Electrochemical sensors

hello,

I am trying my hands in wiring electrochemical sensors to Arduino. Here are those http://www.e2v.com/e2v/assets/File/sensors_datasheets/electrochem/ec4-250-no.pdf http://www.e2v.com/e2v/assets/File/sensors_datasheets/electrochem/ec4-20-no2.pdf

E2V supplied me with a document to connect to a microcontroller but I need help. Here is the link https://rapidshare.com/files/3850199261/EC_Application_Note_AN2.pdf

Please give suggestions on how to make the circuit.

Thanks

Z

I think figure 4, single-rail supply circuit is the best one for use from 5V. You need a low-voltage rail-to-rail dual (or quad) op-amp.

One of the devices you reference wants 300mV bias, which is perfect for that circuit, the other wants 0V bias (the same circuit will do if you use 2.5V instead of 2.2V as the input to the first op-amp.)

Thanks Mark. Are you sure I can use rail-to-rail dual op-amp? I tried finding quad op amp in local market but couldn't.

Well you might want one opamp to set up the analog fake ground (2.5V), but then again that might not be needed. Quad is only convenient if need more than two and want to save space.