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Hioki IM3570 LCR & Impedance Analyzer

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The Electrician:

--- Quote from: KungFuJosh on September 07, 2024, 01:55:08 am ---I gotta send a big thank you out to @mawyatt. Constantly reminding us of the importance of proper open/short correction really helps when trying to find specific characteristics for a component.

For example, getting the open and short distances correct (and remembering to correct the cable length) was essential to get the right values I needed for a 1nF cap for the dissipation factor test on my lcr cal test PCB.

I had to cut a piece of 12AWG copper wire the right length for the 1206 capacitor so the results would make sense. I used a chopstick handle that was about the right size for open compensation. It worked pretty well. 😉

This capacitor model was all too low:


But this one was close to my target of 0.00010:


Thanks, Mike!

-Josh

--- End quote ---
It looks to me like you don't have cable length  set correctly. :(

KungFuJosh:

--- Quote from: The Electrician on September 08, 2024, 10:23:47 pm ---It looks to me like you don't have cable length  set correctly. :(

--- End quote ---

I was using this thingamabob. 😉

indman:

--- Quote from: KungFuJosh on September 11, 2024, 08:58:44 pm ---Attached are the 100kHz and 118kHz screenshots, note that they were taken at different room temperatures, hence the change.
At 1kHz the ST42 makes sense and Z/ESR agree, but at 10kHz Z makes sense, and ESR is too low.

--- End quote ---
Hmm.. I have no serious complaints about the ST42 in terms of ESR measurements; based on your photos, there are more questions about the Hioki results.
He is trying to measure capacitance at a frequency of 100 kHz, but it is clear that this is not easy for him, because the capacitor is already close to or has reached its resonant frequency and it is already more like an inductance than a capacitance. This is one of the reasons why the real capacitance of capacitors of this size is measured far from any resonances at a frequency of 100-120 Hz and this condition is directly stated in the documentation
For example, I took a Hitano EXR 1000mkFx50V capacitor similar to yours, as well as a URL108MOJF08 1000mkFx6.3V polymer capacitor and measured them on DE-5000 and ST42. I attach the results below. I have indicated in red those conditions that you need to pay attention to when assessing the quality of a capacitor. The test results are basically very similar, but with one very important caveat. ST42 tweezers are very sensitive in the range below 10 milliohms. The readings in this area are very unstable and highly dependent on close contact with the part.

KungFuJosh:

--- Quote from: indman on September 12, 2024, 02:43:20 pm ---Hmm.. I have no serious complaints about the ST42 in terms of ESR measurements; based on your photos, there are more questions about the Hioki results.
He is trying to measure capacitance at a frequency of 100 kHz, but it is clear that this is not easy for him, because the capacitor is already close to or has reached its resonant frequency and it is already more like an inductance than a capacitance. This is one of the reasons why the real capacitance of capacitors of this size is measured far from any resonances at a frequency of 100-120 Hz and this condition is directly stated in the documentation

--- End quote ---

I completely agree with you, it's essentially pointless to test C of a 1mF cap at 100kHz. The only reason I test the cap at that range is for an ESR comparison to the datasheet that claims ESR ratings were tested at 100kHz across their full range of capacitors...which I still think is weird. If the cap only shows the correct C value at 120Hz, why wouldn't you take an ESR measurement there too?

KungFuJosh:

--- Quote from: mawyatt on September 12, 2024, 01:08:47 pm ---try a much wider sweep sat 100 to 1MHz Log Scale and post on the IM3570 thread.

--- End quote ---

Warming up the meter now. X or Y or both log scale?

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