Why are they called "resistors"

Yes, it was. If you touched it to attach it to the 'pomona' (not what they are called, idiot). If you touched it to get it out of the packaging as well. If you did not handle it wearing gloves, you very likely reduced its value as read at it voltage limits. Their application is HV. You taking LV readings on them, and touting those as its value is a pretty funny tell about you.

But hell, you do not know how to use a VPD either.

After the HOT alcohol dip, did you place it in a 60°C vacuum chamber for about ten minutes?

The surface epoxy coating can grab up some H2O. Wouldn't expect you to have caught that.

You know very very little about HV resistors.

Yes, it was lower. Yes it IS dirty. Yes, that will lower a read value. Yes, you are unable to know those elements as they are beyond your grasp... obviously. It has been discussed at length, long before you and your fucktarded test rig.

My application is high impedance but not high voltage. But I bought a

1G resistor, and it is a 1G resistor, whether it's clean or fingerprinted.

This part will probably have some small voltage coefficient, since it's a thickfilm, so R will go down a little at high voltages. I doubt that fingerprints will affect that, either. Fingerprints just don't seem to be very conductive on a 1G resistor this big.

I have some 1T ohm, 0805s too. I wired one to another Pomona plug (which is what we call them, since Pomona makes them) and it measured about 10% off, probably because of the resistors in my ancient Keithley. Fingerprinting or cleaning the Pomona plug didn't make much difference, even at 1T ohms.

The 1T thing was just out of curiosity, since the circuit I'm considering only needs a 1G or maybe 10G resistor.

In your experience, how much would fingerprints change the value of a

1G resistor?

John

Do you not even know why a higher HV rating means that the form factor has to change? There are three inch long inch wide versions of the part you illustrated.

Jeez, dude. Think before you speak.

Regardless of any effect you think may or may not occur, you should still never place values that high without sealing it up from being "affected" environmentally, which is their biggest failure mode stat. Pretty simple shit. Don't give it the opportunity to give you a failure mode.

In your LV app, you should not even be using a flatso. axial leaded versions are just fine and would drift less, and can be lead formed as a small, smd device that stand a mm or so above its lead forms, further removing any chance of VOCs or any other thing decreasing its value.

I know who makes them AND why *some* dopes call them that. That was my entire point when I mentioned it the first time, which flew right past you.

It is application and placement and post assembly treatment specific.

I seal anything up that high in value. And I make sure it is pristine clean when placed.

And I clean after assembly and bake at 60C in a vacuum chamber.

But that is for HV apps. Refer to the first line in the response.

For LV, I would still place clean, clean after, and seal after with conformal coating at the very least.

--
I suspect that if they're being used as the high R portion of a HV
divider, the effects of contamination might be more evident.

Are you trying to tell me that this "Archie" that everyone rags on is (a) real, (b) trustworthy, and (c) allowed YOU to filch his address? I think i wall accept if there are three or more confirmations of his trustworthiness.

You, just as the greegor retard, have know knowledge of any form of "worthiness" of any kind.

You could not garner three positive statements about the greegor retard if you interviewed everyone he ever came into contact with in his entire, pathetic life.

Not that you have the qualifications to discern any form of worthiness. I confirm that you are almost as stupid as the greegor kook is.

In fact, I'll be using 0805 surface-mount parts. In ultra-high vacuum.

John

No numbers, no facts, as usual. Just fuzzy ranting.

John

Why?

My measurements didn't change, clean or fingerprinted, within the Keithley's resolution. I actually thought they would, but they didn't.

So fingerprints are highly nonlinear resistors? Short of arcing over, I can't see why.

More important, I have measurements with numbers and other people have opinions. If anybody thinks fingerprints on this sort of resistor affect its voltage coefficient, they should present evidence.

Resistors don't need common ground, they need measuring. Reality doesn't give a damn about concensus.

John

Must be a really lax spec then.

I would place thin slots *across* the span of the pad layout. I would also adjust the pads to increase the distance between them, even to the point of going outside the spec. Maybe a mil or two inside the termination spread. Where it is usually far closer.

The slot can be filled with SMD adhesive, which will seal out VOC incursions, and form a creepage barrier (an HV consideration).

Big flatsos are best untouched or simply potted, but small SMDs (of that high a value)are better off being sealed away from the environment. Also, you do not want you chamber to have any more water in it than it needs to have. A sealed assembly has less total hygroscopy. All depends on what you test set up in that chamber actually is.

Conformal coat isn't always fun, but transformer varnish practically makes the thing monolithic.

You have to have vision to see the numbers in that statement.

They refer to things grubby fucktards like you not only ignore, but are blind to.

Ever heard of a VOC count, chump?

The machine ain't cheap, and I would BET that ALL of your assemblies would FAIL it.

You are clueless.

Proof that you are unaware of the efficacy, or lack thereof, of your supposed "test gear".

HV.

How does Lightning form BEFORE the main stroke?

Get a clue.

It is a known failure mode, John.

You are an HV numbskull.

Cut a slot, then fill it with adhesive? Why?

Any organics would outgass enough to ruin the instrument. A fingerprint can take a day or two to pump down; conformal coating would take a century.

John

Keithley. You don't approve of Keithley?

I had some opinions. Unlike you, I did measurements and left with facts and numbers.

John