US4951028A
Expired / Lapsed
US
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Positive temperature coefficient resistor
Assignee: Massachusetts Institute of Technology
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Filing: 1989-03-03
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Granted: 1990-08-21
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Expires: 2009-03-03
Abstract
Abstract The resistor includes a cooper oxide ceramic with perovskite related structures exhibiting positive temperature coefficient of resistance characteristics in the temperature range of 300°-900° C. Suitable materials are YBa 2 Cu 3 O 7-x , La 2 CuO 4 and related compounds with other rare earth elements substituted for Y and La and other alkaline earth elements substituted for Ba.
Inventors
- 👤 Harry L. Tuller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:37
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/022; H01C7/023; H01C7/025
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
47 words
A temperature sensitive circuit comprising: a temperature sensitive element comprising a copper oxide ceramic with perovskite related structures; and electrical circuitry for exploiting the temperature coefficient of resistance characteristics of the temperature element within a preselected temperature range, the preselected temperature range being located above 300° C.
Claim 2
Dependent Claim
47 words
A temperature sensitive circuit comprising: a temperature sensitive element comprising a copper oxide ceramic with perovskite related structures; and electrical circuitry for exploiting the temperature coefficient of resistance characteristics of the temperature element within a preselected temperature range, the preselected temperature range being located above 300° C.
Claim 3
Dependent Claim
19 words
The temperature sensor of claim 1 wherein the copper oxide ceramic is YBa 2 Cu 3 O 7-x .
Claim 4
Dependent Claim
15 words
The temperature sensor of claim 1 wherein the ceramic is La 2 CuO 4 .
Claim 5
Dependent Claim
17 words
The temperature sensor of claim 1 wherein the ceramic is La 2-x Sr x CuO y .
Claim 6
Dependent Claim
55 words
The temperature sensor of claim 1 wherein the temperature coefficient of resistance of the ceramic oxide exhibits a transition region within the preselected temperature range and wherein the ceramic oxide is in the R--E--Cu--O system, where R is selected from the group of rare earths and E is selected from the group of alkaline earths.
Claim 7
Dependent Claim
10 words
The temperature sensor of claim 5 wherein R is ytrrium.
Claim 8
Dependent Claim
10 words
The temperature sensor of claim 5 wherein E is barium.
Claim 9
Dependent Claim
10 words
The temperature sensor of claim 6 wherein E is barium.
Claim 10
Dependent Claim
10 words
The temperature sensor of claim 5 wherein E is calcium.
Claim 11
Dependent Claim
10 words
The temperature sensor of claim 6 wherein E is calcium.
Claim 12
Dependent Claim
10 words
The temperature sensor of claim 5 wherein E is strontium.
Claim 13
Dependent Claim
10 words
The temperature sensor of claim 6 wherein E is strontium.
Claim 14
Dependent Claim
35 words
The temperature sensor of claim 6 wherein the copper ceramic oxide also includes an element selected from the group of transition metals, said element being partially substituted for the copper in the copper ceramic oxide.
Claim 15
Dependent Claim
17 words
The sensor of claim 13 wherein the element selected from the group of transition metals is nickel.
Claim 16
Dependent Claim
22 words
The sensor of claim 1 wherein the temperature sensitive element exhibits a positive temperature coefficient of resistance within the preselected temperature range.
Claim 17
Dependent Claim
27 words
The temperature sensitive circuit of claim 15 wherein said electrical circuitry exploits the positive temperature coefficient of resistance characteristics of the temperature sensitive element to monitor temperature.
Claim 18
Dependent Claim
34 words
The temperature sensitive circuit of claim 15 wherein the electrical circuitry exploits the positive temperature coefficient of resistance characteristics of the temperature sensitive element so that said element operates as a self regulating heater.
Claim 19
Dependent Claim
19 words
The temperature sensor of claim 17 wherein the copper oxide ceramic is YBa 2 Cu 3 O 7-x .
Claim 20
Dependent Claim
15 words
The temperature sensor of claim 17 wherein the ceramic is La 2 CuO 4 .
Claim 21
Dependent Claim
17 words
The temperature sensor of claim 17 wherein the ceramic is La 2-x Sr x CuO y .
Claim 22
Dependent Claim
55 words
The temperature sensor of claim 17 wherein the temperature coefficient of resistance of the ceramic oxide exhibits a transition region within the preselected temperature range and wherein the ceramic oxide is in the R--E--Cu--O system, where R is selected from the group of rare earths and E is selected from the group of alkaline earths.
Claim 23
Dependent Claim
10 words
The temperature sensor of claim 21 wherein R is yttrium.
Claim 24
Dependent Claim
10 words
The temperature sensor of claim 22 wherein E is barium.
Claim 25
Dependent Claim
10 words
The temperature sensor of claim 22 wherein E is barium.
Claim 26
Dependent Claim
10 words
The temperature sensor of claim 21 wherein E is calcium.
Claim 27
Dependent Claim
10 words
The temperature sensor of claim 22 wherein E is calcium.
Claim 28
Dependent Claim
10 words
The temperature sensor of claim 21 wherein E is strontium.
Claim 29
Dependent Claim
10 words
The temperature sensor of claim 22 wherein E is strontium.
Claim 30
Dependent Claim
35 words
The temperature sensor of claim 17 wherein the copper ceramic oxide also includes an element selected from the group of transition metals, said element being partially substituted for the copper in the copper ceramic oxide.
Claim 31
Dependent Claim
17 words
The sensor of claim 29 wherein the element selected from the group of transition metals is nickel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-20 | 1994-02-19 | 1994-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-20 | 1998-02-19 | 1998-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-20 | 2002-02-19 | 2002-08-21 | $7700.00 | Window Closed / Lapsed |