Keithley 2182A Digital Nanovoltmeter

[Terabyte2007]

Does anyone have any experience with the Keithley 2182A Digital Nanovoltmeter? Is it worth the 3K price tag?

http://www.keithley.com/products/dcac/sensitive/lowvoltage/?mn=2182A

[robrenz]

The Agilent 34420A nanovoltmeter/micro ohmmeter has a built in current source so it can do resistance without a separate current source but it costs a little more.  I don't know which one has better specs for voltage.

[branadic]

Even though this thread is very old, yes it seems to be worth it's price. We have one at work and I have checked relative zero over 2h using the internal RS232 interface with a selfmade short. Both filters analog and digital are active, NPLC is 5. I have never seen Attovolt coming through an USB interface before. 

-branadic-

[Alex Nikitin]

Even though this thread is very old, yes it seems to be worth it's price. We have one at work and I have checked relative zero over 2h using the internal RS232 interface with a selfmade short. Both filters analog and digital are active, NPLC is 5. I have never seen Attovolt coming through an USB interface before. 

-branadic-

How does it compare with the K181?

Cheers

Alex

[Terabyte2007]

Even though this thread is very old, yes it seems to be worth it's price. We have one at work and I have checked relative zero over 2h using the internal RS232 interface with a selfmade short. Both filters analog and digital are active, NPLC is 5. I have never seen Attovolt coming through an USB interface before. 

-branadic-

Nice, I am afraid my lab may have too much background interference to accurately measure that low. I would need to build a shielded enclosure. I have a high resistance meter that will measure well into the TerraOhms but I have to use it with my DUT in a grounded aluminum box. Thanks for the info!

[branadic]

How does it compare with the K181?

Can't tell you that, as I never recorded 2h data with Keithley 181, but you can get a raw idea of Keithley 181 performance in this video:

https://xdevs.com/cm/RandomPics/K181_Cable/20171009_194206.mp4

-branadic-

[kj7e]

How does it compare with the K181?

Can't tell you that, as I never recorded 2h data with Keithley 181, but you can get a raw idea of Keithley 181 performance in this video:

https://xdevs.com/cm/RandomPics/K181_Cable/20171009_194206.mp4

-branadic-

Looks like a CalMachine video.  Damn, now I want one and I don't even have a use for it.

[branadic]

It is a CalMachine video
This piece of kit is really nice, but I'm lacking applications for it beside monitoring the difference between voltage references. Thus, I sold my Keithley 181 and if needed can use the 2182A we have at work.
The nice thing about 2182A is that it has 2 channels, even though the second channel has only 10nV resolution and a maximum input voltage of 12V. Good enough for ratiometric measurements like characterizing voltage dividers without necessarily rearranging probe tips.

-branadic-

[TiN]

I can part with 182M as I got 2182A as repair project already 

[kj7e]

I can part with 182M as I got 2182A as repair project already 

You have the fancy connector for it?  The 182 may be more than I'm willing to spend.

[TiN]

Yup, complete kit. I even have Keithley 1488 short.
I recalibrated it a week ago, using 5700A/3458A.

[kj7e]

Send me a PM with the info.

[Alex Nikitin]

How does it compare with the K181?

Can't tell you that, as I never recorded 2h data with Keithley 181, but you can get a raw idea of Keithley 181 performance in this video:

https://xdevs.com/cm/RandomPics/K181_Cable/20171009_194206.mp4

-branadic-

Here is the result from my Keithley 181 over 5.5 hours - offset compensated, with +/-95nV input voltage applied for some of the time. Recorded by the K34465A at 1sec intervals from the analogue output, vertical scale is in microvolts.

Cheers

Alex

[branadic]

Here is the result from my Keithley 181 over 5.5 hours - offset compensated, with +/-95nV input voltage applied for some of the time. Recorded by the K34465A at 1sec intervals from the analogue output, vertical scale is in microvolts.

Cheers

Alex

Thanks for the plot. Is there any difference in noise using digital data via GPIB or analog output plus a voltmeter? How did you manage to generate those 95nV?

-branadic-

[Alex Nikitin]

Thanks for the plot. Is there any difference in noise using digital data via GPIB or analog output plus a voltmeter? How did you manage to generate those 95nV?

1) No difference. The (isolated) analogue output is generated by a 12-bit DAC, either from the top or from the bottom 3.5 digits. Each step is 1mV and clearly visible on a good meter, like the 34465A on 100mV or 1V range, so 1mV on the output from the bottom end = 1LSB = 1nV input on 2mV range.

2) From a divider - 21M/10R (just an accidental value) mounted in the plug and connected to 200mV output from the Keithley 617.  10 ohm in the divider is probably adding to the noise/drift as it is a simple 1% metal film resistor. I will re-build it with better resistors - probably a metal foil 10R, and a good quality 10M for 1/1000000 divider.

Cheers

Alex

[maxwell3e10]

Cool data. I happen to be playing with the HP 34420A and will record similar data. Let's have a shootout of nanovoltmeters.

[TiN]

Mod then should rename the thread then

[Alex Nikitin]

Mod then should rename the thread then

Perhaps it would be better to start a separate thread.

Cheers

Alex