Calibration
—Type
561
A
Fig.
5-1. Schematic representation of effective
deflection-plate
capacity: (a)
vertical system;
(b)
horizontal system.
This
has an
adverse affect
primarily
bandpass
plug-in unit
near
the
upper
when
using
a v
ide
limit
of
its
bandpass.
Since
the
effective
deflection-plate
capacitance
of
the
crt is
that
capacitance
seen
by
the
plug-in
unit when
the
deflection plates are
driven
push-pull,
it
cannot be measured
directly
with
a
capacitance meter.
However,
the
ciicuit
capacitances
which
make
up
the
effective
deflection
plate
capacitance
of
each
set
of
plates
can
be
measured
with
a
capacitance meter.
The
capacitances may
be
represented
schematically
as shown
in
Fig.
5-1.
Cl
and
C2
in
the
figure
represent
the
capacitance
between
each
plate
and
ground.
C3
represents
the
total
capacitance
between
the
plates. Since
the
deflection
plates
are
driven
push-pull,
the
effective
deflection-plate
capacitance,
C
c
ff
may
be
expressed
in
terms
of
Cl,
C2
and
C3
as
follows:
Cl
and
C3
are fixed for
the
vertical
system.
C2
is
adjust
able by
means of
C760.
Setting
C
e
ff
equal
to
16
pico
farads
and
solving
for C2:
C2
=
32
pf
-
(Cl
+ 4C3).
Thus,
by
measuring
Cl
and
C3,
you
can
determine
the
desired
value
of
C2
for
the
vertical
system.
You
can
obtain
this
value
by
adjusting
C760.
Proceed
as
follows:
1.
Disconnect
the
power
cord
and
isolate
the
oscilloscope
from ground.
2.
Either plug a
spare 24-pin
connector
into
the
vertical
plug-in
connector
or
insert any plug-in
unit
into
the
vertical
opening
and
unsolder
the
leads
from
terminals
17
and
21
in
the
unit.
3.
Connect
the
capacitance
meter
guard
voltage
to
pin
21
of
the
plug-in
connector
and
measure
the
capacity
be
tween pin
17
and
the
oscilloscope
chassis.
This
is
Cl.
4.
Connect
the
guard
voltage to the
oscilloscope
chassis
and
measure
the
capacity
between
pins
17
and
21
of
the
plug-in connector.
This
is
C3.
5.
Substitute
the
measured
values
of
Cl
and
C3
into
the
equation
and
solve
for
C2.
6.
Connect
the
guard
voltage
to
pin
17
and
measure
the
capacity
between
pin
21
and
the
oscilloscope
chassis.
This
is
C2.
7. Adjust
C760
until
the
measured
capacity
in
step
6
equals
the
value
for
C2
obtained
in
step
5.
8.
Disconnect
the
capacitance
meter
and
resolder
any
unsoldered
leads.
Cl
and
C2
are
fixed
for
the
horizontal
system,
but
vary
slightly
among
instruments
and between
openings
of
the
same
instrument.
C3
is
adjustable
by
means
of
C761.
Setting
Ceff
equal
to
16
picofarads
(the
factory
standard)
and
rearranging terms:
C1^C2
4
C2,
you
can
determine
the
obtain
this
value
of
C3
by
adjusting
C761.
Thus,
by
measuring
Cl
and
desired
value
of
C3.
You
can
5-2
Содержание 561A
Страница 44: ...0 Wh T801 TERMINALS CONNECTIONS...
Страница 47: ...RIGHT HAND 07 2 7 62 TYPE 561A OSCILLOSCOPE PLUG IN CONNECTORS...
Страница 49: ...MOD 6860 Type 561A Tent S N 7860 Type RM561A Tent S N 5280 Change to Chassis Mtg Connectors BNC 131 279...
Страница 52: ...RT 5O RT5I IOOV IOOV IOOV PLM I I 2 PART PWR SPLV DIAQ...
