Patent US5295746A successfully refreshed from Google Patents.
US5295746A
Expired / Lapsed
US
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High resolution digital thermometer
Assignee: HEALTH AND HUMAN SERVICES United States, AS REPRESENTED BY DEPARTMENT OF
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Filing: 1992-02-05
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Granted: 1994-03-22
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Expires: 2012-02-05
Abstract
Abstract A high resolution digital thermometer capable of measuring temperature differences on the order of several micro-degrees centigrade. The device includes a bridge circuit having two thermistors in series. An output of the bridge circuit feeds a signal to an analog-to-digital convertor via a high gain amplifier. A computer maintains the balance of the bridge circuit to avoid a situation wherein the range of the analog-to-digital convertor would be exceeded.
Inventors
- 👤 Walter S. Friauf
- 👤 Thomas R. Clem, Sr.
- 👤 Robert L. Berger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:54
CPC Classifications
G; G01; G01K; G01K3/00; G01K3/08; G01K3/14; G01N; G01N25/00; G01N25/20; G01N25/48; G01N25/4806; G01N25/4813; G01N25/482
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
60 words
A high resolution digital thermometer which comprises: a bridge circuit; first and second thermistors arranged in series in said bridge circuit; a high gain amplifier connected to an output of said bridge circuit; an analog-to-digital converter connected to an output of said high gain amplifier; and a computer means for initiating and maintaining said bridge circuit in a balanced state.
Claim 2
Dependent Claim
60 words
A high resolution digital thermometer which comprises: a bridge circuit; first and second thermistors arranged in series in said bridge circuit; a high gain amplifier connected to an output of said bridge circuit; an analog-to-digital converter connected to an output of said high gain amplifier; and a computer means for initiating and maintaining said bridge circuit in a balanced state.
Claim 3
Dependent Claim
45 words
A high resolution digital thermometer according to claim 1, wherein said computer means includes a means for supplying control signals to said bridge circuit, means to receiving output signals from said bridge circuit and means for calculating temperature differences between said first and second thermistors.
Claim 4
Dependent Claim
20 words
A high resolution digital thermometer according to claim 2, further including a means to output information from said computer means.
Claim 5
Dependent Claim
27 words
A high resolution digital thermometer according to claim 1, wherein said first and second thermistors are positioned respectively in test and reference positions in a chemical analyzer.
Claim 6
Dependent Claim
27 words
A high resolution digital thermometer according to claim 1, wherein said first and second thermistors are positioned respectively in test and reference positions in a biological analyzer.
Claim 7
Dependent Claim
64 words
In a device for measuring temperature differences between two thermistors in a bridge circuit, the improvement comprising a computer means for initiating and maintaining said bridge circuit in a balanced state, wherein said computer means includes a means for supplying control signals to said bridge circuit, means for receiving output signals from said bridge circuit and means for calculating temperature differences between said thermistors.
Claim 8
Dependent Claim
64 words
In a device for measuring temperature differences between two thermistors in a bridge circuit, the improvement comprising a computer means for initiating and maintaining said bridge circuit in a balanced state, wherein said computer means includes a means for supplying control signals to said bridge circuit, means for receiving output signals from said bridge circuit and means for calculating temperature differences between said thermistors.
Claim 9
Dependent Claim
24 words
A device for measuring temperature differences between two thermistors according to claim 6, further including a means for outputting information from said computer means.
Claim 10
Independent Claim
85 words
A method of measuring temperature differences which comprises: providing a bridge circuit containing first and second thermistors, wherein an output of said bridge circuit is connected to a high gain amplifier and an output of said high gain amplifier is connected to an analog-to-digital converter; balancing said bridge circuit with a computer means; exposing said second thermistor to a thermal environment different from that of said first thermistor; and determining temperature differences between the first and second thermistors from the output of said analog-to-digital converter.
Claim 11
Independent Claim
85 words
A method of measuring temperature differences which comprises: providing a bridge circuit containing first and second thermistors, wherein an output of said bridge circuit is connected to a high gain amplifier and an output of said high gain amplifier is connected to an analog-to-digital converter; balancing said bridge circuit with a computer means; exposing said second thermistor to a thermal environment different from that of said first thermistor; and determining temperature differences between the first and second thermistors from the output of said analog-to-digital converter.
Claim 12
Dependent Claim
25 words
A method of measuring temperature differences according to claim 8, wherein said thermal environment to which said second thermistor is exposed comprises a biological reaction.
Claim 13
Dependent Claim
24 words
A method of measuring temperature differences according to claim 8, wherein said computer means initiates and maintains said bridge circuit in a balance state.
Claim 14
Dependent Claim
27 words
A method of measuring temperature differences according to claim 8 wherein temperature differences on the order of 1×10 -6 ° to 1×10 -5 ° C. are determined.
Claim 15
Dependent Claim
45 words
A method of measuring temperature differences according to claim 8, further including an initial calibration step wherein said second thermistor is substituting with a known resistance, a known voltage is applied to the first thermistor and a voltage is applied to balance the bridge circuit.
Claim 16
Dependent Claim
25 words
A method of measuring temperature differences according to claim 8, wherein said thermal environment to which said second thermistor is exposed comprises a chemical reaction.
References Cited (Backward Citations)
US3620082A
Cited
US3791214A
Cited
US3722283A
Cited
US3781869A
Cited
US3872728A
Cited
US4022063A
Cited
US3950991A
Cited
US4126042A
Cited
US4143549A
Cited
US4443117A
Cited
US4607962A
Cited
US4814692A
Cited
US4679162A
Cited
US4618848A
Cited
US4642785A
Cited
US5064296A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-03-21 | 1997-09-20 | 1998-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-21 | 2001-09-20 | 2002-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-21 | 2005-09-20 | 2006-03-22 | $7700.00 | Window Closed / Lapsed |