Traveling wave tube with depressed collector power supply

Power supply for a traveling wave tube with depressed collector which tube comprises a cathode, a grid, a collector and a wave structure arranged in the longitudinal direction of the tube, characterized in a voltage source (E, Zi) connected to the cathode (2) of the tube and to a reference potential (0), a first capacitive element (C1) connected to the voltage source for delivering a current to the wave structure (5) during the time interval the tube is conducting, a second capacitive element (C2) connected between the cathode of the tube and the collector (3) for delivering a current to the collector of the tube during the same time interval and an impedance (Z) connected between said capacitive elements (C1, C2) to prevent a current flow between the capacitive elements (C1, C2).