US5166658A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical device comprising conductive polymers
Assignee: FRANKLIN BRASS MANUFACTURING COMPANY A CORP OF
•
Filing: 1990-03-08
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Granted: 1992-11-24
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Expires: 2010-03-08
Abstract
Abstract Circuit protection systems which comprise a PTC resistor and a second resistor, e.g. a thick film resistor, which is thermally and electrically connected to the PTC resistor have a break current IB and a hold current IH such that the ratio IB/IH is at most 20. Suitable PTC resistors are conductive polymer devices which comprise a PTC element which has been radiation crosslinked under conditions such that the average dose rate is at most 3.0 Mrad/minute or during which no part of the PTC element which is in contact with the electrodes reaches a temperature greater than (Tm-60) DEG C., where Tm is the melting point of the polymeric component of the conductive polymer.
Inventors
- 👤 Shou-Mean Fang
- 👤 David A. Horsma
- 👤 Guillaume Peronnet
- 👤 Charles H. Camphouse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:36
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/146; H01; H01C; H01C7/00; H01C7/02; H01C7/021; H01C7/027
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
58 words
A circuit protection system which comprises a PTC resistor and a second resistor which is electrically connected in series with the PTC resistor and is in thermal contact with the PTC resistor, the system having a break current I B and a hold current I H , and the ratio I B /I H being at most 20.
Claim 2
Dependent Claim
58 words
A circuit protection system which comprises a PTC resistor and a second resistor which is electrically connected in series with the PTC resistor and is in thermal contact with the PTC resistor, the system having a break current I B and a hold current I H , and the ratio I B /I H being at most 20.
Claim 3
Dependent Claim
17 words
A system according to claim 1 wherein the ratio I B /I H is at least 3.
Claim 4
Dependent Claim
14 words
A system according to claim 1 wherein the second resistor is a ZTC resistor.
Claim 5
Dependent Claim
24 words
A system according to claim 3 wherein the second resistor is a thick film resistor comprising ruthenium oxide mounted on an insulating ceramic substrate.
Claim 6
Dependent Claim
16 words
A system according to claim 1 wherein the PTC resistor is composed of a conductive polymer.
Claim 7
Dependent Claim
28 words
A system according to claim 5 wherein the PTC resistor comprises a laminar PTC element which is composed of a conductive polymer and at least two laminar electrodes.
Claim 8
Dependent Claim
38 words
A system according to claim 6 wherein at least a part of the PTC resistor does not overlap the thick film resistor when the system is viewed at right angles to the plane of the thick film resistor.
Claim 9
Dependent Claim
57 words
A system according to claim 7 wherein the plane of the PTC element is substantially parallel to the plane of the thick film resistor and the proportion of the PTC element which overlaps the thick film resistor, when the system is viewed at right angles to the plane of the thick film resistor is at most 75%.
Claim 10
Dependent Claim
17 words
A system according to claim 1 wherein the ratio I B /I H is at most 15.
Claim 11
Dependent Claim
17 words
A system according to claim 9 wherein the ratio I B /I H is at most 10.
Claim 12
Dependent Claim
17 words
A system according to claim 2 wherein the ratio I B /I H is at least 5.
Claim 13
Dependent Claim
17 words
A system according to claim 11 wherein the ratio I B /I H is at least 7.
Claim 14
Dependent Claim
15 words
A system according to claim 3 wherein the second resistor is a thick film resistor.
Claim 15
Dependent Claim
23 words
A system according to claim 8 wherein the proportion of the PTC element which overlaps the thick film resistor is at most 50%.
Claim 16
Dependent Claim
23 words
A system according to claim 14 wherein the proportion of the PTC element which overlaps the thick film resistor is at most 25%.
Claim 17
Dependent Claim
21 words
A system according to claim 15 wherein the proportion of the PTC element which overlaps the thick film resistor is 0%.
Claim 18
Dependent Claim
23 words
A system according to claim 1 wherein the total resistance of the PTC resistor and the second resistor is 5 to 200 ohms.
Claim 19
Dependent Claim
24 words
A system according to claim 3 wherein the resistance of the second resistor is at least 2 times the resistance of the PTC resistor.
Claim 20
Dependent Claim
24 words
A system according to claim 18 wherein the resistance of the second resistor is at least 5 times the resistance of the PTC resistor.
Claim 21
Dependent Claim
24 words
A system according to claim 19 wherein the resistance of the second resistor is at least 10 times the resistance of the PTC resistor.
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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) | 1995-11-24 | 1996-05-25 | 1996-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-24 | 2000-05-25 | 2000-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-24 | 2004-05-25 | 2004-11-24 | $7700.00 | Window Closed / Lapsed |