Hi all
I've built a 35V PIC (16F88) LCD meter for measuring 'conductance' in a electrolysis-type setup, at 1 to 1.5mA. The resistance divider takes it to 35mV/ADC. I first measure one probe, then other, then subtract to find difference. Doing this through a 1K resistor gives me the 'amps' flowing in circuit. When not immersed, it gives a reading which is the current drawn by the adc voltage divider. How can I eliminate this to give me the correct amount of mA flowing in my circuit?
Thank you all.

 

This is described in the data sheet. Can you post your circuit also. Your problem could be in the hardware

 

Hi t06afre
Yes Seems to be a hardware thing - measuring through the 1K resistor,
but I can't work out another way. See the attached sketch.

 

Actually need to monitor the electrolysis-like process going on until the current limit is reached, then to monitor the voltage dropping, and do certain things at certain voltages.

 

If you want to measure current you have to "open" the current path, then insert a small resistor and measure voltage drop over this resistor.