Composite circuit protection devices
US5089688A · kind A · utility
74Cited by
31References
23Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1989 |
| Grant date | Feb 18, 1992 |
| Priority date | — |
| Expiry date | Dec 22, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B2203/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Circuit protection devices which comprise a PTC conductive polymer element and a second electrical component which is thermally coupled to the PTC element and which, when a fault causes the current in the circuit to become excessive, generates heat which is transferred to the PTC element, thus reducing the time taken to "trip" PTC element. The second component is for example a voltage-dependent resistor which is connected in series with the PTC element under the fault conditions and is thus protected from damage. Alternatively, the second component is a thick film resistor which is connected in series with the PTC element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.