The dependencies of coercive field and internal bias field on the frequency of the applied external field were experimentally studied in the films of lead titanate and lead zirconate titanate in a wide temperature range. It was demonstrated that with the frequency increase in the above films a build up of coercive field and internal bias field is observed, the rate of which depends on the temperature. The nature of the above phenomenon was analyzed and its relation to activation processes accompanying switching in ferroelectrics was shown.