Self contained electronic digital thermometer
First Claim
1. A digital thermometer device comprising:
- an elongated probe carrying a temperature electrical transducer means at its front end and a first electrical digital display means at its rear end;
said transducer means having an analog output;
switch means mounted on the rear end of said probe for selecting readout of said first display means in either degrees Fahrenheit or degrees Centigrade; and
circuit means housed within said probe for converting the analog output of said transducer means to a digital signal for driving said first display means;
said circuit means including amplifier means fed by said analog output;
said amplifier means having first and second sets of gain and bias parameters selectable by said switch means;
second electrical display means on the rear end of said probe for indicating whether the analog output of said transducer is increasing, decreasing or is substantially stable;
a differentiator means fed by said amplifier means and feeding said display means;
said comparator means having three output signals for feeding said second display means, a first output indicative of whether the output of said differentiator means is greater than a predetermined positive constant;
a second output indicative of whether said differentiator output is less than the negative of said constant; and
a third output indicative of whether said differentiator output is between said positive constant and the negative of said constant.
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Accused Products
Abstract
A self-contained electronic digital thermometer is in the form of an elongated probe has a temperature transducing thermistor at a front end and an electronic digital display at a rear end. Circuitry housed within the probe converts the voltage across the thermistor to a digital signal for driving the display. The circuitry includes an operational amplifier fed by the thermistor voltage via a pair of selectable input resistors for providing different gains for the amplifier and fed by a voltage source via a different pair of selectable input resistors for providing different biases to the amplifier. The different gains and biases are selected by a switch for enabling readout in either degree Fahrenheit or degrees Centigrade. A differentiator and comparators are also provided to drive a series of lights indicative of whether the temperature is increasing, decreasing or stable.
53 Citations
1 Claim
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1. A digital thermometer device comprising:
- an elongated probe carrying a temperature electrical transducer means at its front end and a first electrical digital display means at its rear end;
said transducer means having an analog output;
switch means mounted on the rear end of said probe for selecting readout of said first display means in either degrees Fahrenheit or degrees Centigrade; and
circuit means housed within said probe for converting the analog output of said transducer means to a digital signal for driving said first display means;
said circuit means including amplifier means fed by said analog output;
said amplifier means having first and second sets of gain and bias parameters selectable by said switch means;
second electrical display means on the rear end of said probe for indicating whether the analog output of said transducer is increasing, decreasing or is substantially stable;
a differentiator means fed by said amplifier means and feeding said display means;
said comparator means having three output signals for feeding said second display means, a first output indicative of whether the output of said differentiator means is greater than a predetermined positive constant;
a second output indicative of whether said differentiator output is less than the negative of said constant; and
a third output indicative of whether said differentiator output is between said positive constant and the negative of said constant.
- an elongated probe carrying a temperature electrical transducer means at its front end and a first electrical digital display means at its rear end;
Specification