Keithley 236 Service Manual

SECTION
1
Performance
Verification
1
.5.7
Low
Current
(1
nA
to
1 OmA)
Source
Ranges
Verification
Set up
the equipment
as shown
in Figure
17 and
perform
the
following steps
to verify the
inA
to
lOmA source
ranges:
1. Use Table
1-8
to
caiculate
the allowable
readings
for
the ljiA
through
OmA
ranges.
The values
for
IO9A,
I9tA,
I9OpA, IO9mA
and
IA
were
previously
calculated
and
recorded
in Table
1-3.
After caiculating
the
a1
lowable
readings,
transfer
them
the
Table
1-9.
2.
While in standby,
configure
the
Model
236/237
to
source
OnA on the
lnA source
range
with
a
compli
ance limit of 1.1V
on the
1.1V measurement
range.
3.
While
in
standby,
configure
the Model
263
to
source
OnA
on
the
2nA range.
4. With
ZERO CHECK
enabled,
zero
correct the
Model
617 on
the 2pA
range.
5. On the
Model
617, disable
ZERO CHECK
and place
the Model
236/237
in operate.
Verify
that
the read
ing on the
Model
617
is
within
the limits
specified
in
the first
entry
of Table
1-9.
6. Set
the
Model
617 to
the
2OpA
range,
and set
the
Model 236 to
source
OnA
on
the
lOnA
range.
Verify
that
the reading
on
the
Model
617
is within
the
limits
specified
in
the
second
entry
of
Table
1-9.
7. Using
Table
1-9 as
a
guide,
set
the
Model
236/237
to
source
zero on
the lOOnA
through
lOmA
ranges
and
check
that the
subsequent
readings
are within
the
listed
limits.
8.
Place
the Model
617
in zero check
and
select
the
2OpA range.
9,
Place
the
Model
236/237
in
standby
and
program
it
source
—O.9nA
on
the
inA source
range.
10.
While
stffl in
standby, set
the Model
263
to source
+O.9nA
on the
2nA
range.
11.
Place
both
the
Models
236/237
and
263
in
operate,
and disable
ZERO
CHECK
on
the
Model
617, Verify
that the
reading
on
the
Model
617
is
within thelimits
specified
in the
table.
12.
Place the
Model
617
in
zero check,
and
the
Models
263
and 236/237
in standby.
13.
On
both
the
Models
263
and
236/237,
reverse
the po
larity ofthe
sources.
Thatis,
set the
Mode1236/237
to
+O.9nA
and the
Model
263 to
—O.9nA.
14.
Place
the
Models
236/237
and
263
in
operate,
and
disable
zero
check
on the
Model
617.
Verify that
the
reading
on the
Model
617
is still
within the
limits
specified
in
the table.
15,
Using
Table 1-9
as a
guide,
repeat
the
basic
proce
dure
in steps
8
through
14
to
check
the
lOnA
through
1OmA source
ranges.
Note
that for
the
ljiA
through
lOmA
ranges,
the
source
values
for
the
Model
236/237
are
taken
from Table
1-3.
16.
Place
the
Model 617
in
zero
check,
and
the Models
263
and 236/237
in standby.
Table
1-8,
Allowable
Reading
Caiculations
for
Low
Current
Source
Verification
(lj.tA
to
lOmA)
236/237
Allowable
Reading**
Typical
Source
Range
Reading
Calculations*
Lower
Limit
Upper
Limit
Limits***
1iA
±
[
(0.0005)
IO 9
+
200pA
1 =
—
.
nA
+
.
nA
±O.6500nA
lOj.tA
±
[
(0.00050)
I 9 LA
+
2.00nA
1 =
— .
nA
+ .
nA
±6.500nA
1OO.tA
±
[
(0.00050) I 9o +
20.00nA
j
= —
.
nA
+
.
nA
±65.00nA
lmA
±
[
(0.00050)
IO 9 mA
+
200.OflA
1
.
LA
+
.
iA
±O.65OO.tA
lOmA ±
[
(0.0005)
I9mA +
2.00i.tA 1 =
—
.
jaA
+
.
j.tA
±6.500jiA
*
IO9A,
I9tA, I9OiA,
IO9mA
and
I9A
are
obtained
from
Table
1-3.
**
Allowable
reading
limits
are to
be
transferred to
Table 1-9.
***
The
calculated
allowable
readings
should be
within
the
listed
typicallimits.
These limits
are
based
on
the 90-day
speci
fications
of
the
Model 263
and
193A. A calculated
allowable
reading
that
does
not
fall
within
these
limits
indicates
a
caiculation
error,
or
that
the
Model
263 and/or
Model
193A
is
out of
specification.
1-15

Keithley 236 Specifications

General

Brand	Keithley
Model	236
Category	Measuring Instruments
Language	English