ESI 250-DA - Procedure for Measuring AC Resistance

2.2.3
MEASURING
AC
RESISTANCE
For
greatest
accuracy
resistors
should
always
be measured with dc. The
accuracy
of
ac
measurement
will
be
0,3%
for one
kilocycle
and
below over
the
range
from
one
ohm
to
one
megohm,
for resistors with low reactance.
The
indicated
connections
for
the
phase
correction
capacitor
compensate
for
series
inductance
or
parallel
capacitance.
It
is impossible
to
separate
the
correction
for the
unknown
from that
for the
rest of the
bridge
circuit.
UNKNOWN
RESISTOR
OO 60
0
DETECTOR-
SWITCH
M
Vy
EEBa
IMPfDAMCE
SlflDCE
UNKNOWN
—
—
tJ-
resistor
terminals
NOTE:
If
the
phase cor-
rection
is
small
it
may
be
convenient to
connect
a
fixed
capacitor to
one
terminal
and
a
variable
one
to
the other.
UNKNOWN RESISTOR
PAtAUEl
/
ml
{
SERIES
C]
r
STANDARD
I
RESISTOR
MAIN OlAi
DEKASTAf
CONNECT
UNKNOWN
RESISTOR
TO
L-R
TERMINALS
Make
good contact with the
terminals
,
SET
THE
AMP
CONTROL
WITH
THE
DOT
UP
This
turns on
the unit and pro-
vides
medium detector sensitivity.
The red light
to
the
right
of the
AMP
switch
should light.
SET
THE
OSC
CONTROL
WITH
THE
DOT
UP
This turns
on
the ac
supply and
provides a medium
signal
to
the
bridge. The green
fluorescent
screen of the visual
null indicator
should light.
fel^
250-DA
6/59