tailieunhanh - Electric Circuits, 9th Edition P38

Electric Circuits, 9th Edition P38. Designed for use in a one or two-semester Introductory Circuit Analysis or Circuit Theory Course taught in Electrical or Computer Engineering Departments. Electric Circuits 9/e is the most widely used introductory circuits textbook of the past 25 years. As this book has evolved over the years to meet the changing learning styles of students, importantly, the underlying teaching approaches and philosophies remain unchanged. | 346 Sinusoidal Steady-State Analysis in Fig. depicts these observations. The dotted phasors represent the pertinent currents and voltages before the addition of the capacitor. Thus comparing the dotted phasors of I 2 jl jcuLiI and V5. with their solid counterparts clearly shows the effect of adding C to the circuit. In particular note that this reduces the amplitude of the source voltage and still maintains the amplitude of the load voltage. Practically this result means that as the load increases . as Ia and Ib increase we can add capacitors to the system . increase Ic so that under heavy load conditions we can maintain VL without increasing the amplitude of the source voltage. Figure The effect of the capacitor current Ie on the line current I. Ib Figure The addition of a capacitor to the circuit shown in Fig. . I Figure The effect of adding a load-shunting capacitor to the circuit shown in Fig. if VL is held constant. NOTE Assess your understanding of this material by trying Chapter Problems and . Practical Perspective A Household Distribution Circuit Let us return to the household distribution circuit introduced at the beginning of the chapter. We will modify the circuit slightly by adding resistance to each conductor on the secondary side of the transformer to simulate more accurately the residential wiring conductors. The modified circuit is shown in Fig. . In Problem you will calculate the six branch currents on the secondary side of the distribution transformer and then show how to calculate the current in the primary winding. NOTE Assess your understanding of this Practical Perspective by trying Chapter Problems and . 1 if va -I. 120 œ _ V 2ii ----VA-- - I 120 œ -V 10 -----VA 20f Ï5 Í II O 10íl ll4 I 40 il Figure A Distribution circuit. Summary 347 Summary The general equation for a sinusoidal source is y V cos wi voltage source or i Im cos a i current source where Vm or Z is the maximum .