200 likes | 211 Vues
C H A P T E R. 5. Transient Analysis. 1. 0.8. 0.6. 0.4. 0.2. 0. 0. 0.2. 0.4. 0.6. 0.8. 1.0. 1.2. 1.4. 1.6. 1.8. 2.0. t. (s). (a) Transient DC voltage. 1. 0.5. 0. –. 0.5. –. 1. 0. 0.2. 0.4. 0.6. 0.8. 1.0. 1.2. 1.4. 1.6. 1.8. 2.0. t. (s).
E N D
C H A P T E R 5 Transient Analysis
1 0.8 0.6 0.4 0.2 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 t (s) (a) Transient DC voltage 1 0.5 0 – 0.5 – 1 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 t (s) (b) Transient sinusoidal voltage Figure 5.1 Examples of transient response
t = 0 R Switch C 12 V L Complex load Figure 5.2 Circuit with switched DC excitation
Switch R S Circuit t = 0 containing V s R L / RC combinations Figure 5.3 A general model of the transient analysis problem
A circuit containing energy-storage elements is described by a differential equation. The differential equation describing the series RC circuit shown is di dv 1 S C + i = C dt RC dt _ v + R i R C + i R + _ v ( t ) v ( t ) C S C _ Figure 5.5 Circuit containing energy-storage element
R + + _ v ( t ) C v ( t ) S C _ dv 1 1 C – v – v = 0 RC circuit: C S dt RC RC R + _ v ( t ) i ( t ) L S L di R 1 L i – – v = 0 RL circuit: L S dt L L Figure 5.9 Differential equations of first-order circuits
t = 0 Switch Switch v V C R C B i ( t ) Exponential decay of capacitor current 1 0.9 0.8 0.7 Capacitor voltage, V 0.6 0.5 0.4 0.3 0.2 0.1 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Time, s Figure 5.10 Decay through a resistor of energy stored in a capacitor t = 0
t = 0 i L I L R S Figure 5.15
– + i (0 ) L v ( t ) R L ( ) i t L + i ( t ) L 10 mA 0 t Figure 5.16
t = 0 R R 1 2 + v R V V C C 1 3 2 _ Figure 5.22 A more involved RC circuit
Figure 5.23 The circuit of Figure 6.45 for t > 0 + R R 1 2 v R C C 3 V V 1 2 _
R R R 1 3 2 V V / R 1 2 2 R 1 V V 1 2 + R T R R 1 2 R = R R R T 1 2 3 R T + V _ T Figure 5.24 Reduction of the circuit of Figure 5.23 to Thevenin equivalent form
R T + + V V C _ T C _ Figure 5.25 The circuit of Figure 5.22 in equivalent form for t > 0
R T + v (t) _ C L T Parallel case (a) R T L + _ v ( t ) T C Series case (b) Figure 5.39 Second-order circuits
2 1.5 x ( ) t N 1 – t e 2 0.5 e – t 1 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 t (s) Figure 5.43 Response of overdamped second-order circuit
1 0.8 0.6 x ( t ) N 0.4 – t e 0.2 – t te 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 t (s) Figure 5.44 Response of critically damped second-order circuit
t = 0 _ v ( t ) + C R _ + v ( t ) C R + + V v ( t ) L _ S i ( t ) L _ R = 5000 L = 1 H C = 1 F V = 25 V S Figure 5.46
t = 0 + C R L v ( t ) i ( t ) i ( t ) i ( t ) C R L I _ S L = 2 H C = 2 F I R = 500 = 5 A S Figure 5.48
N N 2 2 = 100 = 100 N N 1 1 N N N N 1 1 2 2 L R L , R , + + P P P P V V B B i i – – spark spark plug plug C C switch switch closed closed Figure 5.52