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P q<br />

s<br />

small region below the axis is the return of energy to the network by the<br />

reactive elements. In general, therefore, the source must supply power<br />

to the circuit most of the time, even though a good percentage of the<br />

power may simply be delivering energy to the reactive elements and<br />

may not being dissipated.<br />

PROBLEMS<br />

SECTIONS 19.1 THROUGH 19.7<br />

1. For the battery of bulbs (purely resistive) appearing in<br />

Fig. 19.40:<br />

a. Determine the total power dissipation.<br />

b. Calculate the total reactive and apparent power.<br />

c. Find the source current Is. d. Calculate the resistance of each bulb for the specified<br />

operating conditions.<br />

e. Determine the currents I1 and I2. 2. For the network of Fig. 19.41:<br />

a. Find the average power delivered to each element.<br />

b. Find the reactive power for each element.<br />

c. Find the apparent power for each element.<br />

d. Find the total number of watts, volt-amperes reactive,<br />

and volt-amperes, and the power factor Fp of the circuit.<br />

e. Sketch the power triangle.<br />

f. Find the energy dissipated by the resistor over one full<br />

cycle of the input voltage.<br />

g. Find the energy stored or returned by the capacitor<br />

and the inductor over one half-cycle of the power<br />

curve for each.<br />

+<br />

E = 50 V ∠0°<br />

–<br />

f = 60 Hz<br />

R<br />

3 �<br />

FIG. 19.41<br />

Problem 2.<br />

+<br />

E<br />

–<br />

I s<br />

240 V<br />

X C XL<br />

5 �<br />

9 �<br />

60 W<br />

20 W<br />

FIG. 19.40<br />

Problem 1.<br />

PROBLEMS ⏐⏐⏐ 879<br />

I 1<br />

40 W<br />

I 2

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