A PTC starter is provided. A first pin is electrically connected to a first electrode of a thermistor. The thermistor and an elastic element are arranged in respective mounting cavities. The elastic element is provided with a connecting piece, through which a second pin is electrically connected to or disconnected from a second electrode of the thermistor. In a normal state of the thermistor, the elastic element is in an elastic deformation state, a first contact part and a second contact part of the elastic element are in electrical contact with the second electrode of the thermistor and the second pin respectively. After the thermistor ruptures, the elastic element resets, which causes the connecting piece to move so that the second contact part of the elastic element detaches from the second pin. An isolation structure is provided between the thermistor mounting cavity and the elastic element mounting cavity.

A radial-leaded over-current protection device comprises a PTC element, a first electrode lead, a second electrode lead and an electrically insulating encapsulation layer. The PTC element comprises a first conductive layer, a second conductive layer and a PTC material layer laminated therebetween. The PTC material layer comprises crystalline polymer and conductive filler dispersed therein. The first electrode lead has an end connecting to the first conductive layer, whereas the second electrode lead has an end connecting to the second conductive layer. The electrically insulating encapsulation layer includes a fluorine-containing polymer, and wraps around an entire outer surface of the PTC element and the ends of the first and second electrodes connecting to the PTC element. The electrically insulating encapsulation layer has a thickness of 10.sup.2˜10.sup.5 nm, and the radial-leaded over-current protection device has an initial resistance R.sub.bf of 0.0017˜0.0027Ω.

A radial-leaded over-current protection device comprises a PTC element, a first electrode lead, a second electrode lead and an electrically insulating encapsulation layer. The PTC element comprises a first conductive layer, a second conductive layer and a PTC material layer laminated therebetween. The PTC material layer comprises crystalline polymer and conductive filler dispersed therein. The first electrode lead has an end connecting to the first conductive layer, whereas the second electrode lead has an end connecting to the second conductive layer. The electrically insulating encapsulation layer includes a fluorine-containing polymer, and wraps around an entire outer surface of the PTC element and the ends of the first and second electrodes connecting to the PTC element. The electrically insulating encapsulation layer has a thickness of 10.sup.2˜10.sup.5 nm, and the radial-leaded over-current protection device has an initial resistance R.sub.bf of 0.0017˜0.0027Ω.

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.1000@16V/50A of the over-current protection device at 25V/50 A by 1000 cycles is 0.90-1.30.

A surface-mountable over-current protection device comprises at least one PTC material layer, a first conductive layer, a second conductive layer, a first electrode, a second electrode, an insulating layer, and a cover layer. The PTC material layer comprises crystalline polymer and conductive fillers dispersed therein. The first conductive layer and the second conductive layer are disposed on a first surface and a second surface of the PTC material layer, respectively. The first electrode and the second electrode are electrically connected to the first conductive layer and the second conductive layer, respectively. The insulating layer is disposed between the first electrode and the second electrode for insulation. The cover layer includes a fluorine-containing polymer, and wraps around an entire outer surface of the surface-mountable over-current protection device.

The invention relates to a PTC heating element (1). The PTC heating element (1) comprises a block-shaped PTC thermistor (2) having two contact surfaces (4a, 4b) and two electrically conductive contact plates (3a, 3b). The PTC thermistor (2) is arranged between the contact plates (3a, 3b) and facing the contact plates (3a, 3b) with the contact surfaces (4a, 4b). An adhesion-promoting electrically conductive bonding layer (6a, 6b) each is arranged between the contact surface (4a, 4b) and the contact plate (3a, 3b). The PTC thermistor (2) is firmly connected to the respective contact plates (3a, 3b) by means of the respective bonding layers (6a, 6b) and electrically conductively contacted.

The adhesion-promoting electrically conductive bonding layer (6a, 6b) according to the invention comprises silicone or consists thereof.

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 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.

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.