ESI 250-DA - Refining Resistor Measurement and Calculations

2,
2.1
MEASURING
RESISTORS
(cont.)
SET
DETECTOR
SWITCH
TO
SHUNTED
METER
This
makes
it
easier
to
find a
rough
null.
SET
GENERATOR
SWITCH
TO
INTERNAL
DC
This
connects
the
generator
to
the
bridge
.
ADJUST
MULTIPLIER
SWITCH
FOR
MINIMUM
GALVANOMETER
DEFLECTION
This
sets
the
range
so
that
the
value
can be
found
with
maximum
reso-
lution
on
the main
dial.
ADJUST
MAIN
DIAL
FOR
NULL
The
detector
sensitivity
can
be
increased
as null
is
approached
by
moving
the
detector
switch
to
direct
meter.
IF
THE
MAIN
DIAL
READING
IS
LESS
This
takes
advantage
of
the
increased
THAN
1.200,
USE
THE
NEXT
LOWER
resolution
near
full
scale
of the
dial.
RANGE
AND*
READJUST
THE
MAIN
DIAL
FOR
NULL
FOR
RESISTANCES
GREATER
THAN
(WARNING:
This
may put
300
volts
lOK
SET
THE
DC
GENERATOR
VOLT-
on
the
unknown
terminals.)
AGE
SWITCH
TO
HIGH
THE
MEASURED
RESISTANCE
IS
THE
PRODUCT
OF
THE
READING
OF
THE
CIRCUIT
SELECTOR
SWITCH,
THE
MULTIPLIER
SWITCH,
AND
THE
MAIN
DIAL
BEFORE
DISCONNECTING
THE
MEASURED
RESISTOR
SET
THE
GENERATOR
SWITCH
TO
EXT
DET,
THE
DETECTOR
SWITCH
TO
SHUNTED
METER,
AND
THE
DC
GENERATOR
VOLTAGE
SWITCH
TO
LOW
before
LEAVING
THE
BRIDGE,
This
turns
off
the
power
supply
and
LOCK
THE
GALVANOMETER
AND
protects
the
galvanometer,
SET
THE
AMP
SWITCH
TO
OFF
This
disconnects
the
generator,
protects
the
meter
and
removes
the
high
voltage
from
the
bridge.
lelsl
n
250-DA
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