ESI 250-DA - Extended Leads

2.4.6
EXTENDED
LEADS
Sometimes
it
is
necessary
to
use
extended
leads.
This
can
be done
easily
without
causing
error
in
the
measurement.
Connect
a
shielded
lead
to
the
unknown C
terminal
marked
LO.
Connect
the
shield
of
this
lead
to
the
EXT D-Q
terminal
marked
G.
Connect
an
ordinary
clip
lea,d
to
the
high
unknown C
terminal.
The
capacitance
between
the
shield
and the
LO
unknown C
terminal
is
now
across
the
detector.
This
keeps
it
from
causing
any
error.
If
this stray
capacitance
is
greater
than
500
^{xf»
it
may
reduce
the
detector
sensitivity.
The
stray
capacitance
from
the
unshielded
lead to
ground
is
across
the
standard
capacitor
arm
of
the
bridge.
Since
the
standard
capacitor
is
100,000
|x|jif,
the
stray
capacitance
will
not
cause
significant
errors
unless
it
exceeds
a
few
lO's
of
CidH
H
lElCT
EXT
J I i I
dgq
-o-o
o
o
i
6
GEN
R C
'
,1 I . in
C)«00l| O'-O
1
X I
I
>
10
sf»ES
I
simfs
Cy
Capacitance
from
LO C
terminal
to
ground
Capacitance
from
unshielded
conductor
to
ground
lel
s
l U
250-DA
7/59