JK2830 Operation Manual Chapter 5 Execute LCR operation and some examples
Chapter 5
Execute LCR operation and some
examples
5.1
Correct connection of DUT
There are 4 pairs of test terminal: Hcur, Hpot, Lpot, Lcur 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 short
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