ESI 250-DA - Measuring AC Current Through Inductors

2.3.6
AC
CURRENT
MEASUREMENT
To
measure
the
ac
current
supplied
to
the unknown inductor:
The ac
voltage
across
the
range
resistor
is proportional to the ac current
through
the
unknown.
At
balance
this voltage is equal
to
the
voltage
across
the standard
capacitor
arm,
which can be
measured with a grounded
volt-
meter.
UNKNOWN INDUCTOR
Connect
the
ground
terminal
of a
high
impedance
sensitive ac
vacuum
tube
voltmeter
to
the
EXT D-Q
terminal
marked
G.
Connect
the
input
terminal
of the
voltmeter
to the
high unknown
capacitor
terminal
of
the
bridge.
Balance
the
bridge
using
either
the
series or
parallel
inductance
circuit.
Read
the
voltmeter.
The
ac
current
in
milliamperes
will be
equal
to
the
voltage
read
(in
volts)
times
the
multiplier
M
from
the
following
table.
I
250-DA
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