Hello,
Recently i have scored two Agilent 34401A DMMs (and absolutely love them), one was sold for part or repair with description that 10MoM range has significant error.
I have tested it and was not able to find any diviations from other 34401A measurments.
But i have tested it on 1/4w 5% carbon resistors. Reading were consistent among both 34401A anb my trusted Fluke 289.
Anyway i found that input resistors of oscilloscope are very precise on my Agilent DSO5054A there are two 0.4993 MoM in series. Then i concluded that probes have to have equal or better precision 9MoM resistor in them, and it looks like it is true. I have measured two Agilent N2890A probes and they show pretty close resistance of 9.029 and 9.000 MoM.
Can we say that there is high tolerance resisters used in scope probes?
Asking it that i was not able to find any at least 0.1% tolerance resistors of MoM range.
Anybody knows what types of resistors used in high quality probes? And can we rely on those to test DMMs?