I have to make a AC to DC circuit. I have 10 uV to 1 mV (+ or -) on
>the input. the output have to be 50mV to 5 V,(one polarity only) to
>drive a VCO.
>The idea is to measure a DC current to or from a battery over
>time .The result will then be read out in Ah ,and the display count up
>when charging, and down when using current.
That's not exactly AC/DC, it's more like an absolute value circuit... the semantic difference being that the polarity reversals are probably infrequent and not periodic.
You can make a very fairly simple circuit that multiplies a signal by
+1 or -1, and drive that from a comparator that detects the input polarity. But at 50 uV, all the parts - amp, polarity switch, comparator - have to be very good.
What does the final data - absolute value of battery charge/discharge
- actually mean?
John