Keithley 237

SECTION1
Getting
Started
-v
·1
10V
Sink
Source
+100rnA
Sink
Source
+110V
v
-v
-11oov
Sink
Source
·100rnA
·I
A.
Model236
B.
Model237
Figure
1-8.
Source-Measure
Capabilities
sink operation will occur
in
the second
quadrant
(source
+V
and
measure -I).
Source
I
Measure
V
The operating boundaries
in
a single
quadrant
for Source
I Measure
V are
shown
in
Figure 1-9. The voltage limit
load line represents
the
programmed
compliance limit
set
by
the
user. The current source load line represents
the source current
programmed
by
the
user. These
load
lines are
boundary
lines
that
represent the operating
lim-
its
of
the Source Measure Unit
for
this
quadrant
of
opera-
tion. The operating boundaries for
the
other three
quad-
rants are similar.
Voltage
Limit
Load
Line
/
'
t
e
Current
:::::1
gj
.-
Source
Q)
E
Load
Line
>
'
I
source
/
Figure
1-9.
!-Source
Operating
Boundaries
1-10
+
·I
+100rnA
Source
+lOrnA
Sink
Source
·15V
+15V
+110V
V
·lOrnA
Source
Sink
Sink
·100rnA
·I
C.
Model238
Where
on
the
boundary
the
Source Measure
Unit
oper-
ates
depends
on
the
load
(OUT)
that
is connected to its
output. Figure
1-10
shows operation examples for resis-
tive loads
that
are
soon
and
1kn
respectively.
In
these ex-
amples, the Source Measure
Unit
is
programmed
to
source 16mA
and
limit (measure) 12V.
In
Figure 1-10A,
the
Source
Measure
Unit
is sourcing
16mA to
the
SOOn
load
and
subsequently measures
8V.
As
long
as
the
OUT
load line intersects the current source
load line,
the
Source Measure
Unit
will
be
able to source
its
programmed
current (16mA).
Figure
1-10B
shows
what
happens
if
the
resistance
of
the
load is increased to
1kn.
The
OUT
load line intersects the
voltage limit
load
line placing
the
Source Measure
Unit
in
compliance.
In
compliance,
the
Source
Measure Unit
will
not
be
able to source its
programmed
current (16mA).
In-
stead,
it
will
source only 12mA.
Notice
that
as resistance increases,
the
slope
of
the
OUT
load line increases. As resistance approaches
infinity
(open output),
the
Source
Measure Unit will source
virtu-
ally
OmA
at
12V. Conversely, as resistance decreases,
the
slope
of
the
OUT
load line decreases.
At
zero resistance
(shorted output), the
Source
Measure Unit
will source
16mA
at
virtually
OV.
Regardless
of
the
load, voltage will never exceed the pro-
grammed
compliance of 12V. Also,
maximum
power
to a
DUTin
thiscasewillneverexceed
192mW (12VX 16mA).
+