An air cleaner including a constant current power supply is provided according to an embodiment of the invention. The air cleaner includes a collector cell and a constant current power supply coupled to the collector cell. The constant current power supply is configured to maintain a substantially constant electrical current output to the collector cell, compare an output voltage of the constant current power supply to an upper voltage threshold V.sub.U and to a lower voltage threshold V.sub.L, and shut down the constant current power supply if the output voltage is not between the upper voltage threshold V.sub.U and the lower voltage threshold V.sub.L.