A thick film resistor excluding a toxic lead component from a conductive component and glass and having characteristics equivalent to or superior to conventional resistors in terms of, in a wide resistance range, resistance values, TCR characteristics, current noise characteristics, withstand voltage characteristics and the like. The thick film resistor is formed of a fired product of a resistive composition, wherein the thick film resistor contains ruthenium-based conductive particles containing ruthenium dioxide and a glass component essentially free of a lead component and has a resistance value in the range of 100 / to 10 M/ and a temperature coefficient of resistance within 100 ppm/ C.

An over-current protection device includes an electrode layer and a heat-sensitive layer. The heat-sensitive layer exhibits a positive temperature coefficient (PTC) characteristic, and is laminated between a top metal layer and a bottom metal layer of the electrode layer. The heat-sensitive layer includes a polymer matrix and a conductive filler. The polymer matrix includes a fluorine-containing copolymer, and its melting point ranges from 210? C. to 240? C. The conductive filler consists of carbon black solely, and is used to form an electrically conductive path in the heat-sensitive layer. In addition, the over-current protection device has a resistance-jump ratio ranging from 1.2 to 1.3 between 40? C. and 130? C.

A ceramic material has a composition represented by Ca.sub.xNa.sub.xMn.sub.yM.sub.yO.sub.12, wherein M denotes at least one of Ni and Cu, and x, x, y, and y satisfy any of (a), (b), and (c) in which x+x=X and y+y=Y:

[00001]$\begin{array}{cc}\frac{0.9}{7.0}\frac{X}{Y}<\frac{1.0}{7.0};& \left(a\right)\end{array}$

at a condition of

[00002]$\begin{array}{cc}\frac{X}{Y}=\frac{1.0}{7.0},\frac{0.03}{8}\frac{x}{X+Y}<\frac{0.30}{8}.Math..Math.\mathrm{and}.Math..Math.0\frac{y}{X+Y}\frac{0.35}{8};\mathrm{and}& \left(b\right)\\ \frac{1.0}{7.0}<\frac{X}{Y}\frac{1.0}{6.9}.& \left(c\right)\end{array}$

Provided are a metal nitride material for a thermistor, which exhibits high reliability and high heat resistance and can be directly deposited on a film or the like without firing, a method for producing the metal nitride material for a thermistor, and a film type thermistor sensor. The metal nitride material for a thermistor consists of a metal nitride represented by the general formula: Ti.sub.xAl.sub.yN.sub.z (where 0.70y/(x+y)0.95, 0.4z0.5, and x+y+z=1), and the crystal structure thereof is a hexagonal wurtzite-type single phase.

A thick film resistor excluding a toxic lead component from a conductive component and glass and having characteristics equivalent to or superior to conventional resistors in terms of, in a wide resistance range, resistance values, TCR characteristics, current noise characteristics, withstand voltage characteristics and the like. The thick film resistor is formed of a fired product of a resistive composition, wherein the thick film resistor contains ruthenium-based conductive particles containing ruthenium dioxide and a glass component essentially free of a lead component and has a resistance value in the range of 100/ to 10 M/ and a temperature coefficient of resistance within 100 ppm/ C.

An object is to provide a temperature sensor element that can suppress a reduction reaction of a heat sensitive body, even after a long time usage in a strong reducing atmosphere.

A temperature sensor element 1 includes: a heat sensitive body 11 of which electric resistance changes according to a temperature; a first coating layer 20 that covers a periphery of the heat sensitive body 11; a pair of lead-out wires 15 and 15 that are connected to the heat sensitive body 11, and also are led out in penetration through the first coating layer 20, toward a rear end side; a second coating layer 25 that covers a periphery of the pair of lead-out wires 15 and 15 which are led out in penetration through the first coating layer 20; and a third coating layer 30 that covers peripheries of the first coating layer 20 and the second coating layer 25. The second coating layer 25 is formed of a mixture of glass and at least one of chromium oxide, manganese oxide, ruthenium oxide powder, iridium oxide powder and platinum oxide.

Apparatus and methods related to negative differential resistance (NDR) are provided. An NDR device includes a spaced pair of electrodes and at least two different materials disposed there between. One of the two materials is characterized by negative thermal expansion, while the other material is characterized by positive thermal expansion. The two materials are further characterized by distinct electrical resistivities. The NDR device is characterized by a non-linear electrical resistance curve that includes a negative differential resistance range. The NDR device operates along the curve in accordance with an applied voltage across the pair of electrodes.

An object of the present invention is to provide a thick film resistor excluding a toxic lead component from a conductive component and glass and having characteristics equivalent to or superior to conventional resistors in terms of, in a wide resistance range, resistance values, TCR characteristics, current noise characteristics, withstand voltage characteristics and the like. The present invention is a thick film resistor formed of a fired product of a resistive composition, wherein the thick film resistor contains ruthenium-based conductive particles containing ruthenium dioxide and a glass component being essentially free of a lead component and has a resistance value in the range of 100 / to 10 M/ and a temperature coefficient of resistance within 100 ppm/ C.

A temperature sensor element includes: an element main body including a heat sensitive body including a thermistor sintered body of which the electrical characteristics change with temperature, and a pair of lead wires that is connected to the heat sensitive body through electrodes; and a protective layer that protects the heat sensitive body. The protective layer has an inner protective layer covering the heat sensitive body and an outer protective layer covering the outer side of the inner protective layer. The inner protective layer is formed of an aggregate of particles that are chemically stable with respect to the thermistor sintered body and made of non-metal.