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Agilent 4338B

Question asked by A123 on Jan 5, 2012
Latest reply on Jan 12, 2012 by lhornburg
I use an Agilent 4338B Milliohmmeter with my work to measure the AC impedance of batteries.

I have followed the instructions for short calibrations and have changed the settings to what is appropriate for the batteries that I measure.

The issue that I am having though is that there is still a (seemingly) huge discrepancy in the readings.

I measured the same cell 10 times without changing anything, removing the leads after taking down the data, and placing the leads in the exact same spot every time.
Keeping this measure of control I still got a spread of .02 mΩ  which is a lot seeing as the impedance is somewhere between .395 - .431 mΩ

any idea on how to narrow this spread?

also short calibration seems totally unreliable as well, connect the leads together and short it to +/- .0009 mΩ disconnect, then reconnect and it will read anywhere in the range of +/- .0700 mΩ (though the number is consistent, like it will either go to .0009 or .0500, and only those 2, not just any random number)

This meter was just calibrated 2 weeks ago, the other that I use has the same issues and was calibrated 6 months ago