Abstract: A high voltage generator 1 for an electrostatic dust precipitator 2 comprises a low voltage oscillator 6, operating from a low voltage continuous source, such as a car battery, which supplies a current chopper 7. The output from the chopper 7 is fed to the primary winding 9 of an induction coil 10. The secondary winding 11 of the coil 10 is connected to one of a metal surface 3 of the dust precipitator to apply a high potential difference between the metal surfaces 3,4 to precipitate dust. Preferably the metal surface 3 is connected to the secondary winding 11 via a high voltage diode.