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AUTOMATIC CALIBRATION CIRCUIT FOR GAS ANALYZERS

  • US 3,812,330 A
  • Filed: 08/18/1972
  • Issued: 05/21/1974
  • Est. Priority Date: 08/18/1972
  • Status: Expired due to Term
First Claim
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1. An automatic calibration circuit for apparatus used for measuring the concentration of a radiation absorbing agent in a gas mixture, comprising:

  • a sample counter capable of counting in forward and reverse directions;

    a reference counter capable of counting in forward and reverse directions;

    first means for activating said sample counter and said reference counter in the forward direction iN response to a first digital signal representative of the quantity of radiation passed through the gas mixture without the radiation absorbing agent;

    means for comparing the count in said sample counter with a preset calibration count;

    first means for disabling said reference counter and said sample counter when the count in said sample detector is equal to the preset calibration count;

    second means for activating said sample counter and said reference counter in the reverse direction in response to a second digital signal representative of the quantity of radiation passed through the gas mixture with the radiation absorbing agent; and

    second means for disabling said reference counter and said sample counter when the count in said reference counter is at a predetermined value.

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