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Voltage drift with time in 2182A

Posted: December 29th, 2018, 11:38 am
by spkeashwar
Hello,

I am using 6221 to source a current(20uA) and 2182A to measure the voltage(0.432mV) across a DUT. However I see that the voltage builds up over time and it takes a few minutes for it to reach a stable value. The DUT is fairly metallic as can be seen from its resistance value. I don't understand what is the reason for this voltage build up over time. It gets worse in devices with higher impedance where it takes longer time to stabilize.
V build.png
V build.png (13.83 KiB) Viewed 1678 times
Thank you,
Pranava.

Re: Voltage drift with time in 2182A

Posted: January 1st, 2019, 7:24 am
by Andrea C
Assuming instruments are warmed up and room environment stable.
It looks like beautiful first order response.
At 20uA and low ohms, the capacitance is massive to have this time constant.
What do your connections look like?
Can you try different levels of current.
Try sourcing negative current. Same RC outcome?