A multivibrator in which a timing capacitor is connected between the collector of a first transistor and the base of a second transistor and in which a current source connected to the collector of the first transistor provides the charging current for the timing capacitor. The conduction path of a third transistor is connected between the collector and base of the first transistor and its control electrode is connected to a control voltage point for controlling the charging period of the capacitor and for ensuring oscillation when the multivibrator is connected as an astable multivibrator.