I've searched the AAC site for info about a fractional gain op amp, but I haven't found anything specific on the subject.
With 100% feedback, the gain will be approximately 1. However, to obtain a gain of less than 1, somehow the feedback would have to be greater than 100%. This might be done by connecting the op amp to a second one which has a gain greater than 1 and feedback its output to the inverting input of the first one. Then the output of the first amp would be fractional.
One idea is to apply a small reference voltage to the non-inverting input (instead of connecting it to ground) and amplify the difference between the inverting and non-inverting inputs.
Another idea is to feedback the output to the non-inverting input through a voltage divider connected to ground, so the difference would always be proportional to the input. I haven't done any calculations yet and at this time, I'm just looking for peer review.
An example of a fractional gain amplifier are "voltage attenuators" which sample a high voltage (such as the 600 VDC input to a traction motor) and provide an output in the range of 0 to 12 VDC which is then inputted to an analog to digital converter.
With 100% feedback, the gain will be approximately 1. However, to obtain a gain of less than 1, somehow the feedback would have to be greater than 100%. This might be done by connecting the op amp to a second one which has a gain greater than 1 and feedback its output to the inverting input of the first one. Then the output of the first amp would be fractional.
One idea is to apply a small reference voltage to the non-inverting input (instead of connecting it to ground) and amplify the difference between the inverting and non-inverting inputs.
Another idea is to feedback the output to the non-inverting input through a voltage divider connected to ground, so the difference would always be proportional to the input. I haven't done any calculations yet and at this time, I'm just looking for peer review.
An example of a fractional gain amplifier are "voltage attenuators" which sample a high voltage (such as the 600 VDC input to a traction motor) and provide an output in the range of 0 to 12 VDC which is then inputted to an analog to digital converter.
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