To express it in the same form as the dc power (P = I 2R), a
special value of current is used It is called root mean square (rms)
current and is donoted by I:
0 707
2
m
m
i
I
i
=
=
Similarly, the rms voltage is defined by
0 707
2
m
m
v
V
v
=
=
We have P = IV = I 2R
3