§ 7-3 Effective values of current and voltage.
The effective value of any periodic current is equal to the
value of the direct current which flowing through a resistance R,
delivers the same power to R as periodic current does.
R RI i
RIP 2? dti
T
RR d ti
TP
TT ?? ??
0
2
0
21
dtiTRRI T?? 0 22 dtiTI T?? 0 21
The root mean square value
dtTV T?? 0 21 ?
22
1 m
m
IT
TI ???
2
mII ??
2
mVVa n d ?
? ?? T m dttITI 0 22 )(co s1 ?? ? ??? Tm dttTI 0 2 )(2co s11 ??
Rms of the sinusoidal waveform: