Products > Test Equipment
Sensitive LCR Meter Measurements
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mawyatt:
BTW we did some measurements the other day with the cheap common 4 Wire Kelvin Clips and our DMM3500 for some low valued precision 2512 SMD chip resistors. Was a real PITA, even had a couple chips "flip out" with these clips :o

Did find them after crawling around on the floor the next morning tho ???

Then we used the Special Custom Split-Kelvin SMD Fixture with the DMM6500 and this was much easier, and we appreciated why we developed this Specialized SMD Fixture  ;)

Also tried the Standard type SMD Fixture and couldn't get anything reasonable as the Zero Cal is too much dependent on the Zero DUT. Just not repeatable down to the levels necessary for good low milli-ohm measurements IMHO. This isn't surprising as these fixtures are more for higher Z components and the termination of the Force and Sense at the Plunger Base doesn't compensate for the variations in contact resistance at the plunger tip to DUT interface.

Best,
Martin72:

--- Quote from: mawyatt on August 20, 2024, 08:48:47 pm ---All those R&S fixtures look like Tonghui. Wouldn't be surprised if R&S LCR Meters are from Tonghui, probably similar to some TH types but with different front panels and maybe different firmware with same PCBs??

Best,

--- End quote ---

I don't think so.
The LCX meters are manufactured in Malaysia, just like the inexpensive spectrum analyzers from R&S.
The test leads/fixtures will certainly be from Tonghui.
I wanted to buy an LCX100.
But only the LCX200 can be upgraded to 10Mhz.
However, all LCXs can be upgraded with a graphics plot.
hpw:

--- Quote from: mawyatt on August 20, 2024, 09:04:32 pm ---BTW we did some measurements the other day with the cheap common 4 Wire Kelvin Clips and our DMM3500 for some low valued precision 2512 SMD chip resistors. Was a real PITA, even had a couple chips "flip out" with these clips :o

Did find them after crawling around on the floor the next morning tho ???

Then we used the Special Custom Split-Kelvin SMD Fixture with the DMM6500 and this was much easier, and we appreciated why we developed this Specialized SMD Fixture  ;)

Also tried the Standard type SMD Fixture and couldn't get anything reasonable as the Zero Cal is too much dependent on the Zero DUT. Just not repeatable down to the levels necessary for good low milli-ohm measurements IMHO. This isn't surprising as these fixtures are more for higher Z components and the termination of the Force and Sense at the Plunger Base doesn't compensate for the variations in contact resistance at the plunger tip to DUT interface.

Best,

--- End quote ---

A week ago, I liked to measure a larger Tantalum Cap (as 2512 SMD sized) using my SMD fixture.

Conclusion:

- 2512 sized: impossible to have any contact

- 402 sized: impossible to have not slipped them under the contact needle

- also missing a nice leakage measurements of 30 old Tantalum (100u / 10V) ...
  Did then with an Siglent 4000 Power supply on 5V & 1K resistor & SDM3065 current graphs almost down to ground noise.
 
mawyatt:

--- Quote from: hpw on August 21, 2024, 07:00:51 am ---
A week ago, I liked to measure a larger Tantalum Cap (as 2512 SMD sized) using my SMD fixture.

Conclusion:

- 2512 sized: impossible to have any contact

- 402 sized: impossible to have not slipped them under the contact needle

- also missing a nice leakage measurements of 30 old Tantalum (100u / 10V) ...
  Did then with an Siglent 4000 Power supply on 5V & 1K resistor & SDM3065 current graphs almost down to ground noise.

--- End quote ---

If you were using the typical SMD LCR Fixture, ones we have can be "opened up" to accommodate the 2512 by sliding the stationary plunger back giving more space. You can use a Zero Ohm 2512 for the Short Cal, or better yet a small section of #12 Cu solid wire, or small rectangular Cu plate.

Even with this effort it's still difficult to get a good Zero Cal reference for reasons previously mentioned, the Custom Split Kelvin SMD fixture is a better choice IMO.

0402 SMDs are indeed difficult. We found that some of the SMD fixtures don't have the plunger thin shaft to tip seated directly on the Insulated "V" shaped support. Placing "shims" under the support can help, we even 3D printed a custom "V" support for one of our cheap SMD fixtures.

If one is constantly working will small 0603, 0402 SMDs, might be worthwhile to create a custom 3D printed "V" support for this, even honing down the plunger tips to a smaller diameter (please don't do this to a quality fixture, use one of the cheap types!).

BTW how do you like the 4000?

Best,
hpw:

--- Quote from: mawyatt on August 21, 2024, 01:13:12 pm ---If you were using the typical SMD LCR Fixture, ones we have can be "opened up" to accommodate the 2512 by sliding the stationary plunger back giving more space. You can use a Zero Ohm 2512 for the Short Cal, or better yet a small section of #12 Cu solid wire, or small rectangular Cu plate.

Even with this effort it's still difficult to get a good Zero Cal reference for reasons previously mentioned, the Custom Split Kelvin SMD fixture is a better choice IMO.

0402 SMDs are indeed difficult. We found that some of the SMD fixtures don't have the plunger thin shaft to tip seated directly on the Insulated "V" shaped support. Placing "shims" under the support can help, we even 3D printed a custom "V" support for one of our cheap SMD fixtures.

If one is constantly working will small 0603, 0402 SMDs, might be worthwhile to create a custom 3D printed "V" support for this, even honing down the plunger tips to a smaller diameter (please don't do this to a quality fixture, use one of the cheap types!).

BTW how do you like the 4000?

Best,

--- End quote ---

Yes, as at best to have various "V" shaped plug's for that matter.

>> SPD4121X

Well, still missing the service manual so how to custom calibrate as an opened task even no copy calibrated to user settings copy menu :palm:

The GUI somewhat different as RIGOL, so to think different. In addition, RIGOL one channel with low voltage.
I needed for oven 4 individual channels, as to go to four times 12V/1.5A.
IMHO also the connections and cables should have 4 individual color pairs, otherwise
red/black to label.

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