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How to use AD7147?

Question asked by 罗年景 on Dec 5, 2016
Latest reply on Jan 29, 2018 by Maurice

Dear all

 Hi, I want to use AD7147 to measure the change of capacitance. One electrode is a grounded aluminum alloy, and the other electrode is a PCB plate, the two electrodes are perpendicular to each other, and the capacitance value is changed by changing the vertical displacement between the plates. Mainly have the following questions:

  1. How much the number of electrical capacity need to change (or how much the initial capacitor required), can the AD7147 be induced?
  2. How to design the electrode size on PCB is reasonable? When changing the distance between the plates, how can I know that the scope of the changed capacitance in the range of AD7147 can be collected?
  3. How to design the peripheral circuit of AD7147?
  4. At least 2 road capacity changes need to collect, is there a higher accuracy CDC?
  5. What is the AC_Shield Signal? if it not needed to be used  when the distance in PCB board is small.
  6. What is the difference Wake up on touch” and “Wake up on proximity”?