Connect public, paid and private patent data with Google Patents Public Datasets

Resistance element

Download PDF

Info

Publication number
US3243753A
US3243753A US23694362A US3243753A US 3243753 A US3243753 A US 3243753A US 23694362 A US23694362 A US 23694362A US 3243753 A US3243753 A US 3243753A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
temperature
particles
resistance
resistor
conductive
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Inventor
Kohler Fred
Original Assignee
Kohler Fred
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B3/00Ohmic-resistance heating
    • H05B3/10Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/146Conductive polymers, e.g. polyethylene, thermoplastics
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00Control of temperature
    • G05D23/19Control of temperature characterised by the use of electric means
    • G05D23/1919Control of temperature characterised by the use of electric means characterised by the type of controller
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00Control of temperature
    • G05D23/19Control of temperature characterised by the use of electric means
    • G05D23/20Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/24Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor
    • G05D23/2401Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor using a heating element as a sensing element
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01CRESISTORS
    • H01C7/00Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01CRESISTORS
    • H01C7/00Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/027Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient consisting of conducting or semi-conducting material dispersed in a non-conductive organic material
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02HEMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/02Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
    • H02H9/026Current limitation using PTC resistors, i.e. resistors with a large positive temperature coefficient
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B3/00Ohmic-resistance heating
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B3/00Ohmic-resistance heating
    • H05B3/10Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic

Description

March 29, 1966 F. ,KOHLER RESISTANCE ELEMENT Filed Nov. 15, 1962 {50 250 fE'MPEPATt/RE- "F PEf/STAA L'E-OHMJ INVENTOR. 59:0 (0w. 0

ATTORNE Y5 United States Patent 3,243,753 RESISTANCE ELEMENT Fred Kohler, 113 E. 31st St., New York 16, N.Y. Filed Nov. 13, 1962, Ser. No. 236,943 10 Claims. (Cl. 338-31) The present invention relates to an improved elect-rical resistance element which varies in resistance in response to changes in temperature and an improved means for manufacturing same. More specifically, the present invention deals with an improved resistor containing a thermoplastic and finely divided conducting particles, said resistor exhibiting a relatively small increase of resistance, for an increase of temperature below a selected temperature value, and which exhibits an extremely high temperature coefiicient of resistance at temperatures above said selected temperature value, such that the resistance of said resistor increases sharply when the selected value of temperature is exceeded.

Heretofore, it has been suggested that a resistance element could be made from plastics, mixed with conductive materials However, in general, such materials have not been put to wide use. The plastic body often will melt during its use or the plastic will deteriorate at elevated temperatures. Further, they have not shown such particular properties which would make their use advantageous.

In accordance with the present invention, means are taught for forming a resistor element which is characterized by its unusual change of resistance with change in temperature. More particularly, the present resistor is in the form of a plastic e.g., a thermoplastic or suitable thermosetting material, preferably a polyolefin plastic, containing a finely divided conductive powder intimately dispersed through the plastic matrix. The relative quantities, types and arrangement of the finely divided conductive particles and the plastic are such that below a certain selected temperature level, particle to particle contact exists between the finely divided particles of the conductive constituents, thus giving the total composition a relatively low resistance. Above said selected or critical temperature the substantial difference in thermal coefiicient of expansion between said conductive particles and the thermoplastic material results in the breaking down of contact between the conductive particles with a resultant sharply increased resistivity. By way of example, a resistance element of the present invention normally exhibits an increase in resistance of more than 250% over a temperature range of less than 25 F., at about said selected critical temperature value. A 1000% increase in resistance or even higher percentage over a temperature range of less than 25 F. at about said critical temperature value has been obtained in experimental samples.

As noted previously, the non-conductive plastic polymer which serves as thematrix holds said conductive particles together and is preferably a polyolefin, such as polyethylene, polypropylene, polyisobutylene, halo-derivatives of polyethylene, such as polytetrafluoroethylene, trifluoromonochloroethylene, copolymers or admixtures thereof. The polyolefin plastic must have 'a substantially greater coefficient of thermal expansion than the conductive particles. The polyolefin polymers may be produced by any of a wide variety of conventional processes now in industrial use, such as high pressure polyolefin processes, relatively low temperature, low pressure polymerization reactions such as the use of titanium halides in combination with alkyl aluminum compounds, etc. The polymer generally has a thermal coefificient of expansion of about 2 l0 C. to 25 10 C., preferably l2 10 C. to '22 10 C., said temperature coeflicient of expansion being at least 3, preferably 30 times greater than the thermal coefficient of expansion of the conductive materials. An example of this is the combination of carbonp woder with a coefiicient of thermal expansion of 5 .4 10- C. and polyethylene which has a coefl'icient of thermal expansion of about 16 lO C.

The finely divided conducting particles are preferably carbon, such as carbon black, graphite, etc. Alternatively the conducting particles may be finely divided metals, alloys, non-metallic conductors, metal salts, etc. Examples thereof include iron, copper, chromium, titanium, tungsten, platinum metals, boron, silicon, silver, gold and aluminum. The conducting particles are normally of a size range of about 0.003 to 1.0 microns, preferably 0.010 to 0.080 micron. In general, the present compositions will contain, based on thermoplastic and conducting particles, 25% to preferably 35.0 to 60.0% thermoplastic, the remainder being finely divided conductive particles. These percentage figures are based on the volumes respectively of the thermoplastic and of the particles in their finely-divided form, such as carbon black.

The present compositions are made in a manner which insures substantial contact among the conductive particles at temperature below the critical temperature of the resistor, with the consequent separation of the conductive particles at the critical temperature due to the substantially greater thermal coefiicient of expansion of the thermoplastic material. The resistor, of course, has a positive resistance-temperature characteristic. As the temperature is raised, the thermoplastic expands more than the conductive particles, thus reducing the compressive force on the particles. As the temperature increases a point is reached where there has been a very substantial decrease in compressive pressure on the conducting particles due to the greater rate of expansion of the thermoplastic. At this point, there is encountered the very sharply increased resistance characteristic of the present resistance element.

The present resistors are preferably produced in a manner characterized by the conductive finely divided particles being under compressive stresses while simultaneously the thermoplastic is formed by in situ polymerization of the appropriate monomer. Thus, for example, the finely divided conductive particles, e.g., carbon black of less than 200 mesh may be mechanically compressed, e.g., pressures of 1 to p.s.i., in a reaction vessel. Conventional catalytic agents for promoting the polymerization of the monomer, e.g., ethylene gas, may be dispersed about said compressed carbon particles. The ethylene gas is then pumped preferably at high pressures of 1000 to 2000 atmospheres and at normal polymerization temperatures into contact with said finely divided conductive particles. At the conventional polymerization temperature range, e.g. 300 to 400 F. the ethylene is polymerized to polyethylene which forms a matrix about and between the carbon particles without substantially disturbing the carbon-carbon particle contact due to the compressive forces exerted by mechanical means on the conducting particles. Very intimate contact between the carbon and polyethylene thus formed is assured and the conducting carbon lattice and plastic matrix will be relatively densely packed together. Under these conditions, the polymerizing monomer will tend to cross-link and intimately line the surface of the carbon particles. This upon cooling will assure particle to particle contact under pressure, provided that enough carbon had been used to form a coherent lattice. The mechanical compression means may take the form of a reaction chamber substantially fully packed with conducting particles, a pistonended reaction zone.

the conducted particles is preferably carried out in a gas phase is in situ polymerization, it may also take the form of a liquid phase reaction zone. As an example of this, the plastic material may be a liquid epoxy resin. As soon as practicable after addition of the catalyst, the liquid mixture is injected under pressure into a reaction vessel tightly packed with carbon particles. The polymerization now takes place around the conductive particles, while particle to particle contact remains relatively undisturbed.

It is also possible to produce the resistance element by solid phase polymerization of a polyolefin of low molecular weight with carbon particles of a very small diameter. For this purpose carbon blacks with a particle size in the order of 3-25 millimicrons are preferred.

To accomplish this, about 60% carbon by weight must be used. This carbon is then intimately mixed with a partially polymerized polyolefin. The mixture is then heated to a temperature where the plastic forms a viscous fluid and then thoroughly blended. This blending is preferentially carried out in a pressure vessel under a pressure of 100 lbs./in. or even higher. Under these conditions, and especially under'the influence of a suitable catalyst such as an organic persulfate, the low molecular weight chain will grow in length along the great amount of surface area, provided by the carbon black. As the percentage of carbon is in the order of 60% by weight of the composition, carbon to carbon contact exits throughout the composition. At a temperature above 350 F. extensive cross-linking of the polymer chains takes place, as well as linkages with the carbon atoms are formed.

The above processes for forming the resistance element of the present invention are distinguished from merely admixing finely divided conductive particles with particles of preformed polymer. Further the concept of mechanically compressing the conductive particles while forming a thermoplastic matrix by in situ polymerization, distinguishes the present process from merely conducting polymerization in a solution containing finely divided particles.

' The resistance elements of the present invention find "a wide variety of interesting applications. For example, they may be employed in space heaters or radiant type wall heaters in which it is. desired that the maximum temperature will be self-limiting. Because of their extremely rapid and sharp increase in resistivity at a selected temperature level, the resistors of the present invention may readily be employed in combustible panels or walls where a maximum temperature may not be exceeded even in the event of, a short circuit. These resistance elements used as heaters have the property of drawing more current as the ambient temperature decreases. This is due to the fact that in colder surroundings the maximum temperature, which these resistor elements reach is a few degrees lower than the maximum temperature reached in a warmer ambient. Consequently, as the resistance body is a few degrees cooler, the resistance is considerably lower. This means that in cooler weather more power is automatically drawn from the power lines, without the use of a thermostat. A heating system using the said resistance elements will consequently be largely self-regulating. They may be employed as a thermal-control element which would permit the construction of time delay relays. In one application of the present invention the resistor may be placed in series with a source of electrical power in the load. Under normal conditions, the resistance of the load is such that relatively little current flows through -Ithe resistor and thus the temperature of the resistor remains below the critical value. If, for example, the load is short circuited, the current in the resistor increases and its temperature is rapidly raised to about its critical value. As a result, the resistance of the thermoplasticfine particle resistance element greatly increases. This means that a great deal of power is dissipated in the resistance element. This power dissipation, however, can only take place for a very short time, such as a fraction of a second, because the dissipated power will raise the temperature of the element to a value where the resistance has become so high, that the original current is limited to a negligibly small value; in fact, a value of current just high enough to maintain the element at its new high temperature-high resistance equilibrium point. Accordingly, the resistor may act as a form of fuse which reduces the current flow through the short circuit load to a safe extremely low value when the resistor is heated to the critical temperature range. Normally, when employed in this manner, it is necessary to first interrupt the current in the circuit 50 as to allow the resistor to cool below its critical temperature before reapplying the current. The electrical circuit thus described is quite advantageous in that it eliminates the need for replacement of fuses, costly circuit breakers or other fuses'characterized by moving parts and offers a highly effective means of controlling maximumcurrent to the circuit. Depending on its mass, and the type of heat-sink it is mounted on, various inverse time vs. current characteristics are possible.

When employed in the above uses, one or more conductive materials are fixed, e.g., clamped, screwed, etc., to the plastic element to form the resistor, the plastic being between two conducting surfaces. The select value of current corresponding to the rapid increase of resistance will depend on and can be varied by, choice of cross-sectional area and surface to value ratio of the resistor, the specific resistivity and thermal characteristics of any heat sink to which the plastic resistor is attached, etc.

With reference to the drawings;

FIGURE 1 depicts the greatly enlarged segment of the present resistor under normal temperature conditions.

FIGURE 2 illustrates the structure of the present resistor upon reaching and exceeding the critical temperature range.

FIGURE 3 graphically illustrates the temperature vs. resistance characteristics of an experimental resistor produced as per the teachings of this application,

FIGURE 4 shows a practical design for a recycling fuse,- which will reduce the current in the circuit to a negligibly small value in a short interval after a certain critical value of current in the circuit has been exceeded.

The various aspects and modifications of the present invention will be made more clearly apparent by reference to the following descriptive examples and accompanying drawings.

Example 1 The following examples illustrate a typical procedure for forming a resistance element in accordance with the present invention.

Finely divided carbon black having a size range of about 0.010 to 0.080 micron is placed in a tubular reaction zone having a movable end segment which can act as a piston. The reaction zone is substantially packed with the carbon particles and the position of the piston and the reactor set so as to employ about 10 pounds per square inch of mechanical pressure across the body of carbon particles. Thereafter, ethylene gas is introduced into the reaction zone which is maintained under reaction conditions of temperature and pressure, e.g., 350 F. and 1000 atmospheres. A suitable catalyst such as an organic persulfate may be dispersed about the packed carbon particles or alternatively injected with the ethylene monomer. The ethylene is thus polymerized in situ upon the carbon particles while simultaneously forming a matrix between and among the conducting particles- Because of the mechanical compression during the polymerization reaction and subsequent cooling, the resulting product recovered is characterized by a highly filled polyethylene plastic wherein the conducting particles are in substantial contact with one another. In the present example the resulting product may contain 40% polyethylene, 60% carbon particles and have a resistance at room temperature of about 1 ohm/inch.

With particular reference to FIGURE 1, shown therein isa greatly enlarged and simplified view of the resultant thermoplastic-carbon particle resistance element thus produced. It is noted that carbon particles 10, although surroundedby thermoplastic matrix 11- are in relatively intimate contact. Both the mechanical compression exerted during the polymerization and the contraction of the polyethylene during cooling of the reaction temperature to-room temperature, insure the close contact of the conducting finely divided particles and thus the relatively low resistance of the resistor unit.

When the temperature of the resistance unit 12 is raised to a critical temperature value, there is a substantial and relatively sharp decrease -in the contact'among the conducting particles due to the substantially greater coefficient of thermal expansion of the thermoplastic as compared to finely divided conductors. This is shown in exaggerated form. in FIGURE. 2. As a consequence, upon r'eachirig'a temperature level at which this elfect becomes pronounced the resistance of the resistor very sharply increases in value.

Example 2 The dramatic increase in resistance of the elements of the present invention is graphically shown in FIGURE 3.. FIGURE 3 illustrates the effect of temperature on a three-inch long by-one-inch diameter tube of a polyethylene carbon material similar to that described above.

This tube had a wall thickness of about .150". It was clamped with a metal ring, similar to a hose clamp at each end, so that the distance between the edges of the rings was about three inches.

' The resistance of the resistor was then measured while varying its temperature from about 80 to 395 The testwas performed by placing the resistance element into an oven,"the temperature of which could be adjusted and measured. A thermometer was placed inside the resistor tube, 'while an ohm-meter was connected to leads connecting to the ends of the resistor. 'Results are set forth in Table 1 and graphically illustrated in FIGURE 3. The specific resistance in terms of ohms-inch is obtained by multiplying the resistance in ohms by thecros's sectional area divided by the length of the strip desired, i.e..47 /3 -0.157.

- TABLE 1 Temp., Resistance, Temp., Resistance,

F. ohms F. ohms As shown in FIGURE 3, the resistor of the present invention exhibits a normal small and positive resistance temperature relationship. This is so under normal temperature conditions to be encountered in its use. In the present example, this could be considered to be temperatures of up to about 250. However, as depicted in FIGURE 3, at this relatively critical temperature level a very sharply increased change in resistance with increased temperature occurs, e.g., a 600% increase in resistance from a temperature of about 255 F. to 266 F. At temperatures beyond this point the resistance increases many fol d beyond that at lower temperatures. It thus becomes apparent that the resistance elements used in the test are characterized by a dramatically increased resistance over a relatively narrow temperature range.

Example 3 The following illustrates a typical application of the present resistance element in terms of its use as a circuit fuse.

By way of example, as shown in FIGURE 4, a simple series cincuit containing a load which may, for example, be a IOU-watt lamp and a resistance element of the present invention is connected by wiring 15 to a standout AC. or DC. voltage source of 110-120 volts. The resistance element may be a polypropylene carbon particle corn position 12 of the present invention wedged or threaded between two metal cylinders 13 and 14 which are connected so as to be in series with the remainder of the circuit. The wedge has a resistance of about 0.05 ohm at room temperature and the resistance of the load element is about 85 ohms. 4

During the course of normal use the temperature of the overall circuit may rise to, for example, 200 F. However, the resistance of the polyethylenecarbon par ticle wedge will only increase to about 0.10 ohm. Heat dissipation in the composition will be about .1 Watt. However, when the load element is short circuited, there is initially a very substantial increase in current passing through the circuit and due to the I R volt-age factor the fuse of the present invention is heated to a temperature within the critical range. This causes the resistance of the fuse element to increase to the order of 1000 ohms at 300 or 50,000 ohms or "greater at 350. Thus a new equilibrium point is 'reachedwhere heat dissipation due. to PR, equals thermal losses. Thus, while normal current flow would not cause heating to the temperature above which there is a rapid increase in resistivity, the increase in current due to the short circuiting gives a sudden increase in heat generation and greatly increases the resistivity of the fuse to such ahigh value that the present composition itself will thus become the current limiting device, thereby limiting the final equilibrium current to a final fraction of its initi-al safe value.

Uponremoving the power source, or opening the circuit on the load side of the fuse of the present invention,

i the initial short circuiting. difficulty has been eliminated the cycle will again be rapidly repeated and the current reduced to a safe value.

When using the electric resistance element of the present invention to control current flow, it generally will comprise less than 5% of the total resistance of the circuit at room temperature. When the current increases to heat theelement to the temperature range of markedly increasing resistance with temperature, the element will comprise more than 95% of the total resistance value of the circuit. The current may thus be limited to less than 5% of its normal value.

Various modifications may be made to the present invention. For example, the following are a number of additional applications of the unusual characteristics of l the present material for useful and practical purposes.

(1) A water heater, which upon evaporation of the water will shut itself off automatically by virtue ofthe material essentially becoming a non-conductor.

(2) A positive temperature-coefiicient thermistor (resistor with high temperature coefiicient of resistivity). (3) A sensing element for a heat or fire detection system.

(4) A protective element for dry-cell batteries, opening the circuit upon any short circuiting, but passing current again upon removal of the short.

(5) An ambient temperature sensitive timing element,

Where the time delay is a function of ambient tempera mm.

(6) A temperature limiting resistance element. This would be useful for applications such as a baseboard heater, baking ovens, electric blankets, electric irons, etc.

(7) A sensing element for an air or water flow meter, in the manner in which the conventional negative thermistor elements are presently used.

(8) In tubular form a heating element for liquids passing through it.

(9) A thermostatic element without moving parts for automatic control systems.

(10) In the form of thin fibres, a memory or storage element for computers (or in any form in which the thermal mass involved is small).

(11) As an element exhibiting negative resistance characteristics over a portion of its operating range.

Having described the present invention, that which is sought to be protected is set forth in the following claims.

I claim:

1. An electrical resistor element comprising a resistor provided with conductive connecting terminals for forming portions of an electrical circuit, said resistor comprising finely divided conductive particles dispersed in a matrix of a relatively non-conductive plastic, said plastic having a coefficient of thermal expansion at least three times greater than that of said conductive particles, said conductive particles being in substantial particle to particle contact, said resistor containing sufiicient conductive particles amounting from about 25% to about 75% of the total volume of the resistor material and dispersed through said plastic matrix so that below a critical temperature level immediate particle to particle contact exists between the conductive particles, whereas above said temperature level and while the resistor remains a solid, said contact between conductive particles is substantially broken due to the differences in thermal coeflicient of expansion between said particles and said non-conductive matrix, said critical temperature being substantially above room temperature and below the temperatures of melting and of substantial deterioration of the plastic, said resistor being characterized by a relatively flat curve of electrical resistance versus temperature below said critical temperature level and by a sharply rising curve beginning at said critical temperature level, said resistor further being characterized by an increase in resistivity of more than 250% over a temperature range of 25 F. at about said critical temperature level.

2. The resistor element of claim 1 wherein said plastic is a polyolefin.

3. The resistor element of claim 1 wherein said finely divided conductive particles comprises carbon.

4. The resistor element of claim 1 wherein said conducting particles range in size from .003 to 1.0 micron.

5. The resistor element of claim 1 wherein said plastic is polyethylene and said conducting particles are carbon particles.

6. An electrical resistor element comprising a resistor provided with conductive connecting terminals for forming portions of an electrical circuit, said resistor comprising a polyolefin polymer containing finely divided carbon particles distributed Within a matrix of said polyolefin polymer, said carbon particles being present in about 25 to 75 volume percent based on total volume of said polyolefin polymer and particles and. being in carbon particle to carbon particle contact at room temperature, said carbon particles having such a substantially lower coefiicient of thermal expansion than said polyolefin and being distributed through said polyolefin matrix, whereby below a critical temperature level immediate carbon particle to carbon particle contact predominates whereas above said temperature level and while the resistor remains a solid, such carbon particle contact is substantially broken so that the resistor exhibits an increase in electrical resistivity of more than 250% over a temperature range of 25 F. at about said temperature level, said resistor being characterized by a relatively fiat curve of electrical resistance versus temperature below said critical temperature level and by a sharply rising curve beginning at said critical temperature level.

7. The resistor element of claim 6 wherein said polyolefin is polyethylene and said carbon particles have a size range of 0.003 to 1.0 micron.

8. An electrical resistor element comprising a resistor provided with conductive connecting terminals for forming portions of an electrical circuit, said resistor comprising finely divided conductive particles having an average particle size of 0.01 to 0.08 micron dispersed in a matrix of a relatively non-conductive plastic, said plastic having a coefficient of thermal expansion at least three times greater than that of said conductive particles, said conductive particles being in substantial particle to particle contact, said resistor containing suflicient conductive particles amounting from about 25% to about of the total volume of the resistor material and dispersed through said plastic matrix so that below a critical temperature level immediate particle to particle contact exists between the conductive particles, whereas above said temperature level and while the resistor remains a solid body, said contact between conductive particles is substantially broken due to the differences in thermal coefficient of expansion between said particles and said non-conductive matrix, said critical temperature being substantially above room temperature and below the temperatures of melting and of substantial deterioration of the plastic, said resistor being further characterized by an increase in resistivity of more than 250% over a temperature range of 25 F. at about said critical temperature level.

9. An electrical resistor element in accordance with the foregoing claim 1 and in which said matrix comprises a polyolefin polymer which is polymerized with the conductive particles in situ substantially in particle-to-particle contact and under pressure.

10. An electrical resistor element in accordance with the foregoing claim 1, and in which said plastic matrix has been polymerized, and its molecules are cross-linked with said particles in situ.

References Cited by the Examiner UNITED STATES PATENTS 2,273,704 2/ 1942 Grisdale 252-504 2,443,073 6/1948 Knudsen 324- 2,588,564 3/1952 Pawlicki 324-105 2,744,981 5/1956 Spears 200-113 2,774,108 12/1956 Wyllie 264-128 X 2,796,505 6/1957 Bocciarelli 338-20 2,799,051 7/1957 Coler et a1 18-475 2,847,391 8/1958 Wheeler 260-41 2,978,665 4/1961 Vernet et al 338-223 3,008,949 11/1961 Langer et al. 260-949 3,055,843 9/1962 Muller et al. 252-511 3,056,750 10/1962 Pass 252-511 FOREIGN PATENTS 676,090 8/1957 Canada.

RICHARD M. WOOD, Primary Examiner. ANTHONY BARTIS, Examiner.

w. D. BROOKS, H. T. POWELL, G. GREENWALD,

Assistant Examiners.

Claims (1)

1. AN ELECTRICAL RESISTOR ELEMENT COMPRISING A RESISTOR PROVIDED WITH CONDUCTIVE CONNECTING TERMINALS FOR FORMING PORTIONS OF AN ELECTRICAL CIRCUIT, SAID RESISTOR COMPRISING FINELY DIVIDED CONDUCTIVE PARTICLES DISPERSED IN A MATRIX OF A RELATIVELY NON-CONDUCTIVE PLASTIC, SAID PLASTIC HAVING A COEFFICIENT OF THERMAL EXPANSION AT LEAST THREE TIMES GREATER THAN THAT OF SAID CONDUCTIVE PARTICLES, SAID CONDUCTIVE PARTICLES BEING IN SUBSTANTIAL PARTICLE TO PARTICLE CONTACT, SAID RESISTOR CONTAINING SUFFICIENT CONDUCTIVE PARTICLES AMOUNTING FROM ABOUT 25% TO ABOUT 75% OF THE TOTAL VOLUME OF THE RESISTOR MATERIAL AND DISPERSED THROUGH SAID PLASTIC MATRIX SO THAT BELOW A CRITICAL TEMPERATURE LEVEL IMMEDIATE PARTICLE TO PARTICLE CONTACT EXISTS BETWEEN THE CONDUCTIVE PARTICLES, WHEREAS ABOVE SAID TEMPERATURE LEVEL AND WHILE THE RESISTOR REMAINS A SOLID, SAID CONTACT BETWEEN CONDUCTIVE PARTICLES IS SUBSTANTIALLY BROKEN DUE TO THE DIFFERENCES IN THERMAL COEFFICIENT OF EXPANSION BETWEEN SAID PARTICLES AND SAID NON-CONDUCTIVE MATRIX, SAID CRITICAL TEMPERATURE BEING SUBSTANTIALLY ABOVE ROOM TEMPERATURE AND BELOW THE TEMPERATURES OF MELTING AND OF SUBSTANTIAL DETERIORATION OF THE PLASTIC, SAID RESISTOR BEING CHARACTERIZED BY A RELATIVELY FLAT CURVE OF ELECTRICAL RESISTANCE VERSUS TEMPERATURE BELOW SAID CRITICAL TEMPERATURE LEVEL AND BY A SHARPLY RISING CURVE BEGINNING AT SAID CRITICAL TEMPERATURE LEVEL, SAID RESISTOR FURTHER BEING CHARACTERIZED BY AN INCREASE IN RESISTIVITY OF MORE THAN 250% OVER A TEMPERATURE RANGE OF 25*F. AT ABOUT SAID CRITICAL TEMPERATURE LEVEL.
US3243753A 1962-11-13 1962-11-13 Resistance element Expired - Lifetime US3243753A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US3243753A US3243753A (en) 1962-11-13 1962-11-13 Resistance element

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US3243753A US3243753A (en) 1962-11-13 1962-11-13 Resistance element
FR928159A FR1397126A (en) 1962-11-13 1963-03-15 An electric resistance element or the like, for producing said element methods, regulation, strength and intensity of courantdans an electrical circuit, and fluid heating
DE19631490164 DE1490164A1 (en) 1962-11-13 1963-11-13 Resistance element and process for its preparation

Publications (1)

Publication Number Publication Date
US3243753A true US3243753A (en) 1966-03-29

Family

ID=22891657

Family Applications (1)

Application Number Title Priority Date Filing Date
US3243753A Expired - Lifetime US3243753A (en) 1962-11-13 1962-11-13 Resistance element

Country Status (3)

Country Link
US (1) US3243753A (en)
DE (1) DE1490164A1 (en)
FR (1) FR1397126A (en)

Cited By (157)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351882A (en) * 1964-10-09 1967-11-07 Polyelectric Corp Plastic resistance elements and methods for making same
US3359521A (en) * 1965-10-26 1967-12-19 Cognitronics Corp Bistable resistance memory device
US3412358A (en) * 1966-09-09 1968-11-19 Gulton Ind Inc Self-regulating heating element
US3413442A (en) * 1965-07-15 1968-11-26 Texas Instruments Inc Self-regulating thermal apparatus
US3414704A (en) * 1965-02-25 1968-12-03 Texas Instruments Inc Self-regulating heating device
US3414705A (en) * 1965-10-24 1968-12-03 Texas Instruments Inc Component oven
US3421054A (en) * 1964-05-14 1969-01-07 Consortium Elektrochem Ind Bistable boron semiconductor or switching device
US3434089A (en) * 1966-01-03 1969-03-18 Texas Instruments Inc Relay with voltage compensation
US3439306A (en) * 1967-06-05 1969-04-15 Sylvania Electric Prod Self-supporting resistance film
US3489884A (en) * 1966-12-28 1970-01-13 Texas Instruments Inc Heated windshield wiper and blade therefor
US3489976A (en) * 1966-01-03 1970-01-13 Texas Instruments Inc Self-protected time delay relay
US3501619A (en) * 1965-07-15 1970-03-17 Texas Instruments Inc Self-regulating thermal apparatus
US3500634A (en) * 1968-01-02 1970-03-17 Texas Instruments Inc Control system and actuator used therein
US3571777A (en) * 1969-07-07 1971-03-23 Cabot Corp Thermally responsive current regulating devices
US3582968A (en) * 1968-12-23 1971-06-01 Texas Instruments Inc Heaters and methods of making same
US3584190A (en) * 1970-02-27 1971-06-08 Texas Instruments Inc Self-regulating heat applicator
US3617695A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3617694A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3619560A (en) * 1969-12-05 1971-11-09 Texas Instruments Inc Self-regulating thermal apparatus and method
US3632971A (en) * 1970-01-27 1972-01-04 Texas Instruments Inc Self-limiting electric hair curler heater
US3646315A (en) * 1967-12-20 1972-02-29 Texas Instruments Inc Self-regulated heating device
US3648002A (en) * 1970-05-04 1972-03-07 Essex International Inc Current control apparatus and methods of manufacture
US3662149A (en) * 1969-09-16 1972-05-09 Braun Pebra Gmbh Heated lock for motorcars
US3689736A (en) * 1971-01-25 1972-09-05 Texas Instruments Inc Electrically heated device employing conductive-crystalline polymers
US3696611A (en) * 1969-09-17 1972-10-10 Scovill Manufacturing Co Thermal motors
US3735417A (en) * 1971-10-26 1973-05-22 Honeywell Inc Temperature regulating heat-recording stylus
US3748439A (en) * 1971-12-27 1973-07-24 Texas Instruments Inc Heating apparatus
US3753198A (en) * 1969-09-19 1973-08-14 Denki Onkyo Co Ltd Varistors
US3760495A (en) * 1970-01-27 1973-09-25 Texas Instruments Inc Process for making conductive polymers
US3787718A (en) * 1972-08-08 1974-01-22 Sondell Res Deve Co Spherical electronic components
DE2345320A1 (en) * 1972-09-08 1974-04-04 Raychem Corp A process for producing self-regulating, electrically conductive products
DE2345303A1 (en) * 1972-09-08 1974-04-18 Raychem Corp A process for the production of electrical widerstandskoerpern with positive, non-linear resistance coefficient
US3878357A (en) * 1965-02-25 1975-04-15 Texas Instruments Inc Component oven
US3943375A (en) * 1974-12-23 1976-03-09 Gte Sylvania Incorporated On-off switch with time delay
US3947658A (en) * 1972-02-22 1976-03-30 Kureha Kagaku Kogyo Kabushiki Kaisha Protector for the plate-shaped heating element
DE2543346A1 (en) * 1974-09-27 1976-04-15 Raychem Corp Polymer compositions with a positive temperature-coefficient of resistance
US3973100A (en) * 1972-12-27 1976-08-03 Texas Instruments Incorporated Self-limiting electric hair curler heater
US3976600A (en) * 1970-01-27 1976-08-24 Texas Instruments Incorporated Process for making conductive polymers
US4000647A (en) * 1971-07-31 1977-01-04 Dornier Gmbh Heating device for flow sondes
JPS52101737A (en) * 1976-02-20 1977-08-26 Matsushita Electric Ind Co Ltd Heating body
US4085286A (en) * 1974-09-27 1978-04-18 Raychem Corporation Heat-recoverable sealing article with self-contained heating means and method of sealing a splice therewith
US4088269A (en) * 1975-11-06 1978-05-09 Vdo Adolf Schindling Ag Electrically heated windshield washer spray nozzle assembly
US4101862A (en) * 1976-11-19 1978-07-18 K.K. Tokai Rika Denki Seisakusho Current limiting element for preventing electrical overcurrent
US4118334A (en) * 1975-09-18 1978-10-03 Gte Laboratories Incorporated Primary electrochemical cell
US4149066A (en) * 1975-11-20 1979-04-10 Akitoshi Niibe Temperature controlled flexible electric heating panel
DE2948281A1 (en) * 1978-12-01 1980-06-19 Raychem Corp Electrical circuitry and circuit-protection device
US4212425A (en) * 1978-02-27 1980-07-15 Vdo Adolf Schindling Ag. Electrically heated windshield washer spray nozzle assembly
US4213031A (en) * 1976-10-21 1980-07-15 Bosch-Siemens Hausgerate Gmbh Heat sealing roller having a temperature self-controlled PTC heating resistor for welding thermoplastic foils
DE3002721A1 (en) * 1979-01-26 1980-08-07 Raychem Corp Battery and method for recharging a battery
US4237441A (en) * 1978-12-01 1980-12-02 Raychem Corporation Low resistivity PTC compositions
US4250631A (en) * 1979-01-24 1981-02-17 Leonard Moses Tobacco-pipe holder and dryer
EP0038715A1 (en) 1980-04-21 1981-10-28 RAYCHEM CORPORATION (a Delaware corporation) Circuit protection devices
US4315237A (en) * 1978-12-01 1982-02-09 Raychem Corporation PTC Devices comprising oxygen barrier layers
US4318220A (en) * 1979-04-19 1982-03-09 Raychem Corporation Process for recovering heat recoverable sheet material
US4329726A (en) * 1978-12-01 1982-05-11 Raychem Corporation Circuit protection devices comprising PTC elements
US4330704A (en) * 1980-08-08 1982-05-18 Raychem Corporation Electrical devices comprising conductive polymers
US4331861A (en) * 1979-09-28 1982-05-25 Siemens Aktiengesellschaft Positive temperature coefficient (PTC) resistor heating device
US4352008A (en) * 1979-01-26 1982-09-28 Firma Fritz Eichenauer Electric heating device for heating the interior of a switch cabinet
US4352083A (en) * 1980-04-21 1982-09-28 Raychem Corporation Circuit protection devices
US4354092A (en) * 1978-10-05 1982-10-12 Matsushita Electric Industrial Co., Ltd. Electric hair curling iron with rechargeable battery power supply
US4388607A (en) * 1976-12-16 1983-06-14 Raychem Corporation Conductive polymer compositions, and to devices comprising such compositions
US4450496A (en) * 1979-08-16 1984-05-22 Raychem Corporation Protection of certain electrical systems by use of PTC device
US4475138A (en) * 1980-04-21 1984-10-02 Raychem Corporation Circuit protection devices comprising PTC element
US4560524A (en) * 1983-04-15 1985-12-24 Smuckler Jack H Method of manufacturing a positive temperature coefficient resistive heating element
US4560498A (en) * 1975-08-04 1985-12-24 Raychem Corporation Positive temperature coefficient of resistance compositions
US4574187A (en) * 1980-08-29 1986-03-04 Sprague Electric Company Self regulating PTCR heater
US4629869A (en) * 1982-11-12 1986-12-16 Bronnvall Wolfgang A Self-limiting heater and resistance material
US4650972A (en) * 1985-10-04 1987-03-17 Emerson Electric Co. Heating cable and method of making same
US4668857A (en) * 1985-08-16 1987-05-26 Belton Corporation Temperature self-regulating resistive heating element
US4698179A (en) * 1983-08-31 1987-10-06 Taiho Kogyo Co., Ltd. Electric conductive and sliding resin material
EP0250776A1 (en) 1983-06-30 1988-01-07 RAYCHEM CORPORATION (a Delaware corporation) Method for detecting and obtaining information about changes in variables
US4764664A (en) * 1976-12-13 1988-08-16 Raychem Corporation Electrical devices comprising conductive polymer compositions
US4775500A (en) * 1984-11-19 1988-10-04 Matsushita Electric Industrial Co., Ltd. Electrically conductive polymeric composite and method of making said composite
EP0287485A1 (en) * 1987-04-15 1988-10-19 Le Carbone-Lorraine Positive temperature coefficient material
US4783587A (en) * 1984-12-18 1988-11-08 Matsushita Electric Industrial Co., Ltd. Self-regulating heating article having electrodes directly connected to a PTC layer
JPS63278396A (en) * 1987-05-11 1988-11-16 Nippon Mektron Ltd Printed circuit board with circuit protecting function
US4794229A (en) * 1987-04-24 1988-12-27 Thermon Manufacturing Company Flexible, elongated thermistor heating cable
US4845838A (en) * 1981-04-02 1989-07-11 Raychem Corporation Method of making a PTC conductive polymer electrical device
US4866253A (en) * 1976-12-13 1989-09-12 Raychem Corporation Electrical devices comprising conductive polymer compositions
US4876440A (en) * 1976-12-13 1989-10-24 Raychem Corporation Electrical devices comprising conductive polymer compositions
US4889975A (en) * 1988-03-16 1989-12-26 The Fluorocarbon Company Self-regulating heater having a heat tape that stops tracking
US4907340A (en) * 1987-09-30 1990-03-13 Raychem Corporation Electrical device comprising conductive polymers
US4922083A (en) * 1988-04-22 1990-05-01 Thermon Manufacturing Company Flexible, elongated positive temperature coefficient heating assembly and method
US4924074A (en) * 1987-09-30 1990-05-08 Raychem Corporation Electrical device comprising conductive polymers
US4937435A (en) * 1987-12-14 1990-06-26 Thermon Manufacturing Company Flexible electric heating pad using PTC ceramic thermistor chip heating elements
US4951382A (en) * 1981-04-02 1990-08-28 Raychem Corporation Method of making a PTC conductive polymer electrical device
US4951384A (en) * 1981-04-02 1990-08-28 Raychem Corporation Method of making a PTC conductive polymer electrical device
US4954695A (en) * 1972-09-08 1990-09-04 Raychem Corporation Self-limiting conductive extrudates and methods therefor
US4955267A (en) * 1981-04-02 1990-09-11 Raychem Corporation Method of making a PTC conductive polymer electrical device
EP0388990A2 (en) 1986-02-20 1990-09-26 RAYCHEM CORPORATION (a Delaware corporation) Method and articles employing ion exchange material
US5057673A (en) * 1988-05-19 1991-10-15 Fluorocarbon Company Self-current-limiting devices and method of making same
US5140297A (en) * 1981-04-02 1992-08-18 Raychem Corporation PTC conductive polymer compositions
US5166658A (en) * 1987-09-30 1992-11-24 Raychem Corporation Electrical device comprising conductive polymers
US5174924A (en) * 1990-06-04 1992-12-29 Fujikura Ltd. Ptc conductive polymer composition containing carbon black having large particle size and high dbp absorption
US5185594A (en) * 1991-05-20 1993-02-09 Furon Company Temperature sensing cable device and method of making same
US5195013A (en) * 1981-04-02 1993-03-16 Raychem Corporation PTC conductive polymer compositions
US5227946A (en) * 1981-04-02 1993-07-13 Raychem Corporation Electrical device comprising a PTC conductive polymer
US5474746A (en) * 1991-09-09 1995-12-12 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Catalyst carrier body for exhaust systems of internal combustion engines
US5537286A (en) * 1991-06-27 1996-07-16 Raychem S.A. Method of preparing planar PTC circuit protection devices
US5614881A (en) * 1995-08-11 1997-03-25 General Electric Company Current limiting device
US5644283A (en) * 1992-08-26 1997-07-01 Siemens Aktiengesellschaft Variable high-current resistor, especially for use as protective element in power switching applications & circuit making use of high-current resistor
US5663702A (en) * 1995-06-07 1997-09-02 Littelfuse, Inc. PTC electrical device having fuse link in series and metallized ceramic electrodes
US5691689A (en) * 1995-08-11 1997-11-25 Eaton Corporation Electrical circuit protection devices comprising PTC conductive liquid crystal polymer compositions
US5705555A (en) * 1991-05-04 1998-01-06 Cabot Corporation Conductive polymer compositions
US5747147A (en) * 1995-03-22 1998-05-05 Raychem Corporation Conductive polymer composition and device
US5793278A (en) * 1993-09-09 1998-08-11 Siemens Aktiengesellschaft Limiter for current limiting
US5802709A (en) * 1995-08-15 1998-09-08 Bourns, Multifuse (Hong Kong), Ltd. Method for manufacturing surface mount conductive polymer devices
US5814264A (en) * 1996-04-12 1998-09-29 Littelfuse, Inc. Continuous manufacturing methods for positive temperature coefficient materials
US5849129A (en) * 1995-08-15 1998-12-15 Bourns Multifuse (Hong Kong) Ltd. Continuous process and apparatus for manufacturing conductive polymer components
US5864280A (en) * 1995-09-29 1999-01-26 Littlefuse, Inc. Electrical circuits with improved overcurrent protection
DE19754976A1 (en) * 1997-12-11 1999-06-17 Abb Research Ltd protection element
US5929744A (en) * 1997-02-18 1999-07-27 General Electric Company Current limiting device with at least one flexible electrode
US5940958A (en) * 1995-05-10 1999-08-24 Littlefuse, Inc. Method of manufacturing a PTC circuit protection device
US5977861A (en) * 1997-03-05 1999-11-02 General Electric Company Current limiting device with grooved electrode structure
US5982271A (en) * 1996-11-28 1999-11-09 Tdk Corporation Organic positive temperature coefficient thermistor
US6020808A (en) * 1997-09-03 2000-02-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficent device
US6023403A (en) * 1996-05-03 2000-02-08 Littlefuse, Inc. Surface mountable electrical device comprising a PTC and fusible element
US6090314A (en) * 1998-06-18 2000-07-18 Tdk Corporation Organic positive temperature coefficient thermistor
US6124780A (en) * 1998-05-20 2000-09-26 General Electric Company Current limiting device and materials for a current limiting device
US6128168A (en) * 1998-01-14 2000-10-03 General Electric Company Circuit breaker with improved arc interruption function
US6133820A (en) * 1998-08-12 2000-10-17 General Electric Company Current limiting device having a web structure
US6144540A (en) * 1999-03-09 2000-11-07 General Electric Company Current suppressing circuit breaker unit for inductive motor protection
US6157286A (en) * 1999-04-05 2000-12-05 General Electric Company High voltage current limiting device
EP1058277A1 (en) * 1999-06-02 2000-12-06 TDK Corporation Organic positive temperature coefficient thermistor
US6172591B1 (en) 1998-03-05 2001-01-09 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6191681B1 (en) 1997-07-21 2001-02-20 General Electric Company Current limiting device with electrically conductive composite and method of manufacturing the electrically conductive composite
US6228287B1 (en) 1998-09-25 2001-05-08 Bourns, Inc. Two-step process for preparing positive temperature coefficient polymer materials
US6236302B1 (en) 1998-03-05 2001-05-22 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6242997B1 (en) 1998-03-05 2001-06-05 Bourns, Inc. Conductive polymer device and method of manufacturing same
US6282072B1 (en) 1998-02-24 2001-08-28 Littelfuse, Inc. Electrical devices having a polymer PTC array
US6290879B1 (en) 1998-05-20 2001-09-18 General Electric Company Current limiting device and materials for a current limiting device
US6323751B1 (en) 1999-11-19 2001-11-27 General Electric Company Current limiter device with an electrically conductive composite material and method of manufacturing
US6373372B1 (en) 1997-11-24 2002-04-16 General Electric Company Current limiting device with conductive composite material and method of manufacturing the conductive composite material and the current limiting device
US6429533B1 (en) 1999-11-23 2002-08-06 Bourns Inc. Conductive polymer device and method of manufacturing same
US20020124847A1 (en) * 2000-03-21 2002-09-12 Smith Daniel John Humidified gases delivery apparatus
US6497951B1 (en) 2000-09-21 2002-12-24 Milliken & Company Temperature dependent electrically resistive yarn
US6535103B1 (en) 1997-03-04 2003-03-18 General Electric Company Current limiting arrangement and method
US6558579B2 (en) 1999-10-01 2003-05-06 Tdk Corporation Organic positive temperature coefficient thermistor and making method
US20030091829A1 (en) * 2001-11-15 2003-05-15 Tdk Corporation Organic PTC thermistor and making method
US6582647B1 (en) 1998-10-01 2003-06-24 Littelfuse, Inc. Method for heat treating PTC devices
US6628498B2 (en) 2000-08-28 2003-09-30 Steven J. Whitney Integrated electrostatic discharge and overcurrent device
US20030218851A1 (en) * 2002-04-08 2003-11-27 Harris Edwin James Voltage variable material for direct application and devices employing same
US20040201941A1 (en) * 2002-04-08 2004-10-14 Harris Edwin James Direct application voltage variable material, components thereof and devices employing same
EP1474031A2 (en) * 2002-01-22 2004-11-10 Sciogen LLC Electrosurgical instrument and method of use
US20040232387A1 (en) * 2001-08-25 2004-11-25 Do-Yun Kim Conductive polymer having positive temperature coefficient, method of controlling positive temperature coefficient property of the same and electrical device using the same
US20050057867A1 (en) * 2002-04-08 2005-03-17 Harris Edwin James Direct application voltage variable material, devices employing same and methods of manufacturing such devices
US20050203507A1 (en) * 2004-03-12 2005-09-15 Surgrx, Inc. Electrosurgical instrument and method of use
US7019613B2 (en) 2002-06-24 2006-03-28 Tdk Corporation PTC thermistor body, PTC thermistor, method of making PTC thermistor body, and method of making PTC thermistor
US20060069388A1 (en) * 2002-04-30 2006-03-30 Csaba Truckai Electrosurgical instrument and method
US20060089448A1 (en) * 2004-10-27 2006-04-27 Wang Shau C Over-current protection device
US20060097231A1 (en) * 2003-03-25 2006-05-11 Tdk Corporation Organic positive temperature coefficient thermistor
US20060114097A1 (en) * 2004-11-29 2006-06-01 Jared Starling PTC circuit protector having parallel areas of effective resistance
US20060231807A1 (en) * 2002-05-29 2006-10-19 Tdk Corporation PTC composition, method of making the same, and thermistor body obtained therefrom
US20070146113A1 (en) * 2004-04-19 2007-06-28 Surgrx, Inc. Surgical sealing surfaces and methods of use
US20080045942A1 (en) * 2001-10-22 2008-02-21 Surgrx, Inc. Electrosurgical instrument and method of use
US20090027821A1 (en) * 2007-07-26 2009-01-29 Littelfuse, Inc. Integrated thermistor and metallic element device and method
US8550072B2 (en) 2000-03-21 2013-10-08 Fisher & Paykel Healthcare Limited Apparatus for delivering humidified gases

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3858144A (en) * 1972-12-29 1974-12-31 Raychem Corp Voltage stress-resistant conductive articles
US4103274A (en) * 1976-09-13 1978-07-25 General Electric Company Reconstituted metal oxide varistor
DE2816872A1 (en) * 1978-04-18 1979-10-31 Wacker Chemie Gmbh A process for the manufacture of electrically conductive organopolysiloxane elastomers
CA2004760C (en) * 1988-12-09 1998-12-01 Norio Mori Composite temperature-sensitive element and face heat generator comprising the same
DE4427161A1 (en) * 1994-08-01 1996-02-08 Abb Research Ltd A process for producing a PTC resistor, and thereafter produced resistance

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2273704A (en) * 1935-10-10 1942-02-17 Bell Telephone Labor Inc Electrical conducting material
US2443073A (en) * 1944-03-17 1948-06-08 Lewis Eng Co Temperature compensated electrical bridge circuit
US2588564A (en) * 1947-05-26 1952-03-11 Atomic Energy Commission Thermoelectrically balanced meter network
US2744981A (en) * 1953-06-16 1956-05-08 Morton F Spears Means for controlling current flow in electric circuits
US2774108A (en) * 1952-09-16 1956-12-18 Gulf Research Development Co Method of making low-resistance ion-exchange membranes
US2796505A (en) * 1952-12-22 1957-06-18 Philco Corp Precision voltage regulating element
US2799051A (en) * 1953-02-04 1957-07-16 Myron A Coler Method for manufacturing resistance elements
US2847391A (en) * 1955-02-24 1958-08-12 Du Pont Vapor-phase polymerization of tetrafluoroethylene in the presence of fillers
US2978665A (en) * 1956-07-11 1961-04-04 Antioch College Regulator device for electric current
US3008949A (en) * 1958-04-25 1961-11-14 Exxon Research Engineering Co Low pressure polymerization of olefins
US3055843A (en) * 1953-10-30 1962-09-25 Itt Tissue-equivalent plastic composition
US3056750A (en) * 1961-01-23 1962-10-02 Air Reduction Resin bonded electrical resistors and methods of producing the same
CA676090A (en) * 1963-12-17 Rosenthal Louis Resistance heating of plastic-metal fiber articles and articles made thereby

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA676090A (en) * 1963-12-17 Rosenthal Louis Resistance heating of plastic-metal fiber articles and articles made thereby
US2273704A (en) * 1935-10-10 1942-02-17 Bell Telephone Labor Inc Electrical conducting material
US2443073A (en) * 1944-03-17 1948-06-08 Lewis Eng Co Temperature compensated electrical bridge circuit
US2588564A (en) * 1947-05-26 1952-03-11 Atomic Energy Commission Thermoelectrically balanced meter network
US2774108A (en) * 1952-09-16 1956-12-18 Gulf Research Development Co Method of making low-resistance ion-exchange membranes
US2796505A (en) * 1952-12-22 1957-06-18 Philco Corp Precision voltage regulating element
US2799051A (en) * 1953-02-04 1957-07-16 Myron A Coler Method for manufacturing resistance elements
US2744981A (en) * 1953-06-16 1956-05-08 Morton F Spears Means for controlling current flow in electric circuits
US3055843A (en) * 1953-10-30 1962-09-25 Itt Tissue-equivalent plastic composition
US2847391A (en) * 1955-02-24 1958-08-12 Du Pont Vapor-phase polymerization of tetrafluoroethylene in the presence of fillers
US2978665A (en) * 1956-07-11 1961-04-04 Antioch College Regulator device for electric current
US3008949A (en) * 1958-04-25 1961-11-14 Exxon Research Engineering Co Low pressure polymerization of olefins
US3056750A (en) * 1961-01-23 1962-10-02 Air Reduction Resin bonded electrical resistors and methods of producing the same

Cited By (201)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3421054A (en) * 1964-05-14 1969-01-07 Consortium Elektrochem Ind Bistable boron semiconductor or switching device
US3351882A (en) * 1964-10-09 1967-11-07 Polyelectric Corp Plastic resistance elements and methods for making same
US3878357A (en) * 1965-02-25 1975-04-15 Texas Instruments Inc Component oven
US3414704A (en) * 1965-02-25 1968-12-03 Texas Instruments Inc Self-regulating heating device
US3413442A (en) * 1965-07-15 1968-11-26 Texas Instruments Inc Self-regulating thermal apparatus
US3501619A (en) * 1965-07-15 1970-03-17 Texas Instruments Inc Self-regulating thermal apparatus
US3414705A (en) * 1965-10-24 1968-12-03 Texas Instruments Inc Component oven
US3359521A (en) * 1965-10-26 1967-12-19 Cognitronics Corp Bistable resistance memory device
US3489976A (en) * 1966-01-03 1970-01-13 Texas Instruments Inc Self-protected time delay relay
US3434089A (en) * 1966-01-03 1969-03-18 Texas Instruments Inc Relay with voltage compensation
US3412358A (en) * 1966-09-09 1968-11-19 Gulton Ind Inc Self-regulating heating element
US3489884A (en) * 1966-12-28 1970-01-13 Texas Instruments Inc Heated windshield wiper and blade therefor
US3439306A (en) * 1967-06-05 1969-04-15 Sylvania Electric Prod Self-supporting resistance film
US3646315A (en) * 1967-12-20 1972-02-29 Texas Instruments Inc Self-regulated heating device
US3500634A (en) * 1968-01-02 1970-03-17 Texas Instruments Inc Control system and actuator used therein
US3582968A (en) * 1968-12-23 1971-06-01 Texas Instruments Inc Heaters and methods of making same
US3571777A (en) * 1969-07-07 1971-03-23 Cabot Corp Thermally responsive current regulating devices
US3662149A (en) * 1969-09-16 1972-05-09 Braun Pebra Gmbh Heated lock for motorcars
US3696611A (en) * 1969-09-17 1972-10-10 Scovill Manufacturing Co Thermal motors
US3753198A (en) * 1969-09-19 1973-08-14 Denki Onkyo Co Ltd Varistors
US3619560A (en) * 1969-12-05 1971-11-09 Texas Instruments Inc Self-regulating thermal apparatus and method
US3976600A (en) * 1970-01-27 1976-08-24 Texas Instruments Incorporated Process for making conductive polymers
US3617695A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3632971A (en) * 1970-01-27 1972-01-04 Texas Instruments Inc Self-limiting electric hair curler heater
US3617694A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3760495A (en) * 1970-01-27 1973-09-25 Texas Instruments Inc Process for making conductive polymers
US3584190A (en) * 1970-02-27 1971-06-08 Texas Instruments Inc Self-regulating heat applicator
US3648002A (en) * 1970-05-04 1972-03-07 Essex International Inc Current control apparatus and methods of manufacture
US3689736A (en) * 1971-01-25 1972-09-05 Texas Instruments Inc Electrically heated device employing conductive-crystalline polymers
US4000647A (en) * 1971-07-31 1977-01-04 Dornier Gmbh Heating device for flow sondes
US3735417A (en) * 1971-10-26 1973-05-22 Honeywell Inc Temperature regulating heat-recording stylus
US3748439A (en) * 1971-12-27 1973-07-24 Texas Instruments Inc Heating apparatus
US3947658A (en) * 1972-02-22 1976-03-30 Kureha Kagaku Kogyo Kabushiki Kaisha Protector for the plate-shaped heating element
US3787718A (en) * 1972-08-08 1974-01-22 Sondell Res Deve Co Spherical electronic components
DE2345320A1 (en) * 1972-09-08 1974-04-04 Raychem Corp A process for producing self-regulating, electrically conductive products
DE2345303A1 (en) * 1972-09-08 1974-04-18 Raychem Corp A process for the production of electrical widerstandskoerpern with positive, non-linear resistance coefficient
US4954695A (en) * 1972-09-08 1990-09-04 Raychem Corporation Self-limiting conductive extrudates and methods therefor
US3973100A (en) * 1972-12-27 1976-08-03 Texas Instruments Incorporated Self-limiting electric hair curler heater
US4085286A (en) * 1974-09-27 1978-04-18 Raychem Corporation Heat-recoverable sealing article with self-contained heating means and method of sealing a splice therewith
DE2543346A1 (en) * 1974-09-27 1976-04-15 Raychem Corp Polymer compositions with a positive temperature-coefficient of resistance
US3943375A (en) * 1974-12-23 1976-03-09 Gte Sylvania Incorporated On-off switch with time delay
US4560498A (en) * 1975-08-04 1985-12-24 Raychem Corporation Positive temperature coefficient of resistance compositions
US4118334A (en) * 1975-09-18 1978-10-03 Gte Laboratories Incorporated Primary electrochemical cell
US4088269A (en) * 1975-11-06 1978-05-09 Vdo Adolf Schindling Ag Electrically heated windshield washer spray nozzle assembly
US4149066A (en) * 1975-11-20 1979-04-10 Akitoshi Niibe Temperature controlled flexible electric heating panel
JPS52101737A (en) * 1976-02-20 1977-08-26 Matsushita Electric Ind Co Ltd Heating body
US4213031A (en) * 1976-10-21 1980-07-15 Bosch-Siemens Hausgerate Gmbh Heat sealing roller having a temperature self-controlled PTC heating resistor for welding thermoplastic foils
US4101862A (en) * 1976-11-19 1978-07-18 K.K. Tokai Rika Denki Seisakusho Current limiting element for preventing electrical overcurrent
US4876440A (en) * 1976-12-13 1989-10-24 Raychem Corporation Electrical devices comprising conductive polymer compositions
US4764664A (en) * 1976-12-13 1988-08-16 Raychem Corporation Electrical devices comprising conductive polymer compositions
US4866253A (en) * 1976-12-13 1989-09-12 Raychem Corporation Electrical devices comprising conductive polymer compositions
US4388607A (en) * 1976-12-16 1983-06-14 Raychem Corporation Conductive polymer compositions, and to devices comprising such compositions
US4212425A (en) * 1978-02-27 1980-07-15 Vdo Adolf Schindling Ag. Electrically heated windshield washer spray nozzle assembly
US4354092A (en) * 1978-10-05 1982-10-12 Matsushita Electric Industrial Co., Ltd. Electric hair curling iron with rechargeable battery power supply
DE2948281A1 (en) * 1978-12-01 1980-06-19 Raychem Corp Electrical circuitry and circuit-protection device
US4329726A (en) * 1978-12-01 1982-05-11 Raychem Corporation Circuit protection devices comprising PTC elements
US4315237A (en) * 1978-12-01 1982-02-09 Raychem Corporation PTC Devices comprising oxygen barrier layers
US4238812A (en) * 1978-12-01 1980-12-09 Raychem Corporation Circuit protection devices comprising PTC elements
US4237441A (en) * 1978-12-01 1980-12-02 Raychem Corporation Low resistivity PTC compositions
US4250631A (en) * 1979-01-24 1981-02-17 Leonard Moses Tobacco-pipe holder and dryer
JPH0613068A (en) * 1979-01-26 1994-01-21 Raychem Corp Battery
JP2574979B2 (en) 1979-01-26 1997-01-22 レイケム・コーポレイション battery
US4352008A (en) * 1979-01-26 1982-09-28 Firma Fritz Eichenauer Electric heating device for heating the interior of a switch cabinet
DE3002721A1 (en) * 1979-01-26 1980-08-07 Raychem Corp Battery and method for recharging a battery
US4255698A (en) * 1979-01-26 1981-03-10 Raychem Corporation Protection of batteries
US4318220A (en) * 1979-04-19 1982-03-09 Raychem Corporation Process for recovering heat recoverable sheet material
US4450496A (en) * 1979-08-16 1984-05-22 Raychem Corporation Protection of certain electrical systems by use of PTC device
US4331861A (en) * 1979-09-28 1982-05-25 Siemens Aktiengesellschaft Positive temperature coefficient (PTC) resistor heating device
US4475138A (en) * 1980-04-21 1984-10-02 Raychem Corporation Circuit protection devices comprising PTC element
US4413301A (en) * 1980-04-21 1983-11-01 Raychem Corporation Circuit protection devices comprising PTC element
US4352083A (en) * 1980-04-21 1982-09-28 Raychem Corporation Circuit protection devices
EP0038715A1 (en) 1980-04-21 1981-10-28 RAYCHEM CORPORATION (a Delaware corporation) Circuit protection devices
US4330704A (en) * 1980-08-08 1982-05-18 Raychem Corporation Electrical devices comprising conductive polymers
US4574187A (en) * 1980-08-29 1986-03-04 Sprague Electric Company Self regulating PTCR heater
US5140297A (en) * 1981-04-02 1992-08-18 Raychem Corporation PTC conductive polymer compositions
US4951384A (en) * 1981-04-02 1990-08-28 Raychem Corporation Method of making a PTC conductive polymer electrical device
US5227946A (en) * 1981-04-02 1993-07-13 Raychem Corporation Electrical device comprising a PTC conductive polymer
US5195013A (en) * 1981-04-02 1993-03-16 Raychem Corporation PTC conductive polymer compositions
US4845838A (en) * 1981-04-02 1989-07-11 Raychem Corporation Method of making a PTC conductive polymer electrical device
US4955267A (en) * 1981-04-02 1990-09-11 Raychem Corporation Method of making a PTC conductive polymer electrical device
US4951382A (en) * 1981-04-02 1990-08-28 Raychem Corporation Method of making a PTC conductive polymer electrical device
EP0140893B1 (en) * 1982-11-12 1988-10-26 BRONNVALL, Wolfgang Self-limiting heater and resistance material
US4629869A (en) * 1982-11-12 1986-12-16 Bronnvall Wolfgang A Self-limiting heater and resistance material
US4560524A (en) * 1983-04-15 1985-12-24 Smuckler Jack H Method of manufacturing a positive temperature coefficient resistive heating element
EP0250776A1 (en) 1983-06-30 1988-01-07 RAYCHEM CORPORATION (a Delaware corporation) Method for detecting and obtaining information about changes in variables
US4830777A (en) * 1983-08-31 1989-05-16 Taiho Kogyo Co., Ltd. Electric conductive and sliding resin material
US4698179A (en) * 1983-08-31 1987-10-06 Taiho Kogyo Co., Ltd. Electric conductive and sliding resin material
US4775500A (en) * 1984-11-19 1988-10-04 Matsushita Electric Industrial Co., Ltd. Electrically conductive polymeric composite and method of making said composite
US4783587A (en) * 1984-12-18 1988-11-08 Matsushita Electric Industrial Co., Ltd. Self-regulating heating article having electrodes directly connected to a PTC layer
US4668857A (en) * 1985-08-16 1987-05-26 Belton Corporation Temperature self-regulating resistive heating element
US4650972A (en) * 1985-10-04 1987-03-17 Emerson Electric Co. Heating cable and method of making same
EP0388990A2 (en) 1986-02-20 1990-09-26 RAYCHEM CORPORATION (a Delaware corporation) Method and articles employing ion exchange material
EP0287485A1 (en) * 1987-04-15 1988-10-19 Le Carbone-Lorraine Positive temperature coefficient material
FR2614130A1 (en) * 1987-04-15 1988-10-21 Lorraine Carbone Material having a resistivity at positive temperature coefficient
US4794229A (en) * 1987-04-24 1988-12-27 Thermon Manufacturing Company Flexible, elongated thermistor heating cable
JPS63278396A (en) * 1987-05-11 1988-11-16 Nippon Mektron Ltd Printed circuit board with circuit protecting function
US5166658A (en) * 1987-09-30 1992-11-24 Raychem Corporation Electrical device comprising conductive polymers
US4907340A (en) * 1987-09-30 1990-03-13 Raychem Corporation Electrical device comprising conductive polymers
US4924074A (en) * 1987-09-30 1990-05-08 Raychem Corporation Electrical device comprising conductive polymers
US4937435A (en) * 1987-12-14 1990-06-26 Thermon Manufacturing Company Flexible electric heating pad using PTC ceramic thermistor chip heating elements
US4889975A (en) * 1988-03-16 1989-12-26 The Fluorocarbon Company Self-regulating heater having a heat tape that stops tracking
US4922083A (en) * 1988-04-22 1990-05-01 Thermon Manufacturing Company Flexible, elongated positive temperature coefficient heating assembly and method
US5057673A (en) * 1988-05-19 1991-10-15 Fluorocarbon Company Self-current-limiting devices and method of making same
US5174924A (en) * 1990-06-04 1992-12-29 Fujikura Ltd. Ptc conductive polymer composition containing carbon black having large particle size and high dbp absorption
US5705555A (en) * 1991-05-04 1998-01-06 Cabot Corporation Conductive polymer compositions
US5313185A (en) * 1991-05-20 1994-05-17 Furon Company Temperature sensing cable device and method of making same
US5185594A (en) * 1991-05-20 1993-02-09 Furon Company Temperature sensing cable device and method of making same
US5537286A (en) * 1991-06-27 1996-07-16 Raychem S.A. Method of preparing planar PTC circuit protection devices
US5474746A (en) * 1991-09-09 1995-12-12 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Catalyst carrier body for exhaust systems of internal combustion engines
US5644283A (en) * 1992-08-26 1997-07-01 Siemens Aktiengesellschaft Variable high-current resistor, especially for use as protective element in power switching applications & circuit making use of high-current resistor
US5793278A (en) * 1993-09-09 1998-08-11 Siemens Aktiengesellschaft Limiter for current limiting
US5985976A (en) * 1995-03-22 1999-11-16 Raychem Corporation Method of making a conductive polymer composition
US5747147A (en) * 1995-03-22 1998-05-05 Raychem Corporation Conductive polymer composition and device
US5940958A (en) * 1995-05-10 1999-08-24 Littlefuse, Inc. Method of manufacturing a PTC circuit protection device
US5955936A (en) * 1995-05-10 1999-09-21 Littlefuse, Inc. PTC circuit protection device and manufacturing process for same
US5663702A (en) * 1995-06-07 1997-09-02 Littelfuse, Inc. PTC electrical device having fuse link in series and metallized ceramic electrodes
US5691689A (en) * 1995-08-11 1997-11-25 Eaton Corporation Electrical circuit protection devices comprising PTC conductive liquid crystal polymer compositions
US5614881A (en) * 1995-08-11 1997-03-25 General Electric Company Current limiting device
US5802709A (en) * 1995-08-15 1998-09-08 Bourns, Multifuse (Hong Kong), Ltd. Method for manufacturing surface mount conductive polymer devices
US5849129A (en) * 1995-08-15 1998-12-15 Bourns Multifuse (Hong Kong) Ltd. Continuous process and apparatus for manufacturing conductive polymer components
US5849137A (en) * 1995-08-15 1998-12-15 Bourns Multifuse (Hong Kong) Ltd. Continuous process and apparatus for manufacturing conductive polymer components
US5880668A (en) * 1995-09-29 1999-03-09 Littelfuse, Inc. Electrical devices having improved PTC polymeric compositions
US6059997A (en) * 1995-09-29 2000-05-09 Littlelfuse, Inc. Polymeric PTC compositions
US5864280A (en) * 1995-09-29 1999-01-26 Littlefuse, Inc. Electrical circuits with improved overcurrent protection
US5814264A (en) * 1996-04-12 1998-09-29 Littelfuse, Inc. Continuous manufacturing methods for positive temperature coefficient materials
US6023403A (en) * 1996-05-03 2000-02-08 Littlefuse, Inc. Surface mountable electrical device comprising a PTC and fusible element
US5982271A (en) * 1996-11-28 1999-11-09 Tdk Corporation Organic positive temperature coefficient thermistor
US5929744A (en) * 1997-02-18 1999-07-27 General Electric Company Current limiting device with at least one flexible electrode
US6535103B1 (en) 1997-03-04 2003-03-18 General Electric Company Current limiting arrangement and method
US5977861A (en) * 1997-03-05 1999-11-02 General Electric Company Current limiting device with grooved electrode structure
US6191681B1 (en) 1997-07-21 2001-02-20 General Electric Company Current limiting device with electrically conductive composite and method of manufacturing the electrically conductive composite
US6020808A (en) * 1997-09-03 2000-02-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficent device
US6223423B1 (en) 1997-09-03 2001-05-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficient device
US6373372B1 (en) 1997-11-24 2002-04-16 General Electric Company Current limiting device with conductive composite material and method of manufacturing the conductive composite material and the current limiting device
US6540944B2 (en) 1997-11-24 2003-04-01 General Electric Company Current limiting device with conductive composite material and method of manufacturing the conductive composite material and the current limiting device
DE19754976A1 (en) * 1997-12-11 1999-06-17 Abb Research Ltd protection element
US6396383B1 (en) 1997-12-11 2002-05-28 Abb Research Ltd. Protective element
US6128168A (en) * 1998-01-14 2000-10-03 General Electric Company Circuit breaker with improved arc interruption function
US6282072B1 (en) 1998-02-24 2001-08-28 Littelfuse, Inc. Electrical devices having a polymer PTC array
US6172591B1 (en) 1998-03-05 2001-01-09 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6236302B1 (en) 1998-03-05 2001-05-22 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6242997B1 (en) 1998-03-05 2001-06-05 Bourns, Inc. Conductive polymer device and method of manufacturing same
US6124780A (en) * 1998-05-20 2000-09-26 General Electric Company Current limiting device and materials for a current limiting device
US6290879B1 (en) 1998-05-20 2001-09-18 General Electric Company Current limiting device and materials for a current limiting device
US6366193B2 (en) 1998-05-20 2002-04-02 General Electric Company Current limiting device and materials for a current limiting device
US6090314A (en) * 1998-06-18 2000-07-18 Tdk Corporation Organic positive temperature coefficient thermistor
US6133820A (en) * 1998-08-12 2000-10-17 General Electric Company Current limiting device having a web structure
US6228287B1 (en) 1998-09-25 2001-05-08 Bourns, Inc. Two-step process for preparing positive temperature coefficient polymer materials
US6582647B1 (en) 1998-10-01 2003-06-24 Littelfuse, Inc. Method for heat treating PTC devices
US6144540A (en) * 1999-03-09 2000-11-07 General Electric Company Current suppressing circuit breaker unit for inductive motor protection
US6157286A (en) * 1999-04-05 2000-12-05 General Electric Company High voltage current limiting device
EP1058277A1 (en) * 1999-06-02 2000-12-06 TDK Corporation Organic positive temperature coefficient thermistor
US6558579B2 (en) 1999-10-01 2003-05-06 Tdk Corporation Organic positive temperature coefficient thermistor and making method
US6711807B2 (en) 1999-11-19 2004-03-30 General Electric Company Method of manufacturing composite array structure
US6323751B1 (en) 1999-11-19 2001-11-27 General Electric Company Current limiter device with an electrically conductive composite material and method of manufacturing
US6429533B1 (en) 1999-11-23 2002-08-06 Bourns Inc. Conductive polymer device and method of manufacturing same
US8550072B2 (en) 2000-03-21 2013-10-08 Fisher & Paykel Healthcare Limited Apparatus for delivering humidified gases
US20020124847A1 (en) * 2000-03-21 2002-09-12 Smith Daniel John Humidified gases delivery apparatus
US7588029B2 (en) 2000-03-21 2009-09-15 Fisher & Paykel Healthcare Limited Humidified gases delivery apparatus
US20040149284A1 (en) * 2000-03-21 2004-08-05 Fisher & Paykel Healthcare Limited Humidified gases delivery apparatus
US6628498B2 (en) 2000-08-28 2003-09-30 Steven J. Whitney Integrated electrostatic discharge and overcurrent device
US20030207107A1 (en) * 2000-09-21 2003-11-06 Deangelis Alfred R. Temperature dependent electrically resistive yarn
US6680117B2 (en) 2000-09-21 2004-01-20 Milliken & Company Temperature dependent electrically resistive yarn
US20030124349A1 (en) * 2000-09-21 2003-07-03 Deangelis Alfred R. Temperature dependent electrically resistive yarn
US6855421B2 (en) 2000-09-21 2005-02-15 Milliken & Company Temperature dependent electrically resistive yarn
US6497951B1 (en) 2000-09-21 2002-12-24 Milliken & Company Temperature dependent electrically resistive yarn
US20040232387A1 (en) * 2001-08-25 2004-11-25 Do-Yun Kim Conductive polymer having positive temperature coefficient, method of controlling positive temperature coefficient property of the same and electrical device using the same
US7041238B2 (en) 2001-08-25 2006-05-09 Lg Cable Ltd. Conductive polymer having positive temperature coefficient, method of controlling positive temperature coefficient property of the same and electrical device using the same
US20080045942A1 (en) * 2001-10-22 2008-02-21 Surgrx, Inc. Electrosurgical instrument and method of use
US9149326B2 (en) 2001-10-22 2015-10-06 Ethicon Endo-Surgery, Inc. Electrosurgical instrument and method
US6778062B2 (en) 2001-11-15 2004-08-17 Tdk Corporation Organic PTC thermistor and making method
US20030091829A1 (en) * 2001-11-15 2003-05-15 Tdk Corporation Organic PTC thermistor and making method
EP1474031A2 (en) * 2002-01-22 2004-11-10 Sciogen LLC Electrosurgical instrument and method of use
EP1474031A4 (en) * 2002-01-22 2007-09-05 Sciogen Llc Electrosurgical instrument and method of use
EP2298152A1 (en) * 2002-01-22 2011-03-23 Sciogen LLC Electrosurgical instrument and method of use
EP2298153A1 (en) * 2002-01-22 2011-03-23 Sciogen LLC Electrosurgical instrument and method of use
US20070146941A1 (en) * 2002-04-08 2007-06-28 Littelfuse, Inc. Flexible circuit having overvoltage protection
US7609141B2 (en) 2002-04-08 2009-10-27 Littelfuse, Inc. Flexible circuit having overvoltage protection
US20070139848A1 (en) * 2002-04-08 2007-06-21 Littelfuse, Inc. Direct application voltage variable material
US20030218851A1 (en) * 2002-04-08 2003-11-27 Harris Edwin James Voltage variable material for direct application and devices employing same
US7132922B2 (en) 2002-04-08 2006-11-07 Littelfuse, Inc. Direct application voltage variable material, components thereof and devices employing same
US20050057867A1 (en) * 2002-04-08 2005-03-17 Harris Edwin James Direct application voltage variable material, devices employing same and methods of manufacturing such devices
US7183891B2 (en) 2002-04-08 2007-02-27 Littelfuse, Inc. Direct application voltage variable material, devices employing same and methods of manufacturing such devices
US7202770B2 (en) 2002-04-08 2007-04-10 Littelfuse, Inc. Voltage variable material for direct application and devices employing same
US20040201941A1 (en) * 2002-04-08 2004-10-14 Harris Edwin James Direct application voltage variable material, components thereof and devices employing same
US7843308B2 (en) 2002-04-08 2010-11-30 Littlefuse, Inc. Direct application voltage variable material
US20060069388A1 (en) * 2002-04-30 2006-03-30 Csaba Truckai Electrosurgical instrument and method
US8075558B2 (en) 2002-04-30 2011-12-13 Surgrx, Inc. Electrosurgical instrument and method
US20060231807A1 (en) * 2002-05-29 2006-10-19 Tdk Corporation PTC composition, method of making the same, and thermistor body obtained therefrom
EP1752993A2 (en) 2002-06-24 2007-02-14 TDK Corporation PTC thermistor body and PTC thermistor
US7019613B2 (en) 2002-06-24 2006-03-28 Tdk Corporation PTC thermistor body, PTC thermistor, method of making PTC thermistor body, and method of making PTC thermistor
US7314583B2 (en) 2003-03-25 2008-01-01 Tdk Corporation Organic positive temperature coefficient thermistor device
US20060097231A1 (en) * 2003-03-25 2006-05-11 Tdk Corporation Organic positive temperature coefficient thermistor
US7955331B2 (en) 2004-03-12 2011-06-07 Ethicon Endo-Surgery, Inc. Electrosurgical instrument and method of use
US20050203507A1 (en) * 2004-03-12 2005-09-15 Surgrx, Inc. Electrosurgical instrument and method of use
US8075555B2 (en) 2004-04-19 2011-12-13 Surgrx, Inc. Surgical sealing surfaces and methods of use
US20070146113A1 (en) * 2004-04-19 2007-06-28 Surgrx, Inc. Surgical sealing surfaces and methods of use
US20060089448A1 (en) * 2004-10-27 2006-04-27 Wang Shau C Over-current protection device
US20060114097A1 (en) * 2004-11-29 2006-06-01 Jared Starling PTC circuit protector having parallel areas of effective resistance
US7119655B2 (en) 2004-11-29 2006-10-10 Therm-O-Disc, Incorporated PTC circuit protector having parallel areas of effective resistance
US20090027821A1 (en) * 2007-07-26 2009-01-29 Littelfuse, Inc. Integrated thermistor and metallic element device and method

Also Published As

Publication number Publication date Type
DE1490164A1 (en) 1969-01-09 application
FR1397126A (en) 1965-04-30 grant

Similar Documents

Publication Publication Date Title
US3564199A (en) Self-regulating electric fluid-sump heater
US3221145A (en) Laminated heating sheet
US3225820A (en) Device for controlling temperature by heat conduction
US3581062A (en) Electronic thermostat
US3500634A (en) Control system and actuator used therein
Sterrett et al. Effect of pressure on the melting of iron
US4761541A (en) Devices comprising conductive polymer compositions
US5841204A (en) Temperature control system and method
US3727029A (en) Composite electrically heated tubing product
US6074576A (en) Conductive polymer materials for high voltage PTC devices
US3187164A (en) Device for the protection of electrical apparatus
US3277419A (en) Laminated heating unit
US2403803A (en) Electric blanket
US3381113A (en) Heat storage apparatus
US5641421A (en) Amorphous metallic alloy electrical heater systems
Bundy Phase Diagram of Bismuth to 130 000 kg/cm 2, 500° C
US4394564A (en) Solid plate heating unit
US4857880A (en) Electrical devices comprising cross-linked conductive polymers
US3947656A (en) Temperature controlled cartridge heater
US5582770A (en) Conductive polymer composition
US4668857A (en) Temperature self-regulating resistive heating element
US3794950A (en) Overcurrent protection system and sensor used therewith
US4841127A (en) Dual temperature hair curler utilizing a pair of PTC heaters
US4045763A (en) Sealed thermostatic heater
US4314231A (en) Conductive polymer electrical devices