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.