Abstract: The present invention provides a composition of dielectric ceramic composition to be used in the frequency region of microwaves.The composition contains lead oxide, calcium oxide, iron, oxide, tantalum oxide and niobium oxide, and is represented by (Pb.sub.1-x Ca.sub.x).sub.1+a {Fe.sub.178 (Ta.sub.1-y Nb.sub.y).sub.178 }O.sub.3+a wherein x, y and a satisfy, respectively, 0.44.ltoreq.x.ltoreq.0.63, 0.0.ltoreq.y.ltoreq.1.0 and 0.0.ltoreq.a.ltoreq.0.08.

Abstract: A dielectric ceramic composition possessing a high relative dielectric constant, a high unloaded Q value, and an excellent temperature characteristic is expressed as xPbO-.sub.y (Mg.sub.1/3 Nb.sub.2/3)O.sub.2 -zCaO, where x+y+z=1, and x, y, z are in the following ranges, 0.05.ltoreq.x.ltoreq.0.45, 0.4.ltoreq.y.ltoreq.0.55, 0.15.ltoreq.z.ltoreq.0.4, or expressed as xPbO-y(Ni.sub.1/3 Nb.sub.2/3) O.sub.2 -zCaO, where x+y+z=1, and x,y, z are in a quadrangular region with vertexes at A (x=0.25 y=0.7 z=0.05), B (x=0.2 y=0.7 z=0.1), C (x=0.2 y=0.45 z=0.35), and D (x=0.35 y=0.45 z=0.2), which are composition points of a ternary system with vertexes at PbO, (Ni.sub.1/3 Nb.sub.2/3)O.sub.2, and CaO.

Abstract: Dielectric ceramic composition consisting essentially of substance selected from those represented by the following formula:Pb.sub.1-x+a Me.sub.x {(Zn.sub.1/3 Nb.sub.2/3)1.sub.-y-z Ti.sub.y (Cu.sub.b M.sub.1-b).sub.2 }O.sub.3+awherein Me is at least one element selected from Sr and Ba; M is at least one element selected from Nb, Ta and W; x and y are within the scope shown in FIGS. 1, 3 or 2; and O.ltoreq.a.ltoreq.0.1, 0.02.ltoreq.b.ltoreq.1.0, 0.002.ltoreq.bz.ltoreq.0.04.Multi-layer capacitors having dielectric layers made of the dielectric ceramic composition exhibit a good temperature coefficient of capacitance.

Abstract: A multilayer ceramic capacitor comprises plural ceramic dielectric layers laminated one on another, and at least two internal electrodes separated by the ceramic dielectric layer and alternately terminated at the opposite sides of the laminated ceramic dielectric layers. The ceramic dielectric layers is composed of a complex oxide including a component (A), a component (B) and copper, wherein the component (A), is at least one element selected from the group consisting of Pb, Ca, Sr and Ba, but contains Pb at the least, wherein the component (B) is at least two elements selected from the group consisting of Mg, Ni, Zn, Ti, Ta, Nb and W, the molar ratio of the component (A) to component (B) being not less than 0.985, but not more than 1.110, and wherein the content of said copper in the complex oxide is more than 0.650 wt %, but not more than 2.200 wt % in terms of Cu.sub.2 O. The internal electrodes are composed of copper or an alloy mainly comprising copper.

Abstract: A multi-layer ceramic capacitor having a large capacitance comprising:(a) internal electrode layers whose thickness is y .mu.m, and(b) ceramic dielectric layers, whose thickness is x .mu.m, extending between the internal electrode layers, where x, y and x/y are defined by the formula 1.0.ltoreq.x.ltoreq.7.0, 0.07.ltoreq.y.ltoreq.0.7 and 10.0.ltoreq.x/y.ltoreq.100.0 respectively.

Abstract: A mutli-layer ceramic capacitor principally made up of (a) internal electrode layers containing at least copper and (b) ceramic dielectric layers extending between the internal electrode layers. The materials which form the ceramic include copper oxide and an oxide component A and B, which component A is selected from group I of lead, calcium, strontium, and barium, and component B is selected from group II of magnesia, nickel, titanium, zirconium, zinc, niobium, tantalum, and tungsten. The component A includes at least lead and component B includes at least two of the substances in group II, and wherein a ratio between values a and b are chosen so that 0.985<a/b<1.110, where the value a denotes the total mol value of the substances in the component A and the value b denotes the total mol value of the substances in component B. The copper oxide component is present in an amount of about 0.03 to 0.65 wt % in terms of Cu.sub.2 O content.