At 23.22 2005.02.13 +0200, you wrote:


>On Sun, 13 Feb 2005, Jinx wrote:
>
>>>For what its worth, I'd suggest deriving the bias voltage from the
>>>regulated 5V supply instead of the battery
>>
>>For that matter you could generate V+ for the op-amp with the
>>PWM module
>
>Afaik the TL081 does not include gnd in either input cmmr or output. Interfacing it with a logic chip is problematic.

Does it mean that its "center" is simply in the middle of V+ and V-?
This will likely guarantee an offset, given that my 7805 and 7905 don't produce the exact (absolute value) voltage.

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