Abstract: A device for generating ions in gas streams is proposed, which has an electrode arrangement exposed to the gas streams and a pulsed high voltage supply, which supplies an alternating sequence of negative and positive pulses with step edges. The electrode arrangement comprises at least one point discharge electrode and at least one counterelectrode associated with one another in fixed, clearly defined manner. The time behaviour of the high voltage signal is fixed in such a way that the duration of the particular pulse corresponds to the transit time of the ions between the electrodes and the spacing of the pulses is adapted to the speed of the gas streams.