Page 87 - Circuit Analysis II with MATLAB Applications

Summary

1
Z = -----------
0
LC
x The quality factor Q 0P at parallel resonance is defined as

Z C 1
0
Q 0P = ---------- = --------------
Z GL
G
0
x The general definition of is
Q
Maximum Energy Stored
Q = 2S------------------------------------------------------------------------------
Energy Dissipated per Cycle

x In a parallel RLC circuit, the half-power frequencies Z and Z are the frequencies at which the
1 2
magnitude of the input admittance of a parallel resonant circuit, is greater than the magnitude at
resonance by a factor of 2 , or equivalently, the frequencies at which the magnitude of the input
impedance of a parallel resonant circuit, is less than the magnitude at resonance by a factor of 2 .

x We call Z 1 the lower half-power point, and Z 2 the upper half-power point. The difference
Z – Z 1 is the half-power bandwidth BW , that is,
2
Bandwidth = BW = Z – Z 1
2
Q
x The bandwidth BW can also be expressed in terms of the quality factor as
Z
0
BW = Z – Z = ---------
2
1
Q
or 0P
f
0
BW = f – f = ---------
2
1
Q
0P

Circuit Analysis II with MATLAB Applications 2-21
Orchard Publications