The development of high sensitivity NTC thermistors

Several requirements for NTC thermistors used for office automation (OA) equipment and home electronics are small size, high sensitivity and high reliability. Commonly used NTC thermistors do not have adequate reliability against thermal shock. Size reduction is difficult due to the multi-phase structure and porosity in ceramics. It is also difficult to realize the required properties because the resistivity-B value relationship control method has not been established. So we have developed a method to control the properties of NTC thermistor by controlling the numbers and the valence of solid solution ions on A and B sites in the single phase spinel structure. Based on these methods, we have also established a method to make a more dense structure. A NTC thermistor series has been developed possessing small size, high sensitivity and high reliability.