Abstract: A thin-film gas sensor and manufacturing method of the same is disclosed which includes a silicon substrate; an insulating layer formed on the surface of the silicon substrate; a heater formed in zigzag on the surface of said insulating layer; a temperature sensor formed in zigzag on the surface of the insulating layer in parallel with the heater; an interlayer insulating layer for electrically insulating the heater and temperature sensor formed on the insulating layer; a plurality of electrodes formed on the interlayer insulating layer placed between the heater and temperature sensor; a plurality of pairs of gas sensing layers disposed in an array on the electrodes and for reacting on detected gas; and a plurality of gas shielding layers formed on one gas sensing layer out of the pair of gas sensing layers and for shielding the detected gas so that the gas sensing layers do not react on the detected gas.

Abstract: A temperature sensor includes a first sensor section having first and second conductors connected at their one ends and defining macroscopic current paths directed in different directions with respect to that of a magnetic field and having resistance values such that the magnetic field produces identical changes in resistance therein, a similarly constituted second sensor section having third and fourth conductors connected to the second and first conductors, and heat coupling means for keeping the temperature of the first and second sensor sections uniform.

Abstract: A balanced wire resistor has two interconnected windings with different temperature coefficients. The electrical resistance of the wire resistor is determined only by the resistance values of the two windings. In a process for the production of the wire resistor, the wire length of a first winding of the newly to be wound wire resistance is calculated by using the measured wire length, as well as measured resistance values of the previously wound wire resistor. The wire length of a second winding of the newly to be wound wire resistance is determined by using the two measured wire lengths of the two windings, as well as measured resistance values of the previously wound wire resistor.

Abstract: The present invention provides thermal detection elements having a controlled relationship between a thermal radiating and thermal sensing element. The thermal detection element includes an insulating substrate having a plurality of conductive interconnection elements formed on the substrate to permit electrical connection of the substrate with other electrical components. A thermal radiating element is at least partially embedded within the substrate and mounted such it electrically communicates with at least one of the conductive interconnection elements. A thermal sensing element is mounted adjacent the thermal radiating element such that a substantial portion of the thermal energy radiated by the thermal radiating element is channeled to the thermal sensing element. The thermal sensing element is also mounted such that it electrically communicates with at least one of the conductive interconnection elements.

Abstract: A method is disclosed for the protection of catalytic converters for exhaust gas purification by measuring the temperature with a heat tone sensor suitable particularly for the implementation of the method, wherein a heat tone sensor composed of at least two NTC or PTC resistors and provided with a coating of a catalytically active material on the sensor in the region of at least one of these resistors is arranged ahead of the catalytic converter in the exhaust gas stream or a part thereof, with the catalytically active material initiating the same exothermal reactions as they take place in the catalytic converter employed for the exhaust gas purification. If the resistor is overheated due to an overly intensive exothermal reaction, resulting in a change in resistance, the heat tone sensor detects the drop in the throughput rate of the catalytic converter.

Abstract: An improved temperature sensor is designed for the sensitive detection of temperature changes. The temperature sensor includes a frame 9 of monocrystalline silicon and a dielectric diaphragm 13 stretched on it. A monocrystalline silicon structure 35 is disposed on or under the dielectric diaphragm which is used for measuring the temperature. In the course of this, the Seebeck effect, as well as the temperature dependence of the electrical resistance, can be used for detection of any temperature changes.

Abstract: The value of an unknown test temperature is measured by heating a test wafer (58) to the unknown temperature, measuring the surface electrical resistivity of the test wafer (58), and determining the value of the unknown temperature from the measured surface electrical resistivity. The test wafer (58) is prepared by providing an initial wafer (50), first ion implanting the initial wafer (50) with a first dose of an ionic species, and annealing the ion implanted initial wafer (50) at an annealing temperature. The preparation is completed by second ion implanting the annealed wafer with a second dose of the same ionic species as used in the first dose to form a test wafer, the second dose being lower than the first dose.

Abstract: A rapid temperature sensor formed of a metal from the platinum group is provided. The rapid temperature sensor includes a substrate over which a platinum resistive layer is provided. A double layer, forming a passivation layer, is provided over the platinum resistive layer to prevent oxidation. The double layer includes a ceramic layer and a glass layer. The double layer prevents oxygen from reaching the platinum resistive layer even at temperatures up to 1,000.degree. C.

Abstract: A thermistor-type temperature sensor having multiple temperature-sensitive elements can detect a wide range of temperatures. In a preferred embodiment, the sensor uses multiple thin thermo-resistive elements having different electrical characteristics, where the elements are disposed on insulating ceramic substrates and covered by insulating sheets. This arrangement provides a low-profile thermistor-type sensor operable over a wide range of temperatures.

Abstract: A positive temperature coefficient temperature sensor for use in exhaust-gas systems of internal-combustion engines includes a sensor element having a multilayer laminate composite structure with a positive temperature coefficient thermistor, formed by at least two resistor tracks arranged one above another and electrically insulated from one another. One of the layers of the multilayer structure is an insulating ceramic base film, and a first one of the at least two resistor tracks, with a supply lead, is printed onto the insulating ceramic base film. A second one of the at least two resistor tracks is disposed separately on the insulating ceramic base film by means of at least one insulating layer printed above the first one of the at least two resistor tracks. The at least two resistor tracks disposed one above another are connected by a land guided through the at least one insulating layer.

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: A double sided primed circuit board is shown wherein one side is etched for receiving a plurality of surface mounted components constituting a control circuit. In one embodiment the control circuit provides for regulating the operation of a plurality to the beverage dispensing valves. An op-amp monitors the conductor for sensing the operation of the beverage dispensing valves as a function of a voltage drop there across. The conductor operates as a resistor, and any heating thereof that occurs as a result of the operation of the beverage dispensing valves is dissipated over the entire surface area of the circuit board. The control circuit also operates a dump valve for periodically dumping beverage if any of the valves have not been operated for a set period of time. The control circuit deactivates the operation of the dump valve during any sensed operation of one of the beverage dispense valves.

Abstract: A resistor for a thermal type of flowmeter includes a ceramic substrate, a thin platinum film formed on the surface of the ceramic substrate, and lead wires for connecting the thin platinum film with an external circuit, and is located in a fluid to detect its flow rate. When the resistance value, R (.OMEGA.) , of the resistor for a thermal type of flowmeter is expressed in terms of a function of temperature, T (.degree.C.):R=R.sub.0 (1+.alpha.T+.beta.T.sup.2)where R.sub.0 is the resistance value in .OMEGA. of the resistor for a thermal type of flowmeter at 0.degree. C., .alpha. is the first-order term coefficient of the temperature coefficient of resistance, and .beta. is the second-order term coefficient of the temperature coefficient of resistance, the value of the first-order term coefficient, .alpha., of the temperature coefficient of resistance is at least 3,650 ppm/.degree.C.

Abstract: A physical quantity sensor e.g., temperature sensor having a resistor pattern and a ceramic support carrying the resistor pattern. The resistor pattern has an ionizing component retention conductor pattern which is branched at its negative terminal side.The resistor pattern with branched pattern are stacked between the ceramic support layers.Migration in the resistor pattern is suppressed to prevent the resistance of the resistor pattern from being increased for assuring accurate measurement of temperature. The sensor is operated without cooling to 0.degree. C.

Abstract: A resistor element includes a cylindrical, insulating ceramic substrate, a spiral resistor formed on said ceramic substrate, first and second lead wires inserted into the open ends of said ceramic substrate, a connector for making electrical connections between said resistor and said first and second lead wires, a layer of inorganic material which covers said ceramic substrate, said resistor and said connector, and a layer of resin material which covers the outer surface of said inorganic material layer. This resistor element is advantageously applied to a thermal type of flow rate sensor.

Abstract: A thermal type flow rate sensor comprising a sensor chip having a rectangular shape. The sensor chip is supported between supporting pins through ribbon-like leads connected to opposite ends of the sensor chip. The ribbon-like leads serve to correctly locate the surface of the sensor chip with respect to flow of fluid. The surfaces of the sensor chip is formed with a thin film heater. A heater portion of the thin film heater comprises a plurality of straight portions and a plurality of turn portions connecting the straight portions to each other. Each turn portion is formed in a smoothly curved shape to avoid the concentration of electric currents and is disposed at an end portion of the sensor chip which has a comparatively low temperature. This structure is effective in preventing generation of cracks in the turn portions. In addition, the plurality of straight portions are alternatively inclined to effectively utilize the surface of the sensor chip to form a long heating portion.

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: An infrared radiation sensor has a bridge portion which bridges a cave portion formed in a sensor substrate. The bridge portion includes an infrared radiation receiving portion and support portions for supporting the infrared radiation receiving portion. The plane shape of the infrared radiation receiving portion is a square or a circle which has a greater side length or a greater diameter than the width of the supporting portions to increase the amount of infrared radiation received by the infrared receiving portion.

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: A sensor element for a thermal type flowmeter including a ceramic substrate, a thin film, resistor of platinum provided on the outer surface of the ceramic substrate and an outer protective layer of glass provided for protecting the resistor. The glass contains Na.sub.2 O and K.sub.2 O in a total amount of up to 3 mol %. The sensor element has a temperature coefficient of resistance approximate to the bulk value of platinum, and can be fabricated with little variation.

Abstract: A thermal conductivity detector includes a thin diaphragm, a heat-generating portion, and a pair of boundary holes. The thin diaphragm is obtained by forming a space in part of a base. The heat-generating portion is formed in the diaphragm. The boundary holes are formed to surround the heat-generating portion.

Abstract: A platinum temperature sensor includes a meandering pattern portion and outlet portions continuously connected to respective ends thereof which are defined by a platinum film which is formed on an insulating substrate. External electrodes are formed to cover the outlet portions as well as the ends of the insulating substrate provided with the outlet portions. Each of the external electrodes comprises a first layer containing platinum or nickel which is in contact with the outlet portion and with the insulating substrate, a second layer containing silver and platinum which is formed on the first layer, a third layer containing nickel which is formed on the second layer, and a fourth layer containing tin or solder which is formed on the third layer. The first layer suppresses diffusion of silver contained in the second layer, and the third layer improves heat resistance of the second layer, while the fourth layer improves solderability.

Abstract: A resistor element for determining a parameter, including a ceramic support, an electrically resistive body formed on the ceramic support, at least one lead wire electrically connected to the electrically resistive body, and an adhesive containing platinum for securing the lead wire(s) to the ceramic support. Each lead wire includes a wire rod having a lower thermal conductivity than platinum, and a covering layer which covers the wire rod and is formed of an alloy including platinum as a major component.

Abstract: An apparatus and method by which a flat film-type resistor is intentionally caused to thermal-shock fracture in response to a predetermined high-voltage overload condition. A stressed spring wire is mounted on such film-type resistor and connected in circuit with it. A predetermined solder and temperature gradient are employed to hold the spring wire in bent condition until the solder melts, whereupon the spring flexes and the circuit breaks. Heatsink portions are provided in the circuit board for such resistor, and receive terminal pins thereof.

Abstract: A temperature sensor includes a ceramic layered product having a multilayer structure formed of a plurality of ceramic sheets, a plurality of resistive patterns, containing copper or nickel, formed on major surfaces of the plurality of ceramic sheets respectively, a conductive path passing through the ceramic sheets for series-connecting the plurality of resistive patterns with each other, and respective terminals connected to both ends of the series-connected plurality of resistive patterns. The ceramic sheets being formed of an unreducible ceramic material prepared from a TiO.sub.2.BaO.CaO.ZrO.sub.2 compound.

Abstract: A micromachined mass air flow sensor comprises a silicon substrate with an air flow opening formed therethrough. One or more silicon members carrying a thin film resistor extend over the air flow opening. The silicon members are thermally isolated from the silicon substrate frame about the air flow opening by thermal isolation zones of porous silicon oxide.

Abstract: The thermometer consists of an operational amplifier ratio bridge which is made up of at least one arm having a 3-terminal high impedance temperature sensor one of whose leads being connected to the output of an operational amplifier whose gain has been stabilized and whose output impedance has been rendered negligible by negative feedback. The other lead being connected to the input of an operational amplifier whose gain has been stabilized and whose input impedance has been rendered negligible by negative feedback. Standard arms, comprising standard resistors and capacitors and operational amplifiers whose gain has been stabilized by negative feedback may be connected in parallel with the first arm.

Abstract: Conductive polymer PTC compositions have improved properties, especially at voltages of 200 volts or more, if they are very highly cross-linked by means of irradiation, for example to a dosage of at least 50 Mrads, preferably at least 80 Mrads, e.g. 120 to 600 Mrads. The cross-linked compositions are particularly useful in circuit protection devices and layered heaters.

Abstract: A thermal flowmeter for determining a parameter of a fluid flowing through a passage, including a detecting element, and a pair of electrically conductive supports fixed to a wall defining the passage for supporting the detecting element. The detecting element includes a substrate, an electrically resistive body disposed on the substrate and having an electrical resistance which varies with an ambient temperature, and a pair of electrical conductors provided at opposite ends of the support and electrically connected to the electrically resistive body. The detecting element is positioned in the passage such that the electrical conductors are secured to the electrically conductive supports. The electrically conductive supports have respective engaging portions which engage the electrical conductors, respectively, for positioning the detecting element with respect to the wall of the passage.

Abstract: The invention relates to a temperature sensor with platinum of temperature-sensitive material, and a process for the production of such a temperature sensor. The problem of the invention is to provide a miniaturized temperature sensor as small as possible which can be used at temperatures of 600.degree. C. to over 1,000.degree. C. For solution, the invention proposes a temperature sensor in which the layer contains finely divided metal platinum in oxide ceramic. Production takes place by mixing together platinum powder, oxide and binder, and after supplying the layer on the support substratum, tempering with this latter.

Abstract: A temperature sensor includes a ceramic layered product having a multilayer structure formed of a plurality of ceramic sheets containing an unreducible ceramic material, a plurality of resistive patterns, containing copper or nickel, formed on major surfaces of the plurality of ceramic sheets respectively, a conductive path passing through the ceramic sheets for series-connecting the plurality of resistive patterns with each other, and respective terminals connected to both ends of the series-connected plurality of resistive patterns.

Abstract: A resistance film of platinum is formed on an insulating substrate of alumina. The resistance film is divided by grooves passing therethrough to provide a zigzag resistance circuit pattern, and the film forms a pair of terminal electrodes electrically connected to end portions of the resistance circuit pattern, respectively. In order to stop transmission of heat generated in the resistance circuit pattern to the terminal electrodes, gaps for stopping heat conduction are formed between the resistance circuit pattern and each of the terminal electrodes.

Abstract: Conductive polymer PTC compositions have improved properties, especially at voltages of 200 volts or more, if they are very highly cross-linked by means of irradiation, for example to a dosage of at least 50 Mrads, preferably at least 80 Mrads, e.g. 120 to 600 Mrads. The cross-linked compositions are particularly useful in circuit protection devices and layered heaters.

Abstract: A PTC temperature sensor, in particular for use in the exhaust gas system of internal combustion engines, has a sensing element including a PTC resistor connected to conductor webs disposed in a housing. The PTC resistor and the conductor webs are composed of a homogeneous material to form a PTC resistor track. The temperature sensing element is formed from a laminated composite of ceramic films in which the PTC resistor track is hermetically encapsulated with respect to the gas being measured and the ambient air.

Abstract: A detecting element for a thermal flow meter, which includes a support having a bearing surface, an electrically resistive body formed on the bearing surface of the support, an electrical conductor which is fixedly secured to the support by means of an adhesive, and an adhesive layer made of the adhesive. The conductor is electrically connected to the electrically resistive body through the adhesive layer. The adhesive layer consists essentially of a glass component and a metal component, such that the glass component has a larger volume than the metal component, and such that the glass and metal components are unevenly distributed in the adhesive layer.

Abstract: A resistor element for determining a parameter, including a ceramic support having a bearing surface, an electrically resistive body formed on the bearing surface of the ceramic support, a conductor or conductors electrically connected to the electrically resistive body, the conductor(s) having a lower thermal conductivity than a conductor made of platinum, and an adhesive for securing the conductor(s) to the ceramic support. The conductor is defined by a lead wire made of an alloy and a covering layer made of a metal which covers the lead wire. The adhesive contains at least one metal of which at least an outer surface of each conductor is formed, so as to increase bonding strength between the conductor(s) and the adhesive.

Abstract: A device capable of accurate temperature measurement down to 0.01.degree. K. of an object whose temperature is to be measured consisting of a heat sink wafer a first conducting pad bonded near one end of the heat sink wafer and a second conducting pad bonded near the other end of the heat sink wafer, an oblong doped semiconductor crystal such as germanium, the oblong doped semiconductor crystal has a third conducting pad bonded on its top surface and a fourth conducting pad bonded on its bottom surface with the oblong doped semiconductor crystal bonded to the heat sink wafer by having the fourth conducting pad bonded to the first conducting pad, a wire bonded between the second and third conducting pads, and current and voltage applying wires bonded to the first and second conducting pads whereby the change in resistance of the oblong doped semiconductor crystal indicates the temperature of an object whose temperature is to be measured.

Abstract: The NTC temperature sensor includes a NTC temperature sensing element having an NTC resistor and made of a laminated composite of ceramic films, which is so designed that the ambient air or oxygen supplied by electrolytic pumping has free access, via a channel in the laminated composite, to the NTC resistor. The NTC resistor is hermetically sealed from a gas being measured. Solid electrolyte films which conduct O.sup.-2 ions, and films based on Al.sub.2 O.sub.3 can be used to make the laminated composite. The NTC resistor characteristic curve is independent of the composition of the gas being measured. The laminated composite can be formed of at least three solid electrolyte ceramic films including a base film provided with punched-out interconnection holes and conductor tracks printed by thick film technology, an intermediate film having a punched-out channel and a channel enlargement around the ends of the conductor tracks forming the electrodes of the NTC resistor, and a covering film.

Abstract: An electrothermal sensor is shown having an electrically conductive substrate, an electrically insulating layer disposed on the substrate, a first thermistor disposed on a central region of the electrically insulating layer, a second thermistor disposed adjacent an edge of the electrically insulating layer, an electrical coupling device on the electrically insulating layer for coupling the first and second thermistors externally of the electrically insulating layer and a pair of electrical connecting devices coupled to the substrate and passing through the electrically insulating layer, the first thermistor being disposed between the pair of electrical connecting devices.

Abstract: This invention relates to a self-limiting electrical heating element comprising resistance components having a positive temperature coefficient and a zero temperature coefficient, arranged in a layered structure with two electrodes placed diagonally within or in contact with two ZTC layers separated by a PTC layer.

Abstract: A temperature sensor is formed with a metal substrate at least a portion of which is coated with a layer of porcelain enamel. At least one conductive element is deposited on the coated portion of the substrate in such a manner as to provide a first sensor configuration for sensing temperature as a function of the resistance of the conductive element itself. This conductive element in operative combination with the porcelain enamel layer and the metal substrate provides a second sensor configuration for sensing temperature over a second temperature range as a function of the resistance of the porcelain enamel layer.

Abstract: A temperature sensor. Two thick films resistor elements are mounted to a substrate and then a thermistor coupled to those elements to form a voltage divider. The resistance of the thermistor is determined at a reference temperature and the thick film resistor elements are precisely trimmed using a laser trimming system to produce a precision voltage divider. To sense temperatures the voltage divider is energized and its resistance ratio is sensed utilizing a bridge circuit.

Abstract: A temperature sensor includes a glass-ceramic substrate and a plurality of conductive elements deposited on the substrate. The substrate serves both as a support for the conductive elements and as a temperature-sensitive resistive material forming an operative part of the sensor itself. The conductive elements are arranged to provide one sensor configuration for sensing temperature over a first temperature range as a function of the resistance of one of the elements, a second sensor configuration for sensing temperature over a second temperature range as a function of the surface resistance of the substrate between two of the elements, and a third sensor arrangement for sensing temperature over a third temperature range as a function of the bulk resistance of the substrate between two of the elements separated by a thickness of substrate material less than the surface distance therebetween. Four contact pads are provided to connect the three sensor configurations to external signal processing circuitry.

Abstract: A gas detecting device includes a substrate and a plurality of gas sensitive elements supported by the substrate. A plurality of predetermined temperatures at which gases are detected are provided. The gas detecting device also includes a plurality of pairs of electrode leads supported by the substrate, each of the plurality of pairs of electrodes being connected to a corresponding one of the gas sensitive elements, and heater leads that are supported by the substrate and heat the plurality of gas sensitive elements so that each of the gas sensitive elements is set at a corresponding one of the plurality of predetermined temperatures.

Abstract: A miniature motor having a positive-coefficient thermistor in which a first supporting member made of an electrically conductive material and electrically connected to at least any one of a pair of brushes housed in a motor cover plate, and a second supporting member made of an electrically conductive material and electrically connected to an external terminal are provided; a positive-coefficient thermistor being supported between the first and second supporting members.This construction makes the assembly of the motor easy, leading to improved productivity, and allows the motor to have a positive overheat preventing function without adding to the number of parts.

Abstract: A thermal radiation sensor is suggested which comprises two receiver surfaces exposed to the radiation, one receiver surface (1) having a high absorption capacity with respect to the thermal radiation, the other (2) having a low absorption capacity, the two receiver surfaces (1) and (2) consist of a NTC resistance material and are combined in a bridge circuit together with two temperature-independent cermet resistors (3) and (4). In order to prevent a dependency of the measurements of such a sensor on the ambient temperature, the NTC resistors (1) and (2) comprise underlying heating layers (6) and (7) which keep the two NTC resistors at a constant temperature. Insulating layers (8) and (9) are provided between the NTC resistors (1) and (2) and the heating layers (6) and (7). The heating layers (6) and (7) consist of a cermet thick film with platinum or of a platinum thick film and have the shape of a meander. The insulating layers (8) and ( 9) preferably consist of a crystallizing glass.

Abstract: A method for measuring a heat transfer coefficient between a heat transfer element and a fluid comprising a measurement of a calorific value by placing the heat transfer element into the fluid and charing the heat transfer element with electricity. A calorific value of a particular surface of the heat transfer element is the true calorific value of the entire heat transfer element, since the particular surface of the heat transfer element is thermally insulated from a residual surface of the heat transfer element so as to prevent a heat transfer of the residual surface of the heat transfer element.

Abstract: An RTD (resistance temperature sensor or detector) sensing device which is a long, thin, unitary device adapted to be distributed across an extended field for the continuous, uninterrupted sensing or interrogation of such field, avoiding the inaccuracy, unreliability, and excessive expense of conventional "point" RTD and thermocouple sensors currently employed for this purpose. According to the invention, a very long, thin, ductile protective metal outer sheath houses a coextensive body of insulation material, which in turn supports and electrically insulates one or more coextensive RTD filaments and in most forms of the invention one or more heater filaments. Distributed RTDs of the invention may, along their lengths, have continuous linear function sensitivity, continuous variable function sensitivity, or step function sensitivity.

Abstract: An infrared detector includes a high resistance substrate, a compound semiconductor disposed on the substrate, a pair of electrodes disposed on the compound semiconductor, and a plurality of grooves in the compound semiconductor perpendicular to a current path between the electrodes, wherein the grooves have shallower than the thickness of the compound semiconductor.

Abstract: Conductive polymer PTC compositions have improved properties, especially at voltages of 200 volts or more, if they are very highly cross-linked by means of irradiation, for example to a dosage of at least 50 Mrads, preferably at least 80 Mrads, e.g. 120 to 600 Mrads. The cross-linked compositions are particularly useful in circuit protection devices and layered heaters.