US4164147A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature sensing apparatus
Assignee: Texas Instruments Inc
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Filing: 1977-12-30
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Granted: 1979-08-14
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Expires: 1997-12-30
Abstract
Abstract A temperature sensor particularly adapted for use with digital displays or controls comprises an oscillator circuit coupled to a capacitor formed of ferroelectric material in order to provide a linear relation of frequency with temperature. Both chip and multilayer capacitors are shown to be useful as the sensing element.
Inventors
- 👤 Bernard M. Kulwicki
- 👤 George Trenkler
- 👤 David C. Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:43
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/34; G01K7/343
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
67 words
A temperature control system comprises oscillator circuit means having an output frequency dependent upon the first power of capacitance and a sensor having a linear output over a wide temperature range coupled to the circuit means, the sensor being formed of ferroelectric material selected such that the operating temperature of the environment in which the sensor is employed is above the Curie temperature of the ferroelectric material.
Claim 2
Dependent Claim
67 words
A temperature control system comprises oscillator circuit means having an output frequency dependent upon the first power of capacitance and a sensor having a linear output over a wide temperature range coupled to the circuit means, the sensor being formed of ferroelectric material selected such that the operating temperature of the environment in which the sensor is employed is above the Curie temperature of the ferroelectric material.
Claim 3
Dependent Claim
24 words
A temperature control system according to claim 1 further including frequency counter and display means coupled to the output of the oscillator circuit means.
Claim 4
Dependent Claim
19 words
A temperature control system according to claim 1 in which the sensor is a chip layer of barium titanate.
Claim 5
Dependent Claim
26 words
A temperature control system according to claim 3 in which the barium titanate has the composition Ba.sub..73 Sr.sub..27 Ti 1 .00 Nb.sub..01 Fe.sub..001 O 3 .
Claim 6
Dependent Claim
26 words
A temperature control system according to claim 1 in which the sensor comprises a plurality of layers of barium titanate electrically coupled in parallel circuit relation.
Claim 7
Dependent Claim
26 words
A temperature control system according to claim 5 in which the barium titanate has the composition Ba.sub..73 Sr.sub..27 Ti 1 .00 Nb.sub..01 Fe.sub..001 O 3 .
Claim 8
Dependent Claim
26 words
A temperature control system according to claim 1 in which the oscillator circuit means has an output frequency which is dependent upon the reciprocal of capacitance.
Claim 9
Dependent Claim
22 words
A temperature control system according to claim 1 in which the ferroelectric material has a high dielectric constant at its Curie temperature.
Claim 10
Dependent Claim
54 words
In a temperature control system comprising an oscillator circuit means having an output frequency dependent upon the first power of capacitance and a sensor coupled to the circuit means, the improvement comprising the sensor of ferroelectric material having a selected Curie temperature such that during normal operation the material is in the paraelectric state.
Claim 11
Dependent Claim
54 words
In a temperature control system comprising an oscillator circuit means having an output frequency dependent upon the first power of capacitance and a sensor coupled to the circuit means, the improvement comprising the sensor of ferroelectric material having a selected Curie temperature such that during normal operation the material is in the paraelectric state.
Claim 12
Dependent Claim
16 words
A temperature control system according to claim 9 in which the ferroelectric material is barium titanate.
Claim 13
Dependent Claim
26 words
A temperature control system according to claim 10 in which the barium titanate has the composition Ba.sub..73 Sr.sub..27 Ti 1 .00 Nb.sub..01 Fe.sub..001 O 3 .
References Cited (Backward Citations)
US2648823A
Cited
US3260116A
Cited
US3338100A
Cited
US3505872A
Cited
US3596262A
Cited
US3728641A
Cited
US3792377A
Cited
US3772748A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-13 | 1983-02-12 | 1983-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-13 | 1987-02-12 | 1987-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-13 | 1991-02-12 | 1991-08-14 | $7700.00 | Window Closed / Lapsed |