In a device for electrically charging particles, a pair of parallel plasma generators are spaced from one another, each of the generators having corona discharge electrodes. A main field forming source of high AC voltage is connected between the plasma generators, to form a main field in the charging space, and intermittently operating corona generating high voltage power sources are coupled to apply high voltages to the respective corona discharge electrodes only when the plasma generators have relative specific polarity, whereby only particles of one polarity are driven into the charging space. The intermittent corona generating high voltage source has a frequency equal to or greater than the frequency of the AC voltage which provides the main AC field.