Research is devoted to investigation of properties of pulsed explosive emission cathodes for X-ray tubes. Three types of annular explosive emission cathodes were studied: metal ceramic with slits (of a comb-shaped kind), ring metal ceramic, and carbon ceramic. A pulsed high-voltage generator used in experiments is characterized with the following parameters: voltage pulse full-width at half-maximum is about 20 ns, pulse voltage amplitude is up to 150 kV, and pulse repetition rate is up to 200 Hz. The installation makes it possible to study demountable models of pulsed X-ray tubes of different designs. Current and voltage waveforms corresponding to different operation modes and rates of rise of X-ray tube anode voltage were analyzed. The obtained characteristics of explosive cathodes depend on the cathode's material, the shape, and the supply voltage of the primary energy storage. The current pulse duration for the ring carbon-ceramic cathode is considerably lower than that for the other cathodes, although it generates a higher radiation dose rate.