Electronic thermometer
AssigneeControl Electronics Co., Inc.
InventorHarold Goldstein
Life of this patent
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Abstract
An electronic circuit for use with a thermistor-type thermometer which makes only two measurements and provides a multiple temperature scale capability, a low-power indicator, a simple counting circuit and an enabling control circuit. The thermistor-type thermometer provides a signal having a pulse rate which varies with the temperature sensed and the electronic circuit of the invention operates on this signal to visually display the final temperature after only thirty seconds. Decade counters and logic gates are used with a crystal controlled oscillator to provide counting and timing signals as well as enabling signals required by a specialized temperature prediction algorithm.
Claims23
An electronic thermometer for producing an estimated final temperature consisting of a means for taking temperature measurements including a temperature responsive element, a means for transforming at first and second predetermined, discrete times said measurements into signals having a variable pulse rate determined by the measured temperatures, a counter means for operating upon said signals in accordance with the algorithm ##EQU1## wherein T.sub.F is the final temperature being measured, T.sub.1 is the temperature measurement at the first time, T.sub.2 is the temperature measurement at the second time, .DELTA.t is the difference in time between the first and second times, .tau. is a thermal time constant which is dependent upon the temperature responsive element and e is the base of the natural log, and means for visually digitally displaying said counter means results, said electronic thermometer further comprising:
- control means electrically connected to said transforming means for selectively enabling said transforming means at said first and second predetermined, discrete times and electrically connected to said counter means for controlling said counter to count the pulses of said signals having a variable pulse rate in accordance with said algorithm.
Dependencies are inferred from the claim text.