PTC thermistor degauss the shadow mask of color picture tubes by reducing the alternating current flowing through the degaussing coil within a short period of time.A large difference between inrush current and residual current is crucial for good degaussing.
Single-phase induction motors(e.g.in compressors for refrigerators and air conditions)can effectively be started when an auxiliary coil is used in the starting phase.The auxiliary coil is cut off from the circuit after the starting phase.For this purpose PTC thermistor are employed.
The positive R/T characteristic means that electric power consumed is qutomatically adapted to the ambient thermal conditions.At an ambient temperature significently lowor than Tref,i.e.with good heat transfer,the thermistor has low resistance and consumes a relatively large amount of power.If the ambient temperature is significently higher than  Tref  or heat transfer is restricted,the resistance of the thermistor rises rapidly and consumption is limited to a very low value.