Abstract: A device for power supply of gas-cleaning electrical precipitators comprises two constant voltage sources (1,2), the unlike poles (5,6) of each of the sources being grounded. Two high-voltage commutators made as triode-type thermionic rectifiers (7,8) with a hollow anode (11) are connected between the other unlike poles of each of the constant voltage sources (1,2) and a corona displaying electrode (16) of an electrical precipitator (17). Connected to a cathode (9) and a control electrode (10) of each of the triode-type thermionic rectifiers (7,8) are modulators (18, 19) of alternating polarity voltage which are connected through isolation transformers (38,39) to a control unit (40), the latter being connected to pickups (49,50,51,52) of electrical and physical parameters.

Abstract: A electron-beam tube comprises a cathode (2) made as individual tapes (6) disposed throughout the length of the tube, whose surfaces are the emitting portions of the cathode (2). Each tape (6) of the cathode (2) is provided with a near-cathode focusing electrode (9) electrically connected to the cathode (2) and disposed in the immediate vicinity of the tape (6), and with a pair of rods (10) of the control electrode (3) disposed in relation to the tape (6) so that the whole electron flow focused by the near-cathode electrode (9) passes between said rods (10). The following relations are observed in the tube:a/b=c/d; 1<d/c.ltoreq.10; e.gtoreq.b.