NF ZM2371, Instruction Manual

Page: 120 / 255

4.8 Using the DC Bias
4-33 ZM2371/ZM2372
！
WARNING
Use the bias voltage within the following range:
(
|
Bias voltage[V]
|
+ 1.41 × Measurement signal level [Vrms]) < 42V
Otherwise, it may cause an electrical shock.
When using the bias voltage beyond the above range, arrange the structural
protection for preventing from touching the charging section. Do not touch the
charged DUT.
It is also possible to measure internal impedance of battery in the same manner as above. If
you don’t intend to take off the load current from the battery, connect the battery only after
charging the C1 and C2 up to the electromotive force of battery by the external power. The
external power should be removed during measurement. Or the resistance value R1 for
charge-/discharging should be increased.

Applying a DC bias current
To measure while DC bias current is running through the DUT like Inductor, external power
is needed. Turn off the DC bias output of
ZM2371 / ZM2372
.
Since the external power is connected with DUT in parallel, insert the choke coil having
excessively higher impedance than that of DUT through the external power in series. It is
impossible to make an OPEN correction while the bias current is running. Besides, to
prevent the DC voltage and current from running through the LCR meter, insert the
capacitor into the H
CUR
terminal and H
POT
terminal respectively in series. If it is possible
that the LCR meter can be damaged due to the high voltage caused by the disconnected DUT,
set the protective diode.
The bias current should be increased/decreased little by little. Sudden changing may cause a
high voltage.
！
WARNING
To connect/disconnect the DUT, the output of external power should be set to
“0”. Once the DUT like inductor is disconnected while the bias current is
running, high voltage may be generated, thereby causing an electrical shock.
If the temperature of DUT can be increased during measurement, do not touch it
until the temperature excessively drops after measurement. If high voltage or
current is applied on the DUT for a long time, high temperature may cause a
burn or DUT/ circumference can be burn out.