Abstract: A multilayer substrate includes a multilayer body in which insulating layers are laminated in a laminating direction, a front electrode that is provided on a front surface side of a first insulating layer which is positioned on a front surface side of the multilayer body among the insulating layers, a first internal electrode that is provided on an opposite side to the front electrode with the first insulating layer interposed therebetween, and a first interlayer connection conductor that electrically connects the front electrode and the first internal electrode with each other. The first interlayer connection conductor includes a front side connection surface that is electrically connected with the front electrode and a back side connection surface that is electrically connected with the first internal electrode.

Abstract: A two-port isolator includes a first center electrode and a second center electrode which are wound around a ferrite to which a direct-current magnetic field is applied from permanent magnets, and the ferrite is mounted on a circuit board having built-in matching circuit devices. The ferrite is preferably substantially rectangular-parallelepiped-shaped having first and second principal surfaces that are substantially parallel to each other, and the long-side length of the principal surfaces is about 1.5 to about 5 times the short-side length. The second center electrode is wound between one and four turns around the ferrite.

Abstract: A two-port isolator includes a first center electrode and a second center electrode which are wound around a ferrite to which a direct-current magnetic field is applied from permanent magnets, and the ferrite is mounted on a circuit board having built-in matching circuit devices. The ferrite is preferably substantially rectangular-parallelepiped-shaped having first and second principal surfaces that are substantially parallel to each other, and the long-side length of the principal surfaces is about 1.5 to about 5 times the short-side length. The second center electrode is wound between one and four turns around the ferrite.

Abstract: An oxygen concentration detector comprises an oxygen concentration sensor made of an oxygen ion conductive metal oxide which produces an electromotive force in accordance with a difference between an oxygen concentration in gas components of a gas under test and an oxygen concentration in a reference gas, an electrode formed on a surface of the oxygen concentration sensor which is to be exposed to the gas under test and an electrode formed on a surface of the oxygen concentration sensor which is to be exposed to the reference gas so that the electromotive force produced by the oxygen concentration sensor is taken across the electrodes, a first porous coating of a refractory metal oxide formed on the surface of the electrode which is to be exposed to the gas under test, said first coating having a number of pores through which the gas under test can pass, and a second porous coating of a refractory metal oxide formed on the surface of the first coating, said second coating having a number of pores which are la

Abstract: Thermistors having a resistor which comprises aluminum oxide (Al.sub.2 O.sub.3) and chromium oxide (Cr.sub.2 O.sub.3) are excellent in heat resistance even when they are used at a high temperature of 400.degree. - 1,100.degree.C. Proportion of Al.sub.2 O.sub.3 and Cr.sub.2 O.sub.3 is preferably 11 mol % of Cr.sub.2 O.sub.3 and 89 mol % - 6 mol % of Al.sub.2 O.sub.3. Furthermore, calcium oxide and silicon oxide may be added to accelerate the sintering of the Al.sub.2 O.sub.3 and Cr.sub.2 O.sub.3. In addition, manganese oxide or titamium oxide may be contained in the resistor for more accurate control of temperature.