mr steve
thanks a ton for the schematic ...
i wanted to clarify
output of N1 in the same schematic is only pulsing between 0 and 12V where as the other part of sensor connected to C2 is always at the same value .. so if i am not wrong the electrolysis will happen for only half the time but will still happen ...
anyways even if it does its much better than using pure DC
next i wanted to know that since i am using 8 sensors can i have one common oscilltor (N1/U1 in this case ) and use other N2/U1 N3/U1 N4/U1 and N1/U2 N2/U2 N3/U2 N4/U2 and N1/U3

if the answer is yes then still the sensor connected to the N1 will dissolve during the course of time due to electrolysis .... as the current will flow from it to the other N's .... though only for half the time