| 摘要 |
PURPOSE: To lower the induced pulse voltage to sufficiently low level at which a human being does not get a shock of electricity and surely carry out lamp lighting by setting the induced pulse voltage induced between a lamp body and the ground by starting pulses for lighting a discharge lamp to be a prescribed level or lower. CONSTITUTION: When electric power voltage is applied to input terminals 7, 8 from a commercial electric power source 1, current flows in a starter 6 which composes a lamp 4 and an auxiliary resistor 43 for starting heats a bimetal 44 and the starter 6 is put in the insulated state. At that moment, current flowing in a series circuit of the input terminal 7, a choke coil 12, the starter 6, and the input terminal 8 is cut off, induction kick at high voltage is generated by a coil 12 of a ballast 2, the high voltage is dropped to a desiring pulse voltage by a varister 11, the resulting pulse voltage is applied between both electrodes of a discharge lamp 14, and the discharge lamp 14 is lighted. Floating electrostatic capacity between poles of a used cable is controlled to be 100-200PF/m (about 100kHz) and thus possible danger at the time when a human being touches a lamp main body 5 can be removed. |
