PPA5xx/15xx user manual
13-1
13 Impedance meter
The IMP mode on the PPA5xx/15xx uses the real and
imaginary components at the fundamental frequency using
DFT analysis as described previously to compute the
impedance of the load and associated parameters.
From the fundamental components of voltage, (a + jb),
and those of the current, (c + jd), the PPA5xx/15xx
computes the complex impedance given by:
z = v / i
= (a + jb) / (c + jd)
The components of the complex impedance are filtered
independently to minimise the effects of noise, which
would have random phase and would, therefore, be
filtered out.
The magnitude of the voltage and current are also
computed.
From the complex impedance the following parameters can
be derived:
resistance
inductance,
capacitance
impedance
phase
tan (= real/imaginary)
Q factor (= imaginary/real)
Values can be displayed for either series or parallel
models.
If the parameter option in LCR menu is set to ‘auto’, the
PPA5xx/15xx will display capacitance or inductance