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SECTION 3
CIRCUIT
DESCRIPTION
Introduction
This
section
contoins
the
theory
of
operation
ol
the
vorious
circuits
in
the
Type
543B.
A
simplified
block
diogrom
analysis
is
given
first
to
explain
(he
operation
of
eoch
cir-
cuit
in
generol
terms,
then
the
operotion of
eoch
circuit
is
covered
in
detoil.
BLOCK
DIAGRAM
DESCRIPTION
Low-Voltage
Power
Supply
The
low-voltoge
power
supply
produces
all
operoring
voltages
for
the
oscilloscope with
the
exception of
parts
of the
ert circuit.
The
low-voltoge supply provides regulated
—
150,
-f-100,
+225,
-J-SSO
ond
+500
volts.
It
also pro-
vides
heater voltages
and
an
unregulated +325-voii
out-
put.
Vertical
Plug-In Preamplifier
Any
Tektronix
letter-
or
1
-scries verticol
piug-in
preampli-
fier
can be used
with
the
Type
5436.
For
a
circuit
descrip-
tion
of the plug-in
unit,
refer
to the plug-in
unit instruction
manual.
Vertical
Input Amplifier
The
vertical
input ompiificr
is
a bolonced
hybrid ampli-
fier
that amplifies the
output
of
the plug-in
vertical
preampli-
fier
end
appiies the omptified
verticol
signol to the
trigger-
pickoff
circuit
and
the
vertical
output
amplifier.
Delay
Line
The
push-pull
output
of
the
verticol
input amplifier
is
opplied through
the
balanced delay
line
to the vertical out-
put amplifier.
The deloy
line
is
a
specioily
braided
1860
line
which
delays
the opplicotion of the
vertical
signol to
the
vertical
output
amplifier
for
200
nsec.
This
provides
time
for
unblanking
the
ert
ond
starting
the horizontal
sweep
before the
vertical
signal
reaches
the deflection
plotes.
The
deloy
allows
the
leading
edge
of
a
single
fost-rising
pulse
to
be
displayed,
The delay
line
requires
no
adjustment
because
of the
precisior>
Construction-
Vertical
Output
Amplifier
The
verticol
output amplifier
is
o
push-pull
coscode
ompli-
fier
thot fakes the
output
of the
deloy
line
ond
amplifies
it
to
0
level
sufficient
to
drive the
verticol
deflection plates
of the
erf,
Trigger-Pickoff
Circuit
The
trigger-pickoff
circuit
opplles
o sompic
of the input
waveform
to
the trigger
circuit
of the
time bose.
The
trigger
IS
picked
oft ot
the
output of the
vertical
input amplifier.
Time-Base Generator
The
time-bose generotor provides accurate
ramp
voltoges
lor the horizortto! deflection
system,
unblanking
for the
ert,
ond
o
+
gale
to
the front-panel connector.
The
time-base
generotor
may
be
triggered
by
signals
derived from
either
infernol
or externa!
sources.
Horizontal Amplifier
The
input to
the horizontal amplifier
is
selected
from
the
output
of the
time-base generafor, or
the
exferrvol
horizontal
input omplifier.
The
selected
input
is
split
in
phase
and
amplified
to
provide
push-pull
drive to the
ert
horizontol
deflection
plates.
External Horizontal Amplifier
The
exterrtol
horizontal
input
omplifier
provides
the
necessory goin
to
drive the horizontol amplifier
from
external
signals.
An
input offenuaior
and
a
gain
control
provide
horizontol deflection
factors
from
0.1
to
about
100
volts/cm,
Crt
Power
Supply
The
crt
power
supply
provides
the
high
voltages
for
operoiing
the
crt.
The power
supply
is
of the
rf
type, using
o
50-kc
Hartley
oscillator.
Secondary
windings
on
the
oscillator
tranriormer
supply voltoges
to
the
high-voltage
rectifiers.
Cafhode-Ray Tube
(Crt)
Tne
cofhode-ray tube used
in
the
Typo
543B
is
a
flat-
faced,
internal
graticule, 5-inch
tube with 6
cm
of
usable
verticol
scan
areo.
The
tube
is
designed
for
low-input
copocitance
to the
vertical
deflection plates
and minimum
x-axis
cenfer-lo-edge defocosing.
Calibrator
The
colibfotor
in
the
Type
5436
is
a
multivibrator
and
cathode
follower
that
provides a
squore-wave
output with
a
maximum
amplitude
of
100
volts at
a
nominal
1
kc,
A
step otfenuotor permits switching the output
amplitude from
the front panel.
DETAILED CIRCUIT DESCRIPTION
The
following description
is
a detailed discussion
of the
operotion
of
eoch
circuit in
the
Type
5438.
While
reading
through
the description of a
particular
circuit,
refer
to
the
proper
scherrofic
diogrom
in
Section
6,
Low-Voltage
Power
Supply
The
low-voltage
power
supply
in
the
Type 5436
(see
Power
Supply schcmotic diogrom)
actually
consists
of
five
in-
3-1
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