An over-current protection device comprises first and second electrode layers and a PTC material layer laminated therebetween. The PTC material layer comprises a polymer matrix and carbon black. The polymer matrix comprises a fluoropolymer having a melting point higher than 150° C. The carbon black is dispersed in the polymer matrix. A resistance jump R.sub.jump_1000@16V/50A of the over-current protection device at 16V/50 A by 1000 cycles is 0.80-1.20. A resistance jump R.sub.jump_1000@25V/50A of the over-current protection device at 25V/50 A by 1000 cycles is 0.90-1.30.

A composite circuit protection device includes: a first positive temperature coefficient (PTC) component; a first voltage-dependent resistor (VOR); a second VOR; and a plurality of conductive leads that correspondingly connect to the first PTC component, the first VOR and the second VOR. The second VOR and the first PTC component are electrically connected in series, the first VOR and the second VOR are electrically connected in parallel, the first PTC component and the first VOR are electrically connected in parallel, and the first VOR has a varistor voltage greater than that of the second VOR as determined at 1 mA.

A composite circuit protection device includes: a first positive temperature coefficient (PTC) component; a first voltage-dependent resistor (VOR); a second VOR; and a plurality of conductive leads that correspondingly connect to the first PTC component, the first VOR and the second VOR. The second VOR and the first PTC component are electrically connected in series, the first VOR and the second VOR are electrically connected in parallel, the first PTC component and the first VOR are electrically connected in parallel, and the first VOR has a varistor voltage greater than that of the second VOR as determined at 1 mA.

A heater cable produces a substantially level voltage across its cross-section, providing a uniform and controllable thermal output along its length. The heater cable includes at least one center bus wire extending axially along a central axis of the heater cable, and at least one radial bus wire extending axially through the heating cable and positioned adjacent to the center bus wire. The heater cable further includes a thermally and electrically conductive interstitial material disposed around the at least one center bus wire and the at least one radial bus wire, and a jacket disposed about the interstitial material, the at least one center bus wire, and the at least one radial bus wire.

A co-continuous mouldable polymeric composite with PTC effect has a matrix that comprises at least two immiscible polymers (HDPE, POM), and an electrically conductive filler (CB) in the matrix. At least one of said immiscible polymers is high-density polyethylene (HDPE), and at least one other of said immiscible polymers is polyoxymethylene (POM).

An over-current protection device comprises first and second electrode layers and a PTC material layer laminated therebetween. The PTC material layer comprises a polymer matrix, a conductive ceramic filler, a carbon-containing conductive filler, and an inner filler. The polymer matrix comprises a fluoropolymer having a melting point higher than 150° C. The inner filler is selected from one of aluminum nitride, silicon carbide, zirconium oxide, boron nitride, graphene, aluminum oxide, or any mixtures thereof, and comprises 2-10% by volume of the PTC material layer. The over-current protection device is able to mitigate negative temperature coefficient (NTC) behavior after trip of device, and achieves high hold current and high endurable power.

An over-current protection device comprises first and second electrode layers and a PTC material layer laminated therebetween. The PTC material layer comprises a polymer matrix, a conductive ceramic filler, a carbon-containing conductive filler, and an inner filler. The polymer matrix comprises a fluoropolymer having a melting point higher than 150° C. The inner filler is selected from one of aluminum nitride, silicon carbide, zirconium oxide, boron nitride, graphene, aluminum oxide, or any mixtures thereof, and comprises 2-10% by volume of the PTC material layer. The over-current protection device is able to mitigate negative temperature coefficient (NTC) behavior after trip of device, and achieves high hold current and high endurable power.

A circuit protection device including a positive temperature coefficient (PTC) device and a backup fuse electrically connected in series with one another, the backup fuse comprising a quantity of solder disposed on a dielectric chip and having a melting temperature that is higher than a trip temperature of the PTC device, wherein the a surface of the dielectric chip exhibits a de-wetting characteristic relative to the solder such that, when the solder is melted, the solder draws away from the surface to create a galvanic opening in the backup fuse.

A circuit protection device including a positive temperature coefficient (PTC) device and a backup fuse electrically connected in series with one another, the backup fuse comprising a quantity of solder disposed on a dielectric chip and having a melting temperature that is higher than a trip temperature of the PTC device, wherein the a surface of the dielectric chip exhibits a de-wetting characteristic relative to the solder such that, when the solder is melted, the solder draws away from the surface to create a galvanic opening in the backup fuse.

A polymer positive temperature coefficient (PPTC) material may include a polymer matrix, the polymer matrix defining a PPTC body; and a graphene filler component, disposed in the polymer matrix, wherein the graphene filler component comprises a plurality of graphene particles aligned along a predetermined plane of the PPTC body.