An over-current protection device comprises first and second electrode layers and a PTC material layer laminated therebetween. The PTC material layer has a resistivity less than 0.05 .Math.cm and comprises a polymer matrix, a conductive ceramic filler and a carbon-containing conductive filler. The polymer matrix comprises a fluoropolymer having a melting point higher than 150 C. and comprises 50-60% by volume of the PTC material layer. The conductive ceramic filler having a resistivity less than 500.Math.cm is dispersed in the polymer matrix and comprises 40-45% by volume of the PTC material layer. The carbon-containing conductive filler is dispersed in the polymer matrix and comprises 0.5-5% by volume of the PTC material layer. At 25 C., a ratio of a hold current to an area of the over-current protection device is 0.21-0.3 A/mm.sup.2, and a ratio of an endurable power to the area of the over-current protection device is 4.8-7.2 W/mm.sup.2.

A method of making a hot surface igniter is described. A silicon carbide composition that includes both fines fraction and a coarse fraction is sintered in a nitrogen and argon reducing atmosphere in a manner that controls the incorporation of nitrogen with in the lattice of recrystallized silicon carbide. The controlled incorporation of nitrogen in the lattice provides enhanced control over heating and electrical properties, while simultaneously achieving a lower surface area fully recrystallized structure for oxidation resistance and long service life.

A connecting-conductor is disclosed. The connecting-conductor may have a first conductor-element and a second conductor-element. Each conductor-element has a first end that is mechanically-connected and electrically-conductively connected to a resistor-element. The resistor-element has an electrical-insulating substrate, and a resistive material annularly disposed on at least part of the electrical-insulating substrate. The first end of each conductor-element is electrically-conductively connected to the resistive material. The first conductor does not touch the second conductor, and an electrical pathway is created via the resistive material from one of the conductor-elements to the other of the conductor-elements.

The invention is directed to a polyimide-based polymer thick film paste composition for forming a polyimide-based polymer thick film resistor, a process for forming the resistor and an electrical device containing a resistor formed using the paste composition The paste composition comprise a functional component, a polyimide, and an organic solvent and can be cured by heating.

There is provided a liquid composition that can form a resistor exhibiting a stable resistance value. One mode of the liquid composition of the invention is a liquid composition comprising (a) an epoxy resin, (b) carbon black particles, (c) carbon nanotubes and (d) a solvent with a vapor pressure of less than 1.3410.sup.3 Pa at 25 C.

The method of making a flexible elastic conductive material for strain sensor and resistance applications using rubbing-in technology is shown. The thin rubber or any conductive material (substrates) is fixed at strained condition on the solid plate, by rubbing-in technology. Nanopowder of nanomaterials (organic semiconductors, carbon nanotubes, copper doped tin oxide, manganese doped tin oxide) at room temperature are embedded into the rubber conductive material to make built-in structure of conductive flexible elastic substrates that can be used for strain sensors, gages and resistance applications. The resultant product showed good sensitivity, stability and reliability during and after the rubbing-in operation.

An apparatus includes a first layer of a rare earth element. The apparatus further includes a thin-film coating layer deposited on the first layer, where the thin-film coating layer includes boron.

A heating paste composition, and a sheet heating element, a heating roller, a heating unit and a heating module, which use the composition, are disclosed. In one aspect, the heating paste composition includes 0.2 parts to 6 parts by weight of carbon nanotube particles, 0.5 parts to 30 parts by weight of graphite particles, 5 parts to 30 parts by weight of a binder mixture, 29 parts to 80 parts by weight of an organic solvent and 0.5 parts to 5 parts by weight of a dispersant, wherein the weights are with respect to 100 parts by weight of the heating paste composition.

A sensor device including a conductive graphene film covered on at least one side by a graphene support layer of parylene, a detection element configured to sense an environmental change, and an electrode. The parylene repairs some defects of the conductive graphene film without damaging, polluting, or degrading the conductivity of conductive graphene film.

An over-current protection device includes a first metal layer, a second metal layer and a heat-sensitive layer laminated therebetween. The heat-sensitive layer exhibits a positive temperature coefficient (PTC) characteristic and includes a first polymer and a conductive filler. The first polymer consists of polyvinylidene difluoride (PVDF), and PVDF exists in different phases such as -PVDF, -PVDF and -PVDF. The total amount of -PVDF, -PVDF and -PVDF is calculated as 100%, and the amount of -PVDF accounts for 48% to 55%. The conductive filler has a metal-ceramic compound.