I have two signals (~70V in reference to GND) that I want to take the difference of and get a DC signal out. Is it possible to feed them into a differential amplifier circuit and get out a DC value (assuming rails of op-amp are greater than the difference) ? The typical DC value that I am already seeing is around 120mV, although it is noisy and I have had some trouble in finding a good filtering circuit, or rather an LC chock circuit that can effectively eliminate the noise well enough.
I have found that an RC circuit does a good job because I have the parts available here, but it loads down to different values depending on the scope or DMM used.
I have found that an RC circuit does a good job because I have the parts available here, but it loads down to different values depending on the scope or DMM used.