Author Topic: Atlas Peak LCR45 reports low values  (Read 678 times)

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Offline wwoofbum

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Atlas Peak LCR45 reports low values
« on: January 17, 2020, 08:53:11 pm »
I recently received an Atlas Peak LCR45.  Doing some initial investigation of various passive components I find resistance and capacitance values consistent with the values specified by the component manufacturers, but consistently low values for inductance.  Testing 18 commercial inductors with values from 150 uH to 1000uH, and two litz wire wound ferrite core coils, I get errors from -9% to -36%.  All inductance measurements were made by the meter at its 200kHz frequency.  The trend is for generally smaller error as nominal (and measured) inductance increases.

I have also conducted the procedure for probe compensation, with no change in outcome.

I am by no means experienced with inductance measurement, so it is possible that I am, somehow, doing it wrong. 

Is there a means by which I could conduct a test that would show, more conclusively, that the meter is not correctly reporting inductance?  Is this something I should take up with the manufacturer of the meter? 

Your advice will be appreciated.
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Online tautech

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Re: Atlas Peak LCR45 reports low values
« Reply #1 on: January 18, 2020, 07:47:48 am »
I recently received an Atlas Peak LCR45.
New or used ?
All inductance measurements were made by the meter at its 200kHz frequency. 
First thing that comes to mind is what was the manufacturers test frequency for the commercial inductors ?
Their datasheets will give clues.  ;)
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Offline PTR_1275

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Re: Atlas Peak LCR45 reports low values
« Reply #2 on: January 18, 2020, 09:03:56 am »
Most of our power inductors at work are specified at 1kHz despite being used at frequencies up to 200kHz.

What are the part numbers of the inductors you’re testing?
 

Offline wwoofbum

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Re: Atlas Peak LCR45 reports low values
« Reply #3 on: January 18, 2020, 02:47:43 pm »
Perhaps this is merely a cautionary tale about buying stuff from China.  In further investigation, I prepared a tank circuit with a (nominally) 100 uH inductor, and a 0.088 uF capacitor (nominally 0.1 uF, also from China).  Oscilloscope reported a resonant frequency of roughly 59 kHz which, calculation suggests, indicates a value of about 82 uH for the inductor.  Testing of this same inductor with the LCR45 gave 78 uH, significantly less error (relative to its measured, not nominal value) than the 9-20% deviation reported above (and given the potential error of the capacitor, not all that far from the 1% error specification for the LCR45 at that value).

I suppose that I should not be surprised, given my tendency to buy stuff off ebay, that all of the inductors I have in my kit measure below their nominal value.  In life (I'm retired, now) I was a cook.  In one memorable incident, I purchased an inexpensive "1 cup measure" that was manufactured in China.  It had all the proper markings on its clear plastic: 1/4c, 1/2c, 3/4c, 1c, and marks at 1, 2, 3, 4, 5, 6, 7, 8 ounces.  Unfortunately the actual volume at the 1 cup mark, compared with other, more reliable measures, was somewhere above 9 fluid ounces.   :palm:
« Last Edit: January 18, 2020, 02:49:43 pm by wwoofbum »
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