U.S. Philips Corporation

Axel Schnell

Detlev F Hennings

Herbert J Schreinemacher

Heinrich A Oepen

A voltage-dependent resistor having a low operational field strength with 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 in-diffusion of at least a metal oxide or at least a metal oxide compound and comprises of an alkaline earth metal titanate having Perowskite structure of the general formula:

Method of manufacturing voltage-dependent resistor

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

Non-linear resistor and method of manufacturing the same

Voltage-dependent resistor and method of manufacturing same

A bistable ceramic deflection element includes an assembly of two ceramic plates of a ferroelectric ceramic material which can be easily polarized and which has a low coercive field strength, one plate thereof being polarized so that the deflection element is deflected. The other plate is not polarized. The depolarization of the polarized plate can be performed simultaneously with the polarization of the plate non-polarized thus far, because the interchanging of the polarization condition can be simply performed by briefly applying a direct voltage via two extreme electrodes, provided on the plates. The direct voltage causes polarization of the plate not polarized thus far.

Ceramic bistable deflection element

A lead germante phase, (Pb.sub.5 Ge.sub.3 O.sub.11) is added to a ceramic sintered body formed from a polycrystalline alkaline earth metal titanate which has been doped with a small quantity of metal oxide to produce a N-type conductivity. A thin insulating layer of this germante is formed at the grain boundaries of the polycrystalline semiconducting alkaline earth metal titanate because of the formation of a liquid phase during sintering. Thus, the varistor effect is immediately available in the overall volume of the resistance body and need not first be induced by means of a forming procedure, as is the case for known resistors formed from N-doped barium titanate.

Voltage-dependent resistor and method of producing such a resistor

A surface testing apparatus includes a bilaminar ceramic flexure element provided with means for generating a voltage which is proportional to the deflection of the flexure element. This voltage is compared with a reference voltage. After amplification the difference voltage is applied to the flexure element so that the applied force remains constant, independently of the deflection.

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Aachen, Germany

Axel Schnell