Circuit
Description
—
Type
575
terminals
in
the
Q253
circuit. Q253 is
connected
in
the
com
mon
emitter
configuration,
as
shown
in
Fig.
3-14,
and
the
load
resistor
R243
is connected
into
the
collecter
circuit.
With
this
configuration
V253
is
a
collector-loaded
amplifier
and
will
produce
a
180-degree
shift
in
the
signal
polarity.
This
will
put
voltage
steps
at
the top
of
R246
in
phase
with
input
steps
(positive-going
steps).
To compensate for
the
additional shift
in
signal
polarity,
the
grids
of
the difference
amplifier
V214-V224
must
be
switched
insofar
as
the
feedback
loops
are
concerned.
That
is,
the grid of
V224
is
now
connected to
the
top
of
R246 and
the grid
of
V214
is
connected
through
R203
to
the
divider
at
the
output
of
the
+1
Amplifier. Notice, in
Fig.
3-14,
that the
grid
circuit
of V214 is
connected
to
the
top
of
the divider
at
the
output
of
the
+1
Amplifier,
while
in
Fig.
3-13
the
grid
circuit of
V224
is
connected to
a
tap
on
the divider.
Since
the
gain of
the
+1
Amplifier
is
just
slightly
greater
than
1,
the
voltage
at
the cathode
of
V233B
is
slightly
great
er
than that
at
the grid
of
V254.
The
voltage
applied
to
the
difference
amplifier
from
the
+1
Amplifier
must
be
equal
to
the
amount of
correction
needed
to
keep the
voltage
across
R246
constant. The
resistance
values
in
the
divider
at
the
output
of
the
+1 Amplifier
are
such
that
the
voltage
drop
across
R275 is
the
same
as
the voltage
at
the grid
of
V254.
This
satisfies
the
requirements
of
the
circuit,
in
Fig.
3-13,
where
the
feedback
is
applied
directly
to
the
grid
of
V224.
In
Fig.
3-14,
the
feedback
is
applied
to
the
grid
of
V214
through
R203,
and,
since
there
is
a
voltage
drop
across
R203,
the
voltage
at
the
output
of
the
+1
Amplifier
must
exceed
the
required
feedback
voltage
by
an
amount
equal
to
this
drop.
For
positive-polarity
signals,
therefore,
the
voltage
at
the
output
of
the
+1
Amplifier
must
exceed
the
voltage
at
the
grid
of
V254
by
an
amount
equal
to
the
drop
across
R203.
CRT
Deflection Amplifiers
The
diagram
of
the
Vertical
and
Horizontal
Amplifiers
in
clude
a
simplified
diagram
of
most
of
the
switching
related
to
these
amplifiers.
The
purpose
of
the
simplified
diagram
is
to
help you
understand
the
relationships
between
the
Verti
cal
and
Horizontal
Amplifiers
and other
parts
of
this instru
ment.
Accordingly,
this
discussion
will
include
switching
in
formation.
The
circuits
of
the
Vertical
and
Horizontal
Amplifiers
are
quite
similar.
Both
consist
of
three
difference
amplifiers
in
cascade.
A
difference
amplifier,
or cathode-coupled
phase
inverter, rejects any
signal
applied
to
both
input grids,
re
sponding
only
to
a
voltage
difference
between
the
input
grids.
The
gain
of
the
difference
amplifiers
in
the Type
575
is
stabilized
by
negative-feedback
paths from
the
plates
of
the
output
amplifier
to
the
opposite
cathodes
of
the input
stage.
The
ranges
of
the
VERTICAL and
HORIZONTAL
switches
are
shown
in
capital letters.
Only
a
few
of
the
positions
in
the
COLLECTOR
MA,
BASE
VOLTS,
and
COLLECTOR
VOLTS
ranges
are
shown.
In
the following
paragraphs,
the
signal
paths
to
the
Vertical
and
Horizontal
Amplifiers
will
be
traced
for
each
range of
the
corresponding
switch.
Collector
MA Display
Collector
current
is displayed
on
the vertical
axis only.
The
collector
current
is
proportional
to
the
voltage
drop
across
a
current-sampling
resistance.
This
voltage
is
fed
di
rectly
to
the
control
grid
of V454,
the
other
input
to
the
verti
cal amplifier being
grounded.
One
volt
must be developed
across
the
current-sampling
resistance
to
cause
a full-scale
vertical
deflection
of
ten
major
divisions. In
all
switch
po
sitions
within the
COLLECTOR
MA
range,
the
Vertical
Ampli
fier
works
at
a
reduced
constant
gain.
This
reduced
gain,
one-tenth of
maximum,
is
accomplished
by
inserting
a
resis
tance
of
about
1
OK ohms,
R447
in
parallel
with
R432B,
be
tween
the
cathodes
of
the
input
stage.
R432B
is
located
on
the
detailed
switching
diagram.
Base
Volts
In
the BASE
VOLTS
position
of
the
VERTICAL
switch,
the
control
grid
of
V454
is
grounded
and
a
signal
from
the
base
of
the
transistor
under
test
is
fed
to
the
control
grid
of
V444.
The
sensitivity
of
the
Vertical
Amplifier
is
varied
by
changing
the
resistance
between
the
cathodes
of
V454
and
V444.
DISSIPATION
LIMITING
1
VjDlV.
2 V/DIV.
S
vjDIV.
Fig.
3-15.
With
this
configuration
an
accurate
display of collector
current
(Vert.
Amp.)
and
collector
voltage
(Horiz.
Amp.)
is
ob
tained.
Collector
Volts
Display
The
diagram
of
Fig.
3-15
shows
the
method
used
to
solve
the
problem
of
presenting
an
accurate
display
of
both
col
lector
current and
collector
voltage
at
the
same
time.
Discus
sion
of
this
diagram does
not
necessarily
apply
to
corres
ponding
parts
of
the
Type
575.
Note
that
two
attenuators
are
used
and
that
the horizontal display
of
collector
voltage
is
obtained
by
using the common-mode rejection
feature
of
the
Horizontal
Amplifier.
As
shown
in
Fig.
3-15,
the
Horizon
tal
Amplifier
amplifies
only
the
voltage
difference
existing
between its
input
grids.
Also
note that
the
true
current-sampling
resistance
is
made
up
of the
10.25-K
resistor
and
the
attenuator
in
parallel
with
it.
Low-Voltage
Power Supply
Plate and
filament
power
for
the
Type
575
is
furnished
by
a
single
power
transformer
T601.
The
primary
windings
may
(A)@I
3-11
Содержание 175
Страница 4: ...VWTICM OINltAlO TRANSISTOR CUM TRACfR UB l COUlClO r hokizoniai VCKIJ O lUnK Hix M Type 575 z ...
Страница 6: ...NOTES ...
Страница 26: ...NOTES ...
Страница 48: ...NOTES ...
Страница 54: ...Recalibration Type 575 C706 Fig 5 3 Left Side View 5 6 ...
Страница 56: ...NOTES ...
Страница 61: ...O I Ui Fig 6 6 Simplified circuit diagram of Type 175 Transistor Curve Tracer High Current A dapter ...
Страница 100: ...INPUT AMPLIF1E ...
Страница 104: ...TYPE 575 TRANSISTOR CURVE TRACER ...
Страница 108: ...OSCILLATOR 4OOV UNREG TYPE 575 TRAN5I5TOR CURVE TRACER AB ...
Страница 114: ...234 VAC 117 VAC PRIMARY CONNECTIONS FOR 234VOLT OPERATION ___I TYPE 175 TRANSISTOR CURVE TRACER HIGH CURRENT ADAPTOR ...
Страница 115: ... 300 ...
Страница 117: ...TYPE 175 TENT S N 393 PARTS LIST CORRECTION CHANGE TO SW510 TRANSISTOR SELECTOR 260 636 M6983 664 ...
Страница 119: ...Type 175 Tent S N 570 PARTS LIST CORRECTION Change to Q233 151 0137 00 2N21U8 MIO 298 1165 ...
Страница 123: ...INSTRUCTIONS cont uu y uj r uu y P 2AO MJ i DfeZOC 4K cx zdd uu gn UJ bK uj bn T JU O Page 4 of 4 040 0223 00 ...
