81
◆
Impedance (Z) and Admittance (Y)
The impedance covers oppositions in AC circuits in-
cluding resistance, inductance, and capacitance and is measured in units of
Ohm (Ω).
In electrical engineering, admittance covers both conductance and suscep-
tance and is the reciprocal of impedance. It is measured in units of Siemens
(S).
⚫
Impedance (Z):
Relevant Equations
：
(
)
(
)
sin
cos
1
2
2
2
2
Z
X
Z
R
X
R
RX
Z
X
R
Z
C
j
R
L
j
R
jX
R
Z
Y
I
E
Z
s
s
p
s
s
=
=
+
=
+
=
−
=
+
=
+
=
=
=
⚫
Admittance (Y):
Relevant Equations
：
(
)
(
)
sin
sin
1
2
2
2
2
Y
B
B
G
Y
B
G
GB
Y
Y
X
B
p
p
s
=
+
=
+
=
=
=
