Biased-plate characterization of pulsed DC ionizers ☆

The operation of a pulsed DC air ionization system was studied in a side-by-side comparison using a charged-plate monitor (CPM) and a biased-plate monitor (BPM). When the pulse period is short compared to the CPM discharge time, both methods give equivalent results. When the pulse period is comparable to the discharge time, however, the CPM suffers from a random error on the order of the pulse period. In addition, the CPM method is more sensitive than the BPM to the motion of persons and other objects in its vicinity. In addition, the BPM provides a continuous indication of the discharge current, which enables a significantly faster way of adjusting pulsed DC ionizers.