A surface mountable over-current protection device comprises a PTC material layer, first and second conductive layers, left and right electrodes, left and right conductive members, and left and right insulating members. The PTC material layer comprises a left notch at a left end and a right notch at a right end. The first conductive layer comprises a primary portion disposed on an upper surface of the PTC material layer and a secondary portion extending over the left notch, and the second conductive layer comprises a primary portion disposed on a lower surface of the PTC material layer and a secondary portion extending over the underside of the right notch. The left conductive member connects to the left electrode and the first conductive layer and isolates from the second conductive layer. The right conductive member connects to the right electrode and the second conductive layer and isolates from the first conductive layer. The left and right insulating members are disposed in the left and right notches, respectively. The PTC material layer is not in direct contact with the left and right conductive members, and the primary portion and the secondary portion of the first or second conductive layer have different thicknesses.

A shunt resistor having improved temperature characteristics has a resistive body, a pair of base materials integrally formed on the resistive body across the resistive body, and measurement terminals fixed onto the base materials. The base materials have a plurality of cutout portions along a longitudinal direction of the base materials, wherein the plurality of cutout portions do not communicate with each other and are provided in a stepped manner.

A positive temperature coefficient ceramic thermistor element includes a sintered thermosensitive ceramic piece that uses lead barium titanate as a base, as well as metal ohmic electrodes which are positioned on two side surfaces of the thermosensitive ceramic piece. The thermistor element has a microporous channel barrier layer, and includes a glass sealing layer which wraps the outer surface of the thermosensitive ceramic piece, or an organic matter sealant which fills and blocks micro-pores in the surfaces of the metal ohmic electrodes combined on the two side surfaces of the thermosensitive ceramic piece and, at the same time, blocks gaps in the surfaces of areas, that do not have the metal ohmic electrodes, of a peripheral edge of the thermosensitive ceramic piece.

A composite thermistor element is described. The element includes a sensor material that is disposed between a pair of electrodes. The sensor material includes particles in a dielectric matrix. Each of the particles have: a core having a temperature dependent resistance, and a cover layer of an inorganic material. The particles form an electron conducting pathway between the electrodes having a temperature dependent resistance and a base-line resistance. Further aspects relate to a method of manufacturing the thermistor, the coated particles, a composition for use in the manufacturing of composite thermistors that includes the particles, and to a temperature sensor including the thermistor described herein.

Disclosed is a reflow solderable positive temperature coefficient circuit protective device, comprising: an upper conductive blade terminal (1), which is composed of a first chip bonding portion (101), a first circuit bonding portion (105) and a connecting portion (103) therebetween, wherein the first chip bonding portion (101) has a first planar profile; a lower conductive blade terminal (2), which comprises a second chip bonding portion (201) having a second planar profile; a positive temperature coefficient chip, which is sandwiched between the upper conductive blade terminal (1) and the lower conductive blade terminal (2) and respectively bonded to the lower surface of the first chip bonding portion (101) and the upper surface of the second chip bonding portion (201) via solder, and has a third planar profile, wherein: the first planar profile and the second planar profile are in the interior of the third planar profile, and the third planar profile has portions that are not covered by the first planar profile and/or the second planar profile, so as to allow the positive temperature coefficient chip to have a free thermal expansion space. By using the device, the stress caused by high temperature thermal expansion in the device, which can lead to device failure, can be reduced in a protection state.

A reflow solderable positive temperature coefficient circuit protection device is provided, the device comprising: an electrically conductive sheet-like upper terminal composed of a first chip junction portion, a first circuit junction portion, and a connection portion therebetween, wherein the first chip junction portion having a first planar profile; an electrically conductive sheet-like lower terminal comprising a second chip junction portion having a second planar profile; and a positive temperature coefficient chip which is sandwiched between the sheet-like upper terminal and the sheet-like lower terminal, and respectively combined with the lower surface of the first chip junction portion and the upper surface of the second chip junction portion by soldering, and the positive temperature coefficient chip having a third planar profile. The first planar profile and the second planar profile are within the third planar profile, and the third planar profile has a portion that is not covered by the first profile and/or the second profile to allow the positive temperature coefficient chip to have a free thermal expansion space. The device can reduce the stress that causes the device failure and is caused by high-temperature thermal expansion in the device in the protected state.

A device may include a lead frame, where the lead frame includes a central portion, and a side pad, the side pad being laterally disposed with respect to the central portion. The device may further include a thyristor device, the thyristor device comprising a semiconductor die and further comprising a gate, wherein the thyristor device is disposed on a first side of the lead frame on the central portion. The device may also include a positive temperature coefficient (PTC) device electrically coupled to the gate of the thyristor device, wherein the PTC device is disposed on the side pad on the first side of the lead frame; and a thermal coupler having a first end connected to the thyristor device and a second end attached to the PTC device.

A self-limiting heater and method for building the self-limiting heater are disclosed. The self-limiting heater consists of a resistor and a PTC resistor coupled together in series with a power supply. Both resistive devices have good thermal coupling. The resistor has a minimal resistance change over changes in temperature while the resistance of the PTC resistor increases with an increase in temperature. The ohmic resistance ratio between the resistor and the PTC may be used to adjust the heater characteristics and limit the characteristic sharpness.

A semiconductor ceramic composition including a compound represented by the following general formula (1) as a main component.
(Ba.sub.vBi.sub.xA.sub.yRE.sub.w).sub.m(Ti.sub.uTM.sub.z)O.sub.3(1)
(wherein, A represents both elements of Na and K; RE is at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er; and TM is at least one element selected from the group consisting of V, Nb and Ta.)
0.01x0.15(2)
xy0.3(3)
0(w+z)0.01(4)
v+x+y+w=1(5)
u+z=1(6)
0.950m1.050(7)
further, 0.001 mol to 0.055 mol of Ca is included and the ratio of Na/(Na+K) is 0.1 or more and less than 1.

A protection element includes a positive temperature coefficient (PTC) material layer, a second conductive layer on a second surface of the PTC material layer, a first electrode lead layer on the first conductive layer, and a second electrode lead layer on the second conductive layer. The first conductive layer includes a plurality of laminated first layers and the second conductive layer includes a plurality of laminated second layers. The first conductive layer has a plurality of first through-holes including a first conductive material to connect at least two of the first layers. The second conductive layer having a plurality of second through-holes including a second conductive material to connect at least two of the second layers.