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I am trying to design an amplifying circuit for a sensor. I would like to bias the sensor (a microphone) at 2.5V DC and have the sensor output amplified around 2.5V as well, such that the output swings between 0V and 5V and 0 volume is 2.5V out.

The catch is that I would like to use a digital potentiometer to set the amplifier gain. Overall the equation for the amplifying circuit would be Vout = A(Vin - 2.5) + 2.5. Unfortunately, I can't figure out how to achieve this. The best I have come up with is using two digital pots, but that is undesirable.

Can anyone help? I get the feeling that there must be an easy solution since it seems like a simple problem.

Cheers

Does this help?

Thankyou, that is a huge help!