
of
the
trace.
Control
to
vary
the
brightness
of
the
trace.
2-2
Operating
Instructions
-
Type
515/515A
AA