1. C H A P T E R 4
AC Network Analysis

2. Figure 4.1 Structure of parallel-plate capacitor+ _
Circuit
symbol C = A d F
permittivity of air
Parallel-plate capacitor with air
gap
(air is the dielectric) 10 12 m
8.854 x

3. Figure 4.2 Combining capacitors in a circuit1 2 3
Capacitances in parallel add EQ
= C
+ C
Capacitances in series combine
like resistors in parallel = +

4. Figure 4.8 Iron-core inductor
Magnetic flux
lines
Iron core
inductor i ( t ) L
Circuit
symbol di dt v
) = _ +

5. Figure 4.9 Combining inductors in a circuitL EQ = 1 + 2 3
Inductances in series add
Inductances in parallel combine
like resistors in parallel

6. Figure 4.13 Analogy between electrical and fluid resistancev 1 2 i q f p R

7. Figure 4.14 Analogy between fluid capacitance and electrical capacitanceq f P 1 p
gas 2 + _ C i v

8. Figure 4.15 Analogy between fluid inertance and electrical inertancev 1 p 2 I f q L + –

9. Figure 4.18 Time-dependent signal sources+ _ v ( t ) i ),
Generalized time-dependent sources
Sinusoidal source

10. Figure 4.19 Periodic signal waveformsT 2 3 4
Time
Sawtooth wave
Square wave
Triangle wave
Pulse train
Sine wave _

11. Figure 4.20 Sinusoidal waveformst A T _
Reference cosine
Arbitrary sinusoid

12. Figure 4.27 Euler’s identityIm j _ 1 Re
sin
cos e
= cos +

13. Figure 4.33 The impedance element+ ~ – v S ( t ) j i R L C
AC circuits
AC circuits in
phasor/impedance form Z
is the
impedance
of each
circuit
element

14. Figure 4.34 Impedances of R, L and C in the complex planeZ R
= R L
= j C = 1 j Im Re – 2
-90

15. Figure 4.42 An AC circuit v ( t ) i R L C j Z A sample circuit1 2 R L x C j Z
A sample circuit
for AC analysis
The same circuit
in phasor form + ~ –

16. Figure 4.45 AC equivalent circuits
Source Z L
(b) Equivalent source S ( j )
Load
(a) Equivalent load + ~ –

17. Figure 4.46 Rules for impedance and admittance reductionZ 1 2
Impedances in parallel behave like resistors in parallel: + Y
Admittances in parallel add:
Admittances in series behave like conductances in series:
Impedances in series add:

18. Figure 4.47 Reduction of AC circuit to equivalent formS Z 2
A phasor circuit
with load L 3 1 4 ab a b
Circuit for the computation of the equivalent
impedance, T OC = SC N
Circuit for the computation of the Th é
venin
equivalent voltage
Circuit for the computation of the Norton
equivalent current
+ ( ||
) + O C + ~ –