Electroceramic particles with electrodes of solder are prepared y a low cost and high productivity process. The electroceramic particles can be used as single particle devices, and moreover as multi-functional devices by their assembling. PTCR material is one of the electroceramics, having a positive temperature coefficient of resistivity. We prepare the PTCR particles with electrodes of solder as follows. Semiconducting barium titanate (BaTiO3) particles, a typical PTCR material, and solder particles are charged into a cylindrical vessel, and the vessel is rotated for several hours. The product is semiconducting BaTiO3 coated by solder particles. The solder particles are flattened out at the surface of the core particle. The solder forms small dot-like islands, and they are isolated each other. Several applications of such kind of composite particles are described. Single particle device is a PTC thermistor, which consists of one composite particle of semiconducting BaTiO3. Flexible and self-thermostatic sheets can be produced by packing the composite particles between two thin electrodes. Using NTC particles instead of the semiconducting BaTiO3 single particle devices of NTC thermistor and flexible NTC sheets can be produced. Twin particles device is a combination of a single particle PTC thermistor and a single particle NTC thermistor in series, and will be a V-type thermistor, having both PTC and NTC properties. The V-type thermistor can be obtained also by stacking the layer of PTC composite particles and that of NTC composite particles in series. It can be applied to a protective device.