Ptc chip thermistor

Abstract

A chip PTC thermistor comprising a conductive polymer having PTC properties, a first outer electrode, a second outer electrode, one or more inner electrodes sandwiched between the conductive polymer, a first electrode electrically directly coupled with the first outer electrode, and a second electrode. The odd-numbered inner electrode among the one-or-more inner electrodes is directly coupled with the second electrode, while the even-numbered inner electrode, with the first electrode. When total number of the inner electrodes is an odd number the second outer electrode makes direct electrical contact with the first electrode, when it is an even number the second outer electrode makes direct electrical contact with the second electrode. Defining a distance from the odd-numbered inner electrode to the first electrode, or from the even-numbered inner electrode to the second electrode, as “a”, while a distance between the adjacent inner electrodes, or a distance between the inner electrode placed the most adjacent to the first outer electrode, or the second outer electrode, and the first outer electrode, or the second outer electrode, as “t”; the PTC thermistors are constituted so that a ratio a/t is within 3-6. The chip PTC thermistors in accordance with the present invention effectively prevent an overcurrent in large current circuits.