Operating
Instructions
—
Type
575
Fig.
2-8.
Collector
family
of
curves
for
a
Type
2N407
transistor.
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Insert
a
test
transistor
into
the
socket
on
the left
side
of
the
Test
Panel,
and
place
the Comparison
Switch
in
the
TRAN-
sistor A position.
Adjust
the
INTENSITY,
FOCUS
and
ASTIGMATISM
controls
for
a
display
of
suitable
brightness
and
clarity.
The
display
should
then
be
similar
to
the
collector
family
shown
in
Fig.
2-8.
How
To
Check The Calibration of The Display
Before
quantative
information
is
taken from
the
display,
a
check
should
be
made
to
see
that
the
calibration of
the
vertical
and
horizontal
scales
is
correct.
The
stability of
the
amplifiers
is
such
that
the
instrument
will
remain
in
calibra
tion
over
long
periods
of
time
if
there are
no
component
failures.
The
display
must
also
be
properly
positioned.
NOTE:
When
you
check
the
calibration
of
this
in
strument,
calibrate
it,
or
take
information
from the
display, be
sure
your
eye
is
at
the same
level
as
the line
at
which
you
are
looking
in
order
to
avoid
errors
due
to
parallax.
Hold
the
VERTICAL AMPLIFIER
CALIBRATION
switch
in the
ZERO
CHECK
position
and
set
the
horizontal
line
even
with
the
top
line
of
the
10-division
graticule.
Next,
hold
this
switch
in
the —10
DIVISIONS position.
The
horizontal
line
should
be
within
1
}/2
minor
divisions
of
the bottom
line
of
the
graticule
if
the
calibration
is
within
tolerance.
Now
hold
the
HORIZONTAL
AMPLIFIER
CALIBRATION
switch
in
the
ZERO
CHECK
position
and
set
the
vertical
line
even
with
the
extreme
right
vertical
line
of
the
graticule.
Next,
hold
this
switch
in
the
—10
DIVISIONS
position.
The
vertical
line
should
move
to within
1
y
2
minor divisions
of
the
extreme
left
vertical
line
of
the
graticule.
®@2
Since
current
steps
are
being
fed
into
the
base
of
the
tran
sistor under test,
it
is
sometimes desirable
to
adjust
the
STEP
ZERO control
(BASE
STEP
GENERATOR)
to
a
point where the
first
horizontal trace
occurs
when
the
base
current
is
zero. To
do
this,
it
is
necessary
to
have an
open-circuit or
zero
base
current
reference
line.
Hold
the ZERO
CURRENT-ZERO
VOLTS
switch
in
the
ZERO
CURRENT
position
and
note
precisely
where
the horizontal
trace
intersects
the
vertical
center
line
of
the
graticule.
Now
release
the
ZERO
CURRENT
switch
and
adjust
the
STEP
ZERO
control
so
that
the
top
line
of
the
display
intersects
the
vertical
center
line
of
the graticule
at
the
same
place.
Applying
Voltage Steps to the Transistor Input
The
control
settings
used in
this
display
are the same
as
for
the
previous
display
except
for
the following:
SERIES
RESISTOR
1
ohm
STEP
SELECTOR
.02
VOLTS
PER
STEP
VERTICAL
COLLECTOR
MA
.05
MA
PER
DIVISION
If
a
complete
and
accurate
display is
desired,
the display
should
be
properly positioned by
the
method
outlined
in
the
next
two
paragraphs.
Hold the amplifier calibration
switch
(VERTICAL
BLOCK)
in
the
ZERO
CHECK
position
and
move
the trace to
the
top
line
of
the
rectangular
graticule.
This
operation
sets
the
zero
collector-current
reference.
Now
depress
the
ZERO CUR
RENT-ZERO
VOLTS
switch
(BASE
STEP
GENERATOR)
in
order
to
ground
the
transistor
base.
The
vertical
displacement
of
the
horizontal
trace
from
the
zero-current
reference
indicates
the
collector
current
at
zero
bias
with a
calibration
of
.05
ma.
per
major
division.
The
STEP
ZERO
control
(BASE
STEP
GENERATOR)
must
now
be
set
so
that
the uppermost curve
(zero
bias)
in
the
family
of
curves
coincides
with
the
position
of
the
single
curve just
displayed.
The
family
of
curves
now
on
the
crt screen
is
that
of
collector
current versus collector
voltage
with
20-millivolt
steps
applied
to
the
transistor
base.
Special
precautions
should
be taken when
voltage
steps
are
fed
to
the
input
of
the
transistor
under
test.
Since
the
input
resistance
of
a
transistor
is
quite
nonlinear
over
its
op
erating
range,
it
is
important
that
the
number of
voltage
steps
used
does
not
cause
excessive
base
current
to
flow.
There
are
two
controls
which
influence
the maximum
base
current
for a
selected value
of
voltage-step amplitude.
One
is
the
STEPS/FAMILY
control,
which
should
be
set
to
4
for
an
initial
test
set-up.
The
other
is
the SERIES RESISTOR
switch,
which
allows you
to
insert
a
protective current-limiting
resistor
in
the
transistor
input
lead.
Excessive
series
resistance
will seri
ously
alter
the
characteristic
curves
displayed,
therefore its
effect
should be
taken
into
consideration before interpreting
curves
where
voltage
steps
are being
fed
into
the
transistor
input.
The
SERIES
RESISTOR
may
also
be
used
to
simulate driving
impedances.
When
series
resistance
is
used,
it
may
not
be
possible
to
make
the
top
curve
of
the
display
coincide
with
the
zero-bias
curve.
2-7
Summary of Contents for 175
Page 4: ...VWTICM OINltAlO TRANSISTOR CUM TRACfR UB l COUlClO r hokizoniai VCKIJ O lUnK Hix M Type 575 z ...
Page 6: ...NOTES ...
Page 26: ...NOTES ...
Page 48: ...NOTES ...
Page 54: ...Recalibration Type 575 C706 Fig 5 3 Left Side View 5 6 ...
Page 56: ...NOTES ...
Page 100: ...INPUT AMPLIF1E ...
Page 104: ...TYPE 575 TRANSISTOR CURVE TRACER ...
Page 108: ...OSCILLATOR 4OOV UNREG TYPE 575 TRAN5I5TOR CURVE TRACER AB ...
Page 115: ... 300 ...
Page 119: ...Type 175 Tent S N 570 PARTS LIST CORRECTION Change to Q233 151 0137 00 2N21U8 MIO 298 1165 ...
