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| variable gain current amp |
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| Simon:
--- Quote from: Jay_Diddy_B on May 15, 2020, 02:12:04 pm ---Hi, I think that double measuring and shorting shunts is the way to get really high dynamic range. Dave did a review of device designed to this in EEVBlog 1304. Look at 31:00 mins plus. There are multiple shunts and a pair of shorting MOSFETs. Quitech Otti USB power measurement and battery analyser: https://www.qoitech.com/ The question is how good do you need to be? Regards, Jay_Diddy_B --- End quote --- they seem to have used some opamps that look quite neet https://www.analog.com/media/en/technical-documentation/data-sheets/14901afd.pdf but actually have 100µV offset to the 3µV of the LTC6102 |
| Jay_Diddy_B:
Hi, You live with a large offset if you have a large signal. I think that there are three shunts in the Qoitech device: One is 1 \$\Omega\$ Another is 22 \$\Omega\$ I suspect that the third one is a low value. Regards, Jay_Diddy_B |
| Vovk_Z:
--- Quote from: Simon on May 15, 2020, 05:33:19 pm ---it will go to a panel meter. I can get meters that measure 200mV, 2V, 20V. I don't need it to be highly accurate. --- End quote --- - but there are ready-made manufactured 5 Amps 5 digit ammeters? Look here. |
| Simon:
You want me to trust something off ebay? I know I said I did not need it highly accurate but I did say it needs to be repeatable. What if those things drift? |
| Vovk_Z:
It is more repeatable than you can make at home. |
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