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Fluctuation in 2182A nanovoltmeter reading

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MANJUNATHA S O
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Fluctuation in 2182A nanovoltmeter reading

Post by MANJUNATHA S O » June 25th, 2012, 7:55 am

I'm using 2182A nano-voltmeter for voltage measurement of the order nV to mV. There is a lot of fluctuation in the voltage reading. And also it is showing some values (fluctuating), even no voltage input is given. I'm using four probe method (supplying current through KEITHLEY 6221 DC current source) for resistivity measurement. I want most stable output for my research. Please help me regarding this issue and let me know if any preliminary connections to be done.

Raghu R
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by Raghu R » June 26th, 2012, 5:40 am

Hello Manjunath

Please provide me your conatct details - and name of the Organization you are working with I will contact you and try to help you

You can send me a mail at [email protected]

MANJUNATHA S O
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by MANJUNATHA S O » June 26th, 2012, 9:55 am

The conversation we had on phone was very helpful and solved almost issues. Thank you for your support sir. My email ID is "[email protected]". I am working as a research scholar in Dept. of physics, MIT, Manipal.

breakwave922
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by breakwave922 » February 13th, 2013, 4:20 pm

Raghu R wrote:Hello Manjunath

Please provide me your conatct details - and name of the Organization you are working with I will contact you and try to help you

You can send me a mail at [email protected]
Hello, Sir,
I'm working as a research assistant in University of Missouri-Columbia. I met a same problem as Mr.Manjunath did.
Can you help me to solve this problem?
Thank you very much.
Feng

Dale C
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by Dale C » February 15th, 2013, 6:50 am

Hello breakwave922,
What level of fluctuation do you see on the 2182A? 10nV, 1uV?, etc.
Connect the HI and LO input terminals together and monitor the voltage.
Then press the REL button.
I would expect less than about 10nV of fluctuation. And then some drift depending on how the temperature changes in the room.

breakwave922
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by breakwave922 » February 19th, 2013, 2:42 pm

Dale C wrote:Hello breakwave922,
What level of fluctuation do you see on the 2182A? 10nV, 1uV?, etc.
Connect the HI and LO input terminals together and monitor the voltage.
Then press the REL button.
I would expect less than about 10nV of fluctuation. And then some drift depending on how the temperature changes in the room.
Sorry for my late reply.
In my case, I saw the fluctuation can be up to 1V.
Sometimes, even when no voltage applied, the voltage value from the nanovoltmeter screen was keeping increasing to 13V, then it stopped.
Have you met this problem before?

Dale C
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by Dale C » February 20th, 2013, 7:14 am

This sounds like the input is open.
Using the Low thermal input cable that is shipped with the Model 2182A (model 2701-4) I would make sure the red and black leads are connected together for channel 1 and the green and white leads are connected together for channel 2.

breakwave922
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by breakwave922 » February 20th, 2013, 11:39 am

Dale C wrote:This sounds like the input is open.
Using the Low thermal input cable that is shipped with the Model 2182A (model 2701-4) I would make sure the red and black leads are connected together for channel 1 and the green and white leads are connected together for channel 2.
Sorry, I do not understand. Do you mean to use the low thermal input cable to connect the red and black leads?

Dale C
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by Dale C » February 21st, 2013, 5:31 am

The Model 2701-4 cable is the input cable.
Connect the red lead to the black lead at the end of the cable. Also connect the other end to the Model 2182A input.
Then select channel 1 and monitor the voltage level.

chris2013
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by chris2013 » June 4th, 2013, 3:19 pm

Hi Dale, I'm having the same problem. Without connecting a sample to the nanovoltmeter 2182A, the reading just keeps going up and up, past even 20V.
"Connect the red lead to the black lead at the end of the cable. Also connect the other end to the Model 2182A input.
Then select channel 1 and monitor the voltage level"
I did that and I see no more fluctuations. What does this mean? What should I do next?

Thank you.

Dale C
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by Dale C » June 5th, 2013, 5:38 am

Shorting the two input leads at the end of the cable would show what noise the Model 2182A and cable are contributing to the experiment.
If the input is open then the high impedance input of the Model 2182A will charge the input and you will see voltage on the display. This is normal.
Just connect the 2182A input to your device to be measured. That should do it.

sayakghoshal
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by sayakghoshal » June 28th, 2013, 6:02 am

Hi
I have also faced the same problem of floating voltage when input leads are open. Surely it does not affect the actual measurement.
I have used different models of Keithley voltmeters and multimeters and for 2182A it is surprisingly and dangerously high. It shows more than 10V and I found, it is actually having 10V across the leads. Now in this condition if you connect the leads to a fragile device (like Graphene sample etc.), the transient immediately snaps the graphene flake. I spoiled lot of devices (each device takes a lot of effort) before I really understood the problem. Afterwards I used a T-junction and before connecting the device I used to short them. That solves the problem. But I really don't understand why other voltmeters are not generating this voltage whereas 2182 does. If this can be somehow avoided it will be helpful for the beginners.

subho10
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Re: Fluctuation in 2182A nanovoltmeter reading

Post by subho10 » December 12th, 2017, 12:44 am

Sir, I have a Keithley 2182A Digital Nano-voltmeter for voltage measurement and Keithley 6221 as current source. From last couple of days I have been experiencing an issue with voltmeter. While the Channel 1 input (red and black) are mated, the reading is fluctuating from -0.06mV to 0.1mV. This is affecting my low voltage measurement, as I am getting erroneous data. As mentioned in manuals, I have given the system to warm up for almost 3 hours but the fluctuation still remains.... Please, Kindly help to sort out the problem. Thank you in advance.

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