Hioki 3532-50, Инструкция по эксплуатации

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5.7 Supplying DC Bias
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5.7.2 How to Supply a DC Bias Current
CAUTION
In order to avoid electric shock accident, be absolutely sure not to
touch the test terminals while the DC bias is being supplied to them.
Due to the inductance of the coil and the sample, counter electromotive
force is generated when the sample is removed or inserted with the DC bias
supplied. This may result in damage to the 3532-50 or to the DC source.
When measuring the element whose DC resistance is high (incl. open state),
a high voltage occurred on the H side may cause damage on the main unit.
Capacitor
C
HC
Z
Choke coil
CH
+
‑
3532-50
+
‑
DC current
source
Sample to be tested
L
POT
L
CUR
H
POT
H
CUR
C
HP
DC Bias Current Circuit
To supply a DC bias, use the optional 9269 DC BIAS CURRENT UNIT
(Maximum input current DC2 A).
For details on using the 9269, refer to the Instruction Manual of the 9269.
(Depending on the test frequency, test signal level, and test range, the 9269
cannot be used.)
If the 9269 is not used, refer to the followings.
To supply a DC bias current to a transformer or a choke coil or the like,
construct an external bias circuit as follows.
Connect the sample to the measuring probe and then gradually raise the
voltage of the DC source to the specified DC bias level. To disconnect the
sample, gradually reduce the voltage of the DC source until the DC bias
supplied to the sample is decreased to zero. You may disconnect the sample
after this is achieved.
Use a choke coil (CH) which has a large enough impedance with reference
to the sample under test ( Z ).
A Hcur side capacitor must have a small enough impedance (i.e. a large
enough capacitance) relative to the output resistance (50
Ω
) while a Hpot
capacitor must have a small enough impedance to the input resistance (10k
Ω
).
Be careful about the polarity when connecting together the probes, the
sample to be tested, and the DC current source.
Be careful not to magnetically saturate the choke coil (CH) with the DC bias current.
It takes a little time for the DC current which is being supplied to the sample
under test to reach the set value, so you should wait for a certain
stabilization time period (which depends upon the sample) before performing
testing. Be careful, because if you perform testing before this stabilization
time period has elapsed, the results will not be reliable.