Re: difference amplifier offset trimming

Hi,

If you want 75pA zero accuracy in a 2mA full-scale circuit,
that's only 0.04 ppm. To attempt to achieve that you'd need
an entirely different approach, a true current source made with
precision electronics, and perhaps with range switching, etc.

So, the current source that I am using is not a true current source.
Would you advice that what is a true current source and how can I
build it?


What are you trying to do?
I am trying to build a system that can stimulate Lab. rat's retinal
tissues. Thats why I am concerned about leakage current.

Thanks
John


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