tom_pay
Member
Hi Guys,
I have been experimenting with a very simple Op-Amp amplifier, based on the LM358. I would like to amplify a small DC signal ranging from about 10mV to approximately 70mV, with a gain of about 48, to be fed into a PIC's ADC. However in doing so I have found that the gain of the amplifier setup changes depending on the input voltage, the gain is not constant.
In an attempt to rectify my problem I have tried lowering the gain, adding supply capacitors and changing the Op-Amp chips, however all of this leaves me with the same problem.
So my question is, is it possible to make the gain nice and constant? Preferably without having to drastically change the setup, or if so, keeping it nice and simple. I have also attached a copy of the circuit I have been using.
Thanks in advance,
Tom
I have been experimenting with a very simple Op-Amp amplifier, based on the LM358. I would like to amplify a small DC signal ranging from about 10mV to approximately 70mV, with a gain of about 48, to be fed into a PIC's ADC. However in doing so I have found that the gain of the amplifier setup changes depending on the input voltage, the gain is not constant.
In an attempt to rectify my problem I have tried lowering the gain, adding supply capacitors and changing the Op-Amp chips, however all of this leaves me with the same problem.
So my question is, is it possible to make the gain nice and constant? Preferably without having to drastically change the setup, or if so, keeping it nice and simple. I have also attached a copy of the circuit I have been using.
Thanks in advance,
Tom
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