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CHAP. 2]

15

CIRCUIT CONCEPTS

Fig. 2-10

Fig. 2-11

2.4

An inductance of 3.0 mH has a voltage that is described as follows: for 0 > t > 2 ms, V ¼ 15:0 V and, for 2 > t > 4 ms, V ¼ 30:0 V. Obtain the corresponding current and sketch vL and i for the given intervals. For 0 > t > 2 ms, i¼

1 L

ðt v dt ¼ 0

1 3  103

ðt

15:0 dt ¼ 5  103 t ðAÞ

0

For t ¼ 2 ms, i ¼ 10:0 A For 2 > t > 4 ms, i¼

1 L

ðt v dt þ 10:0 þ 2103

1 3  103

ðt 30:0 dt 2103

1 ½30:0t þ ð60:0  103 Þ ðAÞ 3  103 ¼ 30:0  ð10  103 tÞ ðAÞ

¼ 10:0 þ

See Fig. 2-12.

2.5

A capacitance of 60.0 mF has a voltage described as follows: 0 > t > 2 ms, v ¼ 25:0  103 t (V). Sketch i, p, and w for the given interval and find Wmax . For 0 > t > 2 ms,

Mahmood_Nahvi_eBook_Schaum_s_Outlines_Theory_An