US3924470A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature measurement circuit
Assignee: Daktronics Inc
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Filing: 1973-09-28
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Granted: 1975-12-09
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Expires: 1993-09-28
Abstract
Abstract A multiamplifier measurement circuit in which each amplifier thereof is a differential amplifier and in which the inputs of each differential amplifier are balanced to provide a temperature stable measurement circuit. In a preferred embodiment, the measurement circuit includes a measurement amplifier, reference amplifier, and output amplifier; the measurement amplifier inputs are connected across opposite sides of a measurement bridge including a thermoelectric transducer in one leg thereof, and the reference amplifier inputs are connected across opposite sides of an offset adjustment bridge including a potentiometer in one leg thereof for adjusting the circuit offset. The output amplifier inputs are respectively connected to the measurement and reference amplifier outputs. The reference and measurement amplifier output impedances are equal which together with the connection of each of the measurement and reference amplifiers across a bridge provides a multiamplifier measurement circuit in which each of the amplifiers have balanced input impedances to provide a temperature stable measurement circuit.
Inventors
- 👤 Duane E Sander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:04
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/16; G01K7/22; G01K7/24
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
184 words
A measurement circuit comprising: A. an output amplifier having a positive input and a negative input for providing an output signal representative of temperature and proportional to the difference between a measured signal and a reference signal throughout a measurement range; B. a measurement amplifier having a positive input and a negative input and having an output connected to one of the inputs of said output amplifier to provide said measured signal to said output amplifier; C. input means to said measurement amplifier selected to provide balanced impedances to said measurement amplifier positive and negative inputs throughout the measurement range; D. a thermoelectric transducer for providing a signal representative of temperature to an input of said measurement amplifier; and E. impedance means having an impedance balanced to the output impedance of said measurement amplifier and connected to the input of said output amplifier not connected to the output of said measurement amplifier to provide a multiamplifier temperature measurement circuit each of the amplifiers of which have balanced input impedances throughout the measurement range whereby the circuit is temperature stable over long periods of time.
Claim 2
Dependent Claim
184 words
A measurement circuit comprising: A. an output amplifier having a positive input and a negative input for providing an output signal representative of temperature and proportional to the difference between a measured signal and a reference signal throughout a measurement range; B. a measurement amplifier having a positive input and a negative input and having an output connected to one of the inputs of said output amplifier to provide said measured signal to said output amplifier; C. input means to said measurement amplifier selected to provide balanced impedances to said measurement amplifier positive and negative inputs throughout the measurement range; D. a thermoelectric transducer for providing a signal representative of temperature to an input of said measurement amplifier; and E. impedance means having an impedance balanced to the output impedance of said measurement amplifier and connected to the input of said output amplifier not connected to the output of said measurement amplifier to provide a multiamplifier temperature measurement circuit each of the amplifiers of which have balanced input impedances throughout the measurement range whereby the circuit is temperature stable over long periods of time.
Claim 3
Dependent Claim
39 words
A measurement circuit according to claim 1 wherein said input means to said measurement amplifier is a bridge connected across the inputs of said measurement amplifier and wherein said thermoelectric transducer is connected to one leg of said bridge.
Claim 4
Dependent Claim
32 words
A measurement circuit according to claim 1 wherein said impedance means is an offset bridge including variable impedance means in one leg thereof to provide a measurement circuit having offset adjustment capability.
Claim 5
Dependent Claim
38 words
A measurement circuit according to claim 3 wherein said impedance means further comprises a reference amplifier having a positive and negative input and in which opposite sides of said bridge are connected across said positive and negative inputs.
Claim 6
Dependent Claim
16 words
A measurement circuit according to claim 1 wherein said impedance means is a voltage divider network.
Claim 7
Dependent Claim
17 words
A measurement circuit according to claim 5 wherein said voltage divider network includes a variable impedance means.
Claim 8
Dependent Claim
20 words
A measurement circuit according to claim 3 wherein said output amplifier and said measurement amplifier each comprises a difFerential amplifier.
Claim 9
Dependent Claim
16 words
A measurement circuit according to claim 7 wherein each said differential amplifier comprises an operational amplifier.
Claim 10
Dependent Claim
27 words
A measurement circuit according to claim 3 wherein said input means to said measurement amplifier is a measurement bridge connected across the inputs of said measurement amplifier.
Claim 11
Dependent Claim
20 words
A measurement circuit according to claim 9 wherein said output amplifier and said measurement amplifier each comprise an operational amplifier.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |