Using
−
=
−


cos(
)
sin
ω
ω
t
t
2π
, we have
i
i
t
=m
−


sin ω
2π
(7 12)
where  
m
m
v
i
= ωL
is the amplitude of the current The quantity w L is
analogous to the resistance and is called inductive reactance, denoted
by XL:
XL = w L
(7 13)
The amplitude of the current is, then
m
m
L
v
i
=X
(7