can ct sensors share a common fixed reference point?

Question

In a previous question, I asked how to amplify a CT sensor, essentially a small transformer that induces a voltage proportional to the current in the primary circuit. The solution has one leg attached to a voltage in the middle (2.5V for a 5V source):

op amp for CT sensor

Can I connect multiple CT circuits sharing the same base voltage or will that create a lot of noise and/or affect each other? In other words, if I want to create 8 of these, can I share the voltage divider among all 8 circuits? Would making C1 larger help? Further, if two CT sensors were observing circuits from different phases, would that be a problem?

My intuitive sense is that a 100uF capacitor and many CT sensors sharing the same base voltage should be more stable rather than less, is that wrong?

Answer 1

Yes, you can probably share the divider. The only currents it sees are capacitively coupled and currents that flow through the op-amp input. They will cause small errors, but probably not significant to you.

I would suggest reducing the divider resistors to 5K or 10K each and increasing the capacitor to 100uF.

Answer 2

You can add a buffer.

^{simulate this circuit – Schematic created using CircuitLab}