Abstract: A color variation inducing device is positioned in contact with or in the proximity of or effects action through air blowing means on a thermally color-varying article provided with a thermally color-varying layer, thereby inducing color variation in the thermally color-varying layer. The device comprises an electrothermal converter device provided with a heat absorbing portion and a heat generating portion based on Peltier effect, a radiator connected to the heat generating side of the electrothermal converter device, and a casing for housing and supporting the electrothermal converter device, wherein the electrothermal converter device is rendered functionable under the application of a DC voltage in such a manner that the heat absorbing side thereof exhibits a temperature reduction of at least 3.degree. C. with respect to the ambient temperature, within an ambient temperature range from 10.degree. to 35.degree. C.

Abstract: An electrothermal color-varying instrument for inducing color change in a color-varying layer includes a heat generating element composed of a sintered barium titanate thermistor in face-to face contact with a heat transmitting member having a heating end portion for transmitting heat to the thermal color-varying layer. The thermistor has:(i) a positive temperature coefficient on the electrical resistance within a temperature range from 25.degree. C. to 70.degree. C.;(ii) a volume resistivity at 25.degree. C. (.rho..sub.25) within a range of 9.8.times.10.sup.-3 to 2.97.times.10.sup.5 .OMEGA..multidot.cm; and(iii) a ratio (.rho..sub.70 /.rho..sub.25) of the volume resistivity at 70.degree. C. to that at 25.degree. C. within a range of 5.ltoreq.(.rho..sub.70 /.rho..sub.25).ltoreq.400.The electrothermal heat generating element generates heat under the application of a voltage in the range of 0.8 to 40 volts and maintains a saturated heating temperature within a range of 30 to 100 degrees C.

Abstract: There is disclosed an electrothermal color-varying device inducing color change in a thermally color-varying layer by heat generation in an electrothermal heat-generating member, in which the heat-generating member is composed of a non-metallic member having a positive temperature coefficient on the electric resistance at least in a temperature range 25.degree. C. to 65.degree. C. and a particular volume resistivity, is adapted to generate heat by the application of a low voltage and is capable of self-control of the saturated heating temperature at an arbitrary temperature within a range of 25.degree. C. to 65.degree. C., whereby improved safety is achieved without the danger of overheating or current leakage. Also there are disclosed toys utilizing such color-varying device.