Ceramic resistance elements

(19)

(11)

EP 0 308 209 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	10.01.1990 Bulletin 1990/02

(43)	Date of publication A2:
	22.03.1989 Bulletin 1989/12

(21)	Application number: 88308516.9

(22)	Date of filing: 15.09.1988

(51)	International Patent Classification (IPC)⁴: H01C 7/04, B60R 16/02, H01C 17/22

(84)	Designated Contracting States:
	AT BE CH DE ES FR GB GR IT LI LU NL SE

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Priority:

15.09.1987 GB 8721687

(71)	Applicant: ELMWOOD SENSORS LIMITED
	North Shields Tyne & Wear, NE29 8SE (GB)

(72)	Inventor:
	Al-Allak, Haider Dr. South Road Durham DH1 3LG (GB)

(74)	Representative: Garratt, Peter Douglas et al
	Mathys & Squire 100 Grays Inn Road London WC1X 8AL London WC1X 8AL (GB)

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References cited: :

(54)	Ceramic resistance elements

(57) A resistance element based on barium titanate has an excessive donor dopant level such that the low temperature resistivity is greater than the high temperature resistivity maximum. The resultant NTC characteristic has an inflexion over which the resistivity is substantially constant. A similar effect is achieved with an excess of acceptor dopant. An advantage of the resistance element lies in automobile or other instrumentation or control devices where a resistance dwell is required over a specified temperature range.

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