Metrohm 746 VA Trace Analyzer - Manual (Page 339)

5.7 Program instructions
746 VA Trace Analyzer / 747 VA Stand
5-188
Description In the AC2MODE measurement mode, a sinusoidal alternating voltage with
a small, constant amplitude and low frequency is superimposed on a
stepwise rising direct voltage ramp. The 2
nd harmonic wave of the alter-
nating current component I produced by the alternating voltage is
measured as a function of the voltage U. The nature of the measurement
is illustrated below using the SMDE as an example.
Adjustable parameters:
AC2MODE
t.step
U.ampl
Modul.freq.
Ph.angle
Prep.cycles
Meas.cycles
SWEEP
U.start
U.end
U.step
t.drop
t
U
t
U.step
U.start Prep.
cycles
Meas.
cycles
t.step
Ph.angle = 0 °
F (Hg)
t.modul = 1/Modul.freq.
U.ampl × √ 2
Ph.angle > 0 °
Ph.angle
Ph.angle < 0 °
90 º 180 º 270 º 360 º
Ph.angle
-180 º -90 º 90 º 180 º 270 º 360 º
(I
n+
)
(current addition)
(I
n–
)
(current subtraction)
t.meas
(I
n+
)
t.meas
(I
n–
)
t.meas
(I
n–
)
t.meas
(I
n+
)
Area (Hg)