US3674713A
Expired / Lapsed
US
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Electric ceramic resistors having positive temperature coefficients and method of manufacturing same
Assignee: US Philips Corp
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Filing: 1970-01-26
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Granted: 1972-07-04
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Expires: 1990-01-26
Abstract
Abstract A barium titanate semiconductive resistor having a high positive temperature coefficient of electrical resistance and containing a small amount of a fluoride.
Inventors
- 👤 Jean Michel Baudry Ghi Yperman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:38
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/022; H01C7/023; H01C7/025; C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
29 words
The electric ceramic resistor of claim 1 wherein said semiconductor body contains 1 to 8 at. percent of fluorine in the form of fluoride based on the barium titanate.
Claim 2
Dependent Claim
30 words
The electric ceramic resistor of claim 1 wherein the ceramic body contains 2 to 6 at. percent inclusive of fluoride in the form of fluoride calculated on the barium titanate.
Claim 3
Dependent Claim
25 words
The electric ceramic resistor of claim 1 wherein the ceramic body contains 1.5 - 2 mol. percent of titanium dioxide calculated on the barium titanate.
Claim 4
Dependent Claim
108 words
In the method of manufacturing a ceramic resistance body consisting of semiconductive barium titanate comprising the steps, first shaping a powder consisting substantially of barium-titanate or compounds heat-convertable to barium titanate and a compound of a metal capable of inducing semiconductivity into the barium titanate into a shaped mass and then sintering the resultant shaped mass by heating in oxygen, the improvement which comprises adding to the powder before shaping at least one fluoride of an element selected from the group consisting of Ca, Sr and Ba in a quantity corresponding to 0.5-10 at. percent of fluorine, calculated on the barium titanate present in the ceramic resistance body.
Claim 5
Dependent Claim
31 words
The method of claim 5 wherein the fluoride is employed in an amount corresponding to 1-8 at. percent of fluorine, calculated on the barium titanate present in the ceramic resistance body.
Claim 6
Dependent Claim
31 words
The method of claim 5 wherein the fluoride is employed in an amount correSponding to 2-6 at. percent of fluorine, calculated on the barium titanate present in the ceramic resistance body.
Claim 7
Dependent Claim
12 words
The method of claim 5 wherein the fluoride is a calcium fluoride.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |