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Original question:

FDC1004: Question

FDC1004: Evaluation results and operating principles

user5929126
Prodigy 150 points
Part Number: FDC1004


Hi.
I have a question.
When measuring the volume of conductive liquid or water using this IC, is there a possibility that the measured value will be smaller than the result measured with an LCR meter?
Isn't it possible to change the capacitance value due to current leaking into the liquid during charging / discharging by the switched capacitor circuit?
Also, I would like detailed materials (voltage, current, charge, etc. at the time of measurement) of the operating principle of the switch capacitor circuit.
Is there anything other than the data sheet?
Best Regards,
Koji Kuboyama
  • 0
    TI__Genius 17440 points

    Hello,

    Yes, it is definitely possible that the capacitance value measured with the FDC1004 will be different than the capacitance value measured with an LCR meter. The FDC1004 is meant to detect changes in capacitance, not replace an LCR meter.

    If the liquid is conductive, it is possible that the liquid will drain charge from the electrodes. For this reason, the FDC1004 is not suitable for measuring the level on conductive liquids. For water this is not a concern.

    Unfortunately the detailed operation of the switched capacitor circuit is proprietary and I'm not able to share it. The only additional information I can offer is in this blog post. 

    Best Regards,