
31-11Immittance Measurement
Since the quantities are complex, Equation 31.33 involves the adjustment of two parameters: magnitude
an
d
p
hase
Z
Z
Z
Z
x x
,= = − +
1
3
2 1 3 2
ϕ ϕ ϕ ϕ
(3
1
.34
)
or
r
eal
a
nd
i
maginary
p
arts,
r
espectively
.
An i
mportant
p
roperty
o
f
a
n
i
mpedance
b
ridge
i
s
t
he
s
ensitivity
ε
ε
=
∂
∂
=
+
V
Z
V
Z
Z Z
d
x x
2
2
2
( )
(3
1
.35
)
or
(
independent
o
f
Z
x
)
ε
=
+
V
Z
Z Z Z
3
2
2 1 3
2
( )
(3
1
.36
)
in
t
he
v
icinity
o
f
z
ero
c
rossing
w
hen
t
he
b
ridge
i
s
b
alanced
.
e pr
ecision
of th
e
me
asurement
no
t
on
ly
de
pends
on th
e
ex
act
ze
ro
ad
justment,
wh
ich
ca
n
be
enhanced by choosing the elements and the voltage according to Equation 31.36 to obtain a high sensi-
tivity, but also on the