Thermistor and method of producing the same

A method of producing negative temperature coefficient thermistor units, wherein each thermistor unit comprises a thermistor element enclosed in an envelope of insulating ceramic material, internal electrodes, and external electrodes, comprising the steps of:

• (a) forming a pair of first green sheets of said insulating ceramic material;
• (b) coating predetermined areas of the surfaces of said first green sheets with paste to be formed into external electrodes;
• (c) preparing a second green sheet made of the same material as said first green sheets and formed with a number of openings arranged at predetermined positions thereof;
• (d) filling up each of said openings with paste for thermistor elements;
• (e) stacking said first green sheet interposing therebetween said second green sheet;
• (f) cutting said stacked sheets into individual thermistor units in such a manner that the cuts do not go through the paste for the thermistor elements;
• (g) co-firing each obtained thermistor unit as to form a sintered body wherein the thermistor element in each thermistor unit is enclosed in an envelope of sintered insulating ceramic material;
• and
• (h) forming a pair of external electrodes on each thermistor unit.

A method of producing negative temperature coefficient thermistor units, wherein each thermistor unit comprises a thermistor element enclosed in an envelope of insulating ceramic material, internal electrodes, and external electrodes, comprising the steps of:

• (a) forming a pair of green sheets wherein each green sheet comprises said insulating ceramic material;
• (b) coating predetermined areas of the surfaces of said green sheets with paste to be formed into diffusion preventing layers;
• (c) providing over said paste for the diffusion preventing layers a coating of a paste to be formed into internal electrodes;
• (d) stacking said green sheets, interposing therebetween in predetermined areas a non-continuous layer of paste for thermistor elements for said thermistor units;
• (e) cutting said stacked green sheets into individual thermistor units in such a manner that the cuts do not go through the paste for the thermistor elements;
• (f) firing said thermistor unit so as to form a sintered body, wherein the thermistor element in each thermistor unit is enclosed in an envelope of sintered ceramic material.

A method of producing negative temperature coefficient thermistor units, wherein each thermistor unit comprises a thermistor element sandwiched between two layers of insulating ceramic material, internal electrodes, and external electrodes, comprising the steps of:

• (a) forming a pair of green sheets wherein each green sheet comprises said insulating ceramic material;
• (b) coating predetermined areas of the surfaces of said green sheets with paste to be formed into internal electrodes in such a manner that the area of one green sheet extends to the position corresponding to one side of the thermistor unit and the area of the other green sheet extends to the position corresponding to the other side of the thermistor unit;
• (c) stacking said green sheets, interposing therebetween in predetermined areas a layer of paste for thermistor elements for said thermistor units;
• (d) cutting said stacked green sheets into individual thermistor units;
• (e) coating both ends of each of said thermistor units with paste for external electrodes;
• and
• (f) firing said thermistor unit so as to form a sintered body, wherein the thermistor element in each thermistor unit is sandwiched between two layers of sintered ceramic material.