I'm currently working in a tomography project which required to acquire RMS measurements between two electrodes. The sine wave frequency is between 10kHz-200kHz. In the experiment I observed the maximum potential difference is 500mV. I tried an example of AD637 circuit from the RMS application circuits from analog device, however the circuit is unsuccessful due to the 0V output Can anyone give some advice what went wrong here? I attached the schematic which been used for simulation and the output graph.