User Manual SM6026
48
c) Press
ON
to turn on the open correction function.
d) Move the cursor to the Short zone,
ON, OFF
and
MEAS SHORT
will be displayed in the soft key zone.
e) Press
ON
to turn on the short correction function.
f) Move the cursor to the
LOAD
zone,
ON, OFF
will be displayed in the soft key zone.
g) Press
OFF
to turn off the load correction function.
h) Move the cursor to the
Freq 1
zone,
ON, OFF, MEAS OPEN, MEAS SHORT
and
MEAS LOAD
will be
displayed in the soft key zone.
i) Press
ON
to turn on the point-frequency correction function of
Freq 1
.
j) Press [5] [.] [5], +5.5 will be displayed in the prompt information zone at the bottom of the screen
meanwhile the available units (
Hz, kHz
and
MHz
) will be displayed in the soft key zone. Press
kHz
, the
FREQ 1
zone will be changed as 5.5000kHz (be the same as that of test frequency).
k) Keep the test fixture be in open status and press
MEAS OPEN
to execute open correction.
l) Insert the short plate (26010) to the test fixture.
m) Press
MEAS SHORT
to execute short correction.
5.2
Correct connection of DUT
There are 4 pairs of test terminal: Hcur, Lcur, Hpot, Lpot and corresponding shielding terminal of each
terminal.
Each terminal contains shielding layer whose function is to reduce the influence of the ground stray
capacitance and the interference of the electromagnetic field. In the process of testing, Hcur, Hpot and
Lpot, Lcur should be connected with DUT lead to form a complete 4-terminal measurement, thus
reducing the effect of the lead and the connection points on the test results (especially the dissipation
measurement). When testing low-ohm components, Hpot, Lpot should be connected to the lead terminal
so as to avoid the impedance being added to the lead impedance and the connection principle is that the
Hpot and Lpot test should be the actual existed voltage on DUT.
In other words, before connecting to DUT, it is not recommended to connect Hcur, Hpot with Lpot, Lcur,
for doing this will increase test error.
If the connection point and the lead resistance R lead are far weaker than the tested impedance (for
example: Rlead<Zx/1000, the accuracy error is required to be less than 0.1%), before connecting to DUT,
it is recommended to connect Hcur, Hpot and Lpot, Lcur (Two terminal test).
In the test with high accuracy requirement, using Kelvin test fixture (standard accessory) will gain better
results than using test leads. When Kelvin test lead is used under 10kHz, a better measurement result
can be obtained.However, when the frequency is higher than 10kHz, it cannot meet the measurement
demand. In high frequency, the change of the clearance between test leads will directly change stray
capacitance and inductance on test terminals and this problem is unavoidable, because the test leads
cannot be fixed in a position.
So, the use of the test fixture should be used as possible in high frequency. If the test fixture is
unavailable or cannot be used, the status of test leads should be the same in the processes of correction
and test.
No matter the standard Kelvin test fixture or Kelvin test leads or user-made fixture is used, the following
requirements should be met.
1. Distribution impedance must be reduced to the Min. especially when testing
high impedance components.
2. Contact resistance must be reduced to Min.
3. Short and open must be available between contact points. Open and short correction can easily
reduce the influence of distribution impedance of the test fixture on measurement. For open correction,
the clearance between test terminals should be the same with that when they connects with DUT. For
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