How to calibrate a current for 1nA by changing 1M resistor?

[fala]

1nA Calibration

Hello, I have to Calibrate a current to voltage converter circuit for 1nA resolution by changing amount of a 1M resistor. resistor that is currently installed is not high quality.I neither have a precise(1nA resolution) current source nor I have a known and very precise resistor in order of 1Mohm. what should I do?

Regards.

 

[Pavka]

Re: 1nA Calibration

Hello, I have to Calibrate a current to voltage converter circuit for 1nA resolution by changing amount of a 1M resistor. .... what should I do?

Regards.

The task is unreal. The best resolution you can obtain from a precise current source is in the order of 10e-5...10e-6 per temperature & time.
You should get some precise resistors with ultra low temperature drift as well.
There are no such at 1 Mohm known.

 

[fala]

1nA Calibration

I have seen many instruments and I've worked with some of them that are routinely used in laboratories(for example electrochemical labs) and they even can measure current down to the picoampere range. my question now is how one can calibrate a current to voltage converter with 1nA precesion. I have a very sensetive voltmeter that can measure 10uV but I don't have very precise ampere meter nor I do have a big and very precise resistor. there should be a way others have done that.

regards