Laminar non-linear device with magnetically aligned particles

Patent 5742223 Issued on April 21, 1998. Estimated Expiration Date:

December 7, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Assignee

Raychem Corporation

Application

No. 568716 filed on 12/07/1995

US Classes:

338/21, Voltage surge-responsive or lightning arrester type338/20, Current and/or voltage (e.g., ballast resistor)338/22RThermistor type

Examiners

Primary: Walberg, Teresa
Assistant: Easthom, Karl D.

Attorney, Agent or Firm

Gerstner; Marquerite E., Burkard; Herbert G.

Foreign Patent References

0 603 565 EP 06/23/1994
2 622 058 FR 04/23/1989
55-162201 JP 12/23/1980
5-3104 JP 01/23/1993
1346851 GB 02/23/1974
2 129 630 GB 05/23/1984
WO86/01634 WO 03/23/1986
WO88/00603 WO 01/23/1988
WO90/05166 WO 05/23/1990
WO91/05014 WO 04/23/1991
WO93/23472 WO 11/23/1993
WO 94/00856 WO 01/23/1994

International Class

H01C 007/10

Abstract

An electrical device in which a first resistive element which is composed of a first electrically non-linear composition is in electrical contact, and preferably in physical and electrical contact, with a second resistive element which is composed of a second composition which has a resistivity of less than 100 ohm-cm. The first composition has a resistivity of more than 109 ohm-cm and contains a first particulate filler. The second composition contains a second particulate filler which (a) is magnetic and electrically conductive, and (b) is aligned in discrete regions in the second polymeric component. The device also contains first and second electrodes which are positioned so that current can flow between the electrodes through the first and second resistive elements. Devices of the invention have relatively low breakdown voltages and can survive high energy fault conditions.