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Solution:
P dc
P dc � V dcI dc
3.6 W
and Idc �����30 mA
Vdc 120 V
Im � �2�Idc � (1.414)(30 mA) � 42.42 mA
Em � �2�Edc � (1.414)(120 V) � 169.68 V
EXAMPLE 13.21 Find the effective or rms value of the waveform of
Fig. 13.55.
Solution:
v 2 (Fig. 13.56):
(9)(4) � (1)(4) 40
Vrms � �� � � � 2.236 V
��8 ��8 EXAMPLE 13.22 Calculate the rms value of the voltage of Fig. 13.57.
4
0
–2
–10
v (V)
Solution:
v 2 (Fig. 13.58):
100
16
4
1 cycle
4 6 8 10 t (s)
FIG. 13.57
Example 13.22.
Vrms ���� ���
(100)(2) � (16)(2) � (4)(2) 240
��� �
10
10
v 2 (V)
� 4.899 V
0 2 4 6 8 10 t (s)
FIG. 13.58
The squared waveform of Fig. 13.57.
3
0
–1
9
1
EFFECTIVE (rms) VALUES ⏐⏐⏐ 549
v (V)
v 2 (V)
1 cycle
4
FIG. 13.55
Example 13.21.
8
(– 1) 2 = 1
t (s)
0 4 8 t (s)
FIG. 13.56
The squared waveform of Fig. 13.55.