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Low cost, low power battery led indication cirucit

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TerminalJack505:
I played around with my circuit in the simulator some more.  I changed the amp and swapped the TL431 with a high-beta NPN transistor.

I tried to do as Vovk_Z suggested but didn't have any luck.  My feeling is that you would need a fairly exotic op amp to do that.  Either that or make the sense resistor much bigger.  I completely nulled-out the offset voltage on a OPA197 (the amp used in my circuit) and the results were a good deal worse than my circuit.

The configuration used in my circuit (with the MOSFET) was designed for high-side sensing by people that are much smarter than myself.

Edit: Had a misprint in the attached image.  The offset voltages in the diagram were listed as mV but are uV.

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