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From: "ArtekManuals" <manuals@...>
To: [email protected]
Sent: Monday, October 12, 2020 2:44:28 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP-3456A - Question Regarding Resistance Measurement

Sounds like since you cant trust the calibration since it is not current
that this is all within the range of uncertainty

I am pretty sure that Mouser and Digikey do not actually measure the
value of 1% resistors going out the door. The resistors are likely made
in China ( need I say more)

This sounds like an analogy of the man with two watches

"A man with one resistor always know exactly what the value is..a man
with two resistors is never quite sure"

What are you trying to do that requires 1% accuracy at these high values?

Dave
NR1DX


On 10/12/2020 3:13 PM, Richard Knoppow wrote:

By 90M do you mean Megohms?? Do you have any other resistors of
similar value and close tolerance, they can be used to check the
meter. I assume they are expensive otherwise I suggest getting a
second resistor. If megohms these are very high values. If the
resistor had read low I would have suspected some leakage resistance
but that would not make it read high.
? It IS possible for a new resistor to be off value.

On 10/12/2020 11:54 AM, n4buq wrote:

I have two brand new 1% tolerance, metal-film resistors that I am
looking to use in a project.? One is 90M and the other is 50M and I'm
using my HP-3456A to measure them.

The 50M tests within 1% (around 49.8M).

The 90M tests at just over 92M which is about 2% over nominal.

2-Wire and 4-Wire show about the same differences.

My meter is not recently calibrated so I know I cannot really trust
either measurement; however, does it make sense that if both
resistors are indeed within 1% (as they should be given that they're
new), would one test correctly and one test incorrectly?

I realize that new parts may not be in spec and at least one of these
may be an example of that but these were bought from reputable
suppliers (e.g. not eBay purchases) so I suspect they are within
tolerance and my meter may be giving me false readings.

If both tested with the same relative difference (e.g. both showed
+2%), then that might make better sense but I'm curious as to whether
it's possible/probable that if both are in tolerance that the meter
would show that kind of variance.

Yeah, I know.? Weird question and maybe too many variables but
thought I'd see what the experts say.

Thanks,
Barry - N4BUQ

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Dave Manuals@... www.ArtekManuals.com

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