Abstract Fast switching in thin ferroelectrics has been investigated from the respective switching current and voltage wave form signals. The polarization inversion process, established for PZT (45/55) thin films in a nanosecond time scale, takes place at the “dynamic coercive electric field” and is mainly limited by the electric circuit components. Due to the low impedance of the ferroelectric during switching, the voltage across the ferroelectric rises only when polarization inversion is getting accomplished. Hence a voltage dependence of the switching has not be found. Pulse phase transition experiments in antiferroelectric PZT (95/5) have been performed, which show that the dynamic behavior of the transition between the ferroelectric and the antiferroelectric state follows the same principle. Thus, fast phase transitions can be realized, too. Derived from the voltage and current wave form data, “pulse hysteresis loops” have been established.