When working with a LM324N opamp, what is the proper way to configure it to accept a bipolar signal, and output it with a positive offset so that it can be inputted into a unipolar ADC? From my understanding, the LM324N is a bipolar opamp, so I was wanting to power the opamp with a single positive supply, and still achieve this.
In addition to this, I would like the input impedance to be 15 megaohms, and the output impedance be 1 megaohm while achieving a gain of 10.
You can do something like this, using a RRIO CMOS-input op-amp, not an LM324.
simulate this circuit – Schematic created using CircuitLab
This accepts -5V to +5V in and produces (almost) 0V to 5V out, with a 15MΩ input resistance.
An LM324 would not work well, even with a balancing resistor on the other input, the offset could be more than +/-500mV (and would likely vary a lot with temperature).
OA1 is the input buffer and gain of 10, OA3 is the reference voltage/2 buffer with gain of 1, OA2 is the adder of two signals.
simulate this circuit – Schematic created using CircuitLab
EDIT: Perhaps replacing 100k resistors with 20k and R2 with 2.2k would give better results.
