PPA5xx/15xx user manual
13-2
according to the phase of the measurement. Alternatively,
the display can be forced to capacitance, inductance or
impedance.
Capacitance is displayed with tan, inductance is displayed
with Q factor, and impedance is displayed in its resistive +
reactive form and as magnitude. The phase of the
impedance is displayed with all options.
For phase critical impedance measurements, is it possible
to offset the phase measurement to allow for phase shift
within the connection leads.
Note that the phase of the impedance is the opposite to
the phase of the current in POWER mode. This is because
the impedance is defined as voltage/current which,
considering the magnitude and phase of Z (impedance), V
(voltage) and A (current), gives:
Zmagnitude = Vmagnitude / Amagnitude
Zphase = Vphase – Aphase
As the phase is referred to the voltage:
Zphase = - Aphase
Therefore, using the phase convention from -180° to
+180°, an inductive load which has an impedance with a
positive phase would cause a current with a negative
phase.