Ver 2.1

12/03/01

3

|Z| =

2

2

Xs

Rs +

Rs = |Zs| cosθ

Xs = |Zs| sinθ

Xs/Rs = tanθ

θ

If θ > 0, the reactance is inductive. In other words, if θ < 0, the reactance is capacitive.

C

2

1

f

π

(C = Capacitance)

Measurement mode

The impedance could be measured in series or parallel mode. The impedance Z in

parallel mode could be represented as reciprocal of admittance Y. The admittance could

be defined as Y = G + jB. The G is the conductance and the B is the susceptance.

Rs: Resistance in series mode

Rp: Resistance in parallel mode

Xs: Reactance in series mode

Xp: Reactance in parallel mode

Cs: Capacitance in series mode

Cp: Capacitance in parallel mode

Ls: Inductance in series mode

Lp: Inductance in parallel mode

There are two factors to provide the ratio of real part and imaginary part. Usually

the quality factor Q is used for inductance measurement and the dissipation factor D is

used for capacitance measurement. D factor is defined as a reciprocal of Q factor.

Q = 1 / D = tanθ

Q = Xs / Rs = 2πf Ls / Rs = 1 / 2πf Cs Rs

Q = B / G = Rp / | Xp | = Rp / 2πf Lp = 2πf Cp Rp

Impedance in serial mode

Rs

jXs

Z = Rs + jXs

Impedance in serial mode

Rs

jXs

Z = Rs + jXs

Admittance in parallel mode

Rp

jXp

Y = 1/Z = 1/Rp + 1/jXp = G + jB

Admittance in parallel mode

Rp

jXp

Y = 1/Z = 1/Rp + 1/jXp = G + jB