| 摘要 |
PURPOSE:To superpose a pulse voltage on a DC voltage in a simple structure by providing a charging/discharging circuit which include a charging/discharging condenser and a bulb gap as a switching element between the output terminals of a DC high voltage generator. CONSTITUTION:A rectifier 12 is connected to the secondary winding of a step- up transformer 10, and the output is connected to the electrodes 31, 32 of an electric dust collector 3 through a reverse current blocking diode 2. A charging/ discharging circuit 4 having a charging/discharging condenser 43, a bulb gap 42 as a switching element, and charging current limiting resistor 45 is connected between the diode 2 and a ground, and a pulse voltage is superposed on a DC high voltage by repeating the discharging via the gap 42 when the charge of the condenser 43 becomes the prescribed value or higher. Accordingly, a pulse voltage can be superposed on the DC voltage without using the coupling capacitor, thereby simplifying the structure. |
