up
elds.
gs
Got a guesstimate on what "a lot noiser" was. Twice the johnson noise over the frequency band? ten times. This obviously depends on the bias level too.
Yeah a few picofarads of stray C can sink a lot of 100 Meg ohm voltage noise.
Putting all the gain you need in one little area can lead to some problems. 10^4 was doable, but at 10^5 I got gain peaking, which screws up the measurment.
George H.
Then what are you talking about? Are the Agilent and Keithley instruments unusable?
You are on record here as saying that high-meg resistor measurements are "impossible to make accurately at the bench or in the field."
So why do Agilent and Keithley sell these instruments?
Explain this:
ftp://jjlarkin.lmi.net/Keithley_1gig.JPG
That's a 1G thickfilm resistor, from Digikey as I recall. If you paw the Pomona plug thing or the resistor, trying to add fingerprints, nothing changes, after the brief electrostatic transient. In the 10G and up turf, things have to be shielded, as any movement nearby can pin the meter.
On the 1e-11 amps range, with a tiny Pomona "antenna", I can kick the needle by rubbing my foot on the carpet, standing 10 feet away. And it goes to 1e-14. It goes negative.
John
Time travel is no trivial thing. Beware the pitfalls. On the brighter side, you could, in theory, go back and kill some unnamed poster's father to be.
mike
Zero common sense. If it ain't the gear it the hand that is on the gear, dippity doo da.
Compared to Al, you are a slug, but you are a slug compared to me as well.
Al has not gone anywhere.
I very strongly suggest that you f*ck off and die. Choose a painful method.
Your assessment has zero credence.
An accurate description of you is not an insult, it is a declaration. Kind of like the one you think you are accurately making here. You are incorrect.
F*ck you, you wimpy little wuss.
A problem which you have never suffered from? Sure... I know better. You are a windows hating little bitch, and you are guilty of that which you accuse others of.
As if your petty assessments have any credence or validity. They do not.
You wouldn't know. You are hard wire pissy little bitch.
Bwuahahahahahahaahaha!
DrParnassus Inscribed thus:
What a plonker !
what a bunch of squabbling kids.....
On a sunny day (Wed, 23 Jun 2010 21:41:44 +0100) it happened "TTman" wrote in :
Drop dead.
^^^^^^^^^^^^ Entomologist.
days ago?
Wow! You're funny today!
AlwaysWrong isn't being silly (that would imply a brain). He's being wrong, as always.
Oh. Right.
He's afraid of numbers and afraid of resistors over a million ohms.
DANGER! 2,000,000 OHMS
John
What is good for the goose is good for the gander.
You more qualify as 'the dander' though.
You're a hypocrite.
Do you even know what 1/f noise is?
John
Sure, we know that. Say, did I ever tell you about the cool PCB cleaning machine we have?
John
Did not "move" anything, dufus; read: all (valid) values.
No, john. I characterized JV circuits for years. We never came across it.
Come back when you are not being an absolute insult to the entire industry, John.
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