Basic Circuit Theory Chpter5 Problems 1 The switch in Fig.5-27 is opened at t = 0, Find i (0 ) and v (0 ) L + L + + - - t=0 + L i ?k1V100 ?k1 L v mH5 Fig. 5-27 For prob.1. 2 The switch is closed at t = 0 in Fig.5-28. Find i(0 ) and i (0 ) if the capacitor is initially uncharged. + C + + - t=0 + - ?5 C v V10 F2 ()ti ?k01 C i Fig. 5-28 For prob.2. 3 (a) The switch in Fig.5-29 is closed at t = 0. If the initial capacitor voltage and inductor current are both zero, find v (0 ) and i (0 ). (b) Suppose the switch in Fig.5-29 has been closed for a long time when it is opened at t = 0. Find v (0 ) and i (0 ). R + R + R + R + + - t=0 + - ?k1 F10μV100 mH10 R v R i Fig. 5-29 For prob.3. 4 For the circuit shown in Fig.5-30, find i 1 (0 ), i (0 ), and v(0 + ). + 2 + + t =0 - ?2 ?8 V24 )(tv H2H1 ?4.0 1 i 2 i Fig. 5-30 For prob.4. 5 After being in the configuration shown for a long time, the switch in Fig.5-31 is opened at t = 0. Determine values for i (0 ), i (0 ), i (0 ), and i (0 ). S ? x ? S + x + + - t=0 x i ?20V34 ?100 ?75 ?25 mF10 s i x i8.0 Fig. 5-31 For prob.5. DaLian Maritime University 1 Basic Circuit Theory Chpter5 Problems 6 The switch in the circuit of Fig.5-32 is a single-pole, double-throw switch that is drawn to indicate that it closes one circuit before opening the other. Assuming the switch has been in the position drawn in the figure for a long time, determine the value of v and i (a) the instant just prior to the switch changing; (b) the instant just after the switch changes. L A5 H3 ?2 ?8 L i v ?12 + - 0=t Fig. 5-32 For prob.6. 7 The switch in Fig.5-33 opens at t = 0 after having been closed for time immemorial. Find i (0 ), i (0 ), and i (0 ), i (0 ). L ? x ? L + x + t=0 x i ?100 L i mH50 ?300 ?150 mA60 Fig. 5-33 For prob.7. 8 After being open for two days, the switch in Fig.5-34 closes at t = 0, sketch v(t) versus t and evaluation v at t = 15s. + t =0 - V6 )(tv?2.1 ?3.0 ?7.0 H2.4 Fig. 5-34 For prob.8. 9 The switch in series with the battery in Fig.5-35, having been closeed for a long time, is opened at t = 0. Over what time interval is the voltage magnitude across the switch greater than 1V? 10 The switch in the circuit shown in Fig.5-36 is opened at t = 0 after being closed for a long time, Find v for t > 0. x t=0 Fig. 5-35 For prob.9. ?100 V12 F200μF400μ ?100 + - t=0 + - ?k1 mA3 V9.0 F5.2 μ ?k2 x v DaLian Maritim Fig. 5-36 For prob.10. e University 2 Basic Circuit Theory Chpter5 Problems Reference Answers to Selected Problems 1: 0.1A, -200V (t=0 ); 0A, 0V (t + ∞→ ). 2: i(0 )=i (0 )=0. + C + 4: (a) 9.6A; (b) 2.4A; (c) 9.6e A; (d) 2.4 e A; (e) 19.2(e - e )V. t2? t4? t4? t2? 5: (a) 290 mA; (b) 200 mA; (c) 50 mA; (d) 277 mA; (e) 33.5 mA. 6: (a) i (0 )=4A, v(0 )=0; (b) i (0 )=4A, v(0 )=48V. L ? ? L + + 8: 0.39V. 9: 2.35 ms. 10: 1.4e V ( t > 0). t200? DaLian Maritime University 3