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Electronic sensing and control circuit

  • US 4,767,940 A
  • Filed: 10/02/1987
  • Issued: 08/30/1988
  • Est. Priority Date: 10/02/1987
  • Status: Expired due to Fees
First Claim
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1. An electronic circuit for sensing the distance to an object, comprising:

  • a single sensing plate spaced from said object;

    means for charging said sensing plate to a value dependent upon a capacitance existing between said sensing plate and said object, said capacitance varying with the position of said object relative to said sensing plate;

    means for sampling the charging current of said sensing plate;

    means for outputting said sampled current, said output current being proportional to said capacitance and varying with the distance between said sensing plate and said object; and

    means for providing an opposing current flow equal to any current flow attributable to any residual capacitance of the electronic circuit so that it is only necessary to detect the change of capacitance involved in distance measuring.

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