3
Theory
on
Material
Measurement
This
chapter
explains
the
basic
principle
and
the
concept
of
material
measurement.
Magnetic
Material
Measurement
P
ermeability
Denition
P
ermeability
in
the
alternating-current
magnetic
eld
is
dened
as
complex
relative
permeability
(
*
r
)
(See
Equation
3-1).
The
real
component
of
the
complex
relative
permeability
(
'
r
)
represents
the
amount
of
energy
stored
in
the
magnetic
material
from
the
alternating-current
magnetic
eld.
On
the
other
hand,
the
imaginary
component
(
"
r
)
indicates
energy
loss
to
the
alternating
current
magnetic
eld.
Equation
3-1.
Denition
of
Complex
Relative
P
ermeability
3
r
=
0
r
0
j
00
r
As
shown
in
Figure
3-1,
complex
relative
permeability
can
be
expressed
in
a
vector
diagram.
The
loss
factor
of
a
magnetic
material
is
expressed
as
loss
tangent
(tan
),
which
is
the
ratio
of
the
imaginary
component
(
"
r
)
to
the
real
component
(
'
r
)
of
the
complex
relative
permeability
.
Figure
3-1.
V
ector
Diagram
of
Complex
Relative
P
ermeability
and
Loss
T
angent
Measurement
Principle
of
Magnetic
Material
When
using
a
LCR
meter
or
an
Impedance
Anlyzer
,
the
inductance
measurement
method
is
employed
to
measure
complex
relative
permeability
.
In
this
method,
a
DUT
(toroidal
core)
is
coiled
with
a
wire
and
relative
permeability
is
calculated
from
the
measured
inductance
values
.
This
section
explains
the
measurement
principle
when
using
the
test
xture
,
16454A.
Theory
on
Material
Measurement
3-1
Summary of Contents for 16454A
Page 1: ...Operation and Service Manual Keysight 16454A Magnetic Material Test Fixture ...
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Page 12: ...APC 7 R is a U S registered trademark of the Bunker Ramo Corporation viii ...
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