Abstract: A circuit for starting a single-phase AC induction motor 11 having a main winding 12 and an auxiliary winding 13, which is so constructed that a PTC element 16 and a triac 17 are connected in series with the auxiliary winding 13 and a gate voltage of the triac 17 is reduced to turn a portion between main terminals of the triac 17 off after a predetermined time period has elapsed since the motor 11 was started, and can effectively lower the power consumption without degrading starting characteristics and can shorten return time required until the motor 11 is restarted and lengthen the life of the PTC element 16.

Abstract: A PTC thermistor has its substrate entirely coated with an insulating glass material except for the area where a silver electrode is formed. Such a thermistor may be produced by coating a substrate with an insulating glass material, forming a silver layer on the coated substrate and fusing the silver layer with a part of the glass material so as to form an electrode adhering to the substrate. An underelectrode may be provided between the substrate and such an electrode. A resistor is formed by encasing such a PTC thermistor with a pair of spring terminals for supporting the thermistor therebetween.

Abstract: A positive temperature coefficient thermistor device has a case, a positive temperature coefficient thermistor element which is disposed in the case, a pair of first terminals which is disposed in the case to be in contact with corresponding electrodes of the thermistor element, a pair of second terminals which is disposed on the case and is associated with the first terminals, and pin members electrically and mechanically connecting the first terminals with the second terminals through an outer wall of the case.

Abstract: A PTC thermistor device includes three PTC thermistors aligned and disposed in a heat transmission relation to each other such that the center PTC thermistor provides heat to the other PTC thermistors which are so connected as to define a part of path for the demagnetizing current. The two PTC thermistors positioned on the opposite sides of the center PTC thermistor increase their temperature rapidly so that a rapid and effective attenuation of demagnetizing current can be obtained.