Recently, the number of published papers on the sintering technologies activated by current have increased exponentially. In particular, it has been reported that the application of electric field as high as 120 V/cm permitted the instantaneous full densification of yttria stabilized tetragonal zirconia at the unusual low temperature of 850°C. The mechanisms of the so called flash sintering phenomenon are elucidated by analyzing the temperature distribution of the bulk sample under the application of the electric field.