Abstract A non-linear resistor having an operational field strength which optionally is formed as a VDR- or as an NTC-resistor having a ceramic sintered body on the basis of a polycrystalline alkaline earth metal titanate doped with a small quantity of a metal oxide so as to produce an N-type conductivity, in which the sintered body comprises at its grain boundaries insulating layers formed by re-oxidation of the sintered body and consists of an alkaline earth metal titanate having a Perowskite structure of the general formula (A.sub.1-x Ln.sub.x)TiO.sub.3.yTiO.sub.2 or A(Ti.sub.1-x Me x )O 3 .yTiO 2 , wherein: A=alkaline earth metal; Ln=rare earth metal; Me=metal having a valency of 5 or more; 0.0005<×<solubility limit in the Perowskite phase; y×0.001 to 0.02. The sintered body becomes adjustable in its non-linear resistance variation by selection of the re-oxidation temperature and of the re-oxidation duration in such manner that an initially present NTC-characteristic gradually is observable only at ever increasing temperatures and changes into a VDR-characteristic in the range of the operating temperature of the resistor.
A non-linear resistor having a ceramic sintered body consisting of a polycrystalline alkaline metal titanate doped to N-type conductance with a metal oxide and which sintered body is provided with electrodes on opposite located surfaces thereof characterized in that said body has a Perowskite structure, consists of an alkaline earth metal titanate containing excess TiO 2 , has a formula selected from the group consisting of (Sr 1-x Ln x ) TiO 3 .yTiO 2 and Sr(Ti 1-x Me x )O 3 .yTiO 2 wherein Ln is a rare earth metal, Me is a metal having a valence of at least 5, 0.0005<x<solubility limit of the Ln in the Perowskite phase and y=0.001 to 0.02 and which sintered body is provided on its grain boundaries with insulating layers produced by re-oxidation.
Claim 2
Dependent Claim
131 words
A non-linear resistor having a ceramic sintered body consisting of a polycrystalline alkaline metal titanate doped to N-type conductance with a metal oxide and which sintered body is provided with electrodes on opposite located surfaces thereof characterized in that said body has a Perowskite structure, consists of an alkaline earth metal titanate containing excess TiO 2 , has a formula selected from the group consisting of (Sr 1-x Ln x ) TiO 3 .yTiO 2 and Sr(Ti 1-x Me x )O 3 .yTiO 2 wherein Ln is a rare earth metal, Me is a metal having a valence of at least 5, 0.0005<x<solubility limit of the Ln in the Perowskite phase and y=0.001 to 0.02 and which sintered body is provided on its grain boundaries with insulating layers produced by re-oxidation.
Claim 3
Dependent Claim
17 words
A non-linear resistor as claimed in claim 1, characterized in that lanthanum is the rare earth metal.
Claim 4
Dependent Claim
22 words
A non-linear resistor as claimed in claim 1, characterized in that niobium is the metal of a valance of at least 5.
Claim 5
Dependent Claim
22 words
A non-linear resistor as claimed in claim 1, characterized in that tungsten is the metal of a valance of at least 5.