of V140B
grid
to
the
quiescent level
after
the
passageof
the positive
voltage.
This
prevents
any
trigger
signals
from
retriggering
the
multi
vibrator
until all
other
capacitances in the
circuit
have had
time
to
reach
their
quiescent
voltage
levels.
Proper
sizes of capacitor
C131
are switched
with
the
TIME/CM switch
so
that
more
recovery
time
is
permitted
for
the slower
sweep
rates
and
the
least necessary
recovery
time
is allowed
for
the faster
sweep
rates.
Horizontal Amplifier
The
time-base
waveform
passes through
the
frequency
- compensated
positioning
network,
R210,
R211,
to the
grid
of
cathode-follower
V210B.
This
cathode
follower
provides
the
necessary
low
impedance
to
drive
the
switch
capacitances
and
the
second
cathode
follower,
V210A. In
the
NORM,
position
of
the
HORIZ.
DISPLAY switch,
an
attenuation
network
is
inserted
between
the
cathode
of
the
Input
C.F.,
V210B
and
the
Driver
C.
F.,
V210A.
In
the
MAG.
position
of
the
HORIZ.
DISPLAY
switch,
this
attenuator
network
is
bypassed,
so
that
the amplitude ofthe
input
signal
to
the
Amplifiers
is
multiplied
by
a
factor
of
five.
In
the
EXT
position,
the
HORIZ.
DISPLAY
switch
connects
the
amplifier
to the
EXT.
HORIZ.
INPUT
binding
post
to
display
the
signal
applied
to
this
binding
post.
Cathode-follower
V210A
applies
the
signal
to the
output
amplifier,
V250A
and
V270A.
The
output
amplifier,
converts
the
signal
for
push-pull
application
to
the
deflection
plates.
R259
varies
the
degeneration
in
the
cathode
circuits
to
set the
gain
of
the
amplifier.
C260
provides high-frequency
compensation
of
the
output
amplifier
by
reducing
the
high-frequency
degeneration.
R214B
provides
horizontal
posi
tioning
when
the
HORIZ.
DISPLAY
switch is
in
the
EXT. position.
The
waveform
at
the
plates of
the
output
amplifier is
applied
to
the
crt
horizontal
deflection
plates via cathode followers
V250B
and
V270B.
Bootstrap
capacitors
C246
and
C272
increase
the
current
in
the
output
amplifiers
at
the high sweep
rates
to
improve
time-base
linearity.
Neon
diodes
NE253
and
NE280
protect
the
cathode
followers from excess
grid
to
cathode voltage when
the
instrument
is
first
turned
on.
CALIBRATOR
The
calibrator
is
a
symmetrical
multivibrator
with V550A
and
V55OB
connected
so
as
to
turn cathode-follower
V570
on
and
off
as
it
oscillates.
During
the
negative
pulse
at
multi
vibrator
V55OA,
the
grid
of
the
cathode
follower
is
driven
well
below
cutoff,
so
the
cathode is
at
ground
voltage.
During
the
positive
pulse
at
the
multivibrator,
the
plate
is
cut
off
and
rests
slightly
below
+100
volts. The
voltage
of
the
plate
during
cutoff
is
determined
by
the
setting
of
R560, part
of
a
divider
between
+
100
volts
and
ground.
R56O
is
a
screwdriver
adjustment
labeled
CAL. ADJ.
Cathode
follower
V570
has
a
tapped,
calibrated
voltage
divider
for
its
cathode
resistor.
When
the
CAL.
ADJ.
control
is
properly
set,
the
cathode-follower cathode
is
at +100
volts
when
V510B
is
cut
off.
The
taps
on
the
divider
provide
eleven
fixed
calibrated
amplitudes.
No
internal
connection from
the
calibrator
to
the
vertical-deflection
circuits
is
provided.
POWER
SUPPLY
Transformer
Plate
and
heater
power
for
the
Type
515/515A
is
provided
by
a
single
power
transformer,
T600.
The
transformer has two equal
117-volt
windings
that
can be
connected
either
in
parallel
for
117-volt
operation,
or in
series
for
234-
volt
operation.
Rectif ie
rs
The
ac
voltage
from
the
high-voltage
wind
ings
is
rectified
by
bridge-connected
full-wave
selenium
rectifiers.
-150-Volt
S apply
All
de
voltage
furnished
by
the
power
supply
are
regulated
with
the exception
of
the
+
360-
Evolt
supply
which
is used only
to
supply circuits
which
are
insensitive
to
voltage
variations.
Reference
voltage
for
the
regulators is
estab
lished
by
means
of
a
gas-diode voltage
reference
tube,
V602.
The voltage-reference
tube
deter
mines
the
grid
voltage
of a
comparator
amplifier,
V607,
in
the
-150-
volt
supply.
The
grid
potential
of
V607B
is compared
with
the voltage
obtained
from
a
divider,
R616,
Circuit
Description
-
Type
515/5
15A
3-5