we're using the AD5933 for bioelectrical electrode impedance measurements. Usually, the electrodes have to be immersed in a saline solution for measuring, and a 2 point measurement (Electrode to Reference electrode) adds unwanted potential offsets to the measurement. For a more accurate measurement, a technique using 3 electrodes is employed:
(Fig. 4 from this link)
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Is there any way to connect the AD5933 in such an arrangement to measure impedance? Do you have any additional suggestions for performing such a measurement?
Thanks and Kindest Regards,
ok, right now we're trying basically your circuit, without the transistor (too simple, I know), hoping that the OpAmp supplies whatever required current for the sensor to produce the desired VREF.
Since we're working with low stimulation currents (around 100 uA), might be that we don't need the extra driving.
If it doesn't work, we're going to put the transistor.
Thanks and kind regards!