B&K Precision 889B - Manual - Manual (Page 5)

4
Cs : Serial Capacitance
Cp : Parallel Capacitance
 Second Parameter Display:
θ
: Phase Angle
ESR : Equivalence Serial Resistance
D : Dissipation Factor
Q : Quality Factor
 Combinations of Display:
Serial Mode : Z –
θ, Cs – D, Cs – Q, Cs – ESR, Ls – D, Ls – Q, Ls – ESR
Parallel Mode : Cp – D, Cp – Q, Lp – D, Lp – Q
1.2 Impedance Parameters
Due to the different testing signals on the impedance measurement instrument, there are DC and AC
impedances. The common digital multi-meter can only measure the DC impedance, but the 889B can do both. It
is very important to understand the impedance parameters of the electronic components.
When we analysis the impedance by the impedance measurement plane (Figure 1.1), it can be visualized by the
real element on the X-axis and the imaginary element on the y-axis. This impedance measurement plane can
also be seen as the polar coordinates. The Z is the magnitude and
θ is the phase of the impedance.
( )
( )
( )
( )
( )
Ohm
Reactance
Resistance
Impedance
= Ω
=
=
=
−
= =
+ = =
Ω ∠ = + =






S
S
X
R
Z
s R
s
X
Tan Sin Z
s
X
s
X
s
R Z Cos Z
s
R
Z s jX s R Z
1
2 2
θ θ
θ
θ
There are two different types of reactance: Inductive (X
L
) and Capacitive (X
C
). It can be defined as follows:
Also, there are Quality factor (Q) and the Dissipation factor (D) that need to be discussed. For component, the
Quality factor serves as a measurement of the reactance purity. In the real world, there is always some
associated resistance that dissipates power, decreasing the amount of energy that can be recovered. The Quality
factor can be defined as the ratio of the stored energy (reactance) and the dissipated energy (resistance). Q is
generally used for inductors and D for capacitors.
s X
s R
( )
s X , R Z s
Z
θ
Imaginary Axis
Real Axis
Figure 1.1
fC C
C
X
fL L
L
X
π ω
π ω
2
1 1
2
= =
= = L = Inductance (H)
C = Capacitance (F)
f = Frequency (Hz)