Industry Standard resistor distortion test?

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Industry Standard resistor distortion test?

Douglas Self makes reference in his books to resistor NON-LINEARITY A3 test results. Vishay has NON-LINEARITY A3 data on their resistor data sheets.
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Douglas Self shows a low distortion output frequency generator supplying two resistors in series and a FFT analyzer across only one of the series resistors.

Does anyone have a reference to this resistor NON-LINEARITY A3 test protocol?

I paid the price


Thank you. I paid the price and received the resistor A3 Non-Linearity test standard.

It looks interesting, however not too applicable to audio. The fundamental or test frequency is 10K Hz the only harmonic that goes into the calculation is H3 or 30K Hz. The reported test result is the ratio of H3 to the fundamental test frequency in db’s.

The really positive thing about the resistor test standard is the use of impedance matching along the chain of oscillator, amplifier, DUT and detector.

Without impedance matching much of the reported audio testing of resistors is done with a 50 ohm output frequency generator and a 100,000 ohm input audio analyzer. Depending on the value of the resistor (DUT) there are serious loading issues that can and do cause issues using an audio analyzer alone.

We could of course make our own standard for known resistor models that are more based on audio needs. Of course of low importance when talking to manufacturers in the beginning anyway. The experts here might enlighten us of how a test should be setup and what to look for.

This is historical


I looked around Google this morning finding nothing magical about this 10K Hz fundamental frequency or the single 30K Hz H3. I found several documents, even the proposed IEC test procedure that was posted prior to it being adopted in 2012. I found a 1978 document, “Nonlinearity Measurements Using Alternating Current”, Electrocompoent Science and Technology 1978, Vol. 5, pp91-98. These workers used a Wheatstone bridge not a single resistor.

This is historical, using 10K/30K and analog filters. The oscillators of the day did not put a very clean sine wave below 10K Hz and digital signal processing did not exist. FFT if it existed was a series of analog filters and RMR volt meters with someone on a ten key adding up the series.

The theory then and now assumes that resistors produce only an odd series of harmonics, H3, H5,……, with H3 being the predominant Harmonic. There you have it a standardized H3 ratio distortion test.

Put this into google I could not attach a copy.

Nonlinearity Measurements Using Alternating Current



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