Abstract: A low-cost, highly-responsive temperature sensor has a thermistor element surface-mounted in a circuit defined by an electrically-conducting layer of a three-layer circuit substrate to be in close thermal coupling to a metal base layer on an opposite side of the substrate. The base layer is adapted to be disposed in heat-collecting relation to a surface whose temperature is to be monitored. An intermediate layer of the substrate has a binder electrically insulating the thermistor from the metal base layer and has thermally-conducting particles dispersed in the binder to improve thermal coupling of the thermistor to the heat-collecting substrate base layer. The circuit defines terminal pads surface-mounting the thermistor element at one end of the substrate and defines interconnected terminal pads at an opposite end of the substrate which are connected to device lead wires in substantial thermal isolation from the thermistor element.

Abstract: Film resistors, for example, thin film thermistors having a negative temperature coefficient (NTCR) or near-zero TCR electronics resistors, are formed of an alloy of both an electrically insulating oxide and an electrically conducting nitride of at least one metal selected from titanium, tantalum, zirconium, hafnium and niobium. The electrically insulating oxide of the at least one metal is preferably present in the film sufficient to impart a negative temperature coefficient of resistance to thermistors which include the film as a component part. Preferably, the metal is reactive with both an oxygen-containing gas and nitrogen and is deposited onto a substrate by reactive sputtering in the presence of an inert gas (e.g., argon). By controlling the volume ratio of the reactive gasses (e.g.

Abstract: An electric motor protector sensor contains a small thermistor of low thermal inertia contained in a high temperature dielectric covering member in which electrical insulated lead wires are connected to opposite sides of the thermistor and extend out of the cover member to a current source to supply electrical current to the thermistor. An electrically insulating, thermally conductive silicone elastomer is positioned around the thermistor and lead wires to absorb forces on the sensor thereby protecting electrical contact between the lead wires and damage to the thermistor. Additionally, the lead wires can be twisted as extending out of the cover member and covered with another sleeve covering to provide improved protection against lead wire separation from thermistor surface electrical contact.

Abstract: Thin or thick film resistor devices (e.g., electronic resistors and thermistors) are trimmable without disturbing the active resistor film or necessarily requiring temperature control during trimming by providing a plurality of electrically conductive fingers having one end integral with one of the electrodes and a terminal end which extends at least substantially across the cross-wise dimension of the resistance film. The electrode fingers thereby electrically bridge a respective surface region of the substrate on which the electrodes and film are disposed. One or more of these fingers may thus be severed from the electrodes at the bridged respective surface region of the substrate so that the resistance value of the device can be controllably selected.

Abstract: A PTC device has two electrodes affixed to opposed surfaces. The electrodes consist of a metal foil having a conductive layer on their surfaces that contact the PTC material. The conductive layer has a thermal coefficient of expansion intermediate between the thermal coefficients of expansion of the metal foil and the PTC material. The intermediate value of the thermal coefficient of expansion of the conductive layer prevents peeling of the electrodes off the PTC element due to the variation of the temperature of the PTC device resulting from repeated voltage applications. In addition, improved adhesion of the electrodes to the PTC material reduces resistance changes after repeated temperature cycling.

Abstract: A thermal probe for measuring and controlling the temperature of a transparent, multi-panel assembly in which one of the panels has an electrically conductive coating which serves as a radiant heat source. A sensor, urged against the panel having the coating, senses the temperature of this panel and controls a power source which powers the coating. A compressible spacing member, fitted between the sensor and the other transparent panel, urges the sensor into proximity with the panel being measured and controlled.

Abstract: A thermistor includes a rectangular parallelepiped thermistor element, electrodes formed over the entire top and bottom surfaces of the thermistor element, and leads connected to the electrodes. The leads have connecting portions for deriving signals, and are bent such that the connecting portions are positioned on substantially the same plane. A sealing resin completely surrounds the thermistor element, the electrodes, and all of the leads except for the connecting portions.

Abstract: A measurement circuit utilizing a thick film sense resistor containing palladium and silver in a weight ratio of about 56/44 to about 60/40 and a specific glass frit composition so that the sense resistor achieves low resistivity and controlled TCR.

Abstract: A PTC thermistor capable of ensuring ohmic contact between a PTC thermistor body and an electrode and preventing deterioration in appearance of the thermistor to increase the yields. The PTC thermistor includes a PTC thermistor body, a first electrode formed of plated Ni of 0.2 to 0.7 .mu.m in thickness and a second electrode arranged on the first electrode and mainly formed of metal of low contact resistance. Moisture or water such as a Ni plating solution enters into the PTC thermistor body during formation of the first electrode on the body. The water then bursts due to expansion during baking of the second electrode formed on the first electrode, to produce craters on a surface of the second electrode. A decrease in thickness of the first electrode to a level as small as 0.2 to 0.7 .mu.m facilitates outward discharge of the water to reduce occurrence of the craters.

Abstract: Method of making positive-temperature-coefficient thermistor (PTCR) heating element involves steps of depositing an insulation adhesive layer having a predetermined pattern on flat surfaces of two heat-radiating means opposite to each other, placing a metal film having a pattern complementary to that of the insulation adhesive layer on uncoated area of flat surface of each of the two heat-radiating means, arranging in sequence a plurality of PTCR pieces on flat surfaces of heat-radiating means, stacking two processed heat-radiating means, with their flat surfaces facing PTCR pieces, applying compressive pressure to the stacked heat-radiating means with PTCR pieces sandwiched therebetween, and allowing insulation adhesive layer to cure under the compressive pressure so that all components are held together intimately and firmly to form a heating element which is cost effective, relatively safe, highly conductive and capable of generating a high and stable thermal output.

Abstract: A terminal for telegraph and telephone systems using as an overvoltage/overcurrent protecting component a positive temperature coefficient thermistor element comprising a plate-shaped ceramic body made of a ceramic material whose Curie temperature is in the range of 60.degree. to 120.degree. C., and having a thickness of 2.5 to 5.0 mm, and electrodes formed on both major surfaces of the ceramic body.

Abstract: An electric resistor has a resistor body arranged between two contract terminals. This resistor core includes an element with PTC behavior which, below a material-specific temperature, forms an electrically conducting path running between the two contact terminals. The resistor can be simple and inexpensive, but still have a high rate current-carrying capacity protected against local and overall overvoltages. This is achieved by the resistor core additionally containing a material having varistor behavior. The varistor material is connected in parallel with at least one subsection of the electrically conducting path, forming at least one varistor, and is brought into intimate electrical contact with the part of the PTC material forming the at least one subsection. The parallel connection of the element with PTC behavior and the varistor can be realized both by a microscopic construction and by a macroscopic arrangement.

Abstract: A continuous temperature sensing cable formed of a polymer containing conductive and semi-conductive fillers such as polyethylene with carbon black, powdered metals and metal oxides. The composition is extruded over a pair of elongated substantially parallel conductors which are spaced apart along the longitudinal length of the cable. The conductors are single-endedly connected to a control/alarm device for monitoring the continuous length of the temperature sensing cable. A critical voltage is applied single-endedly to the conductors and serially connected to an audible alarm to detect tunneling conduction when operated at a temperature near the melt temperature of the composition whereat the composition exhibits a negative temperature coefficient (NTC).

Abstract: In the manner of a tubular heater, a temperature sensor comprises a metallic tubular jacket with internal resistance wire coil embedded in insulating material and closing pieces having electrical connection members, so that a very simple, robust and high temperature-resistant temperature sensor with a measuring range up to e.g. approximately 750.degree. C. is obtained. The temperature sensor jacket can be earthed or grounded. For operating the temperature sensor there is appropriately a test current in the mA range in the case of a test voltage in the mV range, whose temperature-dependent changes are processed by means of an electronic amplifier.

Abstract: A thermistor positioned within a tubular probe adjacent its closed distal end has lead wires connected with terminals by both crimp and weld connections that are independent of one another. A non-rigid heat transfer medium fills the distal end portion of the probe in surrounding relationship to the thermistor. An opening in the sensor housing leads to the interior of the probe and receives a dielectric sleeve in which tail end portions of the terminals are positioned.

Abstract: An electrical device, particularly a self-regulating strip heater, has improved thermal efficiency, good mechanical properties, and acceptable resistance to water penetration when an outer insulating layer is applied in a way that it penetrates the interstices of a braid surrounding the heater. Appropriate penetration may be achieved by pressure-extruding the outer jacket over the braid.

Abstract: A two-level IR detector imaging array of high fill-factor design. The upper microbridge detector level is spaced above and overlies the integrated circuit and bus lines on the substrate surface below.

Abstract: This invention provides a method of preparing an electrical overstress material having a nonlinear resistance which declines sharply in response to an electric field exceeding a clamping voltage so as to be able to shunt out transient surges which method comprises using an adhesive binder, for example a silicone rubber or a ceramics dispersion, and thorough mixing therein of small conductive, and optionally semiconductive particles, for example nickel particles of various morphologies and silicon carbide particles respectively, followed by molding under pressure and curing. The invention is also directed to the electrical overstress material itself which has excellent strength and integrity as well as survivability from multiple surges and has multiple applications in, for example, electrical outlet strips and power cables. The invention is also directed to a power outlet strip comprising a plurality of surge arresting elements composed of the electrical overstress material of the invention.

Abstract: A positive characteristic thermistor, in which the outer periphery of a first electrode including a metal other than silver as its main component is positioned on the inside of the outer periphery of the main body of this thermistor, and is made to coincide with the outer periphery of a second electrode which includes silver as its main component and formed on the first electrode or to be placed on the inside of the periphery of the second electrode.

Abstract: A thermal probe for measuring and controlling the temperature of a transparent, multi-panel assembly in which one of the panels has an electrically conductive coating which serves as a radiant heat source. A sensor, urged against the panel having the coating, senses the temperature of this panel and controls a power source which powers the coating. A compressible spacing member, fitted between the sensor and the other transparent panel, urges the sensor into proximity with the panel being measured and controlled.

Abstract: A PTC element displaying low volume resistivity and excellent PTC characteristics contains conductive carbonaceous particles having a large particle size, small specific surface area and being essentially unstructured such particles being, for example, thermal black or mesocarbon microparticles. The conductive particles are heat treated in an inactive atmosphere, blended with a crystalline polymer and then cross-linked by gamma radiation. In a variant form, the polymer can be chemically grafted onto the particles. The very low resistivity and excellent PTC characteristics of this PTC device make it suitable for miniaturization.

Abstract: A device for heating flowing liquid or gaseous media has a heating element including a PTC resistor arranged between a pair of perforated metallic bodies serving as power supply terminals for the resistor. The heating element is positioned inside a tubular housing defining a flow path for the medium to be heated and made of two mating housing parts, with the heating element extending across the flow path for flow of the medium through the perforations of the metallic bodies to transfer heat to the medium. A bracket on each metallic body fastens the heating element to the housing and is electrically connected to a contact on one end of a power supply cable molded as an integral part of one of the housing parts and terminating at its other end in an electrical plug outlet on the housing part connectable to a battery or electrical network.

Abstract: In a heating apparatus including a plate-shaped positive temperature coefficient thermistor having a pair of electrode films, a pair of terminal plates of an elastic metal material are provided on the pair of electrode films of the thermistor, and there is further provided a spacer including a mounting through-hole which passes through the spacer in a thickness direction thereof. The spacer receives the thermistor in the mounting through-hole so as to position the thermistor therein between the pair of terminal plates. Each terminal plate comprises at least one extending portion extending in a longitudinal direction thereof from one portion of one end thereof, and the extending portion comprises a stopper piece which is folded toward the spacer, the stopper piece including a hook-shaped engaging stopper at an end of the stopper piece.

Abstract: A resistor device for blower motor comprising one plate of PTC element having two side surfaces and a plurality of electrodes disposed on at least one of the two side surfaces. A plurality of different resistance values can be obtained from the one plate of PTC element, which makes it possible to realize a small and compact structure for the resistor device.

Abstract: A heating device for heating flowing media includes a heat exchanger to be heated by PTC resistors. The heat exchanger is formed of thermally conductive metal having a slit-like pocket formed therein defining a given shape and defining pocket surfaces facing one another. A cuboid substrate body has a shape adapted to the given shape and an introduction side to be introduced into the pocket. The substrate body has opposed surfaces with recesses formed therein for receiving the PTC resistors and an internal conduit formed therein for receiving a contact spring. At least the surfaces of the substrate body having the recesses and the pocket surfaces facing the surfaces of the substrate body are beveled for decreasing the cross section of the substrate body and of the pocket from the introduction side inward, and for pressing the PTC resistors against the pocket surfaces upon introduction of the substrate body into the pocket with the PTC resistors located in the recesses.

Abstract: A diffusion resistor comprises a diffusion resistor region formed in a semiconductor layer of a first conductivity type. The diffusion resistor region is formed of a first impurity diffusion region of a second conductivity type opposite to the first conductivity type. A second impurity diffusion region of the second conductivity type is formed in the semiconductor layer separated from the first impurity diffusion region and to surround a side of the first impurity diffusion region. The second impurity diffusion region is connected to a high voltage or a low voltage.

Abstract: Temperature sensors or temperature sensor arrangements made from glass ceramic and bonding film resistors, suitable especially for control and limitation of output in glass ceramic cooking areas, are distinguished in that thin- and/or thick-film resistors are baked on supports of glass ceramic, for example, in the area of the cooking zone of a glass ceramic cooking surface, and one or more glass ceramic resistances are delimited and bonded there, and the film resistors form parallel and/or iterative circuits with the glass ceramic resistances. By suitable selection of the dimensions as well as the surface resistances and temperature coefficients of the bonding film resistors and the type of sensor circuit (parallel and/or iterative circuit), the temperature resistance characteristic of a sensor circuit can be varied within wide limits, e.g., the temperature area of use of a glass ceramic sensor can be considerably expanded toward low temperatures.

Abstract: The invention is a thermistor comprising a thermistor element, a fixed product of a resistive film on an axial surface of the thermistor element and a conductor material on the terminal surfaces of the thermistor element. The fixed resistive film extends to the peripheral edges of the axial surface, thereby influencing conductance from the thermistor element except at its terminal ends.

Abstract: A heater particularly adapted for use in automotive applications as a passenger compartment heater or the like has a housing with an opening and has a plurality of heat-exchanging fin members and self-regulating electrical resistance heater discs of positive temperature coefficient resistivity (PTC) disposed in the housing to heat air or other fluid which is passed through the housing opening in heat-transfer relation to the fin members. A thermally conductive grease is positioned between the PTC heater discs and fin members to enhance heat transfer. Springs resiliently position the fin members, grease and heater discs in thermally and electrically conductive relation to each other between terminals accessible from the housing exterior to retain the fin members, grease and heater discs engaged during thermal expansion and vibration for reliably energizing the heater discs to heat the fin members over a long service life.

Abstract: A resistor circuit which includes a pair of linear conductive films and a resistive film. The resistive film is formed on an area between the conductive films and electrically connected to the conductive films. A pair of terminals are electrically connected to portions of the conductive films respectively. A current source is electrically connected between the terminals to flow an electric current between the terminals. A pair of voltage output terminals are electrically connected to portions of the conductive films respectively. At least one of the voltage output terminals is disposed at a position other than a position in which the terminals are formed. An output voltage output from the voltage output terminals is exactly proportional to a current flowing between them without an influence of change of an ambient temperature.

Abstract: In many cases, the influence of temperature on the quality of a coil has a disturbing effect. Therefore, a coil inductance is produced such that the influence of temperature on the quality of the coil is substantially compensated for in a particular range of the system frequency. To this end, a second coil having a second quality value Q2 is magnetically coupled in series to a first coil having a first quality value Q1. Moreover, the two coils are selected in such a way that for a particular range of the system frequency f, the quality value Q1 decreases as the temperature T increases and the quality value Q2 increases as the temperature T increases. A coil conductor for the first coil made of litz wire and a coil conductor for the second coil made of solid wire may be used to create such a temperature dependence.

Abstract: A self-recovery PTC device for overcurrent protection of electrical circuits is made with a polymer/metal powder composition electrode that displays stable resistivity over a broad range of contact forces. Secure bonding of electrodes to a PTC element is achieved because both components are polymer composites, eliminating the problems associated with attempts to bond metal electrodes to a polymer PTC element. Swelling of metal electrodes, that results from outgassing by a PTC element, is also eliminated, because polymer electrodes are gas permeable.

Abstract: Metal oxide group NTC theremistor material made from MnCO.sub.3 +NiO+CuO+Co.sub.3 O.sub.4 +FeO.sub.3 TiO.sub.2 group as a basic composition. The invention is characterized by metal oxide group thermistor material made from MnCO.sub.3 +NiO+ZnO+Co.sub.3 O.sub.4 +Fe.sub.2 O.sub.3 +TiO.sub.2 group or MnCO.sub.3 +NiO+CuO+ZnO+Fe.sub.2 O.sub.3 +TiO.sub.2 group as a basic composition having respectively composition amounts by weight for each ingredient described in the text. According to the invention, the sintering temperature of the material can be reduced relative to the conventional material, and therefore there is advantage that manufacturing expense of the thermistor can be reduced.

Abstract: An electrical device in which a first connection element is in electrical contact with a resistive element. The first connection element defines a cavity into which, when the cavity is empty, a second connection element can be inserted. The second connection element, which may be connected to a source of electrical power, is partially within the cavity, makes physical and electrical contact with the first connection element, and protrudes from the cavity. Such devices can be made in a continuous process by a method of the invention. They are particularly suitable for insertion into a circuit board.

Abstract: A thermistor element in which in a thermistor body having first and second outer electrodes formed on a pair of its end surfaces, a first inner electrode connected to the first outer electrode and a second inner electrode connected to the second outer electrode are so disposed that their ends are opposed a predetermined distance away from each other.

Abstract: Resistor composition to produce thick film resistors, preferably the resistor films in sensors for temperature measurement, includes glass frit and an oxide which is at least one of CaCu.sub.3 Ru.sub.4 O.sub.12 and LaCu.sub.3 Ru.sub.4 O.sub.12.

Abstract: A positive temperature coefficient ("PTC") device body is formed by compression molding of an organic PTC composition consisting of a crystalline polymer with conductive particles dispersed therein. The body is sandwiched between electrodes to which terminals are attached by spot welding or soldering. The PTC device body is aged at normal pressure and at a temperature higher than the peak resistance temperature, that is, the temperature at which its resistance is a maximum, and lower than 250.degree. C. The resistance of the PTC device does not change either before or after exposure to high temperatures, that is, temperatures substantially greater than 250.degree. C., and the PTC characteristics of the device do not decrease despite aging. Therefore PTC devices made according to the present invention can be surface-mounted.

Abstract: A hair dryer includes a plurality of elongated positive-temperature-coefficient (PTC) semiconductor heating units disposed in transverse side-by-side spaced relation in a linear array in a central air flow passage of an elongated tubular duct connected to a discharge port of a casing having an air fan rotatably mounted in the casing for blowing air through the air flow passage of the duct, each PTC heating unit defining a longitudinal axis disposed perpendicular to a longitudinal axis of the air flow passage of the duct and a plurality of elongated spaced fins longitudinally juxtapositionally mounted on the PTC semiconductor heating unit transversely of the longitudinal axis of the PTC heating unit, whereby upon a powering of the PTC heating unit and the fan to heat air as blown by the fan, the heated air will be guided in the tubular duct by the plurality of elongaed spaced fins to produce laminar air streamflow helpful for smoothly setting and drying hair or the like.

Abstract: For the manufacture of finished, self-stabilizing resistors, i.e. provided with leads, having PTC elements as the active parts, as well as such resistors, particularly on coil windings, such as those of electric motors, the invention provides a method according to which on a metallic carrier strip contact and top surfaces for the PTC elements are punched, a PTC element is placed and fixed to each contact surface, the top surface is bent over the PTC element, the contact and top surfaces are provided with leads and the top and contact surfaces are separated from the remaining carrier strip.

Abstract: An electric heater for air supplied to the passenger compartment of an automobile has a plurality of extruded tubular metal members in side-by-side spaced parallel relationship within an open electrically insulative frame. Each tubular member has a pair of spaced heat sinks with a plurality of spaced lamenallae extending therebetween to form air flow passages. A plurality of PTC heating tablets are positioned in the space between the opposed outer surfaces of the heat sinks of adjacent tubular members, with one face of each PTC tablet fixed to one heat sink by a rigid electrically conductive adhesive and the other face thereof is fixed to the adjacent heat sink by a flexible electrically conductive adhesive. The heat sinks have integral platforms on which the PTC tablets are positioned with the edges of the tablets projecting beyond the edges of the respective platforms.

Abstract: To compensate for the temperature dependence of a resonant circuit, it is known to use an a.c. current source, with which the resonant circuit is excited in dependence upon the ohmic resistance of the coil conductor material. The task of compensating for temperature may to be solved without a costly closed-loop control process and with few losses. A magnetically coupled second coil is connected in parallel with the first coil to be compensated, and an NTC thermistor is connected in series with one of the two coils so that the series connection is connected in parallel with the other of the two coils. The NTC thermistor is selected so that, in conjunction with the two variable sized ohmic resistors of the two coils, the circuit arrangement has a specified total ohmic resistance, which is substantially independent of temperature.

Abstract: A positive temperature coefficient thermistor device comprises a pair of positive temperature coefficient thermistor elements, a common terminal plate having a heat conducting terminal member and a common terminal member and being sandwiched between the positive temperature coefficient thermistor elements, and a pair of terminal plates having spring terminal members for clamping the positive temperature coefficient thermistor elements. The common terminal member of the common terminal plate is formed to have a width between the heat conducting terminal member and an insertion hole in the mounting plate on which the positive temperature coefficient thermistor device is to be mounted that is no larger than necessary for its insertion in the insertion hole. A catch is provided on the heat conducting terminal member for engaging with a wall of the insulating case for preventing extraction of the common terminal plate from the insulating case.

Abstract: A feature of the present invention is that an overcurrent protection circuit is constituted so as to have the voltage relationship of V.sub.2 /V.sub.1 <V.sub.3 /V.sub.2, wherein V.sub.1 is a voltage applied to a positive temperature coefficient resistor at a steady current, V.sub.2 is a voltage applied to said positive temperature coefficient resistor at the maximum current, and V.sub.3 is a voltage applied to said positive temperature coefficient at the equilibrium current. The equilibrium current is rendered less than the steady current, so that heat generation of the load is effectively suppressed and the advantage of enhanced safety of the circuit is achieved.

Abstract: An extended resistance temperature sensor formed of a plurality of lengths of pre-insulated resistance temperature detector (RTD) wire. The RTD wire is either unheated, self heated, alternatingly self heated or is heated by means of strands of heater wire integrated with or placed closely adjacent to the RTD wire. The RTD wire itself, or together with the heater wire, is bonded together in one elongated embodiment. Alternatively the RTD wire, or with the heater wire, may be encased in insulated shrink tubing, thin wall metal tubing or both. Connectors are provided at each end of the elongated structure to supply electrical current for heating purposes or to connect the RTD wire to detection circuitry, or both, and the configuration of RTD wire is doubled back on itself to form a U-shaped structure with the connectors adjacent each other. Protective sheaths are provided over the connectors.

Abstract: A resistor device for blower motor contains a plurality of PTC element plates having both side surfaces and disposed side by side substantially in a same plane. Each PTC element has an electrode formed on each of said both side surfaces thereof. The device has a plurality of terminal plates sandwiching the PTC element plates from the both side surfaces thereof.

Abstract: A positive coefficient thin-film thermistor which is a thin film exhibiting a positive temperature coefficient (PTC) characteristic and having a thickness of 0.005 to 5 .mu.m and electrodes as constituting elements, and wherein the thin film is compound of a barium titanate based composition and the PTC characteristic is represented by a resistance variation in the transition of region of 1-10 orders of magnitude and a maximum resistance temperature variation rate of 1-20 orders/.degree.C.

Abstract: A temperature measuring apparatus consisting of a sensing element, a retaining element which retains the sensing element and which is made of a thermally conductive and electrically insulative material, a holding element which holds the retaining element, and a contact mechanism which elastically contact the retaining element with the top of the surface of the measured body. The sensing element is composed of a thin film thermistor formed on the electrically insulating layer on a substrate. A film having the thermally conductive and electrically insulative material may be inserted between the measured body and the contact area of the retaining element. The retaining element is composed of the polyimide film and a flexible copper lead foil formed on the film and connected to the electrodes of the sensing element.

Abstract: PTC (positive temperature coefficient) thermistors of a novel configuration and a method for their manufacture. The PTC thermistors have a PTC element sandwiched between two electrodes for which leads are formed as an extension of each of the two electrodes protruding beyond the edge of the PTC element. Several manufacturing methods avoid undue thermal and physical stress to the PTC composition while providing PTC thermistors having a variety of shapes and configurations.

Abstract: A self-resetting overcurrent protection element uses an element body made up of a mixture of polymers and carbon black grafted with polymers. A resilient sheathing material covering the element body permits free expansion of the element body to permit the resistance of the overcurrent protection element to increase substantially in response to Joule's heating from high current. The sheathing materials preferably are made of elastic epoxy resins or silicone resins that allow significant expansion of the element body at the time of overcurrent protection, thus increasing the ratio of resistance in the element between an overcurrent state and a normal operating state.

Abstract: A PTC thermistor has its substrate entirely coated with an insulating glass material except for the area where a silver electrode is formed. Such a thermistor may be produced by coating a substrate with an insulating glass material, forming a silver layer on the coated substrate and fusing the silver layer with a part of the glass material so as to form an electrode adhering to the substrate. An underelectrode may be provided between the substrate and such an electrode. A resistor is formed by encasing such a PTC thermistor with a pair of spring terminals for supporting the thermistor therebetween.