83
◆
Quality factor (Q) and Dissipation factor (D)
The quality factor measures energies consumed by relative frequency. In
general, the better a circuit's quality factor the better its selectivity.
The dissipation factor is the reciprocal of quality factor. It is the signal angle
loss by a capacitor (or inductor) and acting frequency at a fixed temperature.
Phase shifts caused by time lag between an externally applied voltage and
current generated may result in loss of current and energy dissipation. Here
the total current (I) is the sum of the charging current (Ic) by a 90
゚
voltage
phase shift and loss current (IR) of the same voltage. The loss angle is the
angle δ between the total current and charging current and tanδ the dissipa-
tion factor (symbol: D) as shown in the figure below:
⚫
Quality factor
(
Q
)
Relevant Equations
:
(
)
(
)
(
)
D
Q
R
C
R
L
Q
R
C
L
R
Q
s
s
s
s
P
p
p
p
1
90
tan
1
values
C
,
L
,
R
series
1
values
C
,
L
,
R
series
=
−
=
=
=
=
=