Page 72 - Circuit Analysis II with MATLAB Applications

Chapter 2 Resonance

We will see later that

Z Resonant Frequency
0
Q = ------------------ = ------------------------------------------------------- (2.11)
Z – Z 1 Bandwidth
2
We also observe from (2.9) that selectivity depends on and this dependence is shown on the plot
R
of Figure 2.6.

High and Low Q Curves
Dependence on R
R

Relative Response 2R

Z

Figure 2.6. Selectivity curves with different values of R

If we keep one reactive device, say , constant while varying , the relative response “shifts” as
C
L
shown in Figure 2.7, but the general shape does not change.

Resonance at Constant L and Variable C
Relative Response C 0.5C

Z
Figure 2.7. Relative response with constant L and variable C

2.3 Parallel Resonance

Parallel resonance (antiresonance) applies to parallel circuits such as that shown in Figure 2.8.

2-6 Circuit Analysis II with MATLAB Applications

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