In the present work the results of detailed researches on characteristics of transient processes, appearing by application of DC field to semiconductor substrate of liquid crystal cell have been carried out. It is shown, that oscillations, caused by longitudinal DC field applied to the semiconductor differ from the oscillations, caused by the Freedericksz transitions. The dependences of character and number of these oscillations on the applied DC field value, the type and thickness of nematic liquid crystal are investigated. The probable mechanisms explaining the observable phenomena are discussed.