Excessive inrush current suppression is important to protect electrical equipment from degradation, particularly in the case of switched-mode power supplies, driving circuits of halogen lamps or motors. For this purpose, a combination of triode AC semiconductor switch (TRIAC) and resistor is generally used in spite of the expensive price. On the contrary, the use of negative temperature coefficient (NTC) thermistors represents a very favorably priced method. However, they have some disadvantages. The conventional NTC thermistors composed of transition metal manganite spinels have relatively high resistances at operating temperature, so that they are not suitable for high current equipment. In order to alleviate these problems, we studied a new material for NTC thermistors, that makes it possible to reduce power loss of equipment.
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