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Electronic Thermometer

  • US 4,838,707 A
  • Filed: 07/17/1987
  • Issued: 06/13/1989
  • Est. Priority Date: 02/01/1984
  • Status: Expired due to Term
First Claim
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1. An electronic measuring device comprising:

  • sensing means having a physical property which varies in response to a quantity to be measured;

    reference means having a physical property like that of the sensing means but which is substantially invariant in response to variations of the quantity being measured;

    permanently programmable storage means for providing a predetermined initial logic adjustment value which represents the difference between the absolute values of the sensing means and the reference means;

    converter means for measuring the reference means during a first measurement period to provide a reference count value and for measuring the sensing means during a second measuring period to provide a sensing count value, each count value being proportional to the respective measurements;

    comparing means having the initial logic adjustment value, the reference count value, and the sensing count value as inputs, the comparing means providing a signal when the sum of the reference count and the initial logic adjustment value attains a predetermined value and a corrected sensing count value as an output at the end of the second measuring period;

    controller means responsive to the signal from the comparing means for establishing the length of the second measuring period; and

    means for changing the corrected sensing count value into a digital value for display of the measured quantity.

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