Methods of performing a sector erase of flash memory devices incorporating built-in self test circuitry are provided. The single electrical cable may provide high voltage to a magnetron of the lamp head and a lesser voltage to an internal blower of the lamp head. Based on the initial voltage variation ratio \u03ba0 and the subsequent voltage variation ratio \u03bat, the terminal leakage existing between the first terminal and the second terminal can be calculated. The highest potential of a gate of the writing transistor can be a high-level potential. The invention has particular application in air pollution control, by promoting agglomeration of fine pollutant particles in air streams into larger particles to thereby facilitate their subsequent removal from the air streams.